Inorganic Chemistry, Vol.42, No.5, 1656-1662, 2003
Hydrogen-bonded extended arrays of the [Re-6(mu(3)-Se)(8)](2+) core-containing clusters
Site-differentiated solvated clusters of the general formula [Re-6(mu(3)-Se)(8)(PEt3)(n)(MeCN)(6-n)](SbF6)(2) (n = 4, cis and trans; n = 5) undergo ligand substitution reaction with isonicotinamide to afford the corresponding amide derivatives, [Re-6(mu(3)-Se)(8)(PEt3)(n)(isonicotinamide)(6-n)](2+) [1 (n = 5); 2 (n = 4, trans); 3 (n = 4, cis)]. Retention of stereochemistry in each case was confirmed by H-1 and P-31 NMR. The solid-state structures of all three compounds were established crystallographically, which revealed self-complementary hydrogen-bonding interactions between adjacent cluster units. While complex 1 exists as hydrogen-bonded dimers in the solid state, compounds 2 and 3 form one-dimensional chains of clusters bridged by paired hydrogen bonds. It is the rigid stereochemistry of the cluster, combined with the classic crystal engineering motif of complementary N-H...O amide hydrogen bonding, that affords the predictable solid-state structures and dimensionality.