Ferrocene-Functionalized Dithiocarbamate Zinc(II) Complexes as Efficient Bifunctional Catalysts for the One-Pot Synthesis of Chromene and Imidazopyrimidine Derivatives via Knoevenagel Condensation Reaction.

Four new mononuclear/coordination polymeric (CP) zinc(II) complexes (1-4) of ferrocenyl/pyridyl-functionalized dithiocarbamate ligands, N-ferrocenylmethyl-N-butyl dithiocarbamate (L1), N-ferrocenylmethyl-N-ethylmorpholine dithiocarbamate (L2), N-ferrocenylmethyl-N-2-(diethylamino)ethylamine dithiocarbamate (L3), and N-4-methoxybenzyl-N-3-methylpyridyl dithiocarbamate (L4), have been synthesized and characterized by elemental analyses, IR, UV-vis, and 1H and 13C{1H} NMR spectroscopic techniques. The solid-state structures of complexes 1, 3, and 4 have been determined by single-crystal X-ray crystallography as well as powder X-ray diffraction. Single-crystal X-ray crystallography revealed a monomeric structure for complex 1 but 1D polymeric structures for complexes 3 and 4. In all complexes, dithiocarbamate ligands are bonded to the Zn(II) metal ion in a S^S chelating mode, and in the CPs, N atoms on the 2-(diethylamino)ethylamine and 3-pyridyl functionalities in the ligands on the neighboring molecules are also bonded to metal centers, leading to the formation of either a discrete tetrahedral molecule in 1 or 1D CP structures in 3 and 4. The Zn(II) metal centers in the polymeric structures exhibited either square-pyramidal or octahedral geometries. The supramolecular structures in these complexes are sustained via C-H···π (ZnCS2, chelate; 3 and 4), C-H···π, and H···H interactions. The catalytic performances of complexes have also been assessed in the Knoevenagel condensation and one-pot multicomponent reactions. Catalysis results showed that the CP 3 acts as a heterogeneous bifunctional catalyst with excellent transformation efficiency at low catalyst loading.

Effect of Substituents on the Crystal Structures, Optical Properties, and Catalytic Activity of Homoleptic Zn(II) and Cd(II) ß-oxodithioester Complexes.

Five novel zinc(II) and cadmium(II) ß-oxodithioester complexes, [Zn(L1)2] (1), [Zn(L2)2]n (2), [Zn(L3)2]n (3) [Cd(L1)2]n (4), [Cd(L2)2]n (5), with ß-oxodithioester ligands, where L1 = 3-(methylthio)-1-(thiophen-2-yl)-3-thioxoprop-1-en-1-olate, L2 = 3-(methylthio)-1-(pyridin-3-yl)-3-thioxoprop-1-en-1-olate, and L3 = 3-(methylthio)-1-(pyridin-4-yl)-3-thioxoprop-1-en-1-olate, were synthesized and characterized by elemental analysis, IR, UV-vis, and NMR spectroscopy (1H and 13C{1H}). The solid-state structures of all complexes were ascertained by single-crystal X-ray crystallography. The ß-oxodithioester ligands are bonded to Zn(II)/Cd(II) metal ions in an O∧S and N chelating/chelating-bridging fashion leading to the formation of 1D (in 2-4) and 2D (in 5) coordination polymeric structures, but complex 1 was obtained as a discrete tetrahedral molecule. Complex 4 crystallizes in the C2 chiral space group and has been studied using circular dichroism (CD) spectroscopy. The multidimensional assemblies in these complexes are stabilized by many important noncovalent C-H···π (ZnOSC3, chelate), π···π, C-H···π, and H···H interactions. The catalytic activities of 1-5 in reactions involving C-C and C-O bond formation have been studied, and the results indicated that complex 3 can be efficiently utilized as a heterogeneous bifunctional catalyst for the Knoevenagel condensation and multicomponent reactions to develop biologically important organic molecules. The luminescent properties of complexes were also studied. Interestingly, zinc complexes 1-3 showed strong lumniscent emission in the solid state, whereas cadmium complexes 4 and 5 exhibited bright luminescent emission in the solution phase. The semiconducting behavior of the complexes was studied by solid-state diffuse reflectance spectra (DRS), which showed optical band gaps in the range of 2.49-2.62 eV.

