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The luminescent properties of Au(I) and Pt(II) compounds are commonly tuned by exploiting the alkynyl ligand with varying electron density. Herein, we describe the synthesis of three new emissive transition metal compounds, tbpyPt(C2pym)2, Ph3PAuC2pym, and Cy3PAuC2pym (where HC2pym = 2-ethynylpyrimidine), verified by 1H-NMR, EA, and a single-crystal X-ray diffraction analysis. The tbpyPt(C2pym)2 complex crystallized as an Et2O solvate in the orthorhombic space group Pbca with Z = 24 with three unique Pt(II) species within the unit cell. The Cy3PAuC2pym species crystallizes in a monoclinic space group with one unique complex in the asymmetric unit. Changing the identity of the phosphine from Cy3P to Ph3P influences interactions within the unit cell. Ph3PAuC2pym, which also crystalizes in a monoclinic space group, has an aurophilic bonding interaction Au–Au distance of 3.0722(2) Å, which is not present in crystalline Cy3PAuC2pym. Regarding optical properties, the use of an electron-deficient heterocycle provides an alternate approach to blue-shifting the emission of Pt(II) transition metals' compounds, where the aryl moiety is made more electron-deficient by exploiting nitrogen within this moiety instead of the typical strategy of decorating the aryl ring with electron withdrawing substituents (e.g., fluorines). This is indicated by the blue-shift in emission that occurs in tbpyPt(C2pym)2 (λmax, emission = 512 nm) compared to the previously reported tbpyPt(C22-py)2 (where HC22-py = 2-ethynylpyridine) complex (λmax, emission = 520 nm). [ABSTRACT FROM AUTHOR]

In the last past twenty years, research on luminescent platinum (II) complexes has been intensively developed for useful application such as organic light emitting diodes (OLEDs). More recently, new photoluminescent complexes based on diazine ligands (pyrimidine, pyrazine, pyridazine, quinazoline and quinoxaline) have been developed in this context. This review will summarize the photophysical properties of most of the phosphorescent diazine Pt(II) complexes described in the literature and compare the results to pyridine analogues whenever possible. Based on the emission color, and the photoluminescence quantum yield (PLQY) values, the relationship between structure modification, and photophysical properties are highlighted. Tuning of emission color, quantum yields in solution and solid state and, for some complexes, aggregation induced emission (AIE) or thermally activated delayed fluorescence (TADF) properties are described. When emitting OLEDs have been built from diazine Pt(II) complexes, the external quantum efficiency (EQE) values and luminance for different emission wavelengths and in some cases, chromaticity coordinates obtained from devices, are given. Finally, this review highlights the growing interest in studies of new luminescent diazine Pt(II) complexes for OLED applications. [ABSTRACT FROM AUTHOR]

The luminescent properties of Au(I) and Pt(II) compounds are commonly tuned by exploiting the alkynyl ligand with varying electron density. Herein, we describe the synthesis of three new emissive transition metal compounds, tbpyPt(C2pym)2, Ph3PAuC2pym, and Cy3PAuC2pym (where HC2pym = 2-ethynylpyrimidine), verified by 1H-NMR, EA, and a single-crystal X-ray diffraction analysis. The tbpyPt(C2pym)2 complex crystallized as an Et2O solvate in the orthorhombic space group Pbca with Z = 24 with three unique Pt(II) species within the unit cell. The Cy3PAuC2pym species crystallizes in a monoclinic space group with one unique complex in the asymmetric unit. Changing the identity of the phosphine from Cy3P to Ph3P influences interactions within the unit cell. Ph3PAuC2pym, which also crystalizes in a monoclinic space group, has an aurophilic bonding interaction Au–Au distance of 3.0722(2) Å, which is not present in crystalline Cy3PAuC2pym. Regarding optical properties, the use of an electron-deficient heterocycle provides an alternate approach to blue-shifting the emission of Pt(II) transition metals’ compounds, where the aryl moiety is made more electron-deficient by exploiting nitrogen within this moiety instead of the typical strategy of decorating the aryl ring with electron withdrawing substituents (e.g., fluorines). This is indicated by the blue-shift in emission that occurs in tbpyPt(C2pym)2 (λmax, emission = 512 nm) compared to the previously reported tbpyPt(C22-py)2 (where HC22-py = 2-ethynylpyridine) complex (λmax, emission = 520 nm).

