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Understanding structure/property correlations in self‐assembly is a key but challenging requirement for developing functional materials. Herein, we explore the importance of ligand geometry to fine‐tune photophysical properties (MMLCT vs. MLCT excited states) and self‐assembly pathways in metallosupramolecular polymerization. To this end, we have designed two hydrophobic Pt(II) complexes, 1 and 2, containing a π‐extended bidentate bipyridine ligand with different substitution pattern, resulting in different molecular geometries (linear vs. V‐shaped). Detailed comparative studies revealed significant differences for both complexes in terms of their photophysical properties and self‐assembly pathways in non‐polar media. The V‐shaped topology of 1 enables facile face‐to‐face molecular stacking with a certain curvature leading to luminescent spherical assemblies exhibiting MMLCT states and short Pt⋅⋅⋅Pt contacts via a single‐step cooperative pathway. On the other hand, the higher preorganized linear topology of complex 2 induces a two‐step competitive self‐assembly process leading to the formation of one‐dimensional supramolecular polymers with slipped packing and MLCT‐originated emission. Our findings broaden the monomer scope for supramolecular polymerization and provide design guidelines for the realization of luminescent supramolecular assemblies. [ABSTRACT FROM AUTHOR]

D-A charge transfer, including through-bond charge transfer and through-space charge transfer between two different electron donors (D) and electron acceptors (A), is a fundamental and powerful tool to tune the optical properties of organic dyes. Herein, we demonstrate a unique strategy to tune phosphorescence and circularly polarized luminescence properties of axially chiral binuclear Pt(II) complexes through long-range charge transfer, even though these molecules have two totally identical segments on either side of the chiral core. The presence of axial chirality would break not only the symmetry of molecular structure and π-conjugation system but also the symmetry of charge distribution for long-range charge transfer. These binaphthyl-based Pt(II) complexes bearing coordinated atoms far away from chiral axis exhibit no Pt-Pt interactions but colorful concentration-dependent phosphorescence with quantum yield up to 86.4% and could be applied as emitters in highly efficient solution-processed organic light-emitting diodes to achieve luminance, luminance efficiency, power efficiency, external quantum efficiency, and asymmetry factor up to 8.94 × 103 cd m−2,41.9 cd A−1,18.8 lm W−1, 12.6% and 2.98 × 10−3, respectively. Therefore, the present work affords a new and simple way to utilize the inherently asymmetric advantage of chirality for the design of D-A-based organic dyes. [ABSTRACT FROM AUTHOR]

A series of D‐π‐A alkynylphosphonium salts with different linker between donor and acceptor groups was used to synthesize two series of trans‐bis‐alkynylphosphonium Pt(II) complexes with different ancillary ligands (triphenylphosphine, P series, and cyanide, CN series). The nature of the ancillary ligand manages the overall charge and emission properties of the complexes obtained. In addition, the variation of the linker in alkynylphosphonium ligands allows fine‐tuning the luminescence wavelength. Dicationic series P is unstable in solution under UV excitation, whereas in the solid state, these complexes are the first example of phosphorescent trans‐phosphine‐bis‐alkynyl Pt(II) compounds. Neutral series CN demonstrates bright emission in solution, including dual emission for 2CN complex with biphenyl linker in alkynylphosphonium ligand. However, in the solid state for the CN series drastic decrease in the emission quantum yield compared to the P series was observed. DFT calculations reveal the complicated emission nature for the both P and CN series with various contributions of 3ILCT, 3LLCT and 3MLCT states. However, in the naphthyl‐containing derivatives 3P and 3CN, the dominating 3LC character with some admixture of CT states is postulated. [ABSTRACT FROM AUTHOR]

Using the cyclometallation reaction, Pt(II) complexes of diarylbipyridynic ligands bearing alkoxy-groups were prepared and then modified with phenylаcetylene derivatives. The target compounds were characterised by absorption and emission spectroscopy, differential scanning calorimetry, small angle X-ray scattering, polarisation microscopy, and DTF calculations. The mesomorphic properties of the obtained compounds were investigated and their liquid crystallinity was confirmed. [ABSTRACT FROM AUTHOR]

Platinum(II) complexes of square-planar geometry are interesting from a crystal engineering viewpoint because they exhibit strong luminescence based on the self-assembly of molecular units. The luminescence color changes in response to gentle stimuli, such as vapor exposure or weak mechanical forces. Both the molecular and the crystal designs for soft crystals are critical to effectively generate the chromic luminescence phenomenon of Pt(II) complexes. In this topical review, strategies for fabricating chromic luminescent Pt(II) complexes are described from a crystal design perspective, focusing on the structural regulation of Pt(II) complexes that exhibit assembly-induced luminescence via metal–metal interactions and structural control of anionic Pt(II) complexes using cations. The research progress on the evolution of various chromic luminescence properties of Pt(II) complexes, including the studies conducted by our group, are presented here along with the latest research outcomes, and an overview of the frontiers and future potential of this research field is provided.

This study utilizes Density Functional Theory (DFT) alongside the Chemical Bond Overlap (OP) Model and Quantum Theory of Atoms in Molecules (QTAIM) to reinterpret the well‐established trans effect in square‐planar Pt(II) complexes. Investigating ligand exchange mechanisms in trans‐[Pt(NH3)2${\rm Pt}{({\rm NH}_3)}_2$(H2O${\rm H}_2{\rm O}$)T] (T = F−${\rm F}^-$, NH3${\rm NH}_3$, Cl−${\rm Cl}^-$, CH3−${\rm CH}_3^-$, CO, CN−${\rm CN}^-$) via transition state localization and intrinsic reaction coordinate calculations, overlap descriptors (OP/TOP) such as density, repulsion, and polarizability are computed for Pt−T and Pt−L bonds for reactants and transition states. Through OP/TOP and QTAIM, key descriptors correlating are identified with the trans‐directing effectiveness of ligands, revealing higher electron density donation and more electron‐rich bonds in stronger trans‐directing ligands. This combined methodology offers insights into ligand trans‐directing character, enhancing understanding of their reactivity and bonding behavior. [ABSTRACT FROM AUTHOR]

Insight into effect of deuterium isotopes on organic near‐IR (NIR) emitters was explored by the use of self‐assembled Pt(II) complexes H‐3‐f and HPh‐3‐f, and their deuterated analogues D‐3‐f and DPh‐3‐f, respectively (Scheme 2). In vacuum deposited thin film, albeit having nearly identical emission spectral feature maximized at ~810 nm, H‐3‐f and D‐3‐f exhibit remarkable difference in photoluminescence quantum yield (PLQY) of 29 % and 50 %, respectively. Distinction in PLQY is also observed for HPh‐3‐f (800 nm, 50 %) and DPh‐3‐f (798 nm, 67 %). We then elucidated the theoretical differences in the impact on near‐infrared (NIR) luminescence between Pt(II) complexes and organic small molecules upon deuteration. The results establish a general guideline for the deuteration on NIR emission efficiency. From a perspective of practical application, NIR OLEDs based on D‐3‐f and DPh‐3‐f emitters attain EQEmax of 15.5 % (radiance 31,287 mW Sr−1 m−2) and 16.6 % (radiance of 32,279 mW Sr−1 m−2) at 764 nm and 796 nm, respectively, both of which set new records for NIR OLEDs of >750 nm. [ABSTRACT FROM AUTHOR]

Cycloplatinated complexes, with their high reactivity, combined with the capability to tailor ligands for specific catalytic processes, play a pivotal role in materials science and coordination chemistry, serving as versatile catalysts for applications in the organic synthesis of industrially relevant processes. In this report, we describe the synthesis and characterization of a new family of Pt(II) complexes based on three isomeric pyridyl‐β‐diketones diversified in terms of N‐atom location in the heterocyclic ring. By appropriate control of the reaction conditions, we were able to generate distinct coordination species, featuring ligands arranged as N,C(sp3)‐ and N,O‐chelates, as well as simple pyridyl‐N donors. Various analytical techniques, including X‐Ray diffraction, NMR spectroscopy and ESI‐MS spectrometry enabled the characterization of different coordination modes of the central atoms and unambiguously established the complex structures. Furthermore, all the Pt(II) coordination units have been found to be highly active and selective catalyst precursors in the hydrosilylation reactions within a broad scope of olefins with hydrosilanes. [ABSTRACT FROM AUTHOR]

