Crystal structure of a new binuclear complex of bis(2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo(3.3.0)octane -3,7-dione-O, O′)-diaqua-hexakis(nitrato-O,O′)-digadolinium(III) monohydrate

Abstract

A centrosymmetric binuclear complex of gadolinium(III) nitrate with bicyclic bisurea (2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo(3.3.0)octane-3,7-dione, or mebicar, Mk) [Gd(C₈H₁₄N₄O₂)(H₂O)(NO₃)₃]₂·H₂O (I) is synthesized and its atomic structure (CIF file CCDC No. 1450653) is determined. The crystals of I are monoclinic: space group P2₁/c, a = 10.3861(2) Å, b = 10.80470(10) Å, c = 21.2707(4) Å, β = 128.413(3)°, V = 1870.32 ų, ρ(calc.) = 2.05094 g/cm³, Z = 2. The gadolinium atom occupies a general position and is coordinated by two oxygen atoms of two Mk molecules related by a symmetry-center operation, three bidentate nitrate anions, and a water molecule. The coordination polyhedron of the gadolinium atom is a nine-vertex polyhedron represented by a distorted three-cap trigonal prism; the Gd⋯Gd distance in the complex is 6.8697(4) Å.