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Designing multifunctional materials that mimic the light‐dark decoupling of natural photosynthesis is a key challenge in the field of energy conversion. Herein, we introduce MnBr‐253, a precious metal‐free metal–organic framework (MOF) built on Al nodes, bipyridine linkers and MnBr(CO)3(bipyridine) complexes. Upon irradiation, MnBr‐253 colloids demonstrate an electron photocharging capacity of ~42 C ⋅ g−1MOF, with state‐of‐the‐art photocharging rate (1.28 C ⋅ s−1 ⋅ g−1MOF) and incident photon‐to‐electron conversion efficiency of ~9.4 % at 450 nm. Spectroscopic and computational studies support effective electron accumulation at the Mn complex while high porosity and Mn loading account for the notable electron storage performance. The charged MnBr‐253 powders were successfully applied for hydrogen evolution under dark conditions thus emulating the light‐decoupled reactivity of photosynthesis. [ABSTRACT FROM AUTHOR]

ABSTRACT An air‐tolerant, simple yet highly efficient copper‐catalyzed methoxylation of (hetero)aryl bromides and some activated chlorides has been developed by using copper(II) chloride/2,2‐bipyridine as catalyst precursor. A wide range of (hetero)aryl bromides and electron‐deficient chlorides could be efficiently methoxylated in good to excellent yields at 1‐mol% catalyst loading albeit showing a functional group compatibility dependent on the electronic properties of aryl ring. Applications of the practical protocol have been demonstrated in multigram synthesis of 3,4,5‐trimethoxytoluene. [ABSTRACT FROM AUTHOR]

In this work, we report on five novel coordination polymers (CPs) based on the linkage of the [Cd(6apic)2] building block [where 6apic = 6-aminopicolinate] by different bipyridine-type organic spacers, forming different coordination compounds with the following formulae: [Cd(μ-6apic)2]n (1), {[Cd(6apic)2(μ-bipy)]·H2O}n (2), {[Cd(6apic)2(μ-bpe)]·2H2O}n (3), [Cd(6apic)(μ-6apic)(μ-bpa)0.5]n (4) and {[Cd2(6apic)4(μ-tmbp)]·7H2O}n (5) [where bipy = 4,4′-bipyridine, bpe = 1,2-di(4-pyridyl)ethylene, bpa = 1,2-di(4-pyridyl)ethane (bpa) and tmbp = 1,3-di(4-pyridyl)propane]. Most of the synthesized compounds form infinite metal–organic rods through the linkage of the building block by the bipyridine-type linker, except in the case of compound 4 whose assembly forms a densely packed 3D architecture. All compounds were fully characterized and their photoluminescence properties were studied experimentally and computationally through density functional theory (DFT) calculations. All compounds display, upon UV excitation, a similar blue emission of variable intensity depending on the linker employed for the connection of the building units, among which compound 2 deserves to be highlighted for its room temperature phosphorescence (RTP) with an emission lifetime of 32 ms that extends to 79 ms at low temperature. These good photoluminescence properties, in addition to its stability in water over a wide pH range (between 2 and 10), motivated us to study compound 2 as a sensor for the detection of metal ions in water, and it showed high sensitivity to Fe3+ through a fluorescence turn-off mechanism and an unspecific turn-on response to Zn2+. Furthermore, the compound is processed as a paper-based analytical device (PAD) in which the phosphorescence emission is preserved, improving the sensing capacity toward Fe3+ ions. [ABSTRACT FROM AUTHOR]

Conjugated homopolymers based on six-member rings, e.g., polyfluorene, always exhibit blue emission and conjugated homopolymers based on five-member rings, e.g., polythiophene, can give red emission with low efficiency. In this work, we report a series of new conjugated homopolymers based on six-member rings with high-efficiency deep-red emission. The repeating units of the red light emitting homopolymers are double B←N bridged bipyridine (BNBP) with the boron atoms functionalized with diphenyl, borafluorene, and 2,7-di-tert-butyl-borafluorene groups, respectively. The relationship between the chemical structures and the opto-electronic properties of the monomers and the homopolymers has been systematically studied. The three polymers emit pure red light (λmax=656 nm) or deep red light (λmax=693 nm) with fluorescence quantum efficiency in solution higher than 60%. The polymers can be used as the emitters in solution-processed organic light-emitting diodes with red emission and decent device performance. This work indicates a new strategy to design highly efficient light emitting conjugated polymers. [ABSTRACT FROM AUTHOR]

Noncovalent cofacial porphyrin dimers have attracted interest due to their potential use as host materials or catalysts. In this study, we introduce a novel coordination‐directed cofacial porphyrin dimer from a meso‐tetraphenylporphyrin derivative modified with 2,2′‐bipyridine moieties at the meta positions of the phenyl groups. Spectroscopic investigation has shed light on the binding processes and the structure of the dimer in solution in detail. Initial Zn2+ ion binding to the porphyrin hinders the subsequent Zn2+ binding and the binding of the second porphyrin. However, once the dimer is formed, additional Zn2+ binding is notably enhanced, resulting in a pronounced S‐shaped binding curve. The detailed structure of the dimer in solution was established based on UV‐vis spectroscopy, various 1H NMR spectroscopy techniques and mass spectrometry. Simulations of ring‐current‐induced chemical shift changes provided evidence for the face‐to‐face porphyrin structure with tetrahedral coordination of the bipyridine ligands. The X‐ray single crystal structure provided conclusive evidence for the structure of the face‐to‐face dimer, which remarkably resembles the model structure from the 1H NMR simulation. The stability of the dimer structure makes it promising for further exploration of this motif in developing new supramolecular structures and for their potential applications as host compounds and catalysts. [ABSTRACT FROM AUTHOR]

A new Cd(II) derivative, [Cd(2-Hstp)(Hbipy)2] (1), was obtained hydrothermally by the combination of Cd(NO3)2·4H2O as metal salt, the flexible aromatic carboxylate, 2-sulfoterephthalic acid (2-stp), and the N-donor ancillary ligand, 4,4′-bipyridine (bipy), as organic linker. Single crystal X-ray diffraction analysis revealed the molecular structure of the complex, in which the Cd(II) atoms show a distorted octahedral geometry. In the asymmetric unit, both the carboxylate and the N-donor connector bridge pairs of cadmium ions; this ultimately leads to the formation of a set of undulated sheets formed by fused rings comprising six cadmium centers, two bipy, and four 2-stp ligands. Considering each complex as a node, the supramolecular structure can be seen as a 6-c uninodal net of the type pcu, with point symbol {412.63} and vertex symbol [4.4.4.4.4.4.4.4.4.4.4.4.*.*.*]. The Cd(II) derivative endowed the material with moderate luminescent properties. Finally, the molecular geometry of 1 has been studied by DFT computation applying the B3LYP/def2-SVP level of theory. [ABSTRACT FROM AUTHOR]

