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The redox non-innocent behaviour of non-chelated μ-bis-η1-N,η1-N BTD (2,1,3-benzothiadiazole)-bridged mixed valent diruthenium and triruthenium complexes is attributed to a moderately coupled delocalised electronic state with Vab ≈ 2640–2890 cm−1.

Waste upcycling to valuable chemicals has gained significant attention in recent years as a way to reduce waste and promote circular economy. The transition to a circular economy that includes...

Recently, metal-organic frameworks (MOFs) have been widely employed as a sacrificial template for the construction of nanostructured materials for a range of applications including energy storage. Herein, we report a facile mixed-ligand strategy for the synthesis of a Cu-MOF, [Cu3(Azopy)3(BTTC)3(H2O)3·2H2O]n (where BTTC = 1,2,4,5-benzenetetracarboxylic acid and Azopy = 4,4'-azopyridine), via a slow-diffusion method at room temperature. X-ray analysis authenticates the two-dimensional (2D)-layered framework of Cu-MOF. Topologically, this 2D-layered structure is assigned as a 4-connected unimodal net with sql topology. Further, nanostructured CuO is obtained via a simple precipitation method by employing Cu-MOF as a precursor. After analysis of their physicochemical properties through various techniques, both materials are used as surface modifiers of glassy carbon electrodes for a comparative electrochemical study. The results reveal a superior charge storage performance of CuO (244.2 F g-1 at a current density of 0.8 A g-1) with a high rate capability compared to Cu-MOF. This observation paves the pathway for the strategic design of high-performing supercapacitor electrode materials.

Because of a continuous increase in energy demands and environmental concerns, a focus has been on the design and construction of a highly efficient, low-cost, environmentally friendly, and noble-metal free electrocatalyst for energy technology. Herein we report facile synthesis of the mixed-valence trinuclear cobalt complex 1 by the reaction of 2-amino-1-phenylethanol and CoCl2·6H2O in methanol as the solvent at room temperature. Further, 1 was reduced by using aqueous N2H4 as a simple reducing agent, followed by calcination at 300 °C for 3 h, yielding a nitrogen-doped mixed phase cobalt [β-Co(OH)2 and CoO] nanocatalyst (N@MPCoNC). Both 1 and N@MPCoNC were characterized by various physicochemical techniques. Moreover, 1 was authenticated by single-crystal X-ray diffraction studies. The hybrid N@MPCoNC reveals a unique electronic and morphological structure, offering a low overpotential of 390 mV for a stable current density of 10 mA cm-2 with high durability. This N@MPCoNC showed excellent electrocatalytic as well as photocatalytic activity for oxygen evolution reaction compared to 1.

A new Na/Co-based heterometallic metal-organic framework, [Na2Co(SDCA)(μ2-OH)2(μ2-H2O)2(Azopy)]n (where Azopy = 4,4'-Azopyridine and SDCA = 2,5'-thiophenedicarboxylic acid) (1) with nanorod-shaped morphology was synthesized using mixed-ligand approach via slow-diffusion technique under ambient conditions. The crystal structure study demonstrates the proportion of Co(II) and Na(I) metal node to be 1:2 and the acquired coordination network reveals as a 3D architecture. Topologically, the 4-c Na(I) ion directs in situ assembly of 4-c SDCA linker and 6-c Co(II) ion, resulting in the formation of 4,4,6-c net with a topology named as smm3. Additionally, 1 was incorporated as a binder-free material for a glassy carbon electrode (1-GCE) to explore its supercapacitor performance, which reveals a high specific capacitance of 321.8 F g-1 at 4 A g-1 and notable rate performance (∼78.9% of initial capacitance up to 16 A g-1) as well as excellent cycling stability (retains 97.4% after 5000 cycles). The demonstrated strategy of employing different heterometallic clusters with mixed ligands markedly increases MOF's complexity and induces synergistic properties, which is highly favorable for electrochemical applications. Hence, the present approach can be extended to build a wide range of MOFs and synergistically enhanced electrochemical performance can be achieved.

Mixed-metal metal-organic frameworks (M-MOFs) consist of at least two different metal ions as nodes in the same framework. The incorporation of a second or more metal ions provides structural/compositional diversity, multi-functionality and stability to the framework. Moreover, the periodical array of different metal ions in the framework may alter the physical/chemical properties of M-MOFs and result in fascinating applications. M-MOFs with exciting structural features offer superior supercapacitor performances compared to single metal MOFs due to the synergic effect of different metal ions. In this review, we summarize several synthetic methods to construct M-MOFs by employing various organic ligands or metalloligands. Further, we discuss the electrochemical performance of several M-MOFs and their derived composite materials for supercapacitor applications.

Herein, we have reported a novel composite of nitrogen doped reduced graphene oxide (N-rGO) and strontium zirconate (SrZrO3). This new composite (N-rGO/SrZrO3) was synthesized using the reflux method. The physicochemical properties of N-rGO/SrZrO3 were determined using different advanced techniques such XRD, FE-SEM, EDX, FTIR and BET. Furthermore, a glassy carbon electrode was modified with N-rGO/SrZrO3 (GCE-2). This modified electrode was employed for the sensing of HQ. The electrochemically active surface area (ECSA) of this modified electrode (GCE-2) was calculated by employing the Randles–Sevcik equation. Furthermore, GCE-2 exhibited a good detection limit (0.61 μM) including high selectivity towards HQ.

