Search

[Rh(α-NaiR)2Cl2]ClO4 (2) (α-NaiR (1), 1-alkyl-2-(naphthyl-α-azo)imidazoles, R = Me (a), Et (b)) complexes react with ArNH2 (where Ar = X C6H4 , X = H (3), Me (4), Cl (5)) to synthesize the naphthyl appended C N fused bis-[1-alkyl-2-{(7-imidoaryl)naphthyl-α-azo}imidazole-N,N′,N″]rhodium(III)perchlorate complexes [Rh(α-NaiR N Ar)2]ClO4 (3–5). The single crystal X-ray diffraction measurements of one of the complexes, [Rh(α-NaiEt N C6H5)2]ClO4 (3b), confirms the structure. The absorption spectra of the complexes 3–5 show high intense broad multiple transitions at 650–800 nm compared to the transition of the precursor 2 at 500 nm and DFT computations have assigned this transition to an admixture of LLCT (ligand-to-ligand charge transfer, imidoaryl → azonaphthyl) and LMCT transitions. The cyclic voltammogram shows a quasireversible oxidation at >0.8 V, which is assigned by DFT computation to oxidation of the imidoaryl chelate, along with azo reductions at

Two discrete manganese(III) coordination compounds, [Mn(L)(OCN)]2 (1) and [Mn(L′)(H2O)2][dnba]·DMF·H2O (2) bearing in situ generated Schiff base ligands H2L [H2L = N,N′-o-phenylenebis(salicylaldimine)] or H2L′ [H2L′ = N,N′-bis(salicylidene)ethylenediamine], were easily prepared by treating Mn(CH3COO)2·4H2O with salicylaldehyde and o-phenylenediamine (for 1) or ethylenediamine (for 2), and in the presence of supporting cyanate ligands or 3,5-dinitrobenzoate (dnba) counter anions, respectively. The obtained products were isolated as air-stable crystalline solids and were fully characterized by spectroscopic methods, single-crystal X-ray diffraction, topological analysis, as well as theoretical methods. The X-ray diffraction of the compound 1 reveals that the structure is dimeric with phenolic oxygen atom acting as bridge between two symmetrically equivalent Mn(III) atoms. The structure of 2 contains mononuclear cationic [Mn(L′)(H2O)2] units along with a 3,5-dinitrobenzoate anion and crystallization DMF molecule. Structural analysis indicates a distorted octahedral geometry for both complexes. Intermolecular hydrogen bonding and π–π stacking interactions are present in the lattice and play an important role in cohesion of the structures. Topological analysis of the compound 2 reveals a binodal 3,4-connected underlying 2D net with the 3,4L13 topology. Noncovalent interactions were investigated in terms of energies and geometries using theoretical calculations. Fluorescence and antibacterial properties of 1 and 2 were also investigated and discussed.

Two novel metal complexes derived from interactions of Cd2+ and Hg2+ ions with 3-aminoquinoline in the molar ratio 1 : 2 are reported. The synthesized and isolated metal complexes were characterized by UV/VIS, FT-IR, 1H- and 13C-NMR, and ESI-MS spectroscopic studies, and elemental analyses. FT-IR and NMR studies confirmed that the NH2 group remains uncoordinated in both synthesized complexes. The molecular structure of the CdII complex was additionally determined by X-ray single-crystal analysis. The Cd complex crystallizes in the triclinic centrosymmetric P space group. Moreover, the CdII complex exists as neutral discrete molecule and was found to show tetrahedral geometry.

A series of two new Zn(II) complexes derived from 3-aminoquinoline are reported. The complexes were synthesized by the interaction of 3-aminoquinoline and Zn(II) ions in 2:1 molar ratio. The structure of synthesized complexes is investigated by elemental analyses, ESI-MS, FT-IR, 1 H and 13 C NMR and UV–Vis spectroscopic studies. A single crystal X-ray diffraction measurement study reveals tetrahedral geometry around the zinc ion, and existence as a neutral discrete molecule.

The three-components reaction of dimethyltin dibromide with imidazo[1,2-a]pyridine and allyl bromide in ethanol affords an ionic complex, bis(1-allylimidazo[1,2-a]pyridinium) dimethyltetrabromostannate(II). X-ray crystal structure analysis of the complex reveals the tin atom to be hexacoordinated, forming a dianion. Organotin(IV) halides on reacting with imidazo[1,2-a]pyridines yield 1:2 complexes. The X-ray crystal structure analysis of such a complex shows the tin atom to be hexacoordinated, with two imidazo[1,2-a]pyridine molecules coordinated through the N1 atom. Bis(imidazo[1,2-a]pyridine)dimethyltin dibromide does not show any reactivity towards allyl bromide or 1-(1-pyrrodinyl)cyclohexene, even on refluxing in ethanol.