By taking advantage of a sequence of oxidative addition/reductive elimination reactions, Pt(II) cyclometalated derivatives are able to promote a rare C(sp2)-C(sp3) bond coupling, resulting in the production of novel methyl-substituted pyridines and bipyridines. Starting from 6-phenyl-2,2′-bipyridine, the step-by-step full sequence of reactions has been followed, leading to the unprecedented 3-methyl-6-phenyl-2,2′-bipyridine, which was isolated and fully characterized. The synthesis involves the following steps: (1) rollover cyclometalation to give the starting complex [Pt(N^C)(DMSO)Me]; (2) the synthesis of a more electron-rich complex [Pt(N^C)(PPh3)Me] by the substitution of DMSO with triphenylphosphine; (3) oxidative addition with methyl iodide to give the Pt(IV) complex [Pt(N^C)(PPh3)(Me)2(I)]; (4) iodide abstraction with silver tetrafluoborate to give an unstable pentacoordinate intermediate, which rapidly evolves through a carbon–carbon reductive coupling, forming a new C(sp3)-C(sp2) bond; (5) finally, the extrusion and characterization of the newly formed 3-methyl-6-phenyl-2,2′-bipyridine. The reaction has been therefore extended to a well-known classical cyclometalating ligand, 2-phenylpyridine, demonstrating that the method is not restricted to rollover derivatives. Following the same step-by-step procedure, 2-phenylpyridine was converted to 2-o-tolyl-pyridine, displaying the potential application of the method to the larger family of classical cyclometalated complexes. The application of this protocol may be useful to convert an array of heterocyclic compounds to their methyl- or alkyl-substituted analogs. [ABSTRACT FROM AUTHOR]

Ni(II) and Pt(II) complexes of tetrazole-containing Schiff bases were synthesized and characterized by physicochemical and various spectroscopic studies. To examine its potential as a candidate anticancer drug, the binding properties of ct-DNA were investigated. The characteristic binding constant (Kb) and binding mode of the complexes with calf thymus DNA (ct-DNA) were determined using absorption titration (1.99 – 76.71 × 104 M-1). According to the kinetic and thermodynamic parameters, the binding constant and spontaneity of the Pt(Tet-SalH) complex were found to be larger. The well-diffusion method was used to deduce the antibacterial potency of Schiff bases and their complexes. All these substances have been examined for antibacterial activity against pathogenic strains and antifungal activity. Only complex [Pt(3,5-Br-Sal-Tet)H2O]Cl∙H2O showed activity against all the microorganisms studied. [ABSTRACT FROM AUTHOR]

Singlet oxygen (1O2), representing an important reactive oxygen species, has promising applications in biomedical, material, and environmental sciences. Photosensitized production of 1O2 using organic dyes is highly desirable and the exploration of highly efficient photosensitizers has received considerable attention. Herein, two tridentate Pt(II) complexes, i.e., cationic 1(PF6) and neutral 2, modified with the ethynylnaphthalimide chromophore, were designed and prepared for the application in 1O2 generation. Spectroscopic studies and computational results suggest that 1(PF6) and 2 display the lowest-energy absorption bands centered at 435–465 nm with the molar extinction coefficients of 0.6–3.2 × 104 M−1 cm−1, originating from the singlet ligand-to-ligand charge transfer (1LLCT) and a mixture of 1LLCT and singlet ligand-centered (LC) transitions, respectively. Moreover, they show similar phosphorescence at 620–640 nm assigned to the Pt-perturbed triplet LC emission of the ethynylnaphthalimide moiety. Thanks to the relatively long phosphorescence lifetimes, these complexes exhibit O2-dependent phosphorescence intensities with good reversibility and stability. They are able to behave as efficient triplet photosensitizers to promote the 1O2 generation with high quantum yields (84–89%). This work indicates that the combination of an organic chromophore with Pt(II) complexes provides an effective method to obtain photosensitizers for 1O2 generation. [ABSTRACT FROM AUTHOR]

The combination of ninhydrin and o-phenylenediamine, followed by their reaction with a phenylhydrazine derivative produces quinoxaline-based ligands (L1 – L6). These ligands react with K2PtCl4 to form Pt(II) complexes (I – VI). The ligands and Pt(II) chelate were characterized through various spectroscopic and analytical techniques, like 1H NMR, 13C NMR, C, H, N-elemental analysis, IR spectroscopy, and mass spectrometry. DFT calculations were used to optimize the structures of metal complexes. To investigate the binding mode of complexes to CT-DNA/BSA, absorption titration, viscosity measurements, and molecular docking analysis were employed. The results indicated that the DNA binding mechanism involved intercalation. The antibacterial efficacy of the compounds was evaluated against five strains of bacteria. The lower minimum inhibitory concentration (MIC) of complexes suggests that they are more potent than quinoxaline-based ligands. The synthesized compounds were evaluated for cytotoxicity using brine shrimp. The LC50 values of ligands and complexes ranged from 7.64 to 11.45 μg/mL and 5.27 to 7.02 μg/mL, respectively. The capacity of the molecule to suppress cell proliferation using the MCF-7 cancer cell was tested, and the IC50 value was discovered to be comparable to that of a standard drug. Thus in this work, complexes demonstrated intercalation as the binding mode with CT-DNA/BSA and exhibited enhanced antibacterial efficacy compared to the ligands. The compounds also showed promising cytotoxicity against brine shrimp and MCF-7 cancer cells, with comparable IC50 values to a standard drug, indicating their potential as therapeutic agents.

The reaction of 2-acetyl pyrazine with phenyl hydrazine gives Schiff base ligands. The Schiff base further reacted with K2PtCl4 to provide Pt(II) complexes. Ligands and Pt(II) complexes were characterized using 1H NMR, IR, mass spectrometry, elemental analysis, electronic spectra, and conductivity measurement. DFT studies were performed to optimize the structure of Pt(II) complexes. ADMET profile of the synthesized molecule was predicted using admetSAR. The antibacterial, DNA-binding, and molecular docking capabilities highlighted the influence of the various functional groups in the Schiff base ligands and platinum(II) complexes. For example, when the electron-withdrawing (nitro or methoxy) group is added to the Schiff base ligands, absorption maxima shifted to a higher wavelength, and antibacterial potency increases. Anticancer properties on the MCF-7 cancer cell line were tested to evaluate the potency of the compounds toward the cancer cell line. The IC50 value of the ligands and metal complexes ranged from 183 to 146 μg/mL and 120 to 88 μg/mL, respectively.