Though a large amount of literature has been reported on outlining the biological significance of zinc(II) Schiff base complexes, yet none of them have explored the influence of nuclearity on their properties. This report elaborates the targeted syntheses of two different hemi-salen ligands for their ability to produce Zn(II)-complexes with different nuclearity. Herein, one dimeric, [Zn2L12(N3)2] (1) and one trimeric [Zn3L22(N3)4] (2) [HL1 = (2-(((2-(diethylamino)ethyl)imino)methyl)phenol, HL2 = 2-(((3-(dimethylamino)-2,2-dimethylpropyl)imino)methyl)-6-methoxyphenol] complexes of hemi-salen ligands have been thoroughly screened for various biological studies including cytotoxic assay, DNA/protein-complex interplay, fluorescence imaging, and antibacterial pathogen tests. The trimer features the IC50 value of 9.651 ± 0.026 μM against the HeLa cancer cell line, one of the best figure by any Zn(II) hemi-salen complex to date. How the nuclearity dependency affects the supramolecular interactions is also a key point of interest in this study. The compounds exhibit strong DNA binding affinity and the dimer 1 predominantly binds to the minor grooves of DNA (binding energy = −5.8 kcal mol−1), whereas trimer 2 prefers the intercalative mode (binding energy = −7.1 kcal mol−1) in contrast to groove binding (binding energy = −6.2 kcal mol−1). The atypical phenomenon behind the conformational changes of biomolecules by these zinc complexes has been investigated through experimental procedures and further corroborated theoretically. Apart from this, it has been found that even at very low concentration (≤10 μM) of the ligand, HL1 and complexes can be effective for live cell imaging. It is worth mentioning that HL1 could be useful for the specific staining of the cell cytoplasm. Furthermore, the complexes have shown promising anti-bacterial activity; thus, they can be convenient for multiple biological applications.

A dysprosium metal–organic framework, {[Dy(μ2-FcDCA)1.5(MeOH)(H2O)]·0.5H2O}n (1), where FcDCA = 1,1′-ferrocene dicarboxylic acid, was prepared by slow-diffusion technique at room temperature. The crystal structure analysis of 1 by single-crystal X-ray diffraction reveals different binding modes of FcDCA linkers coordinated with Dy(III) metal ions, which forms continuous porous two-dimensional (2D) infinite framework. The resulting 2D layers are linked by π···π interactions to build three-dimensional (3D) supramolecular framework. Observably, this thermally stable 3D architecture was topologically simplified as a three-connected uninodal net with fes topology. Furthermore, the practical applicability of 1 was investigated as a fluorescence sensor for the sensitive detection of picric acid in aqueous medium with an impressive detection limit of 0.71 μM with quenching constant (KSV) quantified to be 8.55 × 104 M–1. The distinguished selectivity in the presence of other nitroaromatics suggests the possible in...

A porous, Cu(II)-metal organic framework (Cu-MOF) constituted of a rigid lactam functionalized ditopic ligand (H2L) was synthesized at room temperature under slow evaporation conditions {H2L = (5-(1-oxo-2,3-dihydro-1H-inden-2-yl)isophthalic acid)}. The single crystal X-ray structure revealed the formation of a 3D framework of Cu-MOF with one-dimensional (1D) channels decorated with lactam groups and exposed metal centers in the crystallographic c-axis. Interestingly, Cu(II) coordinated DMF molecules were eliminated from the Cu(II) metal center on activation of Cu-MOF at a temperature of 150 °C under high vacuum to generate a solvent free framework with pores lined with unsaturated Lewis acidic Cu(II) ions, i.e., Cu-MOF'. The lactam functionalized channels inclined toward the CO2, which interact with the Cu(II) metal sites lined in the channels of Cu-MOF' and exhibit fascinating solvent-free heterogeneous catalytic conversion of CO2 to cyclic carbonates at atmospheric pressure of CO2, under mild conditions. Furthermore, the Cu-MOF' catalyst was easily recycled and reused for several cycles without a significant loss in catalytic activity.

Two new coordination complexes containing 5-(4-chlorophenyl)tetrazolato (4-Clptz) and polypyridyl ligands, [Cu2(bipy)2(4-Clptz)4] [1, bipy = 2,2′-bipyridine] and [Cu2(phen)2(4-Clptz)4] [2, phen = 1, 10 phenanthroline] have been synthesized following metal ligated [2 + 3] cycloaddition reaction between copper bound azide polymer containing polypyridyl and 4-chloro benzonitrile. Both the complexes have been fully characterized by different spectroscopic techniques. Single crystal X-ray diffraction study reveals that the complexes are dimeric in nature with penta-coordinated geometry around the Cu(II) centre through N-donor sites. These complexes have been explored as homogeneous catalysts for the selective oxidation (in presence of hydrogen peroxide) of benzene to phenol and benzoquinone under mild conditions in an open atmosphere condition.

The metal–hydrogen (M···H) bonds in transition elements are well documented. However, the attractive AuI···H bond interaction is rare and significant experimental evidence for it still remains a ch...

