Structures and properties of di-μ-oxo dimanganese(IV) complexes with bidentate Schiff bases, N-alkyl-substituted-salicylideneamine
作者:Hitoshi Torayama、Hideyuki Asada、Manabu Fujiwara、Takayuki Matsushita
DOI:10.1016/s0277-5387(98)00144-2
日期:1998.11
Novel di-mu-oxo dimanganese(IV) complexes, [Mn-IV(N-R-X-sal)(2)(mu-O)](2), with bidentate Schiff base ligands, N-alkyl-substituted-salicylideneamine, N-R-X-salH [R= CH3(Me), C2H5 (Et), n-C3H, (Pr), n-C4H9 (Bu), n-C6H13 (Hx), n-C8H17 (Oct), II-C10H21 (Dec), n-C12H25 (Dod), or n-C18H37 (Octd) and X = H or 5,6-benzo]: have been prepared by their reaction with potassium permanganate (KMnO4) in MeCN, while stirring at room temperature. These complexes were characterized by spectroscopy, magnetic susceptibility, thermal analysis and X-ray crystallography. The structures consist of a Mn-2(IV)(mu-O)(2) core with a Mn-Mn separation of 2.731 (4) Angstrom for [Mn-IV(N-Me-sal)(2)(mu-O)](2), 1, 2.769(2) Angstrom for [Mn-2(IV)(N-Et-sal)(2)(mu-O)](2), 2, 2.780(2) Angstrom for [(Mn-IV-Hx-sal)(2)(mu-O)](2), 5, 2.780(2)Angstrom for [Mn-IV(N-Dec-sal)(2)(mu-O)](2), 7, and 2.756(3) Angstrom for [Mn-IV(N-Me-5,6-benzo-sal)(2)(mu-O)](2), 10. The complex 1 is the first di-mu-oxo dimanganese(IV) complex having asymmetrical form in which two manganese ions adopt different configurations each other. Moreover, the complexes 5 and 7 are found to exhibit the longest one among all of the Mn-Mn separation observed for the structurally characterized Mn-2(mu-O)(2) complexes prior to this work. The antiferromagnetic exchange interaction has been found to be J= -83 and -188 cm(-1) for 1 and 7, respectively. (C) 1998 Elsevier Science Ltd. All rights reserved.