Two inner-sphere Pt(II) complexes were synthesized and characterized using various tools, one of which is [Pt(HL2)(H 2 O) 2 ]Cl. When immobilized into to the surface functionalized magnetite, it formed Pt(L2)/MNPs, a multifunctional material suitable for various applications. Among the tested compounds, it exhibited the strongest anticancer and antimicrobial properties that were comparable to the standards. It demonstrated antioxidant activities which were close to the ascorbic acid standard. Additionally, it demonstrated antioxidant activities close to the ascorbic acid standard and had the lowest optical band gaps, indicating its possible use in solar cells and related applications. [Display omitted] • Synthesis of two inner-sphere Platinum(II) complexes. • DFT calculations conducted on ligands and their complexes. • Binding affinity investigation of compounds with Bovine Serum Albumin (BSA). • DNA cleavage studies performed on ligands and Pt(II) complexes. • Immobilization of complexes onto the surface of magnetic nanoparticles (MNPs). • Evaluation of anticancer, antibacterial, and antioxidant activities of all compounds. • Calculation of optical band gap energy for all compounds. This study explores the synthesis, characterization, and biological investigations of two new Pt(II) thiosemicarbazone complexes immobilized in magnetic nanoparticles (MNPs). MNPs exhibit distinctive physical and chemical properties that enhance their interactions with biological targets. These traits make them particularly useful, especially when combined with drugs, increasing therapeutic effectiveness while also serving as efficient diagnostic tools in imaging techniques. The two Pt(II) complexes are represented by the formulas [Pt(HL1)(H 2 O)]Cl and [Pt(HL2)(H 2 O) 2 ]Cl. The ligand, H 2 L1 signifies (Z)-2-(2-oxoindolin-3-ylidene)-N-phenylhydrazine-1-carbothioamide , while H 2 L2 stands for (Z)-N-ethyl-2-(2-oxoindolin-3-ylidene)hydrazine-1-carbothioamide. The ligands and their Pt(II) complexes were characterized through various techniques, including elemental analysis, mass spectrometry, thermal analysis, powder X-ray diffraction (XRD), FT-IR, NMR, and UV–visible spectroscopy. The two complexes form a square planar geometry, in which H 2 L1 performs as a mononegative tridentate while H 2 L2 acts as a mononegative bidentate. Density Functional Theory (DFT) calculations were utilized to investigate the molecular configurations of the ligands and its Pt(II) complexes. The UV–visible and fluorescence spectroscopy techniques were employed to examine the interactions between Pt(II) complexes and Bovine Serum Albumin (BSA). DNA fragmentation studies on the Pt(II) complexes were performed and showed that [Pt(HL2)(H 2 O) 2 ].Cl complex is the strongest degraded on the DNA. [Pt(HL1)(H 2 O)]Cl and [Pt(HL2)(H 2 O) 2 ]Cl complexes were immobilized into MNPs to produce Pt(L1)/MNPs and Pt(L2)/MNPs, respectively. Pt(L1)/MNPs and Pt(L2)/MNPs were identified using FT-IR, PXRD, SEM, TEM, EDX, and UV-spectroscopy. In vitro cytotoxicity tests on these compounds against MCF-7 cell line is applied. Additionally, the antimicrobial activity against two gram + ve bacteria (Bacillus subtilis and staphylococcus aureus) , and two gram −ve bacterial strains (Escherichia coli and Salmonella typhi) was investigated. Furthermore , the antioxidant properties (DPPH) of the investigated compounds were assessed. The results of the study indicated that the [Pt(HL2)(H 2 O) 2 ].Cl complex exhibited a higher biological potency compared to both the [Pt(HL1)(H 2 O) 2 ].Cl complex and their respective ligands. When Pt(II) complexes were incorporated into the MNPs, a significant increase in their biological activity was noted, especially for Pt(L2)/MNPs, which exhibited the strongest antibacterial and anticancer effects. [ABSTRACT FROM AUTHOR]

Substitution reactions of [2-(pyridinecarboxamide)dichloride Pt(II)] [PtCl2], [N-phenyl-(2-pyridinecarboxamide)dichloride Pt(II)] [PhPtCl2], [N-(4-methylphenyl)-2-pyridinecarboxamide)dichloride Pt(II)] [CH3PhPtCl2], [N-(4-methoxyphenyl)-(2-pyridine-carboxamide)dichloride Pt(II)] [CH3OPhPtCl2] and [N-(4-fluorophenyl)-(2-pyridinecarboxamide)dichloride Pt(II)] [FPhPtCl2], with nucleophiles; thiourea (TU), N,N′-dimethylthiourea (DMTU) and N,N,N′,N′-tetramethylthiourea (TMTU) were studied under pseudo first-order conditions. The rates of substitution were investigated as a function of nucleophile concentration and temperature using stopped-flow and UV-visible absorption spectrophotometers. Substitutions of the two coordinated chloride ligands of the Pt(II) complexes occur consecutively, with the first substitution occurring opposite the coordinated pyridyl. The observed pseudo first-order rate constants regressed linearly with concentration of the incoming nucleophiles according to the equation kobs = k2[Nu]. The highest substitution rates were measured for PtCl2, which is attributed to the unsubstituted non-leaving carboxamide ligand. The Pt(II) center of this complex is the most electrophilic as a result of the strong withdrawal of electron density through π-resonance by the carboxamide group. The introduction of a 4′-substituted phenyl group on the amido N of the carboxamide reduces the reactivity of the complexes due to proportional electronic effects from the ancillary substituents on the phenyl ring as well as its conformational disposition with respect to the plane of the complex. The order of reactivity of studied nucleophiles is TU > DMTU > TMTU. The substitution is associatively activated as supported by the negative entropy of activation values for the reactions. [ABSTRACT FROM AUTHOR]

Small molecules have potential usage in cancer therapy due to their remarkable potency of disarranging the natural structure of nucleic acids. In this study, two complexes [Pt(NH3)2(IBgly)]NO3 (1) and [Pt(bipy)(IBgly)]NO3 (2) based on Pt(II), N-isobutylglycine (IBgly), 2,2′-bipyridine, and ammonia were prepared and characterized by spectroscopic methods. Pharmacokinetic ADME data, absorption, distribution, metabolism, excretion, and bioavailability radar showed two complexes can be introduced for Pt-based anti-cancer drugs. Mechanism of tumor inhibition and DNA interaction of these compounds was studied by UV–Vis, fluorescence, and CD spectroscopies. Also, thermodynamic parameters and the binding constants were calculated through absorption measurements. The fluorescence data showed that a static quenching mechanism occurred for both complexes with a binding constant and binding affinity towards DNA (Kb ≈ 3500 M−1 and kq ≈ 2.1 × 1011 M−1 s−1). The thermodynamic parameters indicated electrostatic approaching and groove binding were more feasible than intercalation mode between Pt(II) complexes and DNA. CD spectra indicated the increasing intensity of the positive band and the negative band decreasing. Density functional theory calculations confirmed the experimental data and determined the quantum chemical descriptors including total energy, hardness, chemical potential, electrophilicity, electronegativity, etc. According to this, the binding tendency of these compounds with DNA could be predicted. Further, molecular docking studies were also performed. Docking studies revealed that the desolvation, hydrogen, and electrostatic binding were effective for the interaction between complexes and DNA with binding energy (− 10.44 and − 9.57 kcal/mol) for complexes 1 and 2, respectively, which is mainly of partially electrostatic and groove binding type. The cytotoxic activity of Pt complexes was examined against human colon cancer cell line which indicated good activity with IC50 values of (41.66 and 47.30 μM) for both complexes after 72 h, respectively. Also, they demonstrated more inhibitory effects compared to carboplatin. [ABSTRACT FROM AUTHOR]

[Display omitted] • Encapsulation of Pt(II)-quinolinate complex at single walled carbon nanotubes. • Heterogeneous photocatalyst for the selective oxidation of sulfides in water. • Hybrid catalyst with broad structural scope tolerance. • High affinity for polycondensed aromatics substrates. • Catalyst with full recyclability and negligible Pt leaching. A simple one-step synthesis of a heterogeneous photocatalyst based on the encapsulation of the quinolinate-platinum complex 1 in the inner cavity of Single Walled Carbon Nanotubes (Pt1@oSWNT) is presented. This strategy generates a robust and stable catalyst for photooxidations performed in water media. Pt1@oSWNT is characterized spectroscopically and microscopically to have encapsulated a 2.5 % wt. of the unaltered complex. This material, which only contained 0.04 mol% of 1 , is able to chemoselectively yield a wide variety of sulfoxides in water in the presence of air under 385 nm irradiation. The catalyst also presents affinity for polyaromatic substrates, increasing the reaction rate as a function of the number of condensed rings, achieving turnover frequencies as high as 8187 h−1. Moreover, the heterogeneous catalyst could be recycled for more than six consecutive reaction runs without losing its catalytic activity or detecting catalyst leaching. [ABSTRACT FROM AUTHOR]