With the enhancement in biomimetic and bioinspired synthesis approaches, plant-derived nanostructures provide the most suitable synthesis alternatives in terms of being non-toxic, economical and eco-friendly. The present work focused on Cannabis sativa-derived carbon dots co-doped with nitrogen and sulphur (N–S@CsCD) as a nanosensor. N–S@CsCD exhibited size distribution in the range of 4–6 nm and showed an excitation-independent emission behaviour with an emission wavelength around 414 nm. The XPS spectra confirmed the presence of heteroatom doping by nitrogen and sulphur with the concentrations of 10.71% and 1.94%, respectively. N–S@CsCD showed excellent stability to pH, time and salt concentration. Interestingly, N–S@CsCD exhibited a reversible temperature-responsive fluorescence “turn-off” behaviour. Furthermore, N–S@CsCD showed a selective fluorescence “turn-off” behaviour in the presence of vitamin B12 (VB12), with a limit of detection of 7.87 μg mL−1. The fluorescence lifetimes of N–S@CsCD with and without VB12 were similar, which implied that the sensing behaviour was purely static in nature. Moreover, N–S@CsCD showed biocompatible and non-toxic behaviours with very high cell viability. The fluorescence nature of N–S@CsCD was further evaluated for intracellular imaging.

A new fluorescent receptor HL was synthesized by an easy condensation reaction of ortho-vanillin and 1-(3-aminopropyl) imidazole. The probe HL was found to be highly selective and sensitive towards Zn2+/Cu2+ ions in the presence of a wide range of metal cations. The interaction of HL with Zn2+ ions showed a distinct fluorescence enhancement (turn-on) at 470 nm. Moreover, after the subsequent addition of Cu2+ ions into the same solution, a fluorescence ‘turn-off’ phenomenon was observed. The sensing ability of the chemodosimeter HL towards Zn2+ was confirmed by fluorescence, UV-Vis and 1H NMR titration analysis. The binding mode of HL towards Zn2+ and Cu2+ was authenticated by single crystal X-ray analysis, which divulged the formation of dinuclear complexes 1 and 2. Furthermore, we performed NOESY and COSY studies of complexes 1 and 2 to detect their shapes and interlocking units. Moreover, the cytotoxicity of HL and 1 towards HeLa cancer cells was studied, and both were found to be non-cytotoxic in nature. This prompted us to explore the intracellular fluorescence turn-on sensing activity of HL with Zn2+ ions. The intracellular sensing behavior of HL towards Zn2+ was confirmed towards in two cancer cell lines viz., HeLa and DU-145 cell lines. The limit of detection (LOD) for Zn2+ and Cu2+ sensing was found to be 31.044 nM and 11.64 nM, respectively.

Designing metal complexes as functional models for metalloenzymes remains one of the main targets in synthetic bioinorganic chemistry. Furthermore, the utilization of the product(s) derived from the catalytic reaction for subsequent organic transformation that occurs in biological systems is an even more difficult challenge for biochemists. Urease, the most efficient enzyme known, catalyzes the hydrolysis of urea and it contains an essential dinuclear NiII cluster in the active site. Inspired by the catalytic properties of urease, two dinickel(II) complexes viz. Ni2L12(OAc)2(H2O) (1) and Ni2L22(OAc)2(H2O) (2) [HL1 = 2,4-dimethyl-6-{[(2′-dimethyl aminoethyl)methylamino]methyl}-phenol and HL2 = 2,4-dichloro-6-{[(2′-dimethyl aminoethyl)methylamino]methyl}-phenol] have been synthesized and characterized in this report. Both the complexes have shown the urease kind of activity with the liberation of ammonia from urea in aqueous solution. The plausible mechanistic pathway and kinetics of the reactions have been studied. Besides, the liberated ammonia has been utilized in the one-pot synthesis of biologically active products like 2-amino-3-cyanopyridines and their derivatives in aqueous medium with excellent yields.

The Me3NO initiated reaction between Mn2(CO)10 and 2-mercaptobenzimidazole (mbiH) at room temperature leads to the formation of dinuclear Mn2(CO)6(µ-κ2-mbi)2 (1) in which the metal atoms are linked by the sulfur atoms of the heterocyclic ligands. Complex 1 reacts with triphenylphosphine (PPh3), bis(diphenylphosphino)methane (dppm) and 1,2-bis(diphenylphosphino)ethane (dppe) at room temperature to afford mononuclear Mn(CO)3(PPh3)(κ2-mbi) (2), Mn(CO)3(κ2-dppm)(κ1-mbi) (3) and Mn(CO)3(κ2-dppe)(κ1-mbi) (4), respectively, via metal-sulfur bond scission. Upon gentle heating, 1 also reacts with Os3(CO)10(NCMe)2 and Ru3(CO)12 to yield the mixed-metal clusters MnOs3(CO)13(μ3-κ2-mbi) (5) and MnRu3(CO)13(μ3-κ2-mbi) (6), respectively, which contain a Mn(CO)3(mbi) fragment. All these new complexes have been characterized by analytical and spectroscopic data, together with single crystal X-ray diffraction analyses for 1, 3, 4 and 5.

Functionalization of ferrocenyl moieties with a cyanovinyl system using a unique solid-state synthetic method led to the formation of donor–acceptor type compounds with wide absorption in the visible region. A DSSC study using the ferrocenyl cyanovinyl compound as a dye with an electrolyte-free fabrication system showed an unprecedented open-circuit voltage (VOC) of 763–841 mV. DFT calculations were carried out to understand an unique electron transfer mechanism for the DSSC device which may be responsible for the high VOC.