Cobalt dicarboxylate bipyridine complexes bearing low redox potential and low permeability were designed and synthesized for high-voltage and cycling-stable neutral AORFBs. [Display omitted] [ABSTRACT FROM AUTHOR]

A new bipyridine bridged dicobaloxime complex BrCo(dpgh)2(4,4'‐bipyridine)Co(dpgH)2Br was synthesized and characterized by standard spectroscopic techniques. The synthesized complex was employed as an electrocatalyst for the proton reduction in the presence of acetic acid as an acid source. The catalytic efficiency was calculated to be 0.379. Subsequently the nanocomposite of the complex was prepared with g‐C3N4 nanosheet by hydrothermal method and the composite material was characterized by standard physical characterization techniques. When the nanocomposite was employed as a catalyst for electrochemical sensing of toxic food color Metanil yellow dye using gold electrode, the LOD value was found to be 0.09 nM. These studies show that the dicobaloxime acts as a bifunctional catalyst towards electrochemical proton reduction and for the detection of Metanil yellow dye. [ABSTRACT FROM AUTHOR]

A series of twelve second coordination sphere (SCS) functionalized manganese tricarbonyl bipyridyl complexes are investigated for their electrocatalytic CO2 reduction properties in acetonitrile. A qualitative and quantitative assessment of the SCS functional groups is discussed with respect to the catalysts' thermodynamic and kinetic efficiencies, and their product selectivities. In probing a broad scope of functional groups, it is clear that only the aprotic ortho‐arylester SCS is capable of promoting the highly desired low‐overpotential proton‐transfer electron‐transfer (PT‐ET) pathway for selective CO production. The ortho‐phenolic analogues cause an increase in overpotential with a product selectivity favoring H2 evolution, consistent with a high‐overpotential pathway via the anionic [Mn−H]− intermediate. Alternative aprotic Lewis base functional groups such as trifluoromethyl, morpholine and acetamide are shown to also be capable of intermediate manganese hydride generation. The tertiary amine substituent, 2‐morpholinophenyl, exhibits a desirable product distribution characteristic of syn‐gas (CO : H2=30 : 48) with an impressive turnover frequency, while the secondary amine group, 2‐acetamidophenyl, induces a notable shift in selectivity with a faradaic yield of 55 % for the formate (HCO2−) product. In addition to their catalytic properties, cyclic voltammetry and infrared spectroelectrochemistry (IR‐SEC) studies are presented to probe pre‐catalyst electronic properties and the two‐electron reduction activation pathway. [ABSTRACT FROM AUTHOR]

Bipyridine‐based covalent organic frameworks (COFs) have emerged as promising contenders for the photocatalytic generation of hydrogen peroxide (H2O2). However, the presence of imine nitrogen alters the mode of H2O2 generation from an efficient one‐step two‐electron (2e−) route to a two‐step 2e− oxygen reduction pathway. In this work, we introduce 3,3′‐bipyridine units into imine‐based COF skeletons, creating a pyridyl‐imine structure with two adjacent nitrogen atoms between the pyridine ring and imine linkage. This unique bipyridine‐like architecture can effectively suppress the two‐step 2e− ORR process at the single imine‐nitrogen site, facilitating a more efficient one‐step 2e− pathway. Consequently, the optimized pyridyl‐imine COF (PyIm‐COF) exhibits a remarkable H2O2 production rate of up to 5850 μmol h−1 g−1, nearly double that of pristine bipyridine COFs. This work provides valuable insight into the rational design of functionalized COFs for enhanced H2O2 production in photocatalysis. [ABSTRACT FROM AUTHOR]

In this report, a Cu(II) complex Cu‐L4 containing a new tetradentate benzotriazole‐appended bipyridine ligand was synthesized and characterized fully via spectroscopic and crystallographic techniques. The crystal structure of the complex revealed that the ligand is bound to copper in a tetradentate fashion in a plane and the axial positions are occupied by an anion and a solvent molecule, resulting in a distorted octahedral geometry of the complex in solid‐state. This air‐stable complex was utilized as homogeneous precatalyst for the synthesis of several propargylamine derivatives by 3‐component A3 coupling reactions of aldehydes, amines, and alkynes under aerial atmosphere. [ABSTRACT FROM AUTHOR]

Four 1-D chain coordination polymers containing bent 1,1′-binaphthyl ligands were synthesised with NiII, CuII and AgI. The use of (R)-4,4′-(2,2′-diethoxy-[1,1′-binaphthalene]-6,6′)dipyridine as a ligand yielded isostructural 1-D looping chains with NiII and CuII, whereas the use of AgI yielded both linear and helical 1-D chains. Changing the dipyridyl coordination groups to dicarboxylates in (S)-6,6′-dicarboxyl-2,2′-diethoxy-1,1′-binaphthalene yielded a 1-D looping chain with a CuII paddlewheel motif. The AgI 1-D chain features two crystallographically distinct 1-D chain morphologies with a triple helix and linear strips. The packing arrangement of the 1-D chains differs because of the intermolecular interactions present, with the steric bulk of the ethoxy substituent on the 1,1′-binaphthyl enabling the formation of large void spaces. Chiral supramolecular compounds containing 1,1′-binapthyl are increasingly explored for chiroptical techniques including fluorescence-based sensing. Careful design of these compounds can yield systems with accessible voids and complimentary intermolecular interactions that can be tailored as a function of the 1,1′-binapthyl's steric hinderance and hydrogen bonding ability. (Image credit: Carol Hua.) [ABSTRACT FROM AUTHOR]