Spontaneous Resolution upon Crystallization and Preferential Induction of Chirality in a Discrete Tetrahedral Zinc(II) Complex Comprised of Achiral Precursors.

A pair of enantiomeric tetrahedral complexes (Λ-[Zn(L)2] and Δ-[Zn(L)2]) comprised of the achiral ligand methyl-3-hydroxy-3-phenyl-2-propenedithioate (L) have been synthesized by spontaneous resolution. Two chiral inducers, viz., d-(-)- and l-(+)-tartaric and mandelic acids, have been employed to achieve bulk homochirality and extend the generality of the present work. The work highlights the achievement of bulk homochirality using readily available chiral inducers in the synthesis of a spontaneously resolving chiral tetrahedral zinc(II) complex using achiral starting materials. These findings are established by 30 sets of single-crystal X-ray diffraction data with refined Flack parameters and circular dichroism spectroscopy.

Impact of ligand framework on the crystal structures and luminescent properties of Cu(I) and Ag(I) clusters and a coordination polymer derived from thiolate/iodide/dppm ligands.

New homoleptic hexanuclear Ag(I) and heteroleptic trinuclear Cu(I) clusters and a Cu(I) coordination polymer (CP) of the formulas [Ag6(dtc)6] 1, [Cu3I2(dppm)3(dtc)] 2, and [Cu(ttc)I]∞ 3 (dtc = N-methylbenzyl-N-methyl-thiophenedithiocarbamate; dppm = 1,1-bis(diphenylphosphino)methane; and ttc = dimethyltrithiocarbonate) were synthesized and characterized by elemental analysis, IR, UV-vis, (1)H, (13)C, and (31)P NMR spectroscopies, and their structures were elucidated by X-ray crystallography. The complexes show interesting structures and luminescent properties. Complex 1, which is centrosymmetric, contains four short Ag···Ag interactions at 2 × 2.966(1) and 2 × 3.014(1) Å. There are also several Ag···Ag distances of 3.3-3.4 Å. The molecule shows hexagonal orientation with alternating silver and sulfur atoms of the overlapping Ag3S3 hexagons in the front and rear, along the a axis. Complex 2 is a rare trinuclear cluster complex of Cu(I); the Cu···Cu distances are 2.906(2), 3.551(2), and 3.338(2) Å, the foremost representing a substantial intermetallic contact. The Cu3I2P6S2 core is comprised of three fused distorted hexagonal rings with the I1 atom located at the center participating in all three rings. Complex 3 is an iodide-bridged CP with a "staircase"-like arrangement in which the Cu(I) is tetrahedrally surrounded by a sulfur atom from the ttc ligand and three iodine atoms. Unlike 3, which is nonluminescent, 1 and 2 are strongly luminescent in the solid and solution at room temperature. The time-resolved emission spectra reveal a triexponential decay curve and short mean lifetime characteristic of fluorescence behavior. Diffuse reflectance spectroscopy revealed semiconducting behavior with band gaps of 2.12, 3.01, and 2.18 eV for 1-3, respectively.

The rigidity and chelation effect of ligands on the hydrogen evolution reaction catalyzed by Ni(II) complexes.