Reactions of the tetranuclear mixed-metal clusters ReM3(CO)13(µ3-thpymS) (1, M = Os; 2, M = Ru; thpymSH = tetrahydropyrimidine-2-thiol) with PPh3 are examined. At room temperature reaction between 1 and PPh3 in the presence Me3NO leads to the formation of mono- and bis-phosphine substituted clusters ReOs3(CO)12(PPh3)(µ3-thpymS) (3) and ReOs3(CO)11(PPh3)2(µ3-thpymS) (4). Cluster 3 also reacts with PPh3 under similar conditions to give 4. In contrast, a similar reaction between 2 and PPh3 furnishes only the mono-phosphine substituted clusters ReRu3(CO)12(PPh3)(µ3-thpymS) (3). All the new clusters have been characterized by analytical and spectroscopic data together with single crystal X-ray diffraction for 1, 3 and 5.

The present work focuses on the surfactant mediated synthesis of ZnAl2O4 nanoparticles (1−3) using sol–gel method. 1 has been synthesized without any surfactant and during the synthesis of 2 and 3 cationic (cetyltrimethylammonium bromide) and anionic (sodium lauryl sulfate) surfactant, respectively, have been added. 1–3 have been characterized by P-XRD, FT-IR, SEM, SAED, TEM and BET techniques which suggest that surfactant reduces the particle size of ZnAl2O4 nanoparticles to half (12 nm in 1, 6 nm in 2 and 3). Zeta (ζ) potential measurements have been performed to determine the surface charges of all the samples. Moreover, the photocatalytic activities of these ZnAl2O4 nanoparticles have also been investigated. 2 exhibits better adsorption (28–41%) and degradation (97–99%) efficiency for anionic dyes due to high surface area (129.62 m2 g−1) and positively charged surface (ζ potential 30.06 mV). Radical trapping experiments suggest O2 − and OH to be the major reactive species for the degradation of dyes.

The synthesis of pyridine alcohol based ruthenium carbonyl clusters Ru3(hep)2(CO)8 (1), Ru3(hpp)2(CO)8 (2), and Ru3(bhmp-H)2(CO)8 (3) {hep-H = 2-(2-hydroxyethyl)pyridine, hpp-H = 2-(3-hydroxypropyl)pyridine and bhmp-H2 = 2,6-bis(hydroxymethyl)pyridine} has been carried out by the reaction of the corresponding pyridine-alcohol ligands with Ru3(CO)12. Clusters 1–3 have been characterized using elemental analysis, NMR, FT-IR, mass spectrometry and single-crystal X-ray structures. The clusters were explored for the selective catalytic transformation of primary amines into secondary amines using alcohols as the mono-alkylating agents via hydrogen transfer reactions. All three display efficient catalytic activity with 1 being the most effective.

The alkynyl telluroether (phenylethynyl ferrocenyltelluride) (1) reacts with [M(CO)5(THF)]; (M = Cr, Mo, W) to form the monocoordinated adduct, [M(CO)5(Fc2Te2)] (2-4) and dicoordinated compounds [{M(CO)5}2(Fc2Te2)] (5-7) (Fc = ferrocenyl). Compounds 2-4 readily react with respective [M(CO)5(THF)] to give the corresponding 5-7. In contrast, reaction of 1 with [Fe(CO)5] leads to a scission of the Te-C bond of 1, reaction of the ensuing PhC C fragment and the TeFc fragment with ironcarbonyl to form the unusual fused ferracyclopentenone units, [{Fe(CO)4C(O)C(Ph)=C}2] (8) and the isomeric Fc2Te2 compounds, (9) [Fe2(CO)6(µ-TeFc)2] and 10 [Fe2(CO)6(µ-TeFc)2]. In addition, thermolytic reaction of [Ru3(CO)12] with 1 gives high nuclearity clusters [Ru4(CO)11{μ4-Te-η1:η1:η4-CC(Fc)C6H4}] (11) and [Ru4(CO)10{μ3-Te-η1: η1: η4:η2:η2-CC(Fc)C6H4}] (12) which are formed by Te-C bond breaking, C-C coupling and rearrangement. The easy cleavage of Te-Csp bond also displays the role of ligand for the formation of new clusters. The depth of fragmentation of phenylethynyl ferrocenyltelluride in the resulting complexes depends on the formal electron deficit of the decarbonylated metal fragment. Bonding properties of 11 and 12 have been discussed using the DFT studies.

A set of tetracyanobutadiene (TCBD)- and dicyanoquinodimethane (DCNQ)-bridged ferrocenyl dimers 5–8 were designed and synthesized by the [2 + 2] cycloaddition–retroelectrocyclization reaction of diferrocenyl complexes 3 and 4 with tetracyanoethylene (TCNE) and 7,7,8,8 tetracyanoquinodimethane (TCNQ), respectively. The effect of constitutional isomers (para vs meta) and different acceptors on their donor–acceptor interactions and photophysical and redox properties as well as electronic structures was evaluated using a variety of experimental and theoretical methods. The single-crystal X-ray structures of TCBD- and DCNQ-bridged ferrocenyl dimers 6 and 7 are reported. The DCNQ-bridged ferrocenyl dimers 7 and 8 have lower HOMO–LUMO gap values with red-shifted absorption bands in comparison to those of TCBD-bridged ferrocenyl dimers 5 and 6. Mossbauer spectra of 3–8 are suggestive of very similar isomer shifts and quadrupole splittings in all diferrocene complexes despite their different proximities to the ele...

