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)

Complexes [RuCl(η 6 - p -cymene)(κ 2 - P,X -Ph 2 PCH 2 P{ NP( X)(OR) 2 }Ph 2 )][SbF 6 ] (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(κ 2 - P,C -Ph 2 PCHP{ NP( X)(OR) 2 }Ph 2 )(η 6 - 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 3 − 4a, b with AgSbF 6, in CH 2 Cl 2 at rt, affords the corresponding cationic species [Ru(κ 3 - P,C,X -Ph 2 PCHP{ NP( X)(OR) 2 }Ph 2 )(η 6 - p -cymene)][SbF 6 ] (X = O, R = Et ( 7a ), Ph ( 7b ); X = S, R = Et ( 8a ), Ph ( 8b )) through the intramolecular O - or S -coordination of the free −Ph 2 P NP( X)(OR) 2 fragment. Complexes 7 − 8a, b can also be prepared by reaction of the dicationic derivatives [Ru(η 6 - p -cymene)(κ 3 - P,N,X -Ph 2 PCH 2 P{ NP( X)(OR) 2 }Ph 2 )][SbF 6 ] 2 ( 5 − 6a, b ) with 1 equiv of NaH. Formation of complexes 3 − 4a, b and 7 − 8a, b proceeds, in all cases, in a diastereoselective manner. Phosphorus−carbon bond splitting has been observed upon treatment of complexes 1 − 2a, b, 3 − 4a, b, or 7 − 8a, b with an excess of NaH, in wet THF at rt, affording the novel phosphinito derivatives [Ru(κ 2 - C,X -CH 2 P{ NP( X)(OR) 2 }Ph 2 ){κ 1 - P -P( O)Ph 2 }(η 6 - p -cymene)] (X = O, R = Et ( 10a ); X = S, R = Et ( 11a ), Ph ( 11b )). Protonation and methylation of 10 − 11a, b generates the cationic species [Ru(κ 2 - C,X -CH 2 P{ NP( X)(OR) 2 }Ph 2 ){κ 1 - P -P(OH)Ph 2 }(η 6 - p -cymene)][BF 4 ] (X = O, R = Et ( 12a ); X = S, R = Et ( 13a ), Ph ( 13b )) and [Ru(κ 2 - C,X -CH 2 P{ NP( X)(OR) 2 }Ph 2 ){κ 1 - P -P(OMe)Ph 2 }(η 6 - p -cymene)][CF 3 SO 3 ] (X = O, R = Et ( 14a ); X = S, R = Et ( 15a ), Ph ( 15b )), respectively, via selective electrophilic addition at the Ph 2 P O group. The structure of compounds [RuCl(κ 2 - P,C -Ph 2 PCHP{ NP( O)(OPh) 2 }Ph 2 )(η 6 - p -cymene)] ( 3b ) and [Ru(κ 2 - C,S -CH 2 P{ NP( S)(OEt) 2 }Ph 2 ){κ 1 - P -P( O)Ph 2 }(η 6 -C 6 H 6 )] ( 11a ‘) has been determined by X-ray crystallography.