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3728405 
Journal Article 
Synthesis and characterization of four dicyanamide bridged copper(II) complexes with N2O donor tridentate Schiff bases as blocking ligands 
Bhaumik, PK; Harms, K; Chattopadhyay, S 
2013 
1 
Inorganica Chimica Acta
ISSN: 0020-1693
EISSN: 1873-3255 
405 
400-409 
WOS:000324223200057 
Four copper(II) complexes [Cu(L-1)(dca)](n) (1), [Cu(L-2)(dca)(H2O)](2) (2), [Cu(L-3)(dca)](n) (3) and [Cu(L-4)(dca)](n) (4), where HL1 = 2-[(2-aminoethylimino)methyl]-4-nitrophenol, HL2 = 2-[(2-(methylamino)ethylimino)methyl]-4-nitrophenol, HL3 = 2-[(2-(dimethylamino)ethylimino)methyl]-4-nitrophenol and HL4 = 2[(2-(diethylamino)ethylimino)methyl]-4-nitrophenol are tridentate Schiff base ligands, were synthesized and characterized by elemental analysis, IR and UV-Vis spectroscopy and single-crystal X-ray diffraction studies. Complex 1 and 4 are 1D helical, complex 2 is dimeric and complex 3 is 1D linear chain. X-ray single crystal structure analyses reveal that in complexes 1, 2 and 4, dicyanamide (dca) anions act as a purely mu-1,5-bridging ligand whereas in case of complex 3, two consecutive dca units serve as 1,3-bridging ligand while the third one exhibits end-to-end 1,5-bridging mode. Copper(II) centers in case of two complexes (1 and 3) exhibit square pyramidal geometry as depicted by Addison parameter (tau) values whereas metal centers of complexes 2 and 4 depict distorted octahedral and square pyramidal geometry respectively. The role of weak forces like lone pair ... pi/pi...pi interactions in influencing the self-assembly process appears to be of importance. Such types of interactions leading to supramolecular network in the four complexes are described here. (C) 2013 Elsevier B.V. All rights reserved. 
Crystal structures; Copper(II); Polynuclear; Schiff bases; Dicyanamide