A series of four Werner-type complexes of Pd(II) and Pt(II) with planar, isomeric conjugated aromatic naphtoquinone oximes were synthesized for the first time. These ligands were 1-oxime-2-naphtoquinone (HL1) and 2-oxime-1-napthoquinone (HL2). Compounds were characterized using thermal analysis, spectroscopic methods, and X-ray analysis. TG/DSC data were collected for pure starting organic ligands, their complexes, and indicated vigorous exothermic decomposition with at ~155 °C for starting HL and ~350 °C for transition metal complexes. Crystal structures for two Pt compounds with 2-oxime-1-quinone were determined and revealed the formation of the cis-geometry complexes and incorporation of molecules of stoichiometric solvents in the lattice: acetonitrile and nitrobenzene. Both solvents of crystallization displayed attractive interactions between their C-H groups and the oxygen atoms of the nitroso groups in complexes, leading to short distances in those fragments. Despite the presence of solvents of inclusion, the overall structure motifs in both compounds represent 1D columnar coordination polymer, in which the PtL2 units are held together via metallophilic interactions, thereby forming 'Pt-wires'. The Hirshfield surface analysis was performed for both crystallographically characterized complexes. The results showed intermolecular π–π stacking and Pt–Pt interactions among the planar units of both complexes. In addition, the analysis also verified the presence of hydrogen bonding interactions between the platinum unit and solvent molecules. Solid bulk powdery samples of both PtL12 and PtL22 demonstrated pronounced photoluminescence in the near infrared region of spectrum at ~980 nm, being excited in the range of 750–800 nm. The NIR emission was observed only for Pt-complexes and not for pure starting organic ligands or Pd-complexes. Additionally, synthesized Pt-naphtoquinone oximes do not show luminescence in solutions, which suggests the importance of a 1D 'metal wire' structure for this process. [ABSTRACT FROM AUTHOR]

In this study, a novel derivative of functionalised Calix[4]arene chem-sensor (4-amino thiazole 2-thiol-Calix[4]arene (R-Sensor)) was investigated, using the FT-IR spectroscopic method. Fluorescent properties and the ability to detect the sensor toward different cation ions in acetonitrile aqueous solution were investigated using the UV–Vis method, fluorescence titration, and Job's plot method. The results showed that among the studied cations, the presence of Pt(II) has a greater effect on the intensity and wavelength of the emission. In addition, the optimised structure and electronic properties of this R-sensor was studied, using the density functional theory (DFT), B3LYP and M062X methods, at the LANL2DZ (6-311 + G/CPCM and 6-311++G/CPCM) basis set, and quantum theory of atoms in molecules (QTAIM). The results of these theoretical-computational studies showed that the selectivity of this sensor is related to its molecular structure, electronic properties, and surface electrostatic properties. Theoretical studies have shown that electronic properties such as energy gap, sensitivity, and charge/energy transfer change dramatically in the presence of Pt(II) cations. In addition, the molecular competitive tests showed that this R-sensor could be a good candidate for monitoring/measuring Pt(II) in physiological samples/ environments. [ABSTRACT FROM AUTHOR]

Despite significant strides achieved in organic light emitting diode (OLED) based display technologies during the last decade, the search for highly stable and efficient true blue/deep blue emitters continues to remain elusive. During the past decade, emitters with the basic molecular scaffold consisting of Pt(II) acetylides and N‐heterocyclic carbene (NHC) ligands have opened interesting opportunities to tune the emission properties with desired chromaticity in the blue and deep blue region. With an aim to achieve the desired CIE coordinates along with low device roll‐off efficiencies and satisfactory color purity, a number of variations on the basic molecular fragment have been made. A number of NHC Pt(II) alkyne complexes bearing monodentate, bidentate and tridentate ligands have been synthesized and their photophysical investigations have been reported. Although NHC Pt(II) alkyne complexes have been explored in other areas of applications, much of the investigations have been primarily focused for their interesting emission properties appearing particularly in the shorter wavelength (450–495 nm) part of the electromagnetic spectrum for organic light emitting diode (OLED) devices. In this review, we provide an overview of the investigated NHC Pt(II) acetylide complexes by detailing their synthesis, luminescence properties, performance in devices and future perspectives. [ABSTRACT FROM AUTHOR]