In the present work, we described the preparation and characterization of the micelles based on amphiphilic poly(ε-caprolactone-block-ethylene glycol) block copolymer (PCL-b-PEG) loaded with non-symmetric [Pt(C^N*N'^C')] complex (Pt1) (where C^N*N'^C': 6-(phenyl(6-(thiophene-2-yl)pyridin-2-yl)amino)-2-(tyophene-2-yl)nicotinate). The obtained nanospecies displayed the ignition of near-infrared (NIR) phosphorescence upon an increase in the content of the platinum complexes in the micelles, which acted as the major emission component at 12 wt.% of Pt1. Emergence of the NIR band at 780 nm was also accompanied by a 3-fold growth of the quantum yield and an increase in the two-photon absorption cross-section that reached the value of 450 GM. Both effects are believed to be the result of progressive platinum complex aggregation inside hydrophobic poly(caprolactone) cores of block copolymer micelles, which has been ascribed to aggregation induced emission (AIE). The resulting phosphorescent (Pt1@PCL-b-PEG) micelles demonstrated pronounced sensitivity towards molecular oxygen, the key intracellular bioanalyte. The detailed photophysical analysis of the AIE phenomena revealed that the NIR emission most probably occurred due to the excimeric excited state of the 3MMLCT character. Evaluation of the Pt1@PCL-b-PEG efficacy as a lifetime intracellular oxygen biosensor carried out in CHO-K1 live cells demonstrated the linear response of the probe emission lifetime towards this analyte accompanied by a pronounced influence of serum albumin on the lifetime response. Nevertheless, Pt1@PCL-b-PEG can serve as a semi-quantitative lifetime oxygen nanosensor. The key result of this study consists of the demonstration of an alternative approach for the preparation of NIR biosensors by taking advantage of in situ generation of NIR emission due to the nanoconfined aggregation of Pt (II) complexes inside the micellar nanocarriers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Distinct molecular packing fashions. • Multi-stimuli responsive luminescent behaviors. • Thermo- and mechano-response confidential materials. Information encryption plays a crucial role, and various optical materials based on intricate chromophores have been investigated for anti-counterfeiting purposes. In this study, we designed and synthesized two luminescent Pt(II) complexes by concisely introducing different spatial steric hindrances. The complexes adopt distinct head-to-tail and head-to-head dimeric subunits, respectively, which further stack into one-dimensional (1D) chains and three-dimensional (3D) networks in turns. By doping into polymers, we have developed high-performance optical encryption and anti-counterfeiting materials. The authenticity of documents or products can now be verified through changes in luminescence induced by external stimuli, providing an enhanced level of security owing to the complexity of the chromophores and their unique response to various stimuli. The responsiveness of these materials to different types of external stimuli enables the creation of advanced security features that can be utilized in a variety of applications. The use of luminescent Pt(II) complexes in anti-counterfeiting materials offers a novel approach to verifying the authenticity of documents or products. [ABSTRACT FROM AUTHOR]

Treatment of 3,4,5,6-tetraphenyl-2,2′-bipyridine (LH) (7) with [PtCl2(dmso)2] (dmso = dimethyl sulfoxide) in chloroform afforded the cyclometallated square-planar platinum(II) complex [PtCl(L)] (8) and the octahedral Pt(IV) complex mer-[PtCl3(L)] (9) containing an anionic tridentate (C^N^N) ligand. The chloride of (8) can be easily replaced by trifluoroacetate to yield [(L)PtO2CCF3] (10). Reaction of (8) with the alkyne HC≡CC6H4But-4 resulted in the formation of [(L)PtC≡CC6H4But-4] (11). Treatment of (8) with 4-dimetylaminopyridine (DMAP) and PPh3 in dichloromethane, and the subsequent addition of NH4PF6 in methanol produced the salts [Pt(DMAP)(L)]PF6 (12) and [Pt(PPh3)(L)]PF6 (13), respectively. In a similar manner, reaction of (8) with 0.5 equiv. of bis(diphenyl-phosphino)methane (dppm) formed the dppm-bridged binuclear dicationic salt [(L)Pt(- dppm)Pt(L)][PF6]2 (14).

Anticancer activity of mononuclear Pt(II) complexes bearing organoselenide moiety. [Display omitted] • Syntheses and characterization of four new mononuclear Pt(II) complexes as efficient chemotherapeutic agents. • The complexes were synthesized from heterotridentate coordination core (NOSe) based Schiff bases. • The cytotoxicity of synthesized Pt(II) complexes were examined on MCF-7 and NIH-3T3 cell lines. • ROS generation, flow cytometery and Transwell assays were performed to determine the mechanism of anticancer action. This work features design and syntheses of four mononuclear Pt(II) complexes [Pt(L 1 –H)Cl]; 1, [Pt(L 2 –H)Cl]; 2, [Pt(L 3 –H)Cl]; 3, and [Pt(L 4 –H)Cl]; 4, which were judiciously prepared by tethering with a ONSe donor core of Schiff base ligands (L 1 –L 4). The complexes were fully characterized by IR, NMR spectra, elemental analysis and single crystal X-ray diffraction (sc-XRD) analysis. Notably, cytotoxicity profile of these structurally amended complexes against human breast cancer cell line (MCF-7) and mouse model fibroblast cells (NIH-3T3) cell lines revealed remarkable anticancer activity and selectivity based on their structural activity. [ABSTRACT FROM AUTHOR]

In this research, we have developed a series of PtII(C^N)(N-donor ligand)Cl-type phosphorescent complexes with the four-coordinate organoboron unit in the C^N ligand. Through shifting the coordinating position of the Pt(II) center from phenyl ring to pyridyl ring of the 2-phenylpyridine-type (ppy-type) four-coordinate organoboron unit, the variation of >50 nm in charge-transfer (CT) absorption band and >40 nm in phosphorescent wavelength can be observed in the synthesized PtII(C^N)(N-donor ligand)Cl-type complexes, indicating effective tuning of their photophysical properties incurred by the four-coordinate organoboron unit. In addition, based on the cyclic voltammetry result, obvious variation of electron density on the Pt(II) center of these PtII(C^N)(N-donor ligand)Cl-type phosphorescent complexes can also be observed. Critically, these PtII(C^N)(N-donor ligand)Cl-type complexes with the ppy-type four-coordinate organoboron unit can exhibit aggregation enhanced phosphorescent emission (AEPE) behavior. It seems that the hydrogen bonding among the N-donor ligands and water molecules can affect their AEPE response greatly, representing a new way to tune the AEPE behavior in the PtII(C^N)(N-donor ligand)Cl-type complexes. In the solution-processed organic light-emitting diodes (OLEDs), peak electroluminescent (EL) efficiencies of 15.3%, 10.3 cd A−1 and 9.8 lm W−1 have been achieved with EL at ca. 648 nm. These impressive results have provided key information for tuning optoelectronic properties of the PtII(C^N)(N-donor ligand)Cl-type complexes by the four-coordinate organoboron unit and N-donor ligand. Optoelectronic properties and AEPE behavior tuned by hydrogen bonding of the PtII(C^N)(N-donor ligand)Cl-type complexes with the four-coordinate organoboron unit. [Display omitted] • Pt(II) complexes with four-coordinate organoboron unit showing aggregation enhanced phosphorescent emission (AEPE) behavior. • Tuning AEPE behavior of Pt(II) complexes through hydrogen bonding interaction. • High electroluminescent efficiencies achieved in deep-red solution-processed OLEDs with AEPE emitter. [ABSTRACT FROM AUTHOR]

In the present work, we described the preparation and characterization of the micelles based on amphiphilic poly(ε-caprolactone-block-ethylene glycol) block copolymer (PCL-b-PEG) loaded with non-symmetric [Pt(C^N*N’^C’)] complex (Pt1) (where C^N*N’^C’: 6-(phenyl(6-(thiophene-2-yl)pyridin-2-yl)amino)-2-(tyophene-2-yl)nicotinate). The obtained nanospecies displayed the ignition of near-infrared (NIR) phosphorescence upon an increase in the content of the platinum complexes in the micelles, which acted as the major emission component at 12 wt.% of Pt1. Emergence of the NIR band at 780 nm was also accompanied by a 3-fold growth of the quantum yield and an increase in the two-photon absorption cross-section that reached the value of 450 GM. Both effects are believed to be the result of progressive platinum complex aggregation inside hydrophobic poly(caprolactone) cores of block copolymer micelles, which has been ascribed to aggregation induced emission (AIE). The resulting phosphorescent (Pt1@PCL-b-PEG) micelles demonstrated pronounced sensitivity towards molecular oxygen, the key intracellular bioanalyte. The detailed photophysical analysis of the AIE phenomena revealed that the NIR emission most probably occurred due to the excimeric excited state of the 3MMLCT character. Evaluation of the Pt1@PCL-b-PEG efficacy as a lifetime intracellular oxygen biosensor carried out in CHO-K1 live cells demonstrated the linear response of the probe emission lifetime towards this analyte accompanied by a pronounced influence of serum albumin on the lifetime response. Nevertheless, Pt1@PCL-b-PEG can serve as a semi-quantitative lifetime oxygen nanosensor. The key result of this study consists of the demonstration of an alternative approach for the preparation of NIR biosensors by taking advantage of in situ generation of NIR emission due to the nanoconfined aggregation of Pt (II) complexes inside the micellar nanocarriers.