A molecularly imprinted electrochemiluminescent sensor is developed for the sensitive detection of tetracycline in environmental and food samples. The sensor uses an ionic liquid (i.e. [APMIM]Br) modified graphene-carbon nanotube composite (GMI) material as substrate, a double-layered core-shell metal-organic framework NH2-UiO-66@ZIF-8 (NUZ) loaded bipyridyl ruthenium (NUZ@Ru) as luminescent material, and a molecularly imprinted copolymer of o-phenylenediamine and hydroquinone as recognition element. The ionic liquid-modified graphene-carbon nanotube composite has a favorable three-dimensional structure, high specific surface area, and good hydrophilicity; the core-shell structured metal-organic framework has high stability and plentiful reaction sites for loading; the molecularly imprinted copolymer film has enhanced stability and recognition effect. Hence, the resulting sensor combines the merits of several materials and presents improved performance. Under the optimum detection conditions, it shows a wide linear range of 0.05 µM − 1 mM, a low detection limit of 20 nM, high selectivity, and excellent stability. It has been successfully applied to the detection of tetracycline in different samples. [ABSTRACT FROM AUTHOR]

The reactions of an aqueous solution of potassium dicyanoargentate with a mixture of nickel(II) or copper(II) chloride and ethylenediamine or 4,4'-bipyridyl in ethanol afford coordination polymers [Ni(Еn)2(Ag(CN)2)][Ag(CN)2] (I), [Cu(Еn)2(Ag(CN)2)][Ag(CN)2] (II), and [Cu(4,4'-Вipy)2(Ag(CN)2)2] (III) characterized by XRD (CIF files CCDC nos. 2225984 (I), 2214320 (II), and 2229270 (III)) and IR spectroscopy. According to the XRD data, the crystals of complexes I and II are formed by 1D chains {··NC–Ag–CN–M(Еn)2··}n (M = Ni (I), Cu (II)) linked with each other by the dicyanoargentate anions via argentophilic contacts (Ag···Ag 3.288(8) Å (I), 3.1616(14) Å (II)). The crystal of compound III consists of independent interpenetrating 3D networks built of polymer layers {Cu[Ag(CN)2]2}n bound to each other by the 4,4'-bipyridyl molecules. The bipyridyl linkers connect the Cu centers with the Ag centers of the [Ag(CN)2]– anions thus providing the tridentate coordination of the silver atoms. No Ag···Ag interactions are observed in the crystal of complex III. [ABSTRACT FROM AUTHOR]

The reaction of triphenylcyclopentadienyl potassium and bipyridine with lanthanum, praseodymium, erbium, lutetium, and scandium chloride tetrahydrofuranates results in the formation of binuclear [CpPh3Ln(Bipy)Cl(μ2-Cl)]2 (Ln = La (I), Pr (II)) and mononuclear [CpPh3Ln(Bipy)Cl2(THF)] (Ln = Er (III), Lu (IV), [CpPh3Sc(Bipy)Cl2] (V) complexes (CpPh3 = 1,2,4-triphenylcyclopentadienyl, Bipy = bipyridine). The decrease in the REE radius in the series La...Sc results in the formation of mononuclear instead of binuclear complexes and in a decrease in the coordination number of the central ion. The coplanar arrangement of two different π-systems gives rise to stacking interactions between the triphenylcyclopentadienyl ligand and bipyridine. The molecular structure of complexes I–V was established by X-ray diffraction analysis (CCDC nos. 2308609 (I), 2308608 (II), 2308610 (III), 2308611 (IV), 2308607 (V)). [ABSTRACT FROM AUTHOR]

Photolabile (µ-peroxo)(µ-hydroxo)bis[bis(bipyridyl)-cobalt-based caged oxygen compounds have been synthesized and characterized by optical absorbance spectroscopy, X-ray crystallography. and the quantum yield and redox stability were investigated. Furthermore, conditions were established where redox incompatibilities encountered between caged oxygen compounds and oxygen-dependant cytochrome c oxidase (CcO) could be circumvented. Herein, we demonstrate that millimolar concentrations of molecular oxygen can be released from a caged oxygen compound with spatio-temporal control upon laser excitation, triggering enzymatic turnover in cytochrome c oxidase. Spectroscopic evidence confirms the attainment of a homogeneous reaction initiation at concentrations and conditions relevant for further crystallography studies. This was demonstrated by the oxidizing microcrystals of reduced CcO by liberation of millimolar concentrations of molecular oxygen from a caged oxygen compound. We believe this will expand the scope of available techniques for the detailed investigation of oxygen-dependant enzymes with its native substrate and facilitate further time-resolved X-ray based studies such as wide/small angle X-ray scattering and serial femtosecond crystallography. [ABSTRACT FROM AUTHOR]

In this study, eleven Ru-based dyes have been theoretically designed by substitution of different anchors. Their light harvesting capability in dye-sensitized solar cells (DSSCs) and non-linear optical (NLO) properties were subsequently explored. The structural, optoelectronic and NLO properties of these Ru(II) complexes are analyzed using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods in both the gas phase and acetonitrile. The results illustrate that the changing of the anchoring groups on the bpy ligand of complex [Ru(bpy)2(NCS)2] could reduce the energy gap (Eg), redshift the maximum absorption wavelengths (λmax), increase the oscillator strength (ƒ) and light-harvesting efficiency (LHE), and enhance the driving force of injection (ΔGinj), thus amplifying the efficiency of the DSSC. According to the results, the presence of nitro (–NO2) anchors in the complex [Ru(bpy)2(NCS)2] (Ru-dye 8) led to a reduction in open circuit voltage (Voc = 0.45 eV), while significantly decreasing the energy gap (2.05 eV) and notably increasing the excitation wavelength (657 nm). Ru-dye 9 exhibited the largest static first hyperpolarizability (β0 = 273 × 10−30 e.s.u.) compared to the other Ru-dyes. This study provides valuable insights into the understanding of Ru-based dyes in DSSC devices and NLO materials. [ABSTRACT FROM AUTHOR]

Using the synthesized salt Gd(NCS)3·6H2O, previously unknown mononuclear molecular complexes [Gd(H2O)(bpy)2(NCS)3]·0.5(bpy)·H2O, [Gd(H2O)(phen)2(NCS)3]·phen·0.5H2O as well as ionic ones [Hbpy][Gd(NCS)4(bpy)2]·H2O, [Hphen][Gd(NCS)4(phen)2] (bpy is 2,2'-bipyridine, phen is 1,10-phenanthroline) were prepared. Structural characteristics of the obtained compounds were determined using X-ray diffraction data. The magnetic susceptibility and EPR data of the new Gd complexes are considered taking into account the features of their composition and structure. Due to the peculiarities of the electronic structure, Gd complexes can serve as test systems for analyzing the field strength of ligands and the geometry of the local environment of the 4f-metal ion. It is shown that EPR spectroscopy is highly efficient method for determining the spin Hamiltonian parameters and, consequently, for characterizing the local environment of the gadolinium ion in complexes. However, the EPR method does not allow one to determine the sign of the splitting parameter in the zero field D, which requires additional studies. [ABSTRACT FROM AUTHOR]