Introduction. Infectious diseases remain a serious threat to humanity worldwide as bacterial pathogens grow more diverse. Bacteria, fungi, and parasites develop resistance to clinically approved antimicrobials, which reduces the efficacy of available drugs and treatment measures. As a result, there is an ever growing demand for new highly effective pharmaceuticals. This review describes mono- and polynuclear platinum and palladium complexes with antimicrobial properties. We compared several groups of antibacterial agents: antibiotics, antioxidant biologically active substances, antimicrobial nanoparticles, nanocomposite materials, biopolymers, micellar systems, and plant extracts. Study objects and methods. The review covered relevant articles published in Web of Science, Scopus, and Russian Science Citation Index for the last decade. The list of descriptors included such terms as mononuclear and binuclear complexes of platinum, palladium, and antimicrobial activity. Results and discussion. Chelates of platinum, palladium, silver, iridium, rhodium, ruthenium, cobalt, and nickel are popular therapeutic agents. Their antimicrobial activity against pathogenic microorganisms can be enhanced by increasing their bioavailability. Metalbased drugs facilitate the transport of organic ligands towards the bacterial cell. The nature of the ligand and its coordination change the thermodynamic stability, kinetic lability, and lipophilic properties of the complex, as well as the reactivity of the central atom. Polynuclear platinum and palladium complexes contain two or more bound metal (coordinate) centers. Covalent bonding with bacterial DNA enables them to form a type of DNA adducts, which is completely different from that of mononuclear complexes. Conclusion. Metal-based drugs with functional monodentate ligands exhibit a greater antimicrobial effect compared to free ligands. Poly- and heteronuclear complexes can increase the number of active centers that block the action of bacterial cells. When combined with other antibacterial agents, they provide a synergistic effect, which makes them a promising subject of further research.

We describe the synthesis, characterization, molecular modeling, and in vitro anticancer activity of three benzothiazole aniline (BTA) ligands and their corresponding platinum (II) complexes. We designed the compounds based on the selective antitumor properties of BTA, along with three types of metallic centers, aiming to take advantage of the distinctive and synergistic activity of the complexes to develop anticancer agents. The compounds were characterized using nuclear magnetic resonance spectrometry, Fourier transform infrared spectroscopy, mass spectrometry, elemental analysis, and tested for antiproliferative activity against multiple normal and cancerous cell lines. L1, L2, and L1Pt had better cytotoxicity in the liver, breast, lung, prostate, kidney, and brain cells than clinically used cisplatin. Especially, L1 and L1Pt demonstrated selective inhibitory activities against liver cancer cells. Therefore, these compounds can be a promising alternative to the present chemotherapy drugs.

