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Two new complexes Zn(TBimE)Cl2 1 and Cd(TBimE)(I)2 2 based on a semi-rigid ligand TBimE (TBimE = (E)-1,2-bis(2-benzimidazolyl)ethane) have been synthesized and their structures have been determined...

A new binuclear complex [Ag2(ntb)2](NO3)2·(CH3OH)1.5·(CH3CN)0.5 based on a tripodal ligand ntb (ntb = tris(2-benzimidazolylmethyl)amine) has been synthesized and structurally characterized by X-ray single crystal diffractometry. In the structure of the complex each center Ag(I) ion is coordinated by two N atoms from two benzimidazole arm of one ntb ligand and one N atoms from one benzimidazole arm of the other in a trigonal coordinated geometry, resulting in the construction of a binuclear complex. The complex units are further linked into a 1-D chain by hydrogen bonds. The emission spectrum of the complex has been investigated and shows a red-shift of the emission peak compared to the ligand and the existence of ligand-to-metal charge transfer process (emission peak at 468.2 nm). Cyclic voltammogram of the complex indicates a pair of quasi-reversible redox couple, corresponding to the Ag+/Ag electrochemical process. In the structure of the complex each center Ag(I) ion is coordinated by two N atoms from two benzimidazole arm of one ntb ligand and one N atoms from one benzimidazole arm of the other in a trigonal coordinated geometry, resulting in the construction of a binuclear complex.

A new candidate [Cu(PPh3)2Him]Br (1, PPh3=triphenylphosphine, Him=1-H-imidazole) for nonlinear optical (NLO) materials has been synthesized and characterized crystallographically. The third-order NLO optical properties were measured by the Z-scan technique with an 8 ns pulsed laser at 532 nm. Compound 1 exhibits strong NLO absorptive abilities [a2=(61 +/- 5) x 10(-12)] and effective self-focusing performance [n2=(15 +/- 3) x 10(-18) m2.W-1] in 1.01 x 10(-4) mol.dm(-3) DMF solution. The compound also exhibits luminescence in DMF solution at room temperature and shows narrow emission with maximum at 382 nm. The electronic structure and photoluminescent process were investigated by means of TD-DFT calculations. The results suggest that the contribution to the frontier orbitals from the Cu?Br d bond plays a crucial role in its linear optical properties, and the origin of luminescence is attributable to the p*??n transitions.

Three new complexes ([Cu(OBimB)2](Cl)2·(EtOH)2·(H2O)2 1, [Cu(OBimB)2](NO3)2·(EtOH)2 2, [Ni(OBimB)2](NO3)2·(MeCN)2 3 based on a rigid bis(benzimidazoles) ligand OBimB (OBimB = 1,2-bis(2-benzimidazolyl)benzene) have been synthesized and structurally characterized by X-ray single crystal diffractometry. In the structures of the three complexes each metal ion is coordinated by four N atoms from two twisted V-shaped conformational OBimB ligands in a square-planar geometry. The complex units are further linked into a 2D layer supramolecular network by hydrogen bonds and π···π stacking interactions. The electronic absorption spectra of 1, 2, 3 have also been investigated and show that the two transitions around 220 and 280 nm are mainly assigned to intramolecular charge transfer transitions of the ligand (IL).

A new copper(II) complex based on the rigid ligand OBimB (OBimB = 1,2-bis(2-benzimidazolyl)benzene) has been synthesized and structurally characterized by X-ray single-crystal diffraction. In the structure of the complex, each Cu(II) atom is coordinated by four N atoms from two twisted V-shaped OBimB ligands in a square-planar geometry. The complex has been used as a bulk modifier to fabricate a carbon paste electrode (Cu-CPE). Electrochemical studies of the Cu-CPE in 0.1 M pH 2.0 phosphate buffer solution reveal that the Cu2+/Cu+ redox process is quasi-reversible. Electrocatalytic studies of the Cu-CPE indicate that it has good electrocatalytic activities toward reduction of bromate, hydrogen peroxide, and nitrite.

Two isomorphous new candidates [M(mu(4)-pz25dc)](n) (M = Cd, 1; Zn, 2; pz25dc = pyrazine-2,5-dicarboxylato)for nonlinear optical (NLO) materials have been synthesized hydrothermally and characterized crystallographically as pillared-layer three-nodal frameworks with one four-connected metal nodes and two crystallographically different four-connected ligand nodes. Their optical non-linearities are measured by the Z-Scan technique with an 8 ns pulsed laser at 532 nm. These two coordination polymers both exhibit strong NLO absorptive abilities [alpha(2) = (63 +/- 6) x 10 (12) mW (1) 1, ( 46 +/- 6) x 10 (11) mW (1) 2] and effective self-focusing performance [n(2) = (67 +/- 5) x 10 (18) 1, (13 +/- 3) x 10 (18) m(2) W (1) 2] in 1.02 x 10 (4) 1 and 1.05 x 10 (4) mol dm (3) 2 DMF solution separately. The values of the limiting threshold are also measured from the optical limiting experimental data. The heavy atom effect plays important role in the enhancement of optical non-linearities and optical limiting properties. (C) 2009 Elsevier B. V. All rights reserved.