In this work, the geometrical, optical, and phosphorescence properties of four complexes with general formula [dRpypy—C(OCH3)R′—dRpypy]Pt, with Pt-1 (R = F, R′ = methyl), Pt-2 (R = F, R′ = hexyl), Pt-3 (R = methoxy, R′ = methyl) and Pt-4 (R = methoxy, R′ = hexyl), were studied using the B3PW91 and TD-B3PW91 methods. The effect of the double substitution R and R′ on the electronic properties of the four complexes has been investigated. Replacing the two fluorine atoms with the two methoxy groups modifies the shape of the UV–vis spectra and red shift the phosphorescence spectra, while the substituents on the linker R′ do not induce changes in both absorption and phosphorescence spectra. Normal modes involved in the vibronic structure were identified and analyzed using adiabatic Hessian approaches according to the Franck–Condon approximation. The computed phosphorescence wavelengths agree with the observed ones and indicate that the fluorinated complexes exhibit a bright light blue color, while the methoxy complexes display a light spring green color. Further, temperature effects on simulated phosphorescence spectra were studied. [ABSTRACT FROM AUTHOR]

A multicomponent covalent organic framework (COF-Tfp-BpyDaaq) integrating bipyridine with diaminoanthraquinone through a triformylphoroglucinol linkage was synthesized for the first time as a photocatalyst for overall H2O2 photosynthesis. It exhibits enhanced photo-charge separation and H2O2 production rate over its two-component counterparts, demonstrating the pivotal role of multicomponent synthesis in designing efficient photocatalysts. [ABSTRACT FROM AUTHOR]

Viologen is capable of generating radicals in response to an applied stimulus, giving it an abundance of stimuli responsive properties. However, the radical state of viologen is often unstable, which hinders further studies on the radical properties of viologen. In this paper, the salicylhydrazide group was chosen as a donor group to bond with mono-substituted bipyridyl groups to obtain three novel D–A type viologen compounds. The compounds were harvested and characterized by X-ray single crystal diffraction, optical spectroscopy, EPR and DFT calculation, etc. The results show that compounds 1–3 adopt certain free radical states at room temperature under ambient light, which may be attributed to the electron-donating properties of the salicylhydrazide group and the degree of system conjugation. In addition, compound 1 has a hydrochromic property and compounds 2 and 3 have photocurrent effects under UV radiation. [ABSTRACT FROM AUTHOR]

A systematic study of the effectiveness of various chromophores of the 5-aryl-2,2ʹ-bipyridine series was carried out in terms of sensitization of lanthanide(III) cations. For this purpose, the corresponding DTTA-appended 5-aryl-2,2′-bipyridines were synthesized in good yields by using the "1,2,4-triazine" methodology, and their europium(III) and terbium(III) complexes were prepared. The photophysical properties were studied for all the obtained chelates, and the influence of the nature of the aryl substituent of the bipyridine core was estimated. The positive influence of the halogen atoms as well as a methyl group on the efficiency of the lanthanide(III) cation sensibilization was demonstrated. The influence of the nature of the residue of the polyaminocarboxylic acid fragment in the ligand on the luminescent characteristics of its lanthanide complexes was also studied. [ABSTRACT FROM AUTHOR]

Convenient and highly sensitive detection of oxalate ions in body fluids is of crucial significance for disease prevention, diagnosis, and monitoring of treatment effectiveness. Establishing a simple solid-state electrochemiluminescence (ECL) sensing system for highly sensitive detection of oxalate ions is highly desirable. In this work, a solid ECL sensor was fabricated by immobilizing the commonly used emitter ruthenium(II)tris(bipyridine) (Ru(bpy)32+) on a double-layered bipolar silica nanochannel array film (bp-SNA)-modified electrode, enabling sensitive detection of oxalate ions in serum or urine samples. Cost-effective and readily available indium tin oxide (ITO) was used as the supporting electrode. Convenient fabrication of multiple negatively charged SNA (n-SNA)-modified ITO electrodes was achieved through the one-step Stöber solution growth method. Subsequently, a positive outer layer film (p-SNA) was rapidly prepared using an electrochemical-assisted self-assembly method. The double-layered bipolar silica nanochannel array film achieved stable immobilization of Ru(bpy)32+ on the electrode surface, facilitated by the electrostatic adsorption of Ru(bpy)32+ by n-SNA and the electrostatic repulsion by p-SNA. Utilizing oxalate ions as a co-reactant for Ru(bpy)32+, combined with the electrostatic enrichment of oxalate ions by p-SNA, the constructed sensor enabled highly sensitive detection of oxalate ions ranging from 1 nM to 25 μM and from 25 μM to 1 mM, with a detection limit (LOD) of 0.8 nM. The fabricated ECL sensor exhibited high selectivity and good stability, making it suitable for ECL detection of oxalate ions in serum and urine samples. [ABSTRACT FROM AUTHOR]

Bipyridyl Ruthenium-decorated Ni-MOFs on multi-walled carbon nanotubes (MWCNT-RuBpy@Ni-MOF) were synthesized. In an alkaline solution, the glucose was electrocatalytically oxidized at +0.5 V vs. Ag/AgCl at the composite interface of MWCNT-RuBpy@Ni-MOF on a glassy carbon electrode. The Ni3+/Ni2+ redox couples in Ni-MOFs played a key role as the active center for the catalytic oxidation of glucose at the electrode, where both RuBpy and MWCNTs enhanced the current responses to glucose. The resulting enzymeless glucose sensor from MWCNT-RuBpy@Ni-MOF exhibited a wide range of linear responses, high sensitivity and selectivity for the determination of glucose. [ABSTRACT FROM AUTHOR]

A zinc(II)‐templated catalyst assembling terpyridine and bipyridine organocatalytic ligands has been developed for the asymmetric aldol reaction. The system has been optimized to maximize the formation of the heteromeric bifunctional species through the determination of the equilibrium constants leading to the formation of all the species present. A practical, easy to synthesize catalytic system providing high stereoselectivity has been achieved in this way. [ABSTRACT FROM AUTHOR]