Tetradentate Pt(II) complexes are promising emitters for deep blue organic light‐emitting diodes (OLEDs) due to their emission energy and high photoluminescence efficiency. However, to obtain a pure blue color, spectral red‐shifts, and additional emission peaks at longer wavelengths, originating from strong intermolecular interactions between parallel Pt(II) complexes, must be avoided. Herein, a new class of deep‐blue emitting tetradentate Pt(II) complexes consisting of a non‐planar ligand and a bulky adamantyl group is reported. The six‐membered metallacycle structure renders the Pt(II) complex non‐planar. In addition, the bulky adamantyl groups increase intermolecular distances and decrease red‐shifts in the emission originating from strong dipole–dipole interactions. Therefore, these Pt(II) complexes exhibit little change in emission color with increasing dopant concentration. OLEDs incorporating these new Pt(II) complexes as emitters exhibit deep blue emission with a Commission International de L'Eclairage (CIE) y under 0.13 and a maximum external quantum efficiency of 22.6%, which is one of the highest observed for deep blue (CIE y < 0.15) phosphorescent OLEDs using Pt(II) complexes. These results provide a new approach for designing Pt(II) complexes for high efficiency deep blue OLEDs. [ABSTRACT FROM AUTHOR]

The rates of chloride substitution from [Pt(chlorido)(1,3-bis(2-pyridyl)benzene)]Cl, (PtL2); [Pt(chlorido)(2,6-bis(2-quinolinyl)pyridine)]Cl, (PtL3) and [Pt(chlorido)(1,3-bis(2-quinolinyl)benzene)]Cl (PtL4) by azoles viz., imidazole (Im), 1-methylimidazole (MIm), 1,2-dimethylimidazole (DIm), pyrazole (Pyz) and 1,2,4-triazole (Trz) were measured under pseudo-first-order conditions as a function of concentration and temperature using spectroscopic techniques. The rate data fitted to the equation, kobs. = k2[azole]. Taken together with the literature data of [Pt(chlorido)(2,2′:6,2″-terpyridine)]Cl·2H2O, (PtL1), the order of reactivity was PtL2 > PtL4 > PtL1 > PtL3, and showed a dependent on the strength of the π-back bonding from the metal centre to the tridentate spectator ligand. The cis-quinolinyl moieties of PtL3 and PtL4 accumulated electron density onto the cis Pt-N bonds through a net σ/π-induction donation towards the Pt(II) centre which impeded the attack of the incoming azole nucleophiles. The rate of chloride substitution was thus lowered relative to that of their respective analogues with cis-pyridyl moieties. Moreover, by changing the trans-donor ring from pyridyl (PtL1 and PtL3) to a phenyl (PtL2 and PtL4) in the spectator ligand framework, the trans-labilizing effect on the leaving chloride ligand was accentuated by factors in the range 102-103. The substituting power of the nucleophiles was influenced kinetically by the basicity (Im > Pyz > Trz) and steric effects of the entering nucleophile (MIm > Im > DIm) for all complexes except for PtL3, where MIm and DIm had similar reactivities. The trends in magnitudes of the rate constants correlated well with key DFT-calculated metrics of the geometry-optimized structures of the complexes. The reactions form substitution products through a common reaction pathway which is characterized by a decrease in the entropy of activation, and at a rate that is dependent on the concentration as well as the steric bulk of the azoles. These observations are characteristic of an associative mode of activation for substitution processes.

A new class of tetradentate Pt(II) complexes, Pt(pzpyOczpy‐iPr) and Pt(pzpyOczpy‐mesi), enabling fabrication of deep‐blue and white phosphorescent devices, is successfully synthesized and fully characterized. Their photoluminescent quantum yields in dichloromethane are over 90% with short decay lifetimes less than 4.0 µs. Under low doping concentration, the emission is governed by ligand‐centered triplet transition state (3LC, 3πcz*→πcz) on carbazole group, rendering narrow blue emission with full width at half‐maximum (FWHM) less than 45 nm. When increasing the doping concentration, expanded monomeric and excimeric emissions are demonstrable, displaying broad white emission with FWHM up to 152 nm. Devices fabricated with 2 wt% dopant in DPEPO host achieve a maximum external quantum efficiency (EQEmax) of 17.2% with CIE coordinates of (0.14, 0.15). Otherwise, devices with 50 wt% dopant in mCPCN afford broad white emission with EQEmax of 18.0% and maximum power efficiency of 60.2 lm W−1. More importantly, the concentration‐dependent electroluminescence provides superior stable color under a wide range of current density, revealing a spectrum‐stable emission derived from highly admixed substates in T1. [ABSTRACT FROM AUTHOR]

The design of square‐planar Pt(II) complexes with highly efficient solid‐state near infrared (NIR) luminescence for electroluminescence is attractive but challenging. This study presents the fine‐turning of excited‐state properties and application of a series of isoquinolinyl pyrazolate Pt(II) complexes that are modulated by steric demanding substituents. It reveals that the bulky substituents do not always disfavor metallophilic Pt···Pt interactions. Instead, π–π stacking among chelates, which are fine‐tuned by the associated substituents, also exerts strong influence to the metal‐metal‐to‐ligand charge transfer (MMLCT) transition character. Theoretical calculations indicate that Pt···Pt contacts become more relevant in the trimers rather than the dimers, especially in their T1 states, associated with a change from mixed 3LC/3MLCT transition in the monomer/dimer to mixed 3LC/3MMLCT transition character in the trimer. Electroluminescence devices affording intense deep‐red/NIR emission (near 670 nm) with unprecedentedly high external quantum efficiency over 30% are demonstrated. This work provides deep insights into formation MMLCT transition of square‐planar Pt(II) complexes and efficient molecular design for deep‐red/NIR electroluminescence. [ABSTRACT FROM AUTHOR]

Cisplatin is a widely used chemotherapeutic agent which interacts with DNA to form Pt-DNA adducts, leading to DNA double-strand breaks and apoptosis. Resistance is the major obstacle in the clinical application of cisplatin. A quinoline derivative based Pt(II) complex PtQ was synthesized and characterized. As an analogue of cisplatin, PtQ demonstrated a novel anticancer mechanism in ovarian cancer. PtQ caused excessive production of reactive oxygen species (ROS), which triggered ferroptotic cell death in ovarian cancer. Cystine/glutamate antiporter SLC7A11 and glutathione peroxidase 4 (GPX4) which alleviate lipid peroxidation were both downregulated in PtQ-treated SKOV3 cells. Furthermore, PtQ induced DNA single-strand breaks and suppressed the expression of single-strand breaks repair protein PARP1. Mechanism studies demonstrated that PtQ can hopefully bypass the signaling pathways mediated cisplatin resistance in ovarian cancer. As a CDDP-like Pt(II) complex, PtQ caused DNA single-strand breaks and suppressed the expression of repair protein PARP1. The tumor suppressor p53 was activated following PtQ-induced DNA damage and downregulated the expression of SLC7A11/GPX4 signal axis, which triggered ferroptosis in ovarian cancer. [Display omitted] • A quinoline derivative based Pt(II) complex PtQ with was designed and investigated. • PtQ triggered ferroptosis in ovarian cancer through downregulation of SLC7A11/GPX4. • PtQ caused DNA single-strand breaks and inhibited the expression of PARP1. [ABSTRACT FROM AUTHOR]