With increasing interest in nickel-based electrocatalysts, three heteroleptic Ni(II) dithiolate complexes with the general formula [Ni(II)L(L')2] (1-3), L = 2-(methylene-1,1'-dithiolato)-5,5'-dimethylcyclohexane-1,3-dione and L' = triphenylphosphine (1), 1,1'-bis(diphenylphosphino)ferrocene (DPPF) (2), and 1,2-bis(diphenylphosphino)ethane (DPPE) (3), have been synthesized and characterized by various spectroscopic techniques (UV-vis, IR, 1H, and 31P{1H} NMR) as well as the electrochemical method. The molecular structure of complex 2 has also been determined by single-crystal X-ray crystallography. The crystal structure of complex 2 reveals a distorted square planar geometry around the nickel metal ion with a NiP2S2 core. The cyclic voltammograms reveal a small difference in the redox properties of complexes (ΔE° = 130 mV) while the difference in the catalytic half-wave potential becomes substantial (ΔEcat/2 = 670 mV) in the presence of 15 mM CF3COOH. The common S^S-dithiolate ligand provides stability, while the rigidity effect of other ligands (DPPE (3) > DPPF (2) > PPh3 (1)) regulates the formation of the transition state, resulting in the NiIII-H intermediate in the order of 1 > 2 > 3. The foot-of-the-wave analysis supports the widely accepted ECEC mechanism for Ni-based complexes with the first protonation step as a rate-determining step. The electrocatalytic proton reduction activity follows in the order of complex 1 > 2 > 3. The comparatively lower overpotential and higher turnover frequency of complex 1 are attributed to the flexibility of the PPh3 ligand, which favours the easy formation of a transition state.

Chlorocobaloxime containing N-(4-pyridylmethyl)-1,8-naphthalamide peripheral ligands: synthesis, characterization and enhanced electrochemical hydrogen evolution in alkaline medium.

Two new discrete cobaloxime based complexes with the general formula [ClCo(dioxime)2L] (1 and 2), L1 = N-(4-pyridylmethyl)-1,8-naphthalamide, L2 = 4-bromo-N-(4-pyridylmethyl)-1,8-naphthalamide have been synthesized and characterized by various spectroscopic techniques such as FT-IR, 1H, 13C{1H} NMR and PXRD. The molecular structures of both complexes have also been determined using single crystal X-ray crystallography. The solid state molecular structures revealed distorted octahedral geometry around the Co(III) central metal ion with two dioximes in the equatorial plane and axial positions are occupied by chloro and pyridine nitrogen of N-(4-pyridylmethyl)-1,8-naphthalamide ligands. Both complexes exhibit weaker non-covalent interactions (C-H⋯O, C-H⋯Cl and C-H⋯π(Centroid) in complex 1 whereas C-H⋯O and C-H⋯Br in complex 2) resulting in the formation of dimeric and 1D supramolecular structures. Furthermore, these complexes are immobilized onto the surface of activated carbon cloth (CC) and their electrocatalytic performance for the hydrogen evolution reaction (HER) has been investigated in alkaline and acidic media as well as buffer solution. In alkaline medium, we found that complex 2 exhibited impressive electrocatalytic HER activity and produced a current density of -10 mA cm-2 at an overpotential of 260 mV, whereas complex 1 produced the same current density at an overpotential of 334 mV. An electrochemical impedance spectroscopy (EIS) spectral study revealed the faster charge transfer kinetics of complex 2 than that of complex 1. Similarly, the low Tafel slope (100 mV dec-1) for the HER with complex 2 indicates faster HER kinetics compared to complex 1. The chronoamperometric study showed that complex 2 is stable under electrocatalytic HER conditions for 5 h without losing the initial current density and it has also been established that the complex structure is retained after electrocatalysis.

Homoleptic Ni(II) dithiocarbamate complexes as pre-catalysts for the electrocatalytic oxygen evolution reaction.