New β -diketonate platinum (II) complexes, containing a cyclometalated N-heterocyclic carbene [Pt(Naph^C* iPr)(acac)] (3A) (HNaph^C*- κ C* = 3-isopropyl-1-(naphthalen-2-yl)-1 H- imidazole-2-ylidene), or a cyclometalated pyrazole, [Pt(Naph^N pz)(acac)] (3B) (HC^N pz = 1-(naphthalen-2-yl)- 1H -pyrazole) and [Pt(Naph^N dmpz)(acac)] (3B') (HC^N dmpz = 1-(naphthalen-2-yl)- 1H -3,5-dimethylpyrazole) have been prepared and characterized. Their absorption and emission properties in films of ethyl cellulose (EC) were determined along with those of the already reported for complex [Pt(Naph^C* Me)(acac)] (3A'). They showed that all four β -diketonate complexes display a bright phosphorescent emission with maxima in the blue region (λ max ∼ 480 nm for 3A and 3A '; 490 nm 3B and 3B'). The higher quantum yield (QY), longer decay times and greater oxygen sensitivity were exhibited by the Naph^C* derivatives, compared to the Naph^N ones. Polyacrylamide membranes with entrapped 3A' as dye, and glucose oxidase (GOx) enzyme were used for monitoring glucose level. The RSD is about 5% and the detection limit is at ∼5·10−4 M, with a response time usually of 10–15 min working in stop-flow mode. These platinum-based membranes respond reversibly to glucose for, at least, 20 measures. 3A' is the first Pt(II) complex bearing a cyclometalated N-heterocyclic carbene ever used as dye for sensing glucose. A Cyclometalated N-Heterocyclic carbene derivative [Pt(Naph^C* Me)(acac)] was selected among other counterparts and used as dye in polyacrylamide membranes with entrapped glucose oxidase (GOx) enzyme for monitoring glucose level. The detection limit (∼5·10−4 M) is similar to that found for a PtOEPK-based biosensor. [Display omitted] • Cyclometalated NHCs and acac: well suited ligands for luminescent platinum complexes. • Platinum complexes for dioxygen and glucose sensing. • Cyclometalated NHCs vs cyclometalated pyrazoles in platinum phosphors. [ABSTRACT FROM AUTHOR]

Abstract Three novel template bis-bidentate ligands based on {3,6-di(thien-2-yl)pyridazine} skeleton and four binuclear Pt(II) complexes containing these metalating templates were synthesized and characterized including photophysical study of two emissive compounds. These complexes display phosphorescence from triplet excited state localized primarily at the thienyl-pyridazine aromatic system, the emission bands being unusually strong shifted (ca. 100 nm/4380 cm−1) to the NIR region compared to analogous phenyl-pyridazine complexes. The absorption and emission characteristics of the complexes were analyzed by using DFT and TD DFT calculations. The results of calculations confirm that emission originates from a mixture of 3LC, 3MLCT, 3LLCT with major contribution of the former excited state and show reasonable agreement with the experimental data. Graphical abstract Unlabelled Image Highlights • A series of binuclear platinum complexes based on di-thienyl-pyridazine skeleton have been synthesized and characterized • Two of these complexes display emission in NIR area [ABSTRACT FROM AUTHOR]

Amphiphilic poly(amino acid) as a platinum(Ⅱ) drug delivery platform. [Display omitted] • Novel vinyl- or alkynyl-substituted cysteine N-carboxyanhydride (NCA) monomers were synthesized, and their corresponding amphiphilic block copolymers of mPEG-poly(amino acid) were prepared. • A versatile method for functionalizing poly(amino acid) through thiol-ene/thiol-yne click reactions to deliver platinum (II) drugs was successfully developed. • This system uses thiol-ene/yne click reaction, which has the advantages of mild reaction, fast reaction rate and high yield. • Compared with traditional small molecule chemotherapeutic drugs, the drug delivery system exhibits comparable therapeutic efficacy in vitro. Platinum (II) demonstrates potent anticancer activity, but it is hampered by drawbacks such as poor solubility, facile decomposition, bone marrow suppression, and nephrotoxicity, which severely restrict its clinical use. To overcome these limitations, polymer prodrugs were developed by conjugation of platinum drugs onto polymers. The protective shield provided by polymers enables drugs to evade enzymatic degradation and immune system attacks in the physiological environment, achieving sustained release and long-term efficacy. In this study, we synthesized novel vinyl- or alkynyl-substituted cysteine N -carboxyanhydride (NCA) monomers, followed by the preparation of amphiphilic poly(ethylene glycol)-poly(amino-acid) copolymers through the copolymerization of PEG with the NCAs. Next, 1,2-didentate dicarboxylic groups were introduced into the side chains of the block copolymer by employing the "Thiol-ene" or "Thiol-yne" reactions. These carboxylic acid groups were then chelated with (1R,2R)-1,2-diaminocyclohexane platinum (II)(DACH-Pt) and simultaneously assembled into nanoparticles. The morphology and particle size were characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS). Remarkably, the chelation of platinum (II) led to a decrease in micellar size. In vitro drug release experiments demonstrated a significantly faster release rate in the intracellular environment (pH 5.0) compared to physiological conditions (pH 7.4). MTT assays confirmed the excellent biocompatibility of the polymer. Moreover, concentration-dependent inhibition of cancer cell growth was observed with poly(amino acid)-platinum (II) chelate micelles. Overall, these findings suggest that self-assembled nanoparticles of poly(amino acid)-platinum (II) chelates hold immense potential for drug delivery applications. [ABSTRACT FROM AUTHOR]

