Palladium(II) complexes of tridentate chalcogenated Schiff bases and related ligands of (S, N, S/Se/Te) type: Synthesis and structural chemistry
作者:Pradhumn Singh、Ajai K. Singh
DOI:10.1016/j.ica.2012.01.007
日期:2012.5
The reactions in CH3CN between PdCl2 and Schiff base ligands, 2-MeSC6H4-CH=NCH2CH2E-C6H4-4-R (L1-L3) (E = S or Se, R = H; E = Te, R = OCH3) and their reduced derivatives 2-MeSC6H4CH2-NHCH2CH2E-C6H4-4-R (L4-L6) followed by treatment with AgPF6 or AgClO4 have resulted in complexes [PdCl(L)][ X] (1-6; L = L1-L6; X = PF6 or ClO4) which have been characterized by IR, H-1, C-13H-1}, Se-77H-1} and Te-125H-1} NMR spectroscopy. Single crystal structures of complexes 1-6 reveal nearly square planar geometry around palladium in all of them (Pd-Se = 2.4045(16)-2.4065(6) angstrom; Pd-Te = 2.5052(9)-2.5307(13) angstrom). The various non-covalent interactions in the crystals result in the formation of chains, rings and caging of anions between cations. (C) 2012 Elsevier B.V. All rights reserved.
Synthesis and single crystal structures of first examples of tridentate ligands of (Te, N, S) type and their complexes with palladium(II), platinum(II) and ruthenium(II)
作者:P. Raghavendra Kumar、Shailesh Upreti、Ajai K. Singh
DOI:10.1016/j.ica.2007.09.012
日期:2008.4
The First examples of (Te, N, S) type ligands, 2-CH3SC6H4CH=NCH2CH2TeC6H4-4-OCH3 (L-1) and 2-CH3SC6H4CHNHCH2CH2TeC6H4- 4-OCH3 (L-2), and their metal complexes, [PdCl(L-1)]PF6 center dot CHCl3 0.5H(2)O (4), [PtCl(L-1)] PF6 (5), [PdCl(L-2)] ClO4 center dot CHCl3 (6), [PtCl(L-2)] ClO4 (7), and [Ru(p-cymene)(L-2)](PF6)(2) center dot CHCl3 (8), have been synthesized and characterized. The single crystal structures of 4, 6 and 8 have revealed that both the ligands coordinate in them in a tridentate ( Te, N, S) mode. The geometry around Pd in both the complexes has been found to be square planar, whereas for Ru in a half sandwich complex 8, it is found to be octahedral. Between two molecules of 4 there are intra and inter molecular weak Te center dot center dot center dot Cl [ 3.334(3) and 3.500(3) A, respectively] interactions along with weak intermolecular Pd center dot center dot center dot Te [3.621(2) angstrom] interactions. The Pd-Te bond lengths are between 2.517(6) and 2.541(25) angstrom and the Ru-Te bond length is 2.630(6) angstrom. The crystal structure of [ PdCl2(4-MeO-C6H4-TeCH2CH2NH2)] ( 9) is also determined. It is formed when KPF6 is not added in the synthesis of 4 and Pd-complex of L-1 is recrystallized. Apart from Te center dot center dot center dot Cl secondary interactions, C-H center dot center dot center dot pi interactions also exist in the crystal of 9. (c) 2007 Elsevier B. V. All rights reserved.