Varying coordination modes of amide ligand in group 12 Hg( ii ) and Cd( ii ) complexes: synthesis, crystal structure and nonlinear optical properties

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 44; no. 4; pp. 1933 - 1941
• Main Authors: Mobin, Shaikh M., Mishra, Veenu, Rai, Dhirendra K., Dota, Krithika, Dharmadhikari, Aditya K., Dharmadhikari, Jayashree A., Mathur, Deepak, Mathur, Pradeep
• Format: Journal Article
• Language: English
• Published: England 28.01.2015
• Subjects: Amides; Carbonyl groups; Ligands; Molecular structure; Nitrogen atoms; Nonlinearity; Pyridines; Terminals
• ISSN: 1477-9226; 1477-9234; 1477-9234
• DOI: 10.1039/C4DT02111H

Reactions of the amide ligand, H2L (H 2 L = N , N ′-bis[2-(2-pyridyl)methyl]pyridine-2,6-dicarboxamide) with CdCl 2 and Hg(CH 3 COO) 2 , in 1 : 1 ratio, at 298 K yield dimeric [Hg(L)] 2 ( 1 ) and trimeric [Cd 3 (H 2 L) 4 Cl 6 ] ( 2 ), respectively. In 1 , the H2L is coordinated to Hg( ii ) via six N-atoms of central and terminal pyridines as well as of deprotonated amido groups, whereas the carbonyl groups remain free. However, in 2 , the H2L is coordinated to Cd( ii ) through terminal pyridine N atoms and O atoms from carbonyl groups, whereas the nitrogen atoms of the central pyridine, two terminal pyridine and of all amido groups remain free. Molecular structures of 1 and 2 are confirmed by single crystal X-ray studies. The varying coordination modes of H2L give rise to different electrochemical behavior of 1 and 2 , which has also been rationalized by theoretical calculations. Moreover, nonlinear optical (NLO) behavior of both complexes has been investigated using ultra-short femtosecond laser pulses, which ensures that the NLO response is exclusively from their electronic component.