The influence of benzaldehyde-N-alkyl-thiosemicarbazones on the synthesis of gold(I) ionic complexes: Spectroscopy, ESI-mass, structures and variable H-bonded polymeric networks
作者:Tarlok S. Lobana、Rekha Sharma、Shikha Indoria、Ray J. Butcher
DOI:10.1016/j.poly.2015.01.029
日期:2015.5
The effect of the substituents at the N-1/C-2 atoms of the thiosemicarbazones (RRC2)-R-1-C-2 = N-3-(NH)-H-2-C-1(=S)-(NHR3)-H-1 on the type of gold(I) complexes is investigated. Direct reaction of gold(I) chloride with benzaldehyde-N-methyl thiosemicarbazones (HL1: R-1 = Ph, R-2 = H, R-3 = Me) in a 1:2 M ratio in acetonitrile has yielded an ionic complex, [Au(kappa(1)-S-HL1)(2)]Cl (1). Similarly, the reaction of benzaldehyde-N-ethyl thiosemicarbazone (HL2: R-1 = Ph, R-2 = H, R-3 = Et) has formed another ionic complex, [Au(kappa(1)-S-HL2)(2)]Cl (2). The complexes have been characterized using analytical data, spectroscopy (IR, H-1, C-13 NMR, UV-Vis), fluorescence, ESI-mass and X-ray crystallography. Complexes 1 and 2 represent the first examples obtained from the direct reactions of gold(I) chloride with a thio-ligand without the presence of PPh3 or the use of any intermediate substrate, as has normally been used. Complex 1, with a methyl substituent at N-1, has two independent molecules in the crystal lattice, while complex 2, with an N-ethyl substituent, has only one type of molecule in the crystal lattice. ESI-mass studies reveal the formation of the species: [(AuCl)-Cl-I+H](+) (A), [(AuCl2)-Cl-I(HL1)+2H](+) (B), [Au-I(HL1)(2)] (C) (complex 1) and [Au-I(HL2)(2)-4H](+) (D) (complex 2). Interestingly both complexes have shown intense fluorescence bands in the wide region 340-540 nm, corresponding to the excitation wavelength of 308 nm. (C) 2015 Elsevier Ltd. All rights reserved.