Characterization of the isocyanurate complexes [M(cyan- N)- (H 2O) 5](cyan- N)·2H 2O (M = Ni, Co, Mn) compounds that form molecular ribbons in the solid state

Abstract

The three isocyanurate complexes [M(cyan)-N)(H 2O) 5](cyan- N)·2H 2O M = Mn (1), Co (2), Ni (3); cyan- N = isocyanurate, C 3H 2N 3O 3 −, keto isomer) have been prepared and characterized. The complexes are prepared by reaction of LiC 3H 2N 3O 3 and MCl 2·6H 2O in water. In the solid state, the compounds exist as the pentaaquamonoisocyanurato transition metal complexes, with a free isocyanurate ion and two free molecules of water per complex. The three compounds are isotypic in the crystalline state, crystallizing in monoclinic space group P2 1/ n with Z = 4 For compound 1, a = 14.038(3), b = 6.693(2), c = 17.813(6) A ̊ , β = 97.43(3)° and V = 1659.6(8) A ̊ 3 . For 2, a = 14.017(3), b = 6.612(1), c = 17.067(3) A ̊ , β = 97.84(3)° and V = 1567.0(5) A ̊ 3 . For 3, a = 13.965(6), b = 6.623(3), c = 16.997(8) A ̊ , β = 98.06(4)° and V = 1557(1) A ̊ 3 . The bond lengths to the transition metal centers show the expected monotonic decrease on going from manganese to cobalt to nickel. The complexes in the solid state form an extended aggregate of cross-linked molecular ribbons, which are stacked perpendicular to the crystallographic direction [010]. The crystals grow preferentially in the direction of propagation of the molecular ribbons and the direction of stacking. The formation of the supramolecular structure is implicated as a cause of the composition of the transition-metal complexes.