Synthesis and Crystallographic Characterization of an Octameric Water Complex, (H2O)8

Small water clusters are the subject of considerable theoretical and experimental scrutiny and include a recently isolated water decamer. A detailed understanding of the numerous possible structures and stabilities is important for obtaining insight into the nature of water--water interactions in diverse environments. Of particular interest are octameric water clusters, (H{sub 2}O){sub 8}. A two-to-one combination in acetonitrile of {kappa}{sup 4}-[1,2-bis(2-oxy-2-methylpropanamido)-4,5-dimethoxybenzene]cobaltate(III), [A]{sup {minus}}, with bis-{kappa}{sup 3}-(2,6-diacetamidopyridine)cobalt(II), [B]{sup 2+}, yields the crystalline solvate, [A{sub 2}B]{center_dot}(CH{sub 3}CN){sub 4}. On treatment with humid air for 10 to 12 days, [A{sub 2}B]{center_dot}(CH{sub 3}CN){sub 4} forms the [A{sub 2}B](H{sub 2}O){sub 8} complex without crystal decay; both species have been crystallographically characterized.