A pyrazole-appended quinoline-based 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (L1, BODIPY) has been synthesized and used as a ligand for the preparation of iridium(III) complexes [Ir(phpy)2(L1)]PF6 (1; phpy = 2-phenylpyridine) and [(η5-C5Me5)Ir(L1)Cl]PF6 (2). The ligand L1 and complexes 1 and 2 have been meticulously characterized by elemental analyses and spectral studies (IR, electrospray ionization mass spectrometry, 1H and 13C NMR, UV/vis, fluorescence) and their structures explicitly authenticated by single-crystal X-ray analyses. UV/vis, fluorescence, and circular dichroism studies showed that complexes strongly bind with calf-thymus DNA and bovine serum albumin. Molecular docking studies clearly illustrated binding through DNA minor grooves via van der Waals forces and their electrostatic interaction and occurrence in the hydrophobic cavity of protein (subdomain IIA). Cytotoxicity, morphological changes, and apoptosis have been explored by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromi...

Three new coordination complexes [Cu 2 (phen) 2 (ptz) 4 ] ( 1 ), [Cu(phen)(pmtz) 2 ] ( 2 ) and [Cu(phen)(pytz) 2 ] ( 3 ) (ptz = 5-phenyltetrazolate, pmtz = 5-(2-pyrimidyl)tetrazolate and pytz = 5-(2-pyridyl)tetrazolate) have been synthesized using metal mediated [2+3] cycloaddition reaction between copper bound azide polymer and different organonitriles. All complexes have been structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Complex 1 shows a dinuclear structure via bridging ptz, while 2 and 3 reveal mononuclear structures. These complexes were explored as homogeneous catalysts for the selective peroxidative (with tBuOOH) oxidation of cyclohexane to cyclohexanol and cyclohexanone (KA oil) under very mild and green (solvent- and additive-free) conditions using microwave irradiation. The catecholase-like activity of the synthesized Cu(II) complexes was investigated by employing 3,5-di- tert -butylcatechol (DTBC) as a convenient model substrate, which showed first order kinetics with respect to the substrate in the oxidation of 3,5-di- tert -butyl catechol (DTBC) to 3,5-di- tert -butyl benzoquinone (DTBQ). Further, the interaction of synthesized Cu(II)-tetrazolato complexes with bovine serum albumin (BSA) was studied experimentally as well as through molecular docking to obtain detailed binding information of the Cu(II) complexes with BSA, which revealed higher binding of complex 1 than 2 and 3 .

When hexane or alcohol solutions containing iron pentacarbonyl and bis(dialkoxythiophosphoryl) disulfide (R = Me (1), Et (2), or Pri (3)), were irradiated with 366 nm light, under argon atmosphere at 0 °C, clusters [(μ-RS)Fe2(CO)6](μ4-S)[(μ-(OR)2P)Fe2(CO)6] (4: R = Me, 5: R = Et) and [Fe2(CO)6S{P(OiPr)2}]2 (6) were obtained in hexane and [Fe4(CO)8(μ-CO)2(μ4-S)2P(OR)3] (7: R = Me, 8: R = Et) in MeOH and EtOH respectively. These reactions involve P–S bond cleavage of ligands and desulfurization process and Fe-S and Fe-P bond formation. Computational and experimental bond parameters have been studied on the new compounds.

Heating a benzene solution of the unsaturated cluster Os3(CO)8(μ-dppm)(μ-H)2 (1) [dppm = bis(diphenylphosphino)methane] with MeO2CC CCO2Me (DMAD) or EtO2CC CCO2Et (DEAD) at 80 °C furnished the dinuclear compounds Os2(CO)4(μ-dppm)(μ-η2;η1;к1-RO2CCCHCO2R)(μ-H) (3a, R = Me, 3b, R = Et) and the saturated trinuclear complexes Os3(CO)7(μ-dppm)(μ3-η2;η1;η1-RO2CCCCO2R)(μ-H)2 (4a, R = Me, 4b, R = Et). In contrast, similar reactions using unsaturated Os3(CO)8(μ-dppf)(μ-H)2 (2) [dppf = bis(diphenylphosphino)ferrocene] afforded only the trinuclear complexes Os3(CO)8(μ-dppf)(μ-η2;η1-RO2CCHCCO2R)(μ-H) (5a, R = Me; 5b, R = Et) and Os3(CO)7(μ-dppf)(μ3-η2;η1;η1-RO2CCCCO2R)(μ-H)2 (6a, R = Me; 6b, R = Et). Control experiments confirm that 5a and 5b decarbonylate at 80 °C to give 6a and 6b, respectively. Both 5a and 5b exist as a pair of isomers in solution, as demonstrated by 1H NMR and 31P{1H} NMR spectroscopy. DFT calculations on cluster 5a (as the dppf-Me4 derivative) indicate that the isomeric mixture derives from a torsional motion that promotes the conformational flipping of the cyclopentadienyl groups of the dppf-Me4 ligand relative to the metallic plane. VT NMR measurements on clusters 6a and 6b indicate that while the hydride ligand associated with the dppf-bridged Os-Os bond is nonfluxional at room temperature, the second hydride rapidly oscillates between the two non-dppf-bridged Os-Os edges. DFT examination of this hydride fluxionality confirms a “windshield wiper” motion for the labile hydride that gives rise to a time-average coupling of this hydride to both phosphorus centers of the dppf ligand. Thermolysis of 6a and 6b in refluxing toluene yielded Os3(CO)7(μ-dppf)(μ-η2;η1;к1-CCHCO2R) (7a, R=Me; 7b, R=Et). The vinylidene moieties in 7a and 7b derive from the carbon-carbon bond cleavage of coordinated alkyne ligands, and these two products exhibit high thermal stability in refluxing toluene.