Four new functionalized Ni(II) dithiocarbamate complexes of the formula [Ni(Lx)2] (1-4) (L1 = N-methylthiophene-N-3-pyridylmethyl dithiocarbamate, L2 = N-methylthiophene-N-4-pyridylmethyl dithiocarbamate, L3 = N-benzyl-N-3-pyridylmethyl dithiocarbamate, and L4 = N-benzyl-N-4-pyridylmethyl dithiocarbamate) have been synthesized and characterized by IR, UV-vis, and 1H and 13C{1H} NMR spectroscopic techniques. The solid-state structure of complex 1 has also been determined by single crystal X-ray crystallography. Single crystal X-ray analysis revealed a monomeric centrosymmetric structure for complex 1 in which two dithiocarbamate ligands are bonded to the Ni(II) metal ion in a S^S chelating mode resulting in a square planar geometry around the nickel center. These complexes are immobilized on activated carbon cloth (CC) and their electrocatalytic performances for the oxygen evolution reaction (OER) have been investigated in aqueous alkaline solution. All the complexes act as pre-catalysts for the OER and undergo electrochemical anodic activation to form Ni(O)OH active catalysts. Spectroscopic and electrochemical characterization revealed the existence of the interface of molecular complex/Ni(O)OH, which acts as the real catalyst for the OER. The active catalyst obtained from complex 2 showed the best OER activity achieving 10 mA cm-2 current density at an overpotential of 330 mV in 1.0 M aqueous KOH solution.

Synthesis, structure and light-harvesting properties of some new transition-metal dithiocarbamates involving ferrocene.

Nine new transition-metal dithiocarbamates involving ferrocene (Fc), namely, [M(FcCH(2)Bzdtc)(2)] (M=Ni(II) (1), Cu(II) (2), Cd(II) (3), Hg(II) (4), Pd(II) (5), Pt(II) (6) and Pb(II) (7); Bzdtc=N-benzyl dithiocarbamate) and [M(FcCH(2)Bzdtc)(3)] (M=Co(II) (8) and UO(2) (VI) (9)), have been synthesised and characterised by micro analyses, IR spectroscopy, (1)H and (13)C NMR spectroscopy, and in three cases by single-crystal X-ray analysis. The peak broadening in the (1)H spectrum of the copper complex indicates the paramagnetic behaviour of this compound. A square-planar geometry around the nickel and copper complexes and distorted linear geometry around the mercury complex have been found. The latter geometry is attributed to the bulkiness of the methylferrocenyl and benzyl groups. The observed single quasi-reversible cyclic voltammograms for complexes 2, 8 and 9 indicate the stabilisation of a metal centre other than Fe in their characteristic oxidation state. These complexes have been used as a photosensitiser in dye-sensitised solar cells.

New heteroleptic [Ni(ii) 1,1-dithiolate-phosphine] complexes: synthesis, characterization and electrocatalytic oxygen evolution studies.

Four new heteroleptic Ni(ii) complexes with general formula [Ni(ii)(LL')] (L = 2-(methylene-1,1'-dithiolato)-5-phenylcyclohexane-1,3-dione (L1) and 2-(methylene-1,1'-dithiolato)-5,5'-dimethylcyclohexane-1,3-dione (L2); L' = 1,2-bis(diphenylphosphino)ethane (dppe) and bis(diphenylphosphino)monosulphide methane (dppms) have been synthesized and characterized by elemental analysis and spectroscopy (IR, UV-Vis, 1H, 13C{1H} and 31P{1H} NMR). All complexes 1-4 have also been characterized by PXRD and single crystal X-ray crystallography. The solid state molecular structures revealed distorted square planar geometry about the four-coordinate Ni(ii) metal centre together with rare NiH-C intra/intermolecular anagostic interactions in axial positions. In these complexes supramolecular structures have been sustained by non-covalent C-HO, C-OH-O, C-Hπ, C-Hπ (NiCS2, chelate), ππ and HH interactions. Their electrocatalytic properties have been investigated for oxygen evolution reaction (OER) in which complex 2 showed the highest activity with 10 mA cm-2 at the potential of 1.58 V vs. RHE. In addition, complex 2 also exhibits an OER onset potential at 1.52 V vs. RHE.

Cooperative metal-ligand influence on the formation of coordination polymers, and conducting and photophysical properties of Tl(i) ß-oxodithioester complexes.

