688313-20-4Relevant academic research and scientific papers
Synthesis, crystal structure and magnetic properties of quasi-linear tetranuclear copper(II) Schiff base complexes formed by covalent linkage of asymmetrically dibridged dicopper(II) units
Mukherjee, Arindam,Saha, Manas K.,Rudra, Indranil,Ramasesha, Suryanarayanasastry,Nethaji, Munirathinam,Chakravarty, Akhil R.
, p. 1077 - 1082 (2004)
Alkoxo-phenoxo bridged tetranuclear copper(II) complexes [Cu 4L2(O2CC6H4-p-OH) 2] (1) and [Cu4L2(O2CC 6H4-o-OH)2] (2) containing pentadentate Schiff base ligand N,N′-(2-hydroxypropane-1,3-diyl)bis(salicylaldimine) (H 3L) are prepared and structurally characterized. Crystal structures of the complexes show the covalent linkage between two {Cu2L(O 2CR)}(R = C6H4-p-OH, C6H 4-o-OH) units through the phenoxo atoms of the Schiff base ligand showing axial/equatorial bonding modes. The Cu(1)-O(2)-Cu(2) alkoxo bridge angle is 131° in 1 and 2. The pendant ortho- and para- OH groups of the three-atom bridging carboxylate ligands show no apparent bonding interactions with the metal or other group(s). The complexes show a d-d band near 635 nm in CH2Cl2. Variable temperature magnetic susceptibility measurements in the temperature range 300-18 K show antiferromagnetically coupled spin system. A theoretical fit of the magnetic data using exchange parameters J1 and J2 for the intradimer and interdimer units of the quasi-linear tetrameric core gave values as: J1 = -132,J2 = -72 cm-1 for 1 and J1 = -167,J 2 = -67 cm-1 for 2.
