Synthesis and crystal structure of a supramolecular adduct of the aqua nitrato complex of gadolinium [Gd(NO3)(H2O)7]2+ with macrocyclic cavitand cucurbit[6]uril

A supramolecular adduct of gadolinium aqua nitrato complex and cucurbit[6]uril { [Gd(NO3)(H2O)7](C5H5N)@(C36H36N24O12)}(NO3)2·10H2O is obtained by slow diffusion of methanol into an aqueous solution containing gadolinium nitrate, pyridine, and cucurbit[6]uril. According to single crystal X-ray diffraction data, water molecules coordinated to metal atom make hydrogen bonds to polarized carbonyl groups of the macrocycle. The heptaaquanitratogadolinium(III) [Gd(NO3)(H2O)7]2+ cation is structurally characterized for the first time. Crystal system is triclinic, space group \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$P\overline 1 $$ \end{document}, a = 12.3137(4) Å, b = 14.2334(5) Å, c = 19.5629(6) Å; α = 80.850(1)°, β = 86.879(1)°, γ = 68.855(1)°; V = 3157.15(18) Å3, Z = 2. Oriented hydrogen-bonded chains of alternating cucurbit[6]uril molecules and gadolinium aqua cations form in the crystal structure.