Eight novel Tl(i) ß-oxodithioester complexes, [TlL]n (1-8), with ligands, L = methyl-3-hydroxy-3-(2-furyl)-2-propenedithioate (L1), methyl-3-hydroxy-3-(2-thienyl)-2-propenedithioate (L2), methyl-3-hydroxy-3-(3-pyridyl)-2-propenedithioate (L3), methyl-3-hydroxy-3-(4-pyridyl)-2-propenedithioate (L4), methyl-3-hydroxy-3-(9-anthracenyl)-2-propenedithioate (L5), methyl-3-hydroxy-3-(4-fluorophenyl)-2-propenedithioate (L6), methyl-3-hydroxy-3-(4-chlorophenyl)-2-propenedithioate (L7) and methyl-3-hydroxy-3-(4-bromophenyl)-2-propenedithioate (L8), were synthesized and thoroughly characterized by elemental analysis, and IR, UV-Vis, 1H and 13C{1H} NMR spectroscopy, and their structures were ascertained by X-ray crystallography. Complexes 1 and 2 crystallized in P21 and P212121 chiral space groups, respectively, and were studied using Circular Dichroism (CD) spectra. Solid state structural analyses revealed that the ß-oxodithioester ligands are bonded to Tl(i) ions in (O, S) chelating and chelating-bridging modes, thereby forming different types of 1D and 2D coordination polymeric structures. By considering the metal-assisted bonding interactions, various coordination numbers of 5-8 and 10 are established around the metal centre. Except for 5 and 7a which have TlTl separations at 3.724(1) and 3.767(1), 3.891(1) Å respectively, the remaining complexes have no TlTl distances <4.0 Å. This indicates that the majority of structures contain only weak inter- and intramolecular thallophilic interactions. The structures of 1-8 highlight the role played by variations in substituents in the dithioester unit in the structure and properties of the complexes. The multi-dimensional assembly in these complexes rests on important non-covalent C-Hπ (TlOSC3, chelate), C-HX (X = F, Cl, O, N), C-Hπ, HH and rare TlH-C intermolecular anagostic interactions. The TlH-C anagostic interactions together with C-OTl and C-STl interactions formed 7-, 11- and 12-membered chelate rings about the metal centers. The anagostic interactions in 1, 2 and 7b were assessed by theoretical calculations. All the complexes showed bright green luminescent emissions in solution and solid phases. Time-resolved emission spectra revealed a triexponential decay curve and short mean lifetime for fluorescence behavior.

Monoclinic modification of 1,1,3,3,5,5-hexa-methyl-cyclo-1,3,5-tris-tannathiane.

The asymmetric unit of the title compound, [Sn(3)(CH(3))(6)S(3)], contains two molecules with twist-boat conformations. There are intermolecular S⋯H (2.929 Å), S⋯S (3.433 Å), S⋯C (3.465 Å) and C⋯H (2.898 Å) inter-actions in addition to prominent intermolecular Sn⋯S inter-actions of 3.692 and 3.769 Å.

Influence of the ligand frameworks on the coordination environment and properties of new phenylmercury(II) ß-oxodithioester complexes.