The divalent complex [{Pt(bzq)(μ-L)}2] (1) [Hbzq = benzo[h]quinolone, HL = CF3C4H2N2SH: 4-(trifluoromethyl)pyrimidine-2-thiol] was obtained from equimolar amounts of [Pt(bzq)(NCMe)2]ClO4 and 4-(trifluoromethyl)pyrimidine-2-thiol with an excess of NEt3. The presence of a low intensity absorption band at 486 nm (CH2Cl2), assignable to a metal-metal-to-ligand charge transfer transition (1MMLCT) [dσ*(Pt)2→π*(bzq)], is indicative of the existence of two platinum centers located in close proximity because the rigidity of the half-lantern structure allows the preservation of these interactions in solution. Compound 1 undergoes two-electron oxidation upon treatment with halogens X2 (X2: Cl2, Br2 or I2) to give the corresponding dihalodiplatinum (III) complexes [{Pt(bzq)(μ-L)X}2] (L = CF3C4H2N2S-κN,S; X: Cl 2, Br 3, I 4). Complexes 2–4 were also obtained by reaction of 1 with HX (molar ratio 1:2, 10% excess of HX) in THF with yields of about 80% and compound 2 was also obtained by reaction of [{Pt(bzq)(μ-Cl)}2] with HL (4-(trifluoromethyl)pyrimidine-2-thiol) in molar ratio 1:2 in THF, although in small yield. The X-ray structures of 2 and 3 confirmed the half-lantern structure and the anti configuration of the molecules. Both of them show Pt–Pt distances (2.61188(15) Å 2, 2.61767(16) Å 3) in the low range of those observed in Pt2(III,III)X2 half-lantern complexes.

Four new neutral N,N imidoyl-indazole ligands ( L1 , L3, L6, L7 ) and six new Pt(II)-based complexes ( C1 – 5 and C7 ) were synthesized and characterized by spectroscopic and spectrometric techniques. Additionally, compounds L6 , L7 , C3 , C5 and C7 were analyzed using X-ray diffraction. An evaluation of cytotoxicity and cell death in vitro for both ligands and complexes was performed by colorimetric assay and flow cytometry, in four cancer cell lines and VERO cells as the control, respectively. Cytotoxicity and selectivity demonstrated by each compound were dependent on the cancer cell line assayed. IC 50 values of complexes C1 – 5 and C7 were lower than those exhibited for the reference drug cisplatin, and selectivity of these complexes was in general terms greater than cisplatin on three cancer cell lines studied. In HL60 cells, complexes C1 and C5 exhibited the lowest values of IC 50 and were almost five times more selective than cisplatin. Flow cytometry results suggest that each complex predominantly induced necrosis, and its variant necroptosis, instead of apoptosis in all cancer cell lines studied. DNA binding assays, using agarose gel electrophoresis and UV–visible spectrophotometry studies, displayed a strong interaction only between C4 and DNA. In fact, theoretical calculations showed that C4 -DNA binding complex was the most thermodynamic favorable interaction among the complexes in study. Overall, induction of cell death by dependent and independent-DNA-metal compound interactions were possible using imidoyl-indazole Pt(II) complexes as anticancer agents. [ABSTRACT FROM AUTHOR]