We previously reported a cyclic Zn(II) porphyrin trimer in which three Zn porphyrins are alternately bridged by three 2,2′‐bipyridine (bpy) moieties, enabling the encapsulation of metal complexes within the nanopore formed by the Zn porphyrins. In this study, we introduced a [Re(CO)3Br] fragment into one of the bpy moieties of the cyclic trimer to form the catalytic Re(4,4'‐R2‐bpy)(CO)3Br center (R=methyl ester). The ester groups (R) play an important role in the synthesis of the cyclic structure. However, it was observed that these ester groups significantly deactivated the photocatalytic CO2 reduction reaction. Therefore, we converted the ester groups with a suitable reducing reagent into hydroxymethyl groups, followed by acetylation to form acetoxymethyl groups. This modification remarkably enhanced the photocatalytic activity of the cyclic trimer=Re complex system for CO2 reduction. Moreover, in the modified system, the presence of the Re complex induced room‐temperature phosphorescence of the Zn porphyrin. The phosphorescence was significantly quenched by 1,3‐dimethyl‐2‐phenyl‐2,3‐dihydro‐1H‐benzo[d]imidazole, indicating that efficient electron transfer mediated by the excited triplet state of the Zn porphyrin occurs during the photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

The increasing concentration of CO2 in the atmosphere and its impact on the climate are matters of significant concern. Extensive research is being conducted on molecular catalysts to electrochemically reduce CO2 into valuable products to disrupt the unidirectional carbon flow. This study compares two manganese bipyridine catalysts, tailored with four or two benzylic diethylamine groups in the secondary coordination sphere. Either of these amine‐bearing scaffolds positioned close to the Mn center serves as effective proton relays to facilitate the formation of the corresponding Mn hydride intermediate. Alongside competitive H2 evolution, the reaction of this crucial intermediate with CO2 leads to formate. Our findings underscore the pronounced influence of external Brønsted acids on product selectivity. Notably, when employing the catalyst bearing four amine groups, the HCOO−/H2 ratio varies from 81 : 3 with 1.0 M iPrOH to 16 : 64 with 1.0 M PhOH, while the Mn complex adorned with two amine pendant groups consistently favors HCOO−, irrespective of the utilized proton sources. Infrared spectroelectrochemistry and density‐functional theory calculations unveil distinct disparities in the reactivity of the Mn hydrides toward CO2 due to the change of ligand bulkiness in the two cases. This work substantiates the importance of modulating spatial accessibility while modifying the second sphere encompassing molecular catalysts. [ABSTRACT FROM AUTHOR]

The preparations, photophysical and electrochemical properties of a series of fac‐[Re(CO)3(diimine)Br] complexes are presented. The bipyridine (bpy) based diimine ligands feature symmetrical and asymmetrical 3,3'‐diamino‐2,2'‐bipyridine substitution patterns. Photophysical and electrochemical properties of these complexes are tunable, depending on their organic diimine framework. Introduction of a distal urea bridge via the 3,3'‐substitution pattern led to prolonged phosphorescence lifetimes without a significant change in absorbance and phosphorescence emission wavelengths. Reversible electrochemical bipyridine reduction remained largely unchanged by this derivatization. [ABSTRACT FROM AUTHOR]

Bipyridine and related compounds are starting materials or precursors for a variety of valuable substances such as biologically active molecules, ligands for catalysts, photosensitizers, viologens, and supramolecular architectures. Thus, it is important to classify their synthesis methods and understand their characteristics. Representative examples include methods using homo and heterocoupling of pyridine derivatives in the presence of a catalyst. Because bipyridine compounds strongly coordinate with metal centers, a decrease in catalytic activity and yield is often observed in the reaction system. To address this issue, this review provides insights into advances over the last ~30 years in bipyridine synthesis using metal complexes under both homogeneous and heterogeneous conditions. Moreover, strategies for bipyridine synthesis involving sulfur and phosphorous compounds are examined. These alternative pathways offer promising avenues for overcoming the challenges associated with traditional catalysis methods, providing a more comprehensive understanding of the synthesis landscape. [ABSTRACT FROM AUTHOR]

The thermal decomposition of (XMebpyH)3(H3O)[W(CN)8]·3H2O (where XMebpy denotes 4Mebpy 4,4′-dimethyl-2,2′-bipyridine or 5Mebpy 5,5′-dimethyl-2,2′-bipyridine) in glycerol results in the coordination of XMebpy. Salts of the anion formula [W(CN)6(XMebpy)]2− were isolated for PPh4+ and/or AsPh4+ cations as well as for K+, Rb+, and Cs+ ones. X-ray single-crystal analyses for tetraphenyl-phosphonium and tetraphenyl-arsonium cations are described. IR, UV-Vis, and cyclic voltammetry data are presented. The results were compared with those for [W(CN)6(bpy)]2− (bpy = 2,2′-bipyridine) ion salts. [ABSTRACT FROM AUTHOR]

Isostructural, pillar-layered metal–organic frameworks (MOFs) will provide an ideal structural model for studying the influence of functional groups on fluorescence sensing. Here, we study dipyridyl linkers to tune the detection of Fe3+ ions. Three isostructural analogues of pillar-layered frameworks were used as fluorescence sensors to quickly, sensitively, and selectively detect Fe3+ ions with good repeatability. Importantly, an increase in length of the pillars and accessible volumes may lead to an increase in the fluorescence quenching constants (Ksv(PL-1) = 1.58 × 104 M−1) < (Ksv(PL-2) = 1.72 × 104 M−1) < (Ksv(PL-3) = 2.47 × 104 M−1), which may be related to different dipyridyl ligands acting as pillars. [ABSTRACT FROM AUTHOR]

In graph theory, a topological index is an important descriptor that helps analyze the physicochemical properties of the structure of chemical compounds through a chemical graph. Degree‐based topological indices have been extensively studied and linked to a variety of chemical properties. This work aims to construct a complex ruthenium‐bipyridine polymer structure involving triphenylamine, which will be useful in the manufacture of organic light‐emitting diodes, solar cells, organic field‐effect transistors, and photorefractive materials, especially as hole transport material. In order to study this novel complex ruthenium bipyridine structure, we employ a reliable mathematical tool called M‐polynomial and NM‐polynomial of the topological index, which displays some physical and chemical properties in numerical form. [ABSTRACT FROM AUTHOR]

The dinuclear oxidovanadium(IV/V) complex, [V2(HS2O8)O3(C18H24N2)2]·CH3CN or [V2O2(μ-O)(μ-H(SO4)2)(4,4′-tBubpy)2]·CH3CN (4,4′-tBubpy = 4,4′-di-tert-butyl-2,2′-bipyridine), has crystallographic C2 symmetry and exhibits a distorted octahedral geometry around the vanadium center, where the two 4,4′-tBubpy ligands are nearly orthogonal to each other. The two vanadium ions are linked by an oxo anion and a unique protonated sulfate anion [H(SO4)23−]. In the crystal, intermolecular C—H...π and π–π interactions between the 4,4′-tBubpy ligands are present, leading to a three-dimensional network.