New phenylmercury(II) complexes of the form [PhHg(L1), PhHg(L2) and PhHg(L3)] (L1 = methyl-3-hydroxy-3-(p-methoxyphenyl)-2-propenedithioate (1), L2 = methyl-3-hydroxy-3-(p-bromophenyl)-2-propenedithioate (2) and L3 = methyl-3-hydroxy-(3-pyridyl)-2-propenedithioate (3)) have been synthesized and characterized by elemental analysis, IR, UV-Vis, 1H and 13C NMR. The crystal structures of 1­3 reveal a linear geometry about the mercury atom via ipso-C and S11 atoms. 1 and 2 exhibited O,S-coordination whereas 3 preferred S,S-coordination. Intramolecular Hg∙∙∙O bonding interactions are also observed in 1 and 2 at distances of 2.638(14), 2.644(10) Å respectively. However in 3, incorporation of the 3-pyridyl substituent on the ligand enhanced the proximity of S13 and N14, giving rise to significant intramolecular Hg∙∙∙S and intermolecular Hg∙∙∙N interactions at 3.141(5) Å and 2.77(2) Å respectively generating a 1-D polymeric chain motif. The O,S- or S,S-coordination preference and Hg∙∙∙N interactions have been assessed by DFT calculations. All the complexes show metal perturbed ligand-centred luminescence characteristics in solution and in the solid phase. The band gap values 2.54, 2.66 and 2.61 eV for 1, 2 and 3, respectively, evaluated from the diffuse reflectance spectroscopy show the semiconducting nature of the complexes.

Intermolecular Tl···H-C anagostic interactions in luminescent pyridyl functionalized thallium(I) dithiocarbamates.

Crystal structures of novel pyridyl functionalised [Tl(L)]∞ (L = (N-benzyl-N-methylpyridyl) dithiocarbamate(L1) 1, bis(N-methylpyridyl) dithiocarbamate(L2) 2, (N-methyl(1,4-benzodioxane-6-yl)-N-methylpyridyl)dithiocarbamate(L3) 3, (N-ferrocenyl-N-methylpyridyl) dithiocarbamate(L4) 4) complexes revealed rare intermolecular C-H···Tl anagostic and C-S···Tl interactions forming a six-membered chelate ring about the metal center, which have been assessed by DFT calculations. The strong thallophilic bonding is responsible for the strong luminescent characteristics of the complexes in the solid phase.

Photosensitizing activity of ferrocenyl bearing Ni(II) and Cu(II) dithiocarbamates in dye sensitized TiO2 solar cells.

Biferrocene bearing planar metal dithiocarbamates, namely, [M(FcCH2dtc)2] (dtc = furan-2-ylmethyldithiocarbamate, M = Cu(II) 1, Ni(II) 4; dtc = benzo[d][1,3]dioxol-5-ylmethyl dithiocarbamate, M = Cu(II) 2, Ni(II) 5; dtc = pyridin-2-ylmethyldithiocarbamate, M = Cu(II) 3, Ni(II) 6; Fc = ferrocenyl; Fe(η(5)-C5H5)(η(5)-C5H4-)), have been synthesized and characterized by microanalysis, magnetic susceptibility and cyclic voltammetry. Structures of 1, 2 and 4 have been obtained by single crystal X-ray diffraction. These complexes with pyridyl, piperonyl and furfuryl as heteroaromatic groups in the dithiocarbamate ligands have been exploited as sensitizers in dye sensitized TiO2 solar cells for converting sunlight into electrical energy. Light-to-electrical energy conversion efficiencies achieved using these sensitizers are considerably greater than those obtained with analogous compounds previously reported by us. The overall conversion efficiency (η) is found to be dependent upon the nature of the heteroaromatic conjugated linkers and increases in the order η (ferrocenylfurfuryl) > η (ferrocenylpiperonyl) > η (ferrocenylpyridyl) all values being lower than that obtained in the reference Ru dye N719 under similar experimental conditions. The conversion efficiencies also vary with the metal being higher for Ni (4, 5 and 6) than for Cu complexes (1, 2 and 3). The X-ray structural analyses reveal the existence of rare M···H-C intermolecular anagostic interactions involving the metal atom in chain motifs in 1 and 4, which are retained in solution as evidenced by (1)H NMR spectroscopy.

Facile in situ copper(II) mediated C-S bond activation transforming dithiocarbimate to carbamate and thiocarbamate generating Cu(II) and Cu(I) complexes.

Facile in situ Cu(II) mediated transformation of p-tolylsulfonyldithiocarbimate in conjunction with polypyridyl or phosphine ligands into corresponding carbamate and thiocarbamate led to the formation of new copper complexes with varying nuclearities and geometries, via C-S bond activation of the ligand within identical reaction systems.

