Synthesis and structural investigation of a new manganese-antimony oxoethoxide, Mn7Sb4(μ5-O)2(μ4-O)2(μ3-OEt)2(μ-OEt)16(HOEt)2

A new manganese-antimony oxoethoxide with the formula Mn7Sb4O4(OEt)(18)(HOEt)(2) has been prepared and characterized by single-crystal X-ray diffraction and FT-IR techniques, The structure of the compound has the noncentrosymmetric tetragonal space group symmetry P4(2) (No. 77) with unit-cell parameters a = 15.164(3), c = 14.729(5) Angstrom, V = 3387(2) Angstrom(3), Z = 2, and D-x = 1.803(1) g cm(-1) F-w = 1838.8 g mol(-1), The crystal structure has been refined against the 2227 most significant reflections to an R value of 0.059 (R-w = 0.077), The single-crystal X-ray diffraction intensities were collected at 170(1)K using MoK alpha radiation. The structure analysis shows that the structure consists of roughly spherically shaped molecules of C-2 symmetry and of composition Mn7Sb4O4(OEt)(18)(HOEt)(2). The antimony atoms are five-coordinated by oxygen atoms, while four of the manganese atoms are five-coordinated and three are six-coordinated. The antimony atoms are located in the outer regions of the molecule and the antimony lone pair regions are pointing away from the molecule, Four oxooxygens are located in the core of the molecule, The ethanol molecules coordinating the antimony atoms are involved in short intramolecular hydrogen bonds, A TLS analysis of the rigid-body motion of the central metal-oxygen core structure shows that two oxygen atoms involved in the intramolecular hydrogen bond do not follow the pattern of the rest of the atoms. The agreement between observed and predicted parameters of the remaining atoms supports the assumed rigidity in the central metal and oxygen core fragment. Structural relationships are found to other spherically shaped alkoxides such as Mn8Sb4O4(OEt)(20) and Pb6Nb4O4(OEt)(24). (C) 1997 Academic Press.