Two types of dendrimers with a bipyridine unit in the center of their rigid backbones were prepared. One dendrimer has two azide groups and the other has one ethynyl terminal. These dendrimers were coupled by the copper‐mediated Hüisgen 1,3‐dipolar cycloadditions of the ethynyl and azide terminals to afford a trimer with three bipyridine cores. The addition of Fe(II) to a solution of the trimer resulted in an absorption change characteristic of the formation of tris(bipyridine)Fe(II) complexes. The structural properties of the tris(bipyridine)Fe(II) core are likely reflected in the conformation of the timer because the bipyridine units are attached to the rigid backbones. [ABSTRACT FROM AUTHOR]

Two isostructural lanthanide complexes were synthesized by solvent evaporation with 3-dimethylaminobenzoic acid and 5,5′-dimethyl-2,2′-bipyridine as ligands. The general formula of the structure is a [Ln(3-N,N-DMBA)3(5,5′-DM-2,2′-bipy)]2·2(3-N,N-DMHBA), Ln = (Gd(1), Tb(2)), 3-N,N-DMBA = 3-Dimethylamino benzoate, 5,5′-DM-2,2′-bipy = 5,5′-dimethyl-2,2′ bipyridine. Both complexes exhibited dimeric structures based on X-ray diffraction analysis. At the same time, infrared spectroscopy and Raman spectroscopy were used to measure the spectra of the complex. A thermogravimetric infrared spectroscopy experiment was performed to investigate the thermal stability and decomposition mechanism of the complexes. Measurements of the low-temperature heat capacity of the complexes were obtained within the temperature range of 1.9 to 300 K. The thermodynamic function was calculated by heat capacity fitting. In addition, the fluorescence spectra of complex 2 were studied and the fluorescence lifetime values were determined, and the energy transfer mechanism of complex 2 was elucidated. [ABSTRACT FROM AUTHOR]

A series of [2]catenanes has been prepared from di‐NHC building blocks by utilizing solvophobic effects and/or π⋅⋅⋅π stacking interactions. The dinickel naphthobiscarbene complex syn‐[1] and the kinked biphenyl‐bridged bipyridyl ligand L2 yield the [2]catenane [2‐IL](OTf)4 by self‐assembly. Solvophobic effects are pivotal for the formation of the interlocked species. Substitution of the biphenyl‐linker in L2 for a pyromellitic diimide group gave ligand L3, which yielded in combination with syn‐[1] the [2]catenane [3‐IL](OTf)4. This assembly exhibits enhanced stability in diluted solution, aided by additional π⋅⋅⋅π stacking interactions. The π⋅⋅⋅π stacking was augmented by the introduction of a pyrene bridge between two NHC donors in ligand L4. Di‐NHC precursor H2‐L4(PF6)2 reacts with Ag2O to give the [Ag2L42]2 [2]catenane [4‐IL](PF6)4, which shows strong π⋅⋅⋅π stacking interactions between the pyrene groups. This assembly was readily converted into the [Au2L42]2 gold species [5‐IL](PF6)4, which exhibits exceptional stability based on the strong π⋅⋅⋅π stacking interactions and the enhanced stability of the Au‐CNHC bonds. [ABSTRACT FROM AUTHOR]

Two new luminescent ligands, 4‐(2‐pyridine)‐7‐methyl‐2,1,3‐benzothiadiazole (L1) and 4‐(2,2‐bipyridine)‐7‐methyl‐2,1,3‐benzothiadiazole (L2), based on 2,1,3‐benzothiadiazole and pyridine or bipyridine were obtained by Suzuki coupling reactions. DFT and TD‐DFT type calculations have been performed on L1 and L2 in order to assign their experimental UV‐visible and emission bands. Reaction of L1 and L2 with metal(II) chlorides (M=Zn, Mn, Cu) provided the neutral complexes of formulas [ZnL1Cl2] (1), [Zn(L1)2Cl2] (2), [ZnL2Cl2] (3), [MnL2Cl2] ⋅ 0,5CH2Cl2 (4) and [CuL2Cl2] ⋅ H2O (5) which have been structurally characterized. The Zn(II) ions in 1 and 2 are four‐coordinate in somewhat distorted tetrahedral N2Cl2 surroundings with L1 adopting bidentate (1) and monodentate (2) coordination modes. Complexes 3–5 are isostructural and their metal atoms are five‐coordinate in distorted square pyramidal environments with three nitrogen atoms from the tridentate L2 ligand and a chlorine building the basal plane and another chlorine atom occupying the apical position. The three Zn(II) complexes are strongly luminescent in solution and the solid state, while the cryomagnetic study of the paramagnetic compounds 4 and 5 in the temperature range 2.9–300 K shows a Curie‐Weiss behaviour typical of small antiferromagnetic interactions which are mediated by weak intermolecular contacts. [ABSTRACT FROM AUTHOR]

"2+1B" tricarbonyl complexes of the general formula [M(CO)3(N^N)CN(CH2)4CH(COOMe)SC10H21]-ClO4, where M = 99mTc or Re, N^N = 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen), were prepared by the reaction of [M(CO)3(N^N)(MeOH)]ClO4 with methyl 2-(decylthio)-6-isocyanohexanoate in methanol. The rhenium complexes were isolated and characterized by 1H NMR and IR spectroscopy. The formation of technetium-99m complexes was confirmed by HPLC. The lipophilicity of the technetium complexes was measured. [ABSTRACT FROM AUTHOR]

