A concave, cubic diamond coordination polymer in the versatile chemistry of the aqua-alkaline-earth complex salts of molecular hexanuclear chalcohalide rhenium clusters, [Ca(H2O)(n)]Re(6)Q(6)Cl(8)center dot MH(2)O and [Mg(H2O)(6)]Re6S6Cl8 center dot 2H(2)O (Q=S,Se)

The high temperature solid-state synthesis of the alkaline-earth salts of molecular chalcohalide rhenium cluster dianions, CaRe6S6Cl8, CaRe6Se6Cl8, MgRe6S6Cl8, and MgRe6Se6Cl8 is described. The compounds exhibit a high solubility in a variety of organic solvents which allows a ready access in high yields to the tetrabutylammonium salts (eta-Bu(4)N)(2)Re(6)Q(6)Cl(8) (Q = S, Se). It is further demonstrated that the dissolution of the calcium and magnesium salts and their subsequent crystallization out of organic solvents provides high-quality single crystals of a series of innersphere, heptaaqua- and pentaaqua-calcium(II) and hexaaqua-magnesium(II) complex salts, Ca(H2O)(7)Re(6)Q(6)Cl(8) . 3H(2)O (Q = S, Se), Ca(H2O)(8)Re6S6Cl8 and Mg(H2O)(6)Re6S6Cl8 . 2H(2)O. The latter are fully characterized by liquid secondary ion mass spectroscopy and determination of their crystal structures which reveal remarkable, hydrogen-bonded, one- and three-dimensional associations of the molecular sub-units with unique topologies in coordination chemistry.