Enhanced light harvesting efficiencies of bis(ferrocenylmethyl)-based sulfur rich sensitizers used in dye sensitized TiO2 solar cells.

In this work, the photosensitizing properties of ferrocene (Fc)-based compounds FcCH(2)CS(3)CH(2)Fc (1) and FcCH(2)SSCH(2)Fc (2) were investigated and significant enhancement in the light harvesting efficiency was observed compared to those achieved with previously reported compounds from our lab. The compounds were fully characterized by spectroscopy and X-ray crystallography, and their electrochemical properties studied. DSSCs based on these dyes display efficiencies comparable to those of a standard cell based on N719 under similar experimental conditions. These studies demonstrate that ferrocenyl-based sulfur rich compounds with proper orientation of the Fc groups assisted via suitable linkers, together with desired redox properties and visible region electronic absorption features could constitute a new class of photosensitizers targeting light driven reactions.

Unprecedented coordination of dithiocarbimate in multinuclear and heteroleptic complexes.

An uncommon coordination protocol induced by the p-tolylsulfonyl dithiocarbimate ligand (L) [L = p-CH(3)C(6)H(4)SO(2)N[double bond, length as m-dash]CS(2)(2-)] in conjunction with PPh(3) allowed the formation of novel homodimetallic, Cu(2)(PPh(3))(4)L (1), trinuclear heterometallic Cu(2)Ni(L)(2)(PPh(3))(4) (2) and heteroleptic complexes of general formula cis-[M(PPh(3))(2)L] [M = Pd(ii) (3), Pt(ii) (4)]. The complexes have been characterized by microanalysis, mass spectrometry, IR, (1)H, (13)C and (31)P NMR and electronic absorption spectra and single-crystal X-ray crystallography. 2 uniquely consists of square planar, trigonal planar and tetrahedral coordination spheres within the same molecule. In both heteroleptic complexes 3 and 4 the orientation of aromatic protons of PPh(3) ligand towards the Pd(ii) and Pt(ii) center reveals C-HPd and C-HPt rare intramolecular anagostic or preagostic interactions. These complexes exhibit photoluminescent properties in solution at room temperature arising mainly from intraligand charge transfer (ILCT) transitions. The assignment of electronic absorption bands has been corroborated by time dependent density functional theory (TD-DFT) calculations. Complexes 1 and 2 with σ(rt) values ∼ 10(-6) S cm(-1) show semi-conductor properties in the temperature range 313-403 K whereas 3 and 4 exhibit insulating behaviour.

Syntheses, crystal, photoluminescence and electrochemical investigation of some new phenylmercury(II) dithiocarbamate complexes involving ferrocene.

A series of new heterobimetallic phenylmercury(II) dithiocarbamate complexes incorporating the ferrocenyl moiety (C(5)H(5))Fe(C(5)H(4)) (Fc), namely PhHgS(2)CN(CH(2)Fc)CH(2)C(6)H(5), (1), PhHgS(2)CN(CH(2)Fc)CH(CH(3))(2), (2), PhHgS(2)CN(CH(2)Fc)(CH(2))(3)CH(3), (3) and [PhHgS(2)CN(CH(2)Fc)](2)(CH(2)C(6)H(4)CH(2)), (4) have been prepared and characterized by elemental analysis, UV-Vis, IR, (1)H and (13)C NMR spectroscopies. The crystal structures of 1, 2 and 4 showed a linear core at the Hg(II) centre of the molecule, bound by the sulfur atom of the dithiocarbamate ligand and carbon atom of the aromatic ring. Weak intermolecular Hg...S interactions form "head-to-tail" dimers in the cases of 1 and 2. 4 forms a similar dimeric structure, forming two pairs of Hg...S interactions to generate a tetrametallic unit. The observed quasi-reversible cyclic voltammograms of the complexes have been corroborated by calculating gross electron population at each atom for the neutral as well its oxidized species obtained at the density functional level (DFT) of theory, which suggests an electron withdrawing effect from the organomercury(ii)-dithiocarbamate group. The electronic absorption bands of all the four complexes were assigned with the help of time dependent density functional theory (TD-DFT) calculations. Upon excitation at approximately 440 nm 1, 3 and 4 exhibited a medium strong photoluminescence emission at approximately 500 nm as a consequence of MLCT intraligand charge transfer. 1, when excited at 256 nm exhibits photoluminescence emission at 398 nm.