A redox‐neutral nickel‐catalysed sulfonylation for arylsulfone synthesis was developed. (Hetero)aryl boronic acids reacted with potassium metabisulfite (K2S2O5) and readily available 2‐chlorothiazoles in the presence of air‐stable Ni(OTf)2 and 4,4‐di‐tert‐butyl bipyridine (dtbpy) as a commercially available ligand to produce the corresponding 2‐sulfonylthiazoles in moderate to excellent yields. This practical protocol tolerates a wide range of substrates including boronic acids and 2‐chloro(benzo)thiazoles without additional bases, allowing the direct synthesis of functional arylsulfones. [ABSTRACT FROM AUTHOR]

A series of [Fe(bpy)Cl3X][bpy·H] (X = Cl, Br, I) complexes were prepared from direct treatment of FeCl3·6H2O with 2,2′-bipyridine in the presence of an HX solution. The complexes were characterized by IR, UV–Vis, XRDP, and cyclic voltammetry techniques. Electrochemical studies revealed a possible reduction to form the corresponding Fe0 complexes. A single crystal of [Fe(bpy)Cl4][bpy·H] displayed important H–Cl/Cl–H, H–H, H–C/C–H, and H–N/N–H interactions which were corroborated by a Hirshfeld surface analysis as well as MEP, QTAIM, and NCI studies, and complemented by HOMO/LUMO calculations at the B3LYP/cc-pVDZ + LANL2DZ level. In addition, the complexes displayed catalytic activity for the visible-light-driven the formation of 1-quinolin-4-yl-ethanol from quinoline under acidic conditions. [ABSTRACT FROM AUTHOR]

In the present study, a zinc(II) complex with 4-ethynyl-2,2'-bipyridine (ebpy), [Zn(ebpy)Cl2], was synthesized and characterized by spectroscopic (¹H-NMR, IR and UV-Vis) methods and molar conductivity measurement. The crystal structure of the [Zn(ebpy)Cl2] complex was determined by single-crystal X-ray diffraction analysis, confirming the bidentate coordination of the ebpy ligand through its two nitrogen atoms, while the remaining two coordination sites are occupied by two chloride ions. With the aim to investigate the reactivity of the synthesized zinc(II) complex toward biologically important molecules, its binding affinity to calf thymus DNA (ct-DNA) and bovine serum albumin (BSA) was studied by fluorescence emission spectroscopy. From the obtained results, it can be concluded that [Zn(ebpy)Cl2] complex binds to bovine serum albumin reversibly, while the combination of ethidium bromide (EthBr) and Hoechst 33258 (2'-(4-hydroxyphenyl)-5-[5-(4-methylpiperazine-1-yl)benzimidazo-2-yl]-benzimidazole) competitive binding study suggests that this complex interacts with ct-DNA through the minor groove binding, which is in agreement with molecular docking study. [ABSTRACT FROM AUTHOR]

This study aimed to demonstrate the behavior of different complexes using IR spectroelectrochemistry (SEC), a technique that combines IR spectroscopy with electrochemistry. Four different Mn and Re catalysts for electrochemical CO2 reduction were studied in dry acetonitrile. In the case of Mn(apbpy)(CO)3Br (apbpy = 4(4-aminophenyl)-2,2′-bipyridine), SEC suggested that a very slow catalytic reduction of CO2 also occurs in acetonitrile in the absence of proton donors, but at rather negative potentials. In contrast, the corresponding Re(apbpy)(CO)3Br clearly demonstrated slow catalytic conversion at the first reduction potential. Switching to saturated CO2 solutions in a mixture of acetonitrile and 5% water as a proton donor, the SEC of Mn(apbpy)(CO)3Br displayed a faster catalytic behavior. [ABSTRACT FROM AUTHOR]

The ion exchange of Na+ cations was used to photosensitise titanates nanotubes (Ti-NTs) with tris(2,2'-bipyridine)ruthenium(II) cations (Ru(bpy)32+); this yielded a light-sensitised Ti-NTs composite denoted as (Ru(bpy)3)Ti-NTs, exhibiting the characteristic absorption of Ru(bpy)32+ in visible light. Incident photon-to-current efficiency (IPCE) measurements and the photocatalytic reduction of methyl viologen reaction confirmed that in the photosensitisation of the (Ru(bpy)3)Ti-NTs composite, charge transfer and charge separation occur upon excitation by ultraviolet and visible light irradiation. The photocatalytic potential of titanate nanotubes was tested in the water-splitting reaction and the H2 evolution reaction using a sacrificial agent and showed photocatalytic activity under various light sources, including xenon–mercury lamp, simulated sunlight, and visible light. Notably, in the conditions of the H2 evolution reaction when (Ru(bpy)3)Ti-NTs were submitted to simulated sunlight, they exceeded the photocatalytic activity of pristine Ti-NTs and TiO2 by a factor of 3 and 3.5 times, respectively. Also, (Ru(bpy)3)Ti-NTs achieved the photocatalytic water-splitting reaction under simulated sunlight and visible light, producing, after 4 h, 199 and 282 μmol×H2×gcat−1. These results confirm the effective electron transfer of Ru(bpy)3 to titanate nanotubes. The stability of the photocatalyst was evaluated by a reuse test of four cycles of 24 h reactions without considerable loss of catalytic activity and crystallinity. [ABSTRACT FROM AUTHOR]

By exploiting coordination‐driven self‐assembly, high yields of two 818 molecular metalla‐knots could be obtained using a thiazole‐moiety‐containing asymmetric dipyridyl ligand 2‐(pyridin‐4‐yl)‐5‐(pyridin‐4‐ylethynyl)benzo[d]thiazole (L1), as confirmed using X‐ray crystallographic analysis, electrospray ionization‐time‐of‐flight/mass spectrometry (ESI‐TOF/MS), and detailed liquid‐state nuclear magnetic resonance (NMR) spectroscopy. To modulate the self‐assembled structures, m‐chloroperbenzoic acid (m‐CPBA) was utilized to oxidize thiazole‐based ligand L1 to N‐thiazole‐oxide‐based ligand 2‐(pyridin‐4‐yl)‐5‐(pyridin‐4‐ylethynyl)benzo[d]thiazole 3‐oxide (L2), which enabled the selective construction of the corresponding tetranuclear macrocycles. Notably, two molecular metalla‐knots could be topologically transformed from 818 knots to simple monocycles because the L1 alkyne bond was inert toward m‐CPBA, as confirmed by liquid‐state NMR spectroscopy, ESI‐TOF/MS, and elemental analysis. [ABSTRACT FROM AUTHOR]

