A series of chiral transition metal complexes of (R,R)-(-)-N,N'-bis-(3,5- di-tert-butylsalicylidene)-1,2-cyclohexanediamine[L¹] including Al(L¹)Et, Zr(L^l)Cl₂, Ru(L^l)(CO)₂, Co(L^l), Ti(L^l)CI₂, V(L^l)O, V(L^l)Cl₂, MoO₂(L^l), Fe(L^l)CI and Fe(L^l)(OMe) have been synthesized. The structures of Al(L¹)Et and Co(L¹) have been determined by X-ray crystallography. Al(L¹)Et was characterized by ¹H COSY, ¹³C DEPT and ²⁷Al NMR analysis. The compounds Al(L^l)Et, Zr(L^l)Cl₂ and Ti(L^l)Cl₂ were found to catalyze ring opening for cyclohexene oxide with trimethylsilyl azide to give azido alcohols. Furthermore, the compound Co(L¹) is found to be active catalyst for cyclopropanation of olefins with diazoester with modest e.e.(42%). _{4 2 s2 4} ² _{2 2}...[ Read more ]

A series of chiral transition metal complexes of (R,R)-(-)-N,N'-bis-(3,5- di-tert-butylsalicylidene)-1,2-cyclohexanediamine[L¹] including Al(L¹)Et, Zr(L^l)Cl₂, Ru(L^l)(CO)₂, Co(L^l), Ti(L^l)CI₂, V(L^l)O, V(L^l)Cl₂, MoO₂(L^l), Fe(L^l)CI and Fe(L^l)(OMe) have been synthesized. The structures of Al(L¹)Et and Co(L¹) have been determined by X-ray crystallography. Al(L¹)Et was characterized by ¹H COSY, ¹³C DEPT and ²⁷Al NMR analysis. The compounds Al(L^l)Et, Zr(L^l)Cl₂ and Ti(L^l)Cl₂ were found to catalyze ring opening for cyclohexene oxide with trimethylsilyl azide to give azido alcohols. Furthermore, the compound Co(L¹) is found to be active catalyst for cyclopropanation of olefins with diazoester with modest e.e.(>42%).

High valent osmiurm complexes of bistoluenesulfonamide, [pph₄]₂[O_s2O₄(L²)₂(μ-OH)₂ and O_s2N₂(L²)₂(μ-OH)₂, were synthesized with full characterization and detailed structural analysis. The O_s=O and O_s-N(nitrido) bond lengths of 1.740 ÅA and 1.55 ÅA respectively are typical values for this class of compounds. The latter compound was found to be photoluminescent.

Copper and chromium complexes of quadridentate pyridine-amine ligands were synthesized. The chromium complexes catalyze the epoxidation of olefins with PhIO while the copper complexes are unreactive. An oxo-transfer mechanism from high valent chromium-oxo intermediate to olefins is proposed.

Reactions of C_r(NB_u^t)Cl₃(dme), C_r(NB_u^t)₂Cl₂, Mo(NB_u^t)₂Cl₂ and W(NB_u^t)₂(NHB_u^t)₂ with styrene oxide, cyclohexene oxide and 1,2- epoxyhexane in the presence of trimethylsilyl azide were investigated. The isolated yields for the reaction of styrene oxide are high and the ratio of corresponding regioisomers was determined by GC analysis. A catalytic cycle is proposed for the epoxide ring-opening reactions by chromium and molybdenum imido complexes.