Synthesis and crystal structure of octaaquaerbium(III) 4,7,13,16,21,24-Hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane pentabromide hydrate

Abstract

A new complex salt [Er(H2O)8]3+·[H2(Crypt-222)]2+·5Br−·1.5H2O(I) is synthesized, and its crystal structure is studied by single-crystal X-ray diffraction analysis (space group P21, a = 8.315 A, b = 32.000 A, c = 8.383 A, β = 120.03°, Z = 2; direct method, anisotropic full-matrix least-squares approximation, R = 0.050 for 3755 independent reflections; CAD4 automated diffractometer, λMoK α radiation). The structural units of crystal I are complex cations [Er(H2O)8]3+, disordered dications of the 2.2.2-cryptand (with two protonated nitrogen atoms), Br− anions, and water molecules. The coordination polyhedron of the Er3+ cation is a tetragonal antiprism with the oxygen atoms of eight water molecules at its vertices. The disordered [H2(Crypt-222)]2+ dication contains trifurcate hydrogen bonds N+-H(⋯O)3.