Four new metal complexes (one mononuclear and three dinuclear) viz. [NiL(5-phenyltetrazolato)] (1a), [Ni2L2{5-(2-cyanophenyl)-tetrazolato}2] (1b), [Cu2L2{5-phenyltetrazolato}2]·C6H5CN (2a) and [Cu2L2{5-(2-cyanophenyl)-tetrazolato}2] (2b) [HL = 3-(2-dimethylamino-ethylimino)-1-phenyl-butan-1-one] have been synthesized by in-situ generation of tetrazolato ligands and characterized by X-ray crystallography, different spectroscopic techniques and elemental analyses. Introduction of one nitrile group in the 5-substituted phenyl ring makes the tetrazolato ligand comparatively weaker donor leading the complex to be more vulnerable towards dissociation facilitating subsequent substrate binding for catecholase oxidation study. Copper complex 2b has been found to be more active with respect to analogous nickel complex 1b as it provides the metal centered oxidation route rather than ligand centered oxidation in nickel complex. The comparative catalytic activities of complex 1b and 2b are further explored by DFT calculations which also support the experimental results. UV–Vis and fluorescence-based spectroscopic techniques revealed that two of the metal-tetrazolato complexes (1a and 2b) interact with double stranded DNA via intercalation and also with serum albumin protein BSA. A comparative assessment indicated that the Ni(II)-tetrazolato complex 1a displayed superior DNA binding. The interaction of these compounds with bovine serum albumin (BSA) suggested that the Cu(II)-tetrazolato complex 2b quenched the intrinsic fluorescence of BSA in a static quenching process and shows stronger binding constant.

The requirement of sensitive diagnostic chips for small biomolecules has triggered the urgent development of versatile nanomaterial based platforms. Therefore, numerous materials have been designed with fascinating properties. Herein, we report a facile one-pot synthesis of MoS2-rGO nanoflowers grown by the hydrothermal method and their applicability in the simultaneous sensing of AA, DA and UA. The structure and morphology of nanoflowers have been probed by various physico-chemical techniques such as XRD, SEM/TEM, AFM, Raman and XPS. Furthermore, these nanoflowers were used to construct a glassy carbon based working electrode (MoS2-rGO/GCE), by a facile drop-casting method in the absence of any commercial binder. The electrochemical investigations revealed high separating potency of the MoS2-rGO/GCE towards AA, DA and UA with distinguishable oxidation potentials (AA-DA = 204 mV and DA-UA = 122 mV) and a notable detection limit and reasonable sensitivity for each of these biomolecules. The charge transfer resistance and capacitive components obtained by electrochemical impedance spectroscopy (EIS) were found to be in agreement with the voltammetric observations. The observed synergy between MoS2 and rGO opens up new possibilities to consider the MoS2-rGO nanostructures as the cutting edge material for electrochemical sensor development.

Three ligands L1 [N,N-dimethyl-N′-(1-pyridin-2-yl-ethylidene)-ethane-1,2-diamine], L2 [2-morpholino-N-(1-(pyridin-2-yl)ethylidene)ethanamine] and L3 [(2-(piperidin-1-yl)-N-(1-(pyridin-2-yl)ethylidene)ethanamine)] were introduced to prepare five Cd(II) Schiff base complexes [Cd(L1)2](ClO4)2 (1), [Cd(L1)(Cyanoacetate)(OAc)] (2), [Cd2(L1)2(N3)4] (3), [Cd(L2)(N3)2]n (4), [Cd2 (L3)2(N3)4]n (5) and the corrosion inhibition properties of these complexes on mild steel upon treatment with 15% HCl have been examined where azide complexes have shown corrosion inhibition properties as revealed by electrochemical impedance spectroscopy and potentiodynamic polarization. Field emission scanning electron microscopy (FE-SEM) images show that the mild steel surface was protected by cadmium complexes. Among azido complexes polymeric complexes have higher inhibition activity which was further explained using density functional theory. So finally a new bridge between nuclearity driven coordination inorganic chemistry and materials as well as corrosion engineering was established by this observation.

Herein, we utilized our previously reported highly porous CuMOF, {[Cu2(L)(H2O)2]·(5DMF)·(4H2O)}n, decorated with amine and trifluoromethyl functional groups for energy storage application. This robust framework in CuMOF enhances the chemical and thermal stabilities as well as improves the interfacial binding interactions. The poor conductivity of CuMOF usually restricts its practical utility in energy storage systems, due to which rGO was introduced along with CuMOF to form a CuMOF/rGO composite (1) through a facile ultrasonication technique. The synergistic effects between CuMOF and rGO induce a dramatic enhancement in specific capacitance (462 F g-1 at 0.8 A g-1) of 1 with a cycle life of 93.75% up to 1000 cycles. The results highlight 1 as an emerging contestant for next generation supercapacitors.

A new N,O-based BODIPY ligand was synthesized and further utilized to develop highly fluorescent and photostable Ru(II), Rh(III), and Ir(III) metal complexes. The complexes were fully characterized by different analytical techniques including single-crystal XRD studies. The photostabilities and live cell imaging capabilities of the complexes were investigated via confocal microscopy. The complexes localized specifically in the mitochondria of live cells and showed negligible cytotoxicities at a concentration used for imaging purposes. They also exhibited high photostabilities, with fluorescence intensities remaining above 50% after 1800 scans.