9-Borabicyclo[3.3.1]nonane-based boronium triflates bearing a N-substituted 2-pyridylmethanimine, N,N′-dialkylethane-1,2-diimine, or 2-arylcarbonylpyridine ligand were synthesized. Their tetracoordinate boron structures were determined using 11B NMR spectra and X-ray crystallography. The pyridine-imine complexes exhibited solid-state photoresponsive color changes upon UV irradiation, which indicated that boronium complexes without a bipyridine moiety also have photoresponsive capabilities. Combination of TD-DFT calculations and measurements of UV-vis absorption and fluorescence properties, diffuse reflectance spectra, and ESR spectra provided suggestions on the determining factor of the photoresponsive color change capabilities and structures of the photoproducts. [ABSTRACT FROM AUTHOR]

Unlike traditionally available linear frameworks, cyclic transition‐metal architectures with cycloparaphenylenes (CPPs) ligands provide new access to develop modern nonlinear optical (NLO) materials. In this work, a sequence of "staircase" Pd(II) oligomeric nanohoop complexes with the 2,2′‐bipyridyl‐embedded CPPs ligand unit through "series connection" mode and "Ω‐type" Pd(II) trimeric isomer have been systematically designed and investigated via density functional theory. Herein, we first report the dependence of third‐order NLO responses on the number of bipyridine CPP building ligands in a quantitative way. Impressively, the Pd(II) trimeric complexes possess ultrahigh third‐order NLO responses, which are ascribed to the large orbital delocalization and decreased energy gap. To our delight, the enlargement of the nanohoop size is beneficial to improving third‐order NLO responses for Pd(II) oligomeric nanohoop complexes, and the maximum absorption spikes show the blue shift tendency. The effect of size on the third‐order NLO responses becomes much larger with the addition of bipyridine CPPs ligand. Overall, we hope the current work will deliver a new quantitative structure–property relationship toward the design and synthesis of Pd(II) oligomeric nanohoop complexes with high third‐order NLO responses. [ABSTRACT FROM AUTHOR]

Synthesis, characterization and catalytic activity of cyclometalated iridium complexes with a bidentate POC ligand is presented. Metalation of POC‐H (di‐tert‐butyl(phenoxy)phosphane) with [Ir(COD)Cl]2 proceeded rapidly at room temperature and afforded mixture of (POC)(POC‐H)IrHCl (1 a) and (POC)(COD)IrHCl (1 b), from which complexes (POC)(L)IrHCl where L=PPh3 (1 c), bipyridine (1 d) and [2,2′‐bipyridine]‐6,6′‐diol (1 e) were prepared through ligand exchange. The compounds were tested in acceptorless dehydrogenation of 1‐phenylethanol and transfer dehydrogenation of ethanol in a context of comparison with pincer counterparts (POCOP)IrHCl and (PCN)IrHCl. An attempt to prepare a dihydride complex from 1 e led to dimeric complex [(POC)(bipy‐diol−)IrH]2 (3) that could explain the low activity of 1 e. DFT studies provided insight into POC‐H vs POCOP‐H metalation mechanism. [ABSTRACT FROM AUTHOR]

Mixed-ligand tetranuclear supramolecular coordination complexes (SCCs) of Pt(II)-p-biphenyl and bridging ligands derivatives of 4,4′-bypiridine (8)–(10), were synthesized and characterized. The SCCs were synthesized stepwise, starting from the Pt-p-biphenyl -Pt core. The crystal structure of complex {[Pt(2,2′-bpy)]4(μ-bph)2(μ-(4,4′-bpy)2}{PF6}4 (2,2′-bpy = 2,2′-bipyridine, bph = p-biphenyl and 4,4′-bpy = 4,4′ bipyridine), was determined using single-crystal diffraction methods. The emission profile of the tetranuclear complexes (8)–(10) was influenced by the length of the bridging ligands and was found to depend on solvent polarity. Dual-emission patterns in methanol–water mixtures were observed only in the cases of complexes (9) and (10), attributed to aggregation-induced emission phenomena. [ABSTRACT FROM AUTHOR]

The dinuclear oxidovanadium(IV/V) complex, [V2(HS2O8)O3(C18H24N2)2]⋅- CH3CN or [V2O2(μ-O)( μ-H(SO4)2)(4,4'-tBubpy)2]⋅CH3CN (4,40-tBubpy = 4,4'-di-tert-butyl-2,2'-bipyridine), has crystallographic C2 symmetry and exhibits a distorted octahedral geometry around the vanadium center, where the two 4,4'-tBubpy ligands are nearly orthogonal to each other. The two vanadium ions are linked by an oxo anion and a unique protonated sulfate anion [H(SO4)23-]. In the crystal, intermolecular C--H⋯π and π--π interactions between the 4,4'-tBubpy ligands are present, leading to a three-dimensional network. [ABSTRACT FROM AUTHOR]

The active metal template (AMT) strategy is a powerful tool for the formation of mechanically interlocked molecules (MIMs) such as rotaxanes and catenanes, allowing the synthesis of a variety of MIMs, including π‐conjugated and multicomponent macrocycles. Cycloparaphenylene (CPP) is an emerging molecule characterized by its cyclic π‐conjugated structure and unique properties. Therefore, diverse modifications of CPPs are necessary for its wide application. However, most CPP modifications require early stage functionalization and the direct modification of CPPs is very limited. Herein, we report the synthesis of a catenane consisting of [9]CPP and a 2,2′‐bipyridine macrocycle as a new CPP analogue that contains a reliable synthetic scaffold enabling diverse and concise post‐modification. Following the AMT strategy, the [9]CPP‐bipyridine catenane was successfully synthesized through Ni‐mediated aryl‐aryl coupling. Catalytic C−H borylation/cross‐coupling and metal complexation of the bipyridine macrocycle moiety, an effective post‐functionalization method, were also demonstrated with the [9]CPP‐bipyridine catenane. Single‐crystal X‐ray structural analysis revealed that the [9]CPP‐bipyridine catenane forms a tridentated complex with an Ag ion inside the CPP ring. This interaction significantly enhances the phosphorescence lifetime through improved intermolecular interactions. [ABSTRACT FROM AUTHOR]