Four coordinate molybdenum alkene and alkyne complexes bearing ancillaryimido ligands

Article abstract of DOI:10.1016/0277-5387(94)00336-D

Four coordinate molybdenum alkene complexes of the type Mo(NR)2(PMe3)(CH2CH2R') [R=Bu(t), R'=H (2a); R'=Me (2b); R=adamantyl, R'=H (2c)] have been synthesised by treatment of Mo(NR)2Cl2(dme) [R=Bu(t) (1a); R=adamantyl (1b) with two equivalents of RMgCl (R=Et, n-Pr) in diethylether. The molecular structure of 2b is reported [triclinic, space group P1-, a=9.312(2), b=9.723(2), c=11.203(2) ?, α=78.85(2), β=88.23(2), γ=85.94(2)°, U=992.5(4) ?**3, Z=2, T=293 K]. The alkynederivatives Mo(NR)2(PMe3)(R'C.ident.CR ) [R=Bu(t), R'=R =Ph (3a); R=Bu( t), R'=Ph, R =H (3b); R=adamantyl, R'=R =Ph (3c)] are prepared from 2a and 2c by prolonged warming at 60-70°C in heptane in the presence of one equivalent of the alkyne. The molecular structure of 3a [orthorhombic, space group Pbca (No. 61), a=13.980(3), b=15.333(6), c=24.989(7) ?, U=5356(3) ?**3, Z=8, T=120 K] reveals an analogous pseudo-tetrahedral geometry to that found for 2b. The relationship of these complexes to known zirconocene derivatives is discussed.