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Issue 23, 1995
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A general method of generating agostic interaction between RuII and C–H bonds of tert-butyl, methyl, aryl, heterocyclic or alkenyl groups using azine phosphines

Abstract

Treatment of [RuCl2(PPh3)3]2 with the azine phosphine Z,E-PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]C(Me)But3a, derived from MeC([double bond, length half m-dash]O)But, gave the δ-agostic tert-butyl complex mer,trans-[RuCl2(PPh3){PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]C(Me)But}]4a, in which all nine hydrogens of the tert-butyl group are agostically interacting with ruthenium on the NMR time-scale at 20°C. The analogous δ-agostic tert-butyl complex mer,trans-[RuCl2(PPh3){PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]C(H)But}]4b was also prepared. Treatment of 2 with the symmetrical azine diphosphine Z,Z-PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]C(But)CH2PPh25 gave the δ-agostic tert-butyl complex mer,trans-[RuCl2(PPh3){PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]C(But)CH2PPh2}]6, in which one of the PPh2 groups is unco-ordinated. Treatment of 2 with the azine phosphine Z,E-PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]C10H167, derived from pinacolone–fenchone mixed azine, gave the δ-agostic methyl complex mer,trans-[RuCl2(PPh3){PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]C10H16}]8, in which the methyl group (C10H3) in the 1-position of the fenchone residue interacts with ruthenium (fenchone = 1,3,3-trimethylbicyclo[2.2.1]heptan-2-one). The unsymmetrical camphor azine monophosphine Z,Z-PPh2C10H15[double bond, length half m-dash]N–N[double bond, length half m-dash]C10H169 also gave a similar δ-agostic methyl complex mer,trans-[RuCl2(PPh3){PPh2-C10H15[double bond, length half m-dash]N–N[double bond, length half m-dash]C10H16}]10(camphor = 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one). Treatment of 2 with the azine Z,E-PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]CH(C6H4NMe2-4)11a, derived from 4-dimethylaminobenzaldehyde, gave the δ-agostic complex mer,trans-[RuCl2(PPh3){PPh2CH2C(But)[double bond, length half m-dash]N–N[double bond, length half m-dash]CH(C6H4NMe2-4)}]12a, in which the hydrogens in the 2 and 6 positions of the aryl group are agostically interacting with ruthenium. Similarly, the azines 11b and 11c, derived from 4-methoxybenzaldehyde or 4-nitrobenzaldehyde, gave the δ-agostic complexes 12b and 12c, respectively. Treatment of 2 with the azine 13, derived from 1-methylpyrrole-2-carbaldehyde, gave the δ-agostic complex 14, in which the hydrogen in the 3-position of the heterocyclic group is agostically interacting with ruthenium. Treatment of 2 with the azine 15, derived from benzylideneacetone, gave the δ-agostic alkenyl complex 16. Proton, 31P-{1H} and some 13C-{1H} NMR data are given.

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Article information


J. Chem. Soc., Dalton Trans., 1995, 3861-3866
Article type
Paper

A general method of generating agostic interaction between RuII and C–H bonds of tert-butyl, methyl, aryl, heterocyclic or alkenyl groups using azine phosphines

S. D. Perera and B. L. Shaw, J. Chem. Soc., Dalton Trans., 1995, 3861
DOI: 10.1039/DT9950003861

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