Synthesis and structures of dimanganese(II) complexes with spirotricyclic [Mn(mu-Ge2Se7)Mn] and [Mn(mu-Sn2Se6)Mn] cores

Solvothermal reaction of [MnCl2(cyclam)]Cl with GeSe2 at a 1: 1 molar ratio in CH3OH/H2O (1/1) at 150 degrees C affords the dimanganese(II) complex [{Mn(cyclam)}(2)(mu-Ge2Se7)]center dot CH3OH center dot 1.5H(2)O (1) with a spirotricyclic [Mn(mu-Ge2Se7)Mn] core. The strained four-membered Mn-Se-t-Ge-Se-t' rings (Se-t = terminal Se atom) exhibit long Mn-Se-t distances in the range 2.725(2)-2.745(2) angstrom and narrow average Se-t-Mn-Se-t' angles of 85.87(4)degrees. The solvothermal reaction of [MnCl2(cyclam)]Cl with SnSe and Se leads to formation of the analogous complex [{Mn(cyclam)}(2)(mu-Sn2Se6.15)](2), in which bridging [Sn2Se6](4-) and [Sn2Se7](4-) ligands are disordered at a ratio of 85:15. Employment of [MnCl2(terpy)] under similar conditions generates two complexes of the formula [{Mn(terpy)}(2)(mu-Sn2Se6)] 3 and 4, of which the former also contains a spirotricyclic core, whereas the Set atoms of the latter coordinate symmetry-related Mn-II atoms in a 1-D polymer. The Mn-Se-t bond distances of 2.584(1) and 2.549(1) angstrom in the resulting chair-shaped eight-membered rings of 4 are much shorter than in 1 and 2.