Galactose Oxidase (GOase) and catechol oxidase (COase) are the metalloenzymes of copper having monomeric and dimeric sites of coordination, respectively. This paper summarizes the results of our studies on the structural, spectral and catalytic properties of new mononuclear copper (II) complexes [CuL(OAc)] (1), and [CuL2] (2), (HL = 2,4‑dichloro‑6‑{[(2′‑dimethyl‑aminoethyl)methylamino]methyl}‑phenol) which can mimic the functionalities of the metalloenzymes GOase and COase. The structure of the compounds has been elucidated by X-ray crystallography and the mimicked Cu(II) catalysts were further characterized by EPR. These mimicked models were used for GOase and COase catalysis. The GOase catalytic results were identified by GC–MS and, analyzed by HPLC at room temperature. The conversion of benzyl alcohol to benzaldehyde were significant in presence of a strong base, Bu4NOMe in comparison to the neutral medium. Apart from that, despite of being monomeric in nature, both the homogeneous catalysts are very prone to participate in COase mimicking oxidation reaction. Nevertheless, during COase catalysis, complex 1 was found to convert 3,5‑ditertarybutyl catechol (3,5-DTBC) to 3,5‑ditertarybutyl quinone (3,5-DTBQ) having greater rate constant, kcat or turn over number (TON) value over complex 2. The generation of reactive intermediates during COase catalysis were accounted by electrospray ionization mass spectrometry (ESI-MS). Through mechanistic approach, we found that H2O2 is the byproduct for both the GOase and COase catalysis, thus, confirming the generation of reactive oxygen species during catalysis. Notably, complex 1 having mono-ligand coordinating atmosphere has superior catalytic activity for both cases in comparison to complex 2, that is having di-ligand environment.

The preparation of Ru4 ruthenium-cubane cluster [Ru4(hmp)4(CO)8] 1 containing four 2-pyCH2O-bridged ligands (hmp) is described along with its remarkable application in a photoelectrochemical cell (PEC) as an efficient anodic material for solar water splitting. The catalyst assembly undergoes light-driven water oxidation at pH 13.5 in a 1M in NaOH. With illumination using a white light source of 100 mW cm−2, photocurrents of up to 0.44 mA cm−2 were observed under 0.95 V vs Ag/AgCl applied bias with a Faradaic efficiency for O2 production of 91.9 %. The result establishes cluster 1 as an important candidate for electrodes in photocatalytic water splitting.

Facile synthesis of cyanovinylhydrazone bridged diferrocenyl compounds using a unique solid state synthetic method led to the formation of donor-acceptor type compounds with wide absorption in the visible region. Crystallographic analysis, spectroscopic characterization and absorption-emission spectral properties were studied to understand the structural identity and electronic nature of the molecular compounds. Fabrication of a solar cell device using the diferrocenyl donor-acceptor compound as a bifunctional system showed a moderate open-circuit voltage (VOC) of 331 mV. DFT calculation was carried out to study the electron transfer processes during the operation of the solar cell device and to understand its potential for future application.

The reactivity of unsaturated [HOs3(CO)8{µ3-Ph2PCH2PPh(C6H4)}] (1) with activated alkynes (RC CR) such as diethyl acetylenedicarboxylate (DEAD, R = CO2Et) and dimethyl acetylenedicarboxylate (DMAD, R = CO2Me) is investigated. Reaction of 1 with DEAD or DMAD at 80 °C affords four different types of products namely [Os3(CO)7(µ-CO)(µ3,η2-RCCR)(µ-dppm)] (2), [Os3(CO)7{µ,η2-RCC(H)R}{µ3,η2,κ1,κ1-Ph2PCH2P(Ph)C6H4}] (3), [Os3(CO)7{µ3,η4-(RCCR)2}(µ-dppm)] (4) and [Os3(CO)8{µ,η2,κ1-RCC(H)R}{µ3,η1,κ1,κ1-Ph2PCH2P(Ph)C6H4}] (5). Cluster 2 is formed by simple coordination of alkyne to the cluster core, whereas 3 and 5 are formed via 1,2-insertion of the alkyne into the Os−H bond of 1. Dimerization of alkynes on cluster surface leads to the formation of 4. Thermolysis of 2 under similar experimental conditions affords another new product [Os3(CO)7(µ-CO){µ3,η2,κ1,κ1-RCCC6H4(Ph)PCH2PPh2}] (6) via C C coupling between the coordinated alkyne and one of the phenyl rings of dppm. The molecular structures of the different types of products isolated from these reactions have been confirmed by single crystal X-ray diffraction analyses.

Synthesis of four new diferrocenyl hydrazone-enone compounds have been carried out by two step reaction process involving 1,1'-diacetylferrocene, hydrazides and ferrocenyl carboxyaldehyde.Structural characterization of two compounds, 6 and 7 by single crystal X-ray diffraction study showed the presence of more stable eclipsed conformation with the two ferrocenyl moieties oriented in trans- geometry.Electrochemical and metal ion sensing properties for the diferrocenyl bifunctionalized compounds have been explored to understand their potential in electronic communication and as receptor molecule.Compounds, 1,1'-[(η5-C5H5)Fe(η5-C5H4)CH═CHC(O)(η5-C5H4)Fe{(η5-C5H4)C(CH3)═N-N(H)C(O)-R}] {R = C6H4-OH (6), C6H4N-p (7) }, showed selective interaction with Pb2+ metal cation and distinct binding interaction with BSA protein.The mode of metal-receptor interaction has been established by DFT studies.The redox properties for the diferrocenyl compounds with variable end groups revealed distinct electronic communication between the two electroactive groups.

