The activation of chiral titanium(IV) complexes with additives, phenolic N-oxides, is found to provide an alternative strategy for asymmetric cyanosilylation of ketones in excellent yield with up to 82% ee. 2004 Elsevier Ltd. All rights reserved. Recent years, there are a number of important observations made in regarding the effect of additives on asymmetric catalytic reactions. The addition o...

the complexes of mn(oac)3 and/or mn(acac)3 with nucleic bases and nucleosides (adenine, guanine, xanthine, adenosine and guanosine) have been synthesized in nonaqueous solution. polarographic and spectroscopic (ir and visible) methods have been used to establish the active site(s) on the imidazole and pyrimidine rings in the nucleic bases and nucleosides for the interaction with the mn(iii) com...

The preparation of a number of binuclear (salen)osmium phosphinidine and phosphiniminato complexes using various strategies are described. Treatment of [Os(VI)(N)(L(1))(sol)](X) (sol = H(2)O or MeOH) with PPh(3) affords an osmium(IV) phosphinidine complex [Os(IV){N(H)PPh(3)}(L(1))(OMe)](X) (X = PF(6)1a, ClO(4)1b). If the reaction is carried out in CH(2)Cl(2) in the presence of excess pyrazine t...

Salen complexes of the heavy alkaline-earth metals, calcium and strontium, were prepared by the reaction of various salen(t-Bu)H(2) ligands with the metals in ethanol. Six new calcium and strontium compounds, [Ca(salen(t-Bu))(HOEt)(2)(thf)] (1), [Ca(salen(t-Bu))(HOEt)(2)] (2), [Ca(salpen(t-Bu))(HOEt)(3)] (3), [Ca(salophen(t-Bu))(HOEt)(thf)] (4), [Sr(salen(t-Bu))(HOEt)(3)] (5), and [Sr(salophen(...

Single-chain magnets (SCMs) are materials composed of magnetically isolated one-dimensional (1D) units exhibiting slow relaxation of magnetization. The occurrence of SCM behavior requires the fulfillment of stringent conditions for exchange and anisotropy interactions. Herein, we report the synthesis, the structure, and the magnetic characterization of the first actinide-containing SCM. The 5f-...

The electroactivity of zeolite-encapsulated redox-active transition metal complexes, {M(L)}Z, was explored for Co(salen) and [Fe(bpy)3] formed in NaY zeolite (where salen ) N,N′-bis(salicylidene)ethylenediamine and bpy ) 2,2′-bipyridine). The zeolite boundary was characterized via X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry in nonaqueous electrolyte at either zeolite-modified ...

A series of cationic ruthenium(VI) nitrido species containing the cyclohexyl-bridged salen ligand (L) and its derivatives, [RuVI(N)(L)]+, have been prepared by treatment of [NBun4][RuVI(N)Cl4] with H2L in methanol. The structure of [RuVI(N)(L)](ClO4) (1a) has been determined by X-ray crystallography, d(RuN) = 1.592 A. In solvents such as DMF or DMSO, [RuVI(N)(L)]+ undergoes a facile N...N coupl...