• Tunable k r and k nr values by systematic variation of substitution patterns and co-ligands. • Peripheral substituents facilitate processability. • High photoluminescence quantum yields with variable excited triplet state lifetimes become accessible. In this work, the synthesis as well as the structural and photophysical characterization encompassing a series of Pt(II) complexes bearing cyclometalating pyrazole-based C^N^N ligands as tridentate luminophores are reported. By varying the substitution pattern of the main luminophore and by exchanging the ancillary co-ligand, different Pt(II) complexes were synthesized and compared regarding their excited state properties. The complexes C1 - C8 bear differently decorated luminophores and a chlorido co-ligand; compounds C9 – 15 possess stronger ancillary ligands, such as cyanido and substituted acetylido derivates. While all complexes showed luminescence from metal-perturbed ligand-centered triplet states (3MP-LC), there are significant differences regarding the photoluminescence lifetimes (τ) and quantum yields (Φ L), both resulting from variations in the average radiative (k r) and radiationless (k nr) deactivation rate constants. Although the chlorido complexes generally show lower Φ L , the OH-substituted compound C3 reaches a surprisingly high value of 36 %. Complex C9 with a cyanido co-ligand shows the longest τ of the series with 15.76 µs at room temperature in an Ar-purged solution, whereas all chlorido complexes C1 - C8 possess lifetimes below 1.90 µs. The highest Φ L is achieved with phenylacetylido as the co-ligand. In general, the insertion of electron-withdrawing moieties at the main luminophore on the meta -position (with respect to the cyclometallation site) has a detrimental impact on the overall performance, whereas electron donors improve the photoluminescence efficiency. The t -butyl group on the main luminophore enhances the processability without affecting the excited state properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract Phosphorescent near‐infrared (NIR) organic light‐emitting devices (OLEDs) have drawn increasing attention for their promising applications in the fields such as photodynamic therapy and night‐vision readable displays. Here, three simple phosphorescent Pt(II) complexes are synthesized, and their intermolecular interactions are investigated in crystals and neat films by X‐ray single crystal diffraction and grazing‐incidence wide‐angle X‐ray scattering, respectively. The photophysical properties, molecular aggregation (including Pt–Pt interaction), molecular packing orientation, and electron transport ability are all influenced by the strong intermolecular hydrogen bonds. Consequently, the nondoped OLEDs based on tBu‐Pt and F‐Pt show electroluminescent emissions in NIR region with the highest external quantum efficiencies of 13.9% and 16.7%, respectively.

A series of six tridentate cyclometallated N^N^C Pt(II) complexes with different halide auxiliary ligands and different aliphatic side chains have been prepared. All complexes show concentration‐dependent NMR spectra. Their self‐association was studied by a dilution method monitoring both the 1H as well as 195Pt nuclei. Both techniques show similar results validating that 195Pt NMR is an important methodology to study self‐association of potentially any Pt complex regardless of the nature of the ligands. Experimental data allowed to predict the most probable geometry of the dimers and to get insight into the structural and thermodynamic specificity of the aggregation. The in‐depth analysis of the data suggests that the halide auxiliary ligand has no significant influence on self‐association while the effect of the aliphatic side chain depends on the length and the structure of the chain. [ABSTRACT FROM AUTHOR]

The present work describes the synthesis, solvolysis and cytotoxic activity of Pt (II) complexes of the type trans -[PtCl 2 (DMSO) (L)] and cis -[PtCl 2 (L) 2 ], where L = benzhydrazide (BH), 4-nitrobenzhydrazide (4NH) and 4-(trifluoromethyl)benzhydrazide (4 TF). The structures of these complexes were proposed using spectroscopic methods. All complexes undergo fast solvolysis generating four identical species in DMSO, being that the species cis - and trans -[PtCl 2 (DMSO) (L)] are the most important. As to the stability in DMF, Pt (II) complexes of the type cis -[PtCl 2 (L) 2 ] are very stable, while Pt (II) complexes of the type trans -[PtCl 2 (DMSO) (L)] react at a slower rate than those verified in DMSO. The cytotoxic activity of the compounds was evaluated in a chronic myelogenous leukemia cell line. A relationship between solvolysis and cytotoxic activity was verified. Moreover, our results showed that some Pt (II) complexes were more cytotoxic than the free ligands, carboplatin and cisplatin. Image 1 • PtII complexes of the type trans -[PtCl 2 (DMSO) (L)] and cis -[PtCl 2 (L) 2 ] were prepared. • Both types of complexes generate four identical species in DMSO. • The cytotoxic activity of compounds was investigated in K562 cell line. [ABSTRACT FROM AUTHOR]

Abstract On the basis of great diverse applications of nonlinear optical (NLO) materials, organometallic complexes have attracted considerable attention. In this paper, we present a detailed investigation on a series of Pt(II) dithienylcyclopentene(DTE)-based complexes via density functional theory method with the aim of evaluating their structures, electronic absorption spectra and first hyperpolarizabilities. The calculations demonstrate that the first hyperpolarizabilities can be enhanced by the introduction of quinolone into the complexes because of the enlarged spatial separation of electron density. However, Pt(II) complexes containing perfluorocyclopentene ring exhibit decreasing NLO response attributed to lower amount of charge transferred and short effective CT distance. The static first hyperpolarizabilities (β tot) of monometallic Pt(II) complexes are larger than those of bimetallic Pt(II) complexes due to correlative mixed charge-transfer patterns. More importantly, the closed-ring (1c) complex comprising DTE unit exhibits the largest β tot value approaching 144 × 10−30 esu, with the contrast over five times compared to corresponding open-ring due to the better π-conjugated delocalization and smaller HOMO and LUMO energy gap. In general, we envision our work will be beneficial for further rational design of DTE-containing Pt(II) complexes as high performance NLO materials. Graphical abstract Image 1 Highlights • Monometallic Pt(II) DTE-based complexes exhibit the largest β tot values. • The second-order NLO response of bimetallic Pt(II) complexes can be altered by various ligands. • The switching of NLO properties has been achieved by photoisomerization. [ABSTRACT FROM AUTHOR]

• Metallosupramolecular Pt(II) complexes as highly active catalyst for the hydrosilylation reaction. • Remarkably high activity and regioselectivity in hydrosilylation of versatile functionalized olefins with a broad scope of commercially available hydrosilanes. • High efficiency and low catalyst loading required for the reactions. Two new air- and water-stable Pt(II) metallosupramolecular complexes based on ambidentate ligands have been designed, synthesized and fully characterized. The structure of complexes has been determined by various analytical techniques including NMR spectroscopy and TOF-MS. Additionally, the single crystal structure of 2 was determined by X-ray diffraction. The catalytic activity of these complexes in hydrosilylation has been investigated, establishing that both have similar high activity and selectivity within a broad scope of structurally distinct olefins and hydrosilanes. [ABSTRACT FROM AUTHOR]

Abstract A library of 1,2- cyclometalated Pt(II) complexes based on various bidentate N ,C-chelate chromophores have been studied for their uses as luminescent oxygen sensing probes (OSPs). The bidentate chelate ligands have been found to have a distinct impact on the performance of the Pt(II) compounds as OSPs. For some of the complexes, attachment of a dimesityl boron group (BMes 2) to the chelate ligands enhances their oxygen sensitivity. For phenyl-1,2,3-triazole (Phtrz) based Pt(II) complexes, the attachment of a diphenyl amino moiety to the N ,C-chelate ligand substantially enhances phosphorescence quenching and the performance of the OSP. A high k SV app value (0.0667 Torr−1) for the OSP based on the diphenyl amino functionalized Pt(II) complex was achieved, which is the highest value reported to date for OSPs based on bidentate Pt(II) complexes. Graphical abstract Image 1 Highlights • A library of N ,C-chelate Pt(II) compounds were examined for use as oxygen sensors. • Some of the Pt(II) compounds have been found to be highly efficient oxygen sensors in polym matrices. • Substituents were found to have a key impact on stability and sensitivity of the oxygen sensors. [ABSTRACT FROM AUTHOR]