A novel 2-Amino-6-nitrobenzothiazole (2A6NBT) complex of tetrathiafulvalene (TTF) was synthesized and crystal structure of (TTF)-(2A6NBT) 2 is reported. The asymmetric unit is found to have half molecule of TTF and one molecule of 2-Amino-6-nitrobenzothiazole. Several short interactions of type π–π, nonconventional Van der Waals and hydrogen bonding were observed in this complex. Localization of the inversion center lead to the presence of 2A6NBT moieties in the trans position. Van der Waals type short interactions existed predominantly between one TTF and six 2A6NBT molecules. The C–C bond length of 1.314 A in (TTF)-(2A6NBT) 2 is the shortest C–C bond distance reported among the TTF molecules studied so far. TTF's and 2A6NBT molecules are nearly orthogonal to each other. TTF form segregated stacks along the c axis and exhibit a novel “stair case” structure. The extensive short interactions lead to supramolecular architectures. Two probe room temperature conductivity value of powder was (∼1.4×10 −7 S/cm) found to be within the semiconducting range measurements. Density functional calculations using the hybrid functional B3LYP with 6–31 G (d) basis set indicated thermodynamically favored product. Scanning electron microscopy images revealed rod like microstructures.

A novel series of Pd(II) complexes derived from 2-thiophenecarboxaldehyde and 1,8-diaminonaphthalene has been synthesized and characterized by various physico-chemical and spectroscopic techniques viz., elemental analyses, IR, UV–vis, 1 H and 13 C NMR spectroscopy, and ESI-mass spectrometry. The structure of ligand, 2-(2-thienyl)-2,3-dihydro-1H-perimidine has been ascertained on the basis of single crystal X-ray diffraction. All Pd(II) complexes together with the corresponding ligand have been evaluated for their ability to suppress the in vitro growth of microbes, Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa , Citrobacter sp., Bacillus subtilis and Stenotrophomonas acidaminiphila and results show that Pd(II) complexes have more significant antimicrobial activity than their corresponding ligand. Fluorescence spectroscopic measurements clearly support that both of the Pd(II) complexes show significant DNA binding with calf thymus DNA.

A family of novel platinum group metal complexes containing bidentate chelating 1-pyrimidyl-3-methylimidazolyl bromide ( HL1 · Br ) and 1-pyrimidyl-3-methylimidazolyl-2-thione ( L2 ) ligands has been synthesized. The synthetic protocol for the formation of these complexes differs from one ligand to the other. Treatment of ligand ( HL1 · Br ) with the metal precursors led to the formation of complexes via in situ carbene transfer reactions. The silver–NHC complex ( 1 ) was formed by the reaction of HL1 · Br with silver oxide under light-free conditions. Subsequent addition of appropriate metal precursors to the silver–NHC complex yielded [(η 6 -arene)Ru( L1 )Cl]PF 6 complexes {arene = C 6 H 6 ( 2 ), p - i PrC 6 H 4 Me ( 3 ), C 6 Me 6 ( 4 )} on stirring at room temperature, whereas the complexes [CpRu( L1 )(PPh 3 )]PF 6 {Cp = C 5 H 5 (5), C 9 H 7 ( 6 )} were obtained under reflux conditions. In the case of ligand L2 , stirring of equimolar quantities of metal precursors and the ligand at room temperature yielded [(η 6 -arene)Ru( L2 )Cl]PF 6 {arene = C 6 H 6 (7), p - i PrC 6 H 4 Me ( 8 ), C 6 Me 6 ( 9 )}, and [Cp ∗ M( L2 )Cl]PF 6 {Cp ∗ = C 5 Me 5 , M = Rh ( 10 ), Ir ( 11 )}. All these complexes were characterized by CHN analysis, IR, NMR and mass spectrometry besides confirmation by single crystal X-ray diffraction studies for some representative complexes as their hexafluorophosphate salts [ 3 ]PF 6 , [ 5 ]PF 6 , [ 8 ]PF 6 and [ 10 ]PF 6 .

Experimental and theoretical studies of a new class of novel annulated imidazolium scffords 2a, 2b, 2c and their Hg(II)–NHC complexes 3a, 3b and 3c have been synthesized and characterized by different spectroscopic techniques. Molecular structures of 3a and 3b have been determined by single crystal X-ray diffraction studies. Virtual linear geometry [Ccarbene–Hg–Ccarbene 176.56(17)°] around Hg of the complex 3b is observed where as in 3a and 3c its deviate a more. DFT calculations provide geometrical parameters in conformity with the experimental values in case of 3a. The molecules prefer syn configuration over the anti due to lower energy supported by theoretical studies. Attention has given paid for theoretical calculations and comparison of 3a and 3c to observe the steric effect of –CH3 group in the scaffords where as in case of 3b the –CH3 group remain innocent.

Reaction of aqueous hydroxylamine with carbon disulfide in acetonitrile or in tetrahydrofuron unprecedentedly results in the formation of ammonium thiocyanate and sulfur.