Cisplatin and its platinum (Pt) (II) derivatives play a key role in the fight against various human cancers such as testicular, ovarian, head and neck, lung tumors. However, their application in clinic is limited due to dose- dependent toxicities and acquired drug resistances, which have prompted extensive research effort toward the development of more effective Pt (II) delivery strategies. The synthesis of Pt (IV) complex is one such an area of intense research fields, which involves their in vivo conversion into active Pt (II) molecules under the reducing intracellular environment, and has demonstrated encouraging preclinical and clinical outcomes. Compared with Pt (II) complexes, Pt (IV) complexes not only exhibit an increased stability and reduced side effects, but also facilitate the intravenous-to-oral switch in cancer chemotherapy. The overview briefly analyzes statuses of Pt (II) complex that are in clinical use, and then focuses on the development of Pt (IV) complexes. Finally, recent advances in Pt (IV) complexes in combination with nanocarriers are highlighted, addressing the shortcomings of Pt (IV) complexes, such as their instability in blood and irreversibly binding to plasma proteins and nonspecific distribution, and taking advantage of passive and active targeting effect to improve Pt (II) anticancer therapy. [ABSTRACT FROM AUTHOR]

Highlights: [•] X-ray structures deviate from square planar into two types of structures, X and bowed (B) forms. [•] X and B forms exhibit circular dichroism in the solid state. [•] Circular dichroism spectra can be correlated with optimized structures determined by DFT calculations. [•] Heteronuclear interactions are observed by NMR between 195Pt and ring protons of phenanthroline and biphenyl ligand. [•] A Hammett sigma correlation exists with the most downfield proton resonance. [Copyright &y& Elsevier]

Abstract: A novel Pt(II) complex [(L)PtCl] (HL=4-{p-[N-(4-(9-carbazole))butyl-N-phenyl] aniline}-6-phenyl-2,2′-bipyridine) has been synthesized and verified by 1H NMR, elemental analysis and X-ray crystallography. The crystal (C44H35N4ClPt, M r =850.30) belongs to monoclinic system, space group P2(1)/c, with a =21.864(6), b =9.306(3), c =17.240(5) Å, β =96.483(6)°, Z =4, V =3485.3(16) Å3, D C =1.620g/cm3, μ(Mo-Kα)=4.141mm−1, F(000)=1688, R 1 =0.0591, wR 2 =0.0976. The coordinate geometry of the Pt atom is a distorted square planar configuration. The complex molecules are stacked by a weak π–π interaction in a head-to-tail fashion along the b axis to form 1D chain and the alternating 1D chains are packed to form the 2D lamellar system. The complex shows an intense metal-to-ligand charge transfer (1MLCT) (dπ(Pt)→ π*(L)) transitions (ε ∼2×104 dm3 mol−1 cm−1) at 448nm in the UV–Vis absorption spectrum and a strong phosphorescence at 592nm in CH2Cl2 solution at room temperature. An intramolecular energy transfer process from the carbazole unit to the arylamine-modified [(C^N^N)PtCl] emissive center exists in the complex. [Copyright &y& Elsevier]

The new ligands 1-arylazo-2-ethyl sulfanyl benzene, LH (1) [LH is 2-(RC6H4–N𝄗N)C6H4SEt; R = p-H (for L1H), p-Me (for L2H) and p-Cl (for L3H), H of LH represents the dissociable proton upon orthometallation] and their orthoplatinated complexes of the type PtII(L)Cl have been synthesized by the reaction of LH with K2PtCl4 where [L]− ligands bind the metal in a tridentate (C, N, S) fashion. On the other hand, new platinum (IV) cyclometallates, PtIV(L)I3, were obtained directly on treating K2PtI4 with LH. The complexes and ligands were characterized from spectroscopic data. The X-ray structure of Pt(L)I3 authenticated its formation. [Copyright &y& Elsevier]

