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Base-Assisted Cyclometalation and Phosphorus−Carbon Bond Cleavage in (Arene)ruthenium(II) Complexes Containing Functionalized Iminophosphorane-Phosphine Ligands Ph2PCH2P{NP(X)(OR)2}Ph2 (X = O, S; R = Et, Ph)

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journal contribution
posted on 2004-07-05, 00:00 authored by Victorio Cadierno, Josefina Díez, Joaquín García-Álvarez, José Gimeno
Complexes [RuCl(η6-p-cymene)(κ2-P,X-Ph2PCH2P{NP(X)(OR)2}Ph2)][SbF6] (X = O, R = Et (1a), Ph (1b); X = S, R = Et (2a), Ph (2b)) react with a stoichiometric amount of NaH, in THF at rt, to generate the neutral cyclometalated compounds [RuCl(κ2-P,C-Ph2PCHP{NP(X)(OR)2}Ph2)(η6-p-cymene)] (X = O, R = Et (3a), Ph (3b); X = S, R = Et (4a), Ph (4b)), via selective deprotonation of the methylenic backbone of the coordinated iminophosphorane-phosphine ligands. Treatment of 34a,b with AgSbF6, in CH2Cl2 at rt, affords the corresponding cationic species [Ru(κ3-P,C,X-Ph2PCHP{NP(X)(OR)2}Ph2)(η6-p-cymene)][SbF6] (X = O, R = Et (7a), Ph (7b); X = S, R = Et (8a), Ph (8b)) through the intramolecular O- or S-coordination of the free −Ph2PNP(X)(OR)2 fragment. Complexes 78a,b can also be prepared by reaction of the dicationic derivatives [Ru(η6-p-cymene)(κ3-P,N,X-Ph2PCH2P{NP(X)(OR)2}Ph2)][SbF6]2 (56a,b) with 1 equiv of NaH. Formation of complexes 34a,b and 78a,b proceeds, in all cases, in a diastereoselective manner. Phosphorus−carbon bond splitting has been observed upon treatment of complexes 12a,b, 34a,b, or 78a,b with an excess of NaH, in wet THF at rt, affording the novel phosphinito derivatives [Ru(κ2-C,X-CH2P{NP(X)(OR)2}Ph2){κ1-P-P(O)Ph2}(η6-p-cymene)] (X = O, R = Et (10a); X = S, R = Et (11a), Ph (11b)). Protonation and methylation of 1011a,b generates the cationic species [Ru(κ2-C,X-CH2P{NP(X)(OR)2}Ph2){κ1-P-P(OH)Ph2}(η6-p-cymene)][BF4] (X = O, R = Et (12a); X = S, R = Et (13a), Ph (13b)) and [Ru(κ2-C,X-CH2P{NP(X)(OR)2}Ph2){κ1-P-P(OMe)Ph2}(η6-p-cymene)][CF3SO3] (X = O, R = Et (14a); X = S, R = Et (15a), Ph (15b)), respectively, via selective electrophilic addition at the Ph2PO group. The structure of compounds [RuCl(κ2-P,C-Ph2PCHP{NP(O)(OPh)2}Ph2)(η6-p-cymene)] (3b) and [Ru(κ2-C,S-CH2P{NP(S)(OEt)2}Ph2){κ1-P-P(O)Ph2}(η6-C6H6)] (11a‘) has been determined by X-ray crystallography.