SYNTHESIS AND STRUCTURE CHARACTERIZATION OF MOLYBDENUM COMPLEXES WITHAN ELECTRONIC MODEL-COMPOUND OF FULLERENE - METHYL ACRYLATE (ETA(2)-CH2=CHCOOME)(2)MO(CO)(2)(BIPY)

The title complexes were synthesized by the reaction of Mo(CO)(4) (bip y) with methyl acrylate, an electron-deficient alkene model compound o f fullerene. Two crystals 1 and 2 of a pair of geometrical isomers wer e obtained under different crystalization conditions and characterized by XRD and IR. Crystal 1 belongs to the monoclinic system with space group P2(1)/n, a=0.780 0(2) nm, b=1.901 5(4) nm, c=1.399 6(2) nm, beta =103.20(3)degrees, V=2.021 0(8) nm(3), D-c=1.579 g/cm(3), Z=4. The fin al R is 0.023 5 for 3 021 reflections [F>4.0 sigma(F)]. Crystal 2 belo ngs to the monoclinic system with space group P2(1)/n, a 0.907 5(2) nm , b=1.949 1(4) nm, c=1.1291(2) nm, beta=100.52(3)degrees, V=1.963 6(7) nm(3), D-c=1.686 g/cm(3), Z=4. The final R is 0.081 8 for 1 473 refle ctions [F>4. 0 sigma(F)]. In the molecules of both crystals, molybdenu m atom coordination is distorted octahedral with the two CO groups cis to each orther, but each trans to a pyridyl group of 2,2'-bipyridine. The Mo atom is bound in an eta(2)-fashion to C-C double bonds of two methyl acrylates in axial direction of the octahedron. The main differ ence in the two geometrical isomers is that the methyl ester groups of the two methyl acrylate are rotated 180 degrees.