Efficient phenylmercury(II) methylferrocenyldithiocarbamate functionalized dye-sensitized solar cells.

Two new heterobimetallic phenylmercury(ii) dithiocarbamate complexes incorporating the ferrocenyl moiety (C(5)H(5))Fe(C(5)H(4)) (Fc), namely PhHgS(2)CN(CH(2)Fc)CH(2)C(5)H(4)N, (1) and PhHgS(2)CN(CH(2)Fc)CH(2)C(4)H(3)O, (2) have been prepared and characterized by elemental analysis, UV-Vis, IR, (1)H and (13)C NMR spectroscopies. The crystal structures of 1 and 2 showed a linear core at the Hg(ii) centre of the molecule, bound by the sulfur atom of the dithiocarbamate ligand and carbon atom of the aromatic ring. Weak intermolecular HgS interactions form "head-to-tail" dimers in the cases of 1 and 2. The observed quasi-reversible cyclic voltammograms of the complexes have been corroborated by calculating gross natural electron population and gross natural electron spin population at each atom for the neutral as well its oxidized species obtained at density functional level (DFT) of theory, which suggests that the delocalization of electron spin population can affect the magnitude of ΔE(p). The electronic absorption bands of both the complexes were assigned with the help of time dependent density functional theory (TD-DFT) calculations. The light harvesting properties of both 1 and 2 in conjunction with our previously reported compound PhHgS(2)CN(CH(2)Fc)CH(2)C(6)H(5) (3) have been reported.

Syntheses, crystal and molecular structures, and properties of some new phenylmercury(II) dithiolate complexes.

A series of new phenylmercury(II) dithio complexes [PhHg(Bun2dtc)] (; Bun2dtc-=di-n-butyldithiocarbamate), [PhHg(morphdtc)] (; morphdtc-=morpholinedithiocarbamate), [PhHg(Bz2dtc)] (; Bz2dtc-=dibenzyldithiocarbamate), [PhHg(methoxethxant)] (; methoxethxant-=2-methoxyethylxanthate) [(PhHg)2NED] (; NED2-=1-nitroethylene-2,2-dithiolate) and [(PhHg)2CDC] (; CDC2-=cyanodithioimidocarbonate) have been prepared and characterized by elemental analysis, UV-Vis, IR, 1H and 13C NMR spectra and mass spectrometry. The crystal structures of , and showed a linear Hg(II) core at the center of the molecules. The weak intra- and intermolecular HgS interactions provide a molecular chain framework. The reaction of PhHgO2CCH3 with Bun2dtcH gave the known dimeric complex Hg(Bun2dtc)2 while the Ni(O2CCH3)2 mediated reaction gave instead of the expected heterobimetallic complex [PhHgNi(Bun2CS2)2]O2CCH3 which has been corroborated by natural charges at each atom obtained at the density functional level (DFT) of theory. Upon excitation at 358 nm exhibited a medium strong photoluminescence emission at 420 nm as a consequence of intraligand pi-->pi* transitions. The electronic absorption bands of were assigned from time dependent density functional theory (TD-DFT) calculations. Geometrical configurations of , and have been optimized using the DFT method. All of the complexes are weakly conducting (sigmart approximately 10(-12) S cm(-1)). However and exhibited semiconductivity with band gaps of 0.39 and 0.94 eV respectively.