A SERIES OF [CR-2(MU-OH)(N)(MU-RCO2)(3-N)(BISPMA)(2)] TYPE CHROMIUM(III) DINUCLEAR COMPLEXES (N = 1, 2) WITH TRIDENTATE BIS(2-PYRIDYLMETHYL)AMINE (BISPMA) - SYNTHESIS, CRYSTAL-STRUCTURE, AND MAGNETIC-PROPERTIES

A series of chromium(III) dinuclear complexes with general formula [Cr -2(mu-OH)(n)(mu-RCO2)(3-n)(bispma)(2)]X-m . yH(2)O (bispma = bis(2-pyr idylmethyl) amine; n = 1, m = 3, R = H, Me, Et, CH2Cl, CH2CICH2; m = 4 , R = CH2NH3, CH2CH2NH3, CH2CH2CH,NH3, CH(CH3)NH3, CH(OH)NH3; n = 2, m = 3, R = CH3, H) was prepared and characterized by elemental analysis , UV-Vis, IR absorption and H-2 NMR spectra, magnetic susceptibility m easurements, and X-ray crystal structure analysis. The crystal of [Cr- 2(mu-OH)(2)(mu-HCO2) (bispma)(2)] [ClO4](3) . 0.5H(2)O was orthorhombi c with space group Pnma, a = 14.771(3), b = 12.346(6), c = 19.054(4) A ngstrom, U = 3474(1) Angstrom(3), Z = 4. Two complexes for R = H and C H2Cl were found to exhibit alternating magnetic properties from antife rromagnetic to ferromagnetic interaction with change of counter ions. This anomalous magnetism was examined by comparison with the reported magneto-structural relationship. (C) 1998 Elsevier Science S.A. All ri ghts reserved.