Crystal structures of two Pt(II) complexes with square-planar geometry were determined. Cytotoxic activity of the compounds was studied towards HeLa, HL-60 and U-937 tumor cell lines. Cytotoxicity was only shown in non-solid tumor cell lines, the lowest IC 50 being produced by PtDMPzTn in U-937 cells. [Display omitted] Cisplatin is one of the most used chemotherapeutic agents nowadays. However, it presents several and severe side effects. For that, the synthesis of new analogues of cisplatin is crucial to improve the current therapies. In this work, two squared-planar Pt(II) analogues of cisplatin were presented. These analogues included a bidentate ligand molecule with a 3,5-dimethyl-pyrazole ring and a thiazine (DMPzTz) or thiazoline (DMPzTn) ring. The chemical characterization covered single-crystal X-ray diffraction, infrared spectroscopy (IR) and elemental analysis. Their potential anticarcinogenic ability was studied in three different human tumor cell lines, i.e., histiocytic lymphoma (U-937), promyelocytic leukemia (HL-60) and epithelial cervix carcinoma (HeLa) via cytotoxicity assay. The results showed moderate cytotoxic effect of the complexes on leukemic cell lines, with scarce effect on solid tumor cell line HeLa. Lower IC 50 values were found for U-937 cell line, being 32.3 ± 1.2 µmol/dm3 for PtDMPzTn and 43.0 ± 1.4 µmol/dm3 for PtDMPzTz. The comparison with previously synthesized analogues with phenyl substitutions or no substitutions in the pyrazole ring, allows to conclude that the presence of ligands with methyl substituted-pyrazole ring did not improve the effect of the complexes. In addition, the main effect of these potential chemotherapeutic agents is produced by the presence of platinum(II) as metal center, since the free ligands do not show any significant activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel water-soluble amino acid–Pt complexes based on 1,10-phenanthroline-5,6-dione. • Theoretical studies using ADME analysis, DFT calculations, and molecular docking. • DNA binding investigations by Fluorescence, UV–Vis, and CD spectroscopy. • Evaluation of cytotoxicity of Pt-complexes against A2780SP and A2780CP cell lines. In the present work, two water-soluble amino acid–Pt complexes, [Pt(phd)(AA)]ClO 4 , (phd = 1,10-phenanthroline-5,6-dione; 1 , AA = L -isoleucine and 2 , AA = L -leucine) have been introduced. The preparation and characterization of two novel water-soluble platinum complexes were performed. Molecular docking, ADME, and DFT were used to study these complexes theoretically. The mechanism of DNA binding was studied using fluorescence, UV–Vis, and CD spectroscopy. Fluorescence data indicated a static mechanism for quenching DNA. According to thermodynamic parameters, DNA and Pt(II) complexes interact via groove binding and intercalation. CD spectra indicated that both complexes show an increase in intensity across all bands. Experimental data agree with docking studies and DFT calculations. In sum, groove binding and intercalation are the mechanisms of binding to DNA. Based on cytotoxicity studies, both complexes showed higher anticancer activity against A2780SP cell line than cisplatin. Moreover, complex 2 is more active than complex 1 according to all theoretical and experimental evidence. [ABSTRACT FROM AUTHOR]

We here report our studies on the reaction with the platinum(II) ion of a nucleoamino acid constituted by the l-2,3-diaminopropanoic acid linked to the thymine nucleobase through a methylenecarbonyl linker. The obtained new platinum complexes, characterized by spectroscopic and mass spectrometric techniques, were envisaged to exploit synergistic effects due to the presence of both the platinum center and the nucleoamino acid moiety. The latter can be potentially useful to protect the complexes from early deactivation, as well as to facilitate their cell internalization. The biological activity of the complexes in terms of antiproliferative effects was evaluated in vitro on different cancer cell lines and healthy cells, showing the best results on human cervical adenocarcinoma (HeLa) cells along with good selectivity for cancer over normal cells. In contrast, the metal-free nucleoamino acid did not show any cytotoxicity on both normal and cancer cell lines. Finally, the ability of the novel Pt(II) complexes to bind various DNA model systems was investigated by circular dichroism (CD) spectroscopy and polyacrylamide gel electrophoresis analyses proving that the newly obtained compounds can potentially target DNA, similarly to other well-known anticancer Pt complexes, with a peculiar G-quadruplex vs. duplex selectivity.

In past two decades, lots of bidentate Pt(II) complexes are developed as potential organic light emitting diodes due to their simple synthetic process. The relative low quantum efficiency is one of the major blocks for their applications. Two new heteroleptic Pt(II) complexes bearing an n-hexyloxy substituted phenyllepidine-based ligand and either a picolinate (pic) ( 1 ) or acetylacetonate (acac) ( 2 ) ancillary ligand are synthesized as orange-red-emitter by Wawrzinek and coauthors. The quantum efficiency of 2 is much larger than that of 1 indicating that the variation of ancillary ligand has a great effect on the performance. Inspired by it, other two new bidentate Pt(II) complexes are theoretically designed with the same primary ligand along with pyrazolone (pzl) ( 3 ) or N-substituted carbazole (NCaz) ( 4 ) ancillary ligand. The phosphorescent properties are explored by density functional theory (DFT) and time dependent DFT (TDDFT) methods with the ultimate goal to explore the influence of ancillary ligand. Moreover, the emission rule is confirmed. Finally, the quantum yield is estimated according to the radiative rate constant ( k r ) and nonradiative rate constant ( k nr ). The smaller k nr is the vital item to determine the high quantum yield. [ABSTRACT FROM AUTHOR]

Herein, we present three new tetradentate C^N*N^C luminophores and their platinum(II) complexes. We describe the influence of the degree of fluorination at the phenylpyridine luminophore on the photophysical properties of the monomeric species. A blue-shift can be observed with increasing number of fluorine atoms (0–6), which is related to a growing HOMO-LUMO gap that reaches a maximum for four halogen moieties. Increasing degree of fluorination enables intermolecular Pt–Pt interactions and promotes emission from 3MMLCT states in amorphous solids and matrices, with the drawback of lowered solubility. A clear trend towards layered packing patterns in crystals has been observed within the series. This knowledge is important for the design and realization of triplet emitters with aggregation-controlled luminescence towards potential applications in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Graphical abstract Investigation of excited states of isomeric tetra-platinated porphyrins. Highlights • Excited state and intersystem crossing mechanism for platinum(II) porphyrins were investigated. • NLO properties of platinum(II) porphyrins were investigated. • WLCZ-Scan technique was explored in the platinum(II) porphyrins derivatives. Abstract In the present work, the excited states (singlet and triplet) for three different porphyrins, with and without coordinated Pt(II) complex derivatives, were investigated by three different temporal laser regimes were employed in the Z-Scan technique. Intersystem crossing time (singlet to triplet conversion mechanism) was obtained by a combination of Z-Scan with single or with a train of picosecond laser pulses. These measurements have shown that the excited state absorption spectrum shows distinct absorption behaviors. Also, the absorption cross-section is equivalent to the ground state, describing no changes in the optical transmittance. Fluorescence lifetimes and quantum yields were determined, respectively, by time resolved fluorescence analysis. To determine the intersystem crossing time constant, two additional levels were incorporated to the rate equation model. Moreover, fluorescence decays, internal conversion and ISC times have shown a strong dependence in Pt(II) derivatives and their position to the porphyrin ring ( meta or para position). [ABSTRACT FROM AUTHOR]

Abstract: In this work we describe the synthesis and DFT‐supported photophysical characterization of a series of Pt(II) complexes bearing tetradentate luminophores with increasing degree of fluorination. Aggregation into crystalline phases leads to substitution‐dependent arrangements that in all cases hinder intermetallic coupling, as intermolecular interactions are dominated by hydrogen bonding and π‐stacking. In amorphous matrices, on the other hand, we observed that an increasing level of fluorination favors the tendency towards Pt−Pt interaction upon aggregation, leading to a red‐shifted phosphorescence, if compared with monomeric species in dilute solutions and crystalline solids. [ABSTRACT FROM AUTHOR]

