Synthesis and application of diphenylbis (3,5-dimethylpyrazol-1-yl)methane to form η2-arene complexes of molybdenum
作者:Kom-Bei Shiu、Li-Yuan Yeh、Shie-Ming Peng、Ming-Chu Cheng
DOI:10.1016/0022-328x(93)83147-n
日期:1993.11
The neutral nitrogen-bidentate ligand, diphenylbis(3,5-dimethylpyrazol-1-yl)methane, Ph(2)CPz'(2), can readily be obtained by the reaction of Ph(2)CCl(2), with excess HPz' in a mixed-solvent system of toluene and triethylamine. It reacts with [Mo(CO)(6)] in 1,2-dimethoxyethane to give the eta(2)-arene complex, [Mo(Ph(2)CPz'(2))(CO)(3)] (1). This eta(2)-ligation appears to stabilize the coordination of Ph(2)CPz'(2) in forming [Mo(Ph(2)CPz'(2))(CO)(2)(N2C6H4NO2-p)][BPh(4)] (2) and [Mo(Ph(2)CPz'(2),)(CO)(2)(N(2)Ph)][BF4] (3) from the reaction of 1 with the appropriate diazonium salt but the stabilization seems not strong enough when [MoP(OMe)(3)}(3)(CO)(3)] is formed from the reaction of 1 with P(OMe)(3). The solid-state structures of 1 and 3 have been determined by X-ray crystallography: 1-CH2,Cl-2, monoclinic, P2(1)/n, a = 11.814(3), b = 11.7929(12), c = 19.460(6) Angstrom, beta = 95.605(24)degrees, V = 2698.2(11) Angstrom(3), Z = 4, D-calc = 1.530 g/cm(3), R = 0.044, R(w) = 0.036 based on 3218 reflections with I> 2 sigma(I); 2 (3)-1/2 hexane-1/2 CH3OH-1/2 H2O-1 CH2Cl2, monoclinic, C2/c, a = 41.766(10), b = 20.518(4), c = 16.784(3) Angstrom, beta = 101.871(18)degrees, V = 14076(5) Angstrom(3), Z = 8, D-calc = 1.457 g/cm(3), R = 0.064, R(w) = 0.059 based on 5865 reflections with I> 2 sigma(I). Two independent cations were found in the asymmetric unit of the crystals of 3. The average distance between the Mo and the two eta(2)-ligated carbon atoms is 2.574 Angstrom in 1 and 2.581 and 2.608 Angstrom in 3. The unfavourable disposition of the eta(2)-phenyl group with respect to the metal centre in 3 and the rigidity of the eta(2)-arene ligation excludes the possibility of any appreciable agostic C-H --> Mo interaction.