Intramolecular Trapping of an Intermediate in the Reduction of Imines by a Hydroxycyclopentadienyl Ruthenium Hydride: Support for a Concerted Outer Sphere Mechanism
摘要:
Reduction of imines by [2,5-ph(2)-3,4-Tol(2)(eta(5)-C4COH)]Ru(CO)(2)H (1) produces kinetically stable ruthenium amine complexes. Reduction of an imine possessing an intramolecular amine was studied to distinguish between inner sphere and outer sphere mechanisms. 1,4-(BnNH)-N-15(c-C6H10)=NBn (12) was reduced by 1 in toluene-d(8) to give 85% of [2,5-Ph-2-3,4-Tol(2) (eta(4)-C4CO)](CO)(2)RuNHBn(c-C6H10)(NHBn)-N-15 (16-RuN,N-15), resulting from coordination of the newly formed amine to the ruthenium center, and 15% of trapping product [2,5-Ph-2-3,4-Tol(2) (eta(4)-C4CO)](CO)(2)(RuNHBn)-N-15(c-C6H10)NHBn (16-(RuN)-N-15,N), resulting from coordination of the intramolecular trapping amine. These results provide support for an outer sphere transfer of hydrogen to the imine to generate a coordinatively unsaturated intermediate, which can be trapped by the intramolecular amine. An opposing mechanism, requiring coordination of the imine nitrogen to ruthenium prior to hydrogen transfer, cannot readily explain the observation of the trapping product 16-(RuN)-N-15,N.
Stabilization of [(nBu2SnCl)(μ-Cl)2(ClSnnBu2)] within the solid-state structure of a Chlorodi-n-butyltin(IV) dithiocarbamate
作者:Ericka Santacruz-Juárez、Jorge Cruz-Huerta、Aarón Torres-Huerta、María G. Hernández-Cruz、Victor Barba、Hugo Tlahuext、Herbert Höpfl
DOI:10.1016/j.jorganchem.2014.07.027
日期:2014.11
The combination of bis-dithiocarbamate ligands derived from N,N'-dibenzylcyclohexane-trans-1,4-diamine with dimethyl- and di-n-butyltin(IV) dichloride provided two discrete dinuclear complexes of the composition [(Me2SnCl)(2)(bis-dtc)]center dot 2CHCl(3) (1) and [(nBu(2)SnCl)(2)(bis-dtc)] (2) with bis-dtc = N,N'-dibenzylcyclohexane-trans-1,4-diamine-bisdithiocarbamate. Additionally, single crystals of the composition [(nBu(2)SnCl)(mono-dtc)]center dot[nBu(2)SnCl(2)](2) (3) with mono-dtc = N,N'-dibenzylcyclohexane-trans-1,4-diamine-monodithiocarbamate were isolated. Within the crystal structures of the three complexes, a varied number of common (C-H center dot center dot S, C-H center dot center dot center dot Cl and N-H center dot center dot center dot Cl) and less common (S center dot center dot center dot S, S center dot center dot center dot Cl, Cl center dot center dot center dot Cl, Cl center dot center dot center dot N and Cl center dot center dot center dot Sn) secondary interactions were observed and analyzed. The supramolecular solid-state organization of [(Me2SnCl)(2)(bis-dtc)]center dot 2CHCl(3) revealed the presence of channels, which were filled with chloroform molecules. In the crystal structure of [(nBu(2)SnCl)(mono-dtc)]center dot[nBu(2)SnCl(2)](2), the di-n-butyltin dichloride units are arranged in form of a so far unknown dimeric aggregate of the composition [(nBu(2)SnCl)(mu-Cl)(2)(ClSnnBu(2))]. The latter assembly represents thus a rare example for a two-component co-crystalline assembly, in which a relatively large non-solvent molecule with unusual molecular structure is stored and stabilized. (C) 2014 Elsevier B. V. All rights reserved.