Square planar mononuclear platinum(II) complexes having general formula [Pt(Ln)Cl2], (where, Ln = L1-4) were synthesized with neutral bidentate heterocyclic 1,3,5-trisubstituted bipyrazole based ligands. The synthesized compounds were characterized by physicochemical method such as TGA, molar conductance, micro-elemental analysis and magnetic moment, and spectroscopic method such as, FT-IR, UV-vis, 1H NMR, 13C NMR and mass spectrometry. Biological applications of the compounds were carried out using in vitro brine shrimp lethality bioassay, in vitro antimicrobial study against five different pathogens, and cellular level cytotoxicity against Schizosaccharomyces pombe (S. Pombe) cells. Pt(II) complexes were tested for DNA interaction activities using electronic absorption titration, viscosity measurements study, fluorescence quenching technique and molecular docking assay. Binding constants (Kb) of ligands and complexes were observed in the range of 0.23-1.07 × 105 M−1 and 0.51-3.13 × 105 M−1, respectively. Pt(II) complexes (I-IV) display an excellent binding tendency to biomolecule (DNA) and possess comparatively high binding constant (Kb) values than the ligands. The DNA binding study indicate partial intercalative mode of binding in complex-DNA. The gel electrophoresis activity was carried out to examine DNA nuclease property of pUC19 plasmid DNA. [ABSTRACT FROM AUTHOR]

Pd (II) and Pt(II) complexes of ( E )-3-(4-(dimethylamino)phenyl)-1-(pyridin-2-yl) prop-2-en-1-one (L) and its Pd (II) and Pt(II) formulated as [Pt(L 1 ) 2 ] Cl 2 . 2H 2 O, [Pd (L 1 ) 2 ] Cl 2 0.5H 2 O, [Pd (L 1 ) 2 ] (AcO) 2 CH 3 OH have been synthesized. Elemental analyses, molar conductance, thermal technique, molecular modeling, IR and electronic spectral measurements were used to verify the structures of the complexes. The titled ligand behaves as a neutral bidentate ligand coordination via pyridine nitrogen and carbonyl oxygen atoms. These complexes have square planar geometry. The kinetic and thermodynamic parameters of the decomposition steps were evaluated. The in-vitro antimicrobial and antitumor activities of the investigated compounds were screened against different microorganisms and the human hepato-cellular carcinoma cells, HEPG2, respectively. The data showed that the metal complexes have more antimicrobial and antitumor activities than the ligand itself. Molecular docking studies were performed by Docking Server and SwissDock using X-ray crystallographic structures of the proteins (3t88, 4m01, 4ynt, 1zap & 121P) from Protein Data Bank (PDB). The ligand and possibly its complexes showed favorable binding with the receptors of the microorganisms (3t88, 4m01, 4ynt, 1zap) and H-ras oncoprotein. Hence, our results present the synthesized complexes as potential antimicrobial and anticancer drug candidates. [ABSTRACT FROM AUTHOR]

A series of platinum(II) complexes ( C1 – C6 ), incorporating an intercalating substituted benzimidazole (2-aminomethylbenzimidazole) and varied leaving groups such as chloride, chelating carboxylates, and thiols, was synthesized to achieve more potent and specific metallodrugs. Spectroscopic titrations, viscosity and electrophoresis measurements revealed that the complexes bound to DNA via an intercalative mode. The complexes were also found to have high affinity towards serum albumin, BSA. Cell viability experiments against three human cancer cell lines (A549, MCF-7, MDA-MB-231) in vitro indicated that the antitumor activities were comparable with cisplatin and its successors, with the greatest efficiency towards A549. Interestingly, complexes C1 – C4 were 1.3–1.6 times more potent than cisplatin towards MDA-MB-231 cells. The complexes generate lower degrees of oxidative stress and are almost non-toxic to normal L6 myotubes, indicative of selective toxicity for tumor cells over normal cells. Further studies with A549 cell line revealed that the inhibition of cancer cell proliferation by the complexes is brought about by a combination of cell cycle arrest at the G2/M phase and induction of a caspase-mediated apoptosis. [ABSTRACT FROM AUTHOR]

Four new platinum(II) complexes [Pt(dpen)(bpy)](ClO4)2 (1), [Pt(dpen)(phen)](ClO4)2 (2), [Pt(dpen)(dpq)](ClO4)2 (3) and [Pt(dpen)(dppz)](ClO4)2 (4) comprising of different N,N-donor ligands, viz., 2,2′-bipyridine (bpy), 1,l0-phenanthroline (phen), dipyridoquinoxaline (dpq), dipyrido-[3,2-d:2¢,3¢-f–phenazine] (dppz), and chiral ancillary ligand 1R,2R-1,2-diphenylethylenediamine (dpen) have been synthesized and characterized. The interaction of these complexes 1–4 with calf-thymus DNA (CT-DNA) has been explored using absorption, circular dichroism spectral and cyclic voltammetric studies. The absorption spectrum of complex 4 with dppz ligand exhibits a major red shift with an overall hypochromic as well as a hyperchromic effect in the presence of DNA, other complexes (1–3) show only hypochromism. From these absorption spectral studies, the intercalative ability of the complexes follows the order as, 4 > 3 > 2 > 1, which is further confirmed by CD and cyclic voltammetry measurements. CD spectral studies show that DNA becomes more A-like upon interaction with the complexes 1 & 2 but the complexes 3 & 4 bring about B-form to Z- form DNA conformational transition. The DNA cleavage study of these Pt(II) complexes 1–4 carried out by gel electrophoresis revealed that complexes 1–4 can cleave super coiled (SC) pUC18 DNA efficiently into open circular form (form II) under hydrolytic and oxidative conditions. [ABSTRACT FROM AUTHOR]

Pt(II) complexes having 2-[(Methylamino)methyl]pyridine (MAMP) as a carrier ligand have been synthesised and characterised. DNA binding ability of all the complexes have been investigated with Calf thymus DNA (CT-DNA) through absorption titration, competitive binding with ethidium bromide, viscosity titration and gel electrophoresis. Bovine serum albumin (BSA) binding property has also been explored through fluorometric titration and different binding parameters for their interaction with DNA as well as BSA have been evaluated. Cytotoxicity of all the studied complexes are investigated on three different cancer cell lines A549, MCF7, MDA-MB-231 as well as normal cell line L6 myotubes through MTT assay and subsequently compared with three predominantly used Pt(II) based anticancer drugs cisplatin, carboplatin and oxaliplatin. All the Pt(II) complexes have been considered for the study of reactive oxygen species (ROS) generation and degree of lipid peroxidation (LPO) to explore their toxicity on normal cells. Study of cell cycle arrest by the complexes on A549 has also been performed through flow cytometry. Finally, in order to understand the underlying mechanism of cancer cell death, degree of apoptosis has been studied through immunoblot and immunofluorescence to measure the activated capase 3 by the studied complexes. [ABSTRACT FROM AUTHOR]

Two novel sulfonated CNN-pincer ligands 1b and 1c and the corresponding chloro and aqua complexes K[CNNLPtCl] and CNNLPt(H2O), 3b- 3c and 2b- 2c, were prepared and fully characterized including single crystal X-ray diffraction. Along with the previously described complexes 2a and 3a, the derivatives of a CNN pincer ligand 1a, these complexes form a family of structurally similar compounds where the pincer core rigidity increases in the series 2a (3a)< 2b (3b)< 2c ( 3c), as deduced from their XRD data. The increased ligand rigidity affects the aqua ligand dissociation energy of the CNNLPt(H2O) complexes, as it follows from DFT calculations and as is reflected in the increased reactivity of the aqua complexes 2a, 2b and 2c in processes that involve aqua ligand loss. Among these processes the formation of the presumed dinuclear complexes CNNL2Pt2 and, importantly, catalytic C−D bond cleavage in C6D6 were studied in 2,2,2-trifluoroethanol solutions. The C−D bond cleavage reactivity was quantified as the rate of H/D exchange between C6D6 and CF3CH2OH at 80 °C. [ABSTRACT FROM AUTHOR]