Abstract: The reactions of diorganotin oxides with o-diphenylphosphinobenzoic acid ([PPh2(o-C6H4COOH)], LH) in 1:1 stoichiometry afforded tetraorganodistannoxanes [{R2Sn(OOC-C6H4PPh2)}2O]2 (R=Me, Et, Pr n , Bu n ). o-(Diphenylphosphino)benzoic acid complexes of palladium (II) and platinum (II) with the formulae [MCl2(LH)2], [MCl2(PR3)(LH)] (PR3 =PEt3, PBu3, PMePh2; M=Pd, Pt) have been prepared. Reactions of [{Bu2Sn(OOC-C6H4PPh2)}2O]2 with PtCl2(PhCN)2 in 1:1 and 1:2 ratio gave a complex mixture of products from which [Pt(O2CC6H4PPh2)2] was isolated. All the complexes have been characterized by elemental analyses, IR, NMR (1H, 13C{1H}, 31P{1H} and 119Sn{1H}) and UV–Vis spectroscopy. The stereochemistry of these complexes has been deduced from spectroscopic data. The structures of [{Bu2Sn(OOC-C6H4PPh2)}2O]2 and [Pt(O2CC6H4PPh2)2] have been established by X-ray crystallography. [Copyright &y& Elsevier]

Abstract: We report the electrochemical characterization of a family of five platinum phenylethynyl complexes by cyclic voltammetry, bulk electrolysis, and spectroelectrochemistry. All have irreversible oxidations near +1.2 V vs. Ag∣AgCl. None has any reductive electrochemistry within the potential window of 50/50 benzene+acetonitrile. trans-Bis(tri-n-butylphosphine)bis(phenylethynyl)platinum(II) undergoes reduction in THF at −2.786 V vs. Ag∣AgCl. The number of electrons passed during the oxidation ranges from 1.15 to 2.29. Photophysical measurements show that as the phenylethynyl chain length increases, the absorbance wavelength increases and the emission wavelength shows a weak but similar trend. Spectroelectrochemistry illustrates the loss of the absorbance band over successive oxidative sweeps. Results indicate that the oxidation takes place at the Pt(II) center and is followed by chemical reactions that generate a new species. [Copyright &y& Elsevier]

Abstract: The non-covalent interaction of the complexes [Pt(bpy)(R,R′NCSNR″,R‴)2]Cl2 (bpy=2,2′-bipyridine; R=R′=R″=R‴=H; R=Me, R′=R″=R‴=H; R=n-Bu, R′=R″=R‴=H; R=p-tolyl, R′=R″=R‴=H; R=Et, R′=H, R″=Et, R‴=H) with calf thymus DNA has been studied at pH 7 and 25 °C. The processes give rise to: (i) reversible bathochromic shifts and strong hypochromicity of the absorption bands of the complexes, (ii) induced circular dichroism and (iii) an increase both in the melting temperature and viscosity of the DNA comparable to that observed for other well known metallointercalators. The binding constants, KB, have been determined spectrophotometrically using the McGhee von Hippel equation. Plot of logKB vs −log[Na+] for the complex with unsubstituted thiourea gives a straight line with a slope value close to that expected for a dicationic intercalator. The binding affinity of the various complexes for DNA is independent of the thiourea nature; this suggests that the intercalation occurs through stacking of the bpy moiety while the ancillary ligands lie outside the nucleobases far away from the sugar phosphate backbone. The data show also that the electronic effects of the ligand substituents are not transmitted to the intercalating unit. [Copyright &y& Elsevier]

We describe the synthesis, characterization, molecular modeling, and in vitro anticancer activity of three benzothiazole aniline (BTA) ligands and their corresponding platinum (II) complexes. We designed the compounds based on the selective antitumor properties of BTA, along with three types of metallic centers, aiming to take advantage of the distinctive and synergistic activity of the complexes to develop anticancer agents. The compounds were characterized using nuclear magnetic resonance spectrometry, Fourier transform infrared spectroscopy, mass spectrometry, elemental analysis, and tested for antiproliferative activity against multiple normal and cancerous cell lines. L1, L2, and L1Pt had better cytotoxicity in the liver, breast, lung, prostate, kidney, and brain cells than clinically used cisplatin. Especially, L1 and L1Pt demonstrated selective inhibitory activities against liver cancer cells. Therefore, these compounds can be a promising alternative to the present chemotherapy drugs. [ABSTRACT FROM AUTHOR]