New anthracene derived dinuclear Au(I)-diacetylide complex (1) has been synthesized in which two Au(I) units are attached at 9,10-positions of ethynyl anthracene moiety. 1 exhibits rare non-covalent intermolecular Au center dot center dot center dot H-C interactions, leading to the formation of a supramolecular 2D-network. Further, to understand the effect of C CAuPPh3 units at different position, complexes (2) and (3) were synthesized, where C CAuPPh3 units are attached to 2,6-and 1,8-positions of anthracene, respectively. The absorption and emission spectra of 1-3 have been studied and surprisingly 1 was found to be highly fluorescent with high quantum yield compared to 2 and 3, this may be due to more perturbation of Au(I) on pi system. Complexes 1-3 have been characterized by elemental analysis, NMR and Mass spectroscopy and authenticated by their single-crystal X-ray structures. (C) 2016 Elsevier B.V. All rights reserved.

A series of water-soluble troponate/aminotroponate ruthenium(II)-arene complexes were synthesized, where O,O and N,O chelating troponate/aminotroponate ligands stabilized the piano-stool mononuclear ruthenium-arene complexes. Structural identities for two of the representating complexes were also established by single-crystal X-ray diffraction studies. These newly synthesized troponate/aminotroponate ruthenium-arene complexes enable efficient C-H bond arylation of arylpyridine in water. The unique structure-activity relationship in these complexes is the key to achieve efficient direct C-H bond arylation of arylpyridine. Moreover, the steric bulkiness of the carboxylate additives systematically directs the selectivity toward mono- versus diarylation of arylpyridines. Detailed mechanistic studies were performed using mass-spectral studies including identification of several key cyclometalated intermediates. These studies provided strong support for an initial cycloruthenation driven by carbonate-assisted deprotonation of 2-phenylpyridine, where the relative strength of η(6)-arene and the troponate/aminotroponate ligand drives the formation of cyclometalated 2-phenylpyridine Ru-arene species, [(η(6)-arene)Ru(κ(2)-C,N-phenylpyridine) (OH2)](+) by elimination of troponate/aminotroponate ligands and retaining η(6)-arene, while cyclometalated 2-phenylpyridine Ru-troponate/aminotroponate species [(κ (2)-troponate/aminotroponate)Ru(κ(2)-C,N-phenylpyridine)(OH2)2] was generated by decoordination of η(6)-arene ring during initial C-H bond activation of 2-phenylpyridine. Along with the experimental mass-spectral evidence, density functional theory calculation also supports the formation of such species for these complexes. Subsequently, these cycloruthenated products activate aryl chloride by facile oxidative addition to generate C-H arylated products.

We report the synthesis of six new heteroleptic Hg(II) complexes (1–6) with general composition [Hg(II)(bpy)L2] where bpy = 2,2′-bipyridine, L = benzoic acid (1), 2-amino benzoic acid (2), 3-amino benzoic acid (3), 4-amino benzoic acid (4), 2-hydroxy benzoic acid (5), 4-hydroxy benzoic acid (6). 1, 2, 4–6 are monomer with hexa coordinated Hg(II) center whereas 3 is a zig–zag 1D-polymer with hepta-coordinated Hg(II) ion. Unlike other substituted benzoic acids, the 3-amino benzoic acid shows both –NH2 and –COOH groups having affinity towards Hg(II) centers. Therefore, on reaction of HgCl2/HgBr2 with 3-amino benzoic acid it was observed that only –NH2 group coordinates to Hg(II) center and –COOH group remains uncoordinated yielding 7 and 8. 1–6 have been characterized by elemental analysis, FT-IR, thermo gravimetric analysis as well as single crystal X-ray studies. Their photo-physical properties were also investigated and maximum quantum yield was observed for 3. Polymer 3 exhibited different fluorescence spectra in different solvents with maximum emission in chloroform. The electronic communication and geometry optimization have been performed by Density Functional Theory.

Herein, we report the structural and biological activities of a deprotonated Schiff base ligand (H2L) {H2L = 1,1′-(1E,1′E)-(2,4,6-trimethyl-1,3-phenylene)bis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)dinaphthalen-2-ol} towards Co(II), Ni(II) and Cu(II) complexes obtained under different conditions. Four new metal complexes have been synthesized: isostructural dimers [Co(L)]2 (1)/[Cu(L)]2 (3), a monomer (Cl3NiH2L)·(Et3NH) (2) and a tetramer [Cu(L)]4 (4). The bioactivity of 1–3 has been investigated through molecular docking with DNA and various proteins, known to be involved in the proliferation of viral diseases or progression of cancer. Complex 1 shows the best results, through a strong binding affinity with NS2B/NS3 protease (dengue virus) in terms of binding energy (−11.21 kcal mol−1) and inhibition constant (6.02 nM). The experimental evidence for the effective binding of 1–4 with the Bovine Serum Albumin (BSA) protein and calf thymus DNA (CT-DNA) is in agreement with our molecular docking results. In addition, the cytotoxicity and antibacterial activity of 1–4 were examined and found to be compatible with biological systems, with 4 showing the highest antibacterial activity. All four complexes were analyzed by elemental analysis and UV/vis analysis, and their molecular structures were authenticated by single crystal X-ray studies.