Differential Reactivity of [TpRu(κ2P,N-iPr2PXPy)Cl] (X = NH, S) Bearing Hemilabile Coligands Towards NaBAr4F, Lithium Acetylide, and Acetylenes

In contrast with [TpRu(P-2,N-iPr(2)PNHPy)Cl] (1a, Tp = trispyrazolylborate), [TpRu(P-2,N-iPr(2)PSPy)Cl] (1b) reacts with sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBAr4F) in fluorobenzene under nitrogen to afford the dinuclear complex [{TpRu(P-2,N-iPr(2)PSPy)}(2)(-Cl)][BAr4F] (1b). Through diverse synthetic strategies, a series of neutral acetylides [TpRu(CCR)(P-2,N-iPr(2)PXHPy)] [X = NH; R = Ph (2a), SiMe3 (2b); X = S; R = Ph (2c), p-C6H4Br (2d), COOMe (2e)], cationic vinylidene complexes [TpRu(=C=CHR)(P-2,N-iPr(2)PNHPy)](+) [X = NH; R = Ph (3a), SiMe3 (3b); X = S; R = Ph (3c), p-C6H4Br (3d)] and [TpRu(=C=CH2)(P-2,N-iPr(2)PNHPy)](+) (3e), and a cationic (2)-alkyne complex [TpRu((2)-HCCCOOMe)(P-2,N-iPr(2)PSPy)][BAr4F] have been efficiently synthesized from 1a and 1b. The methoxy(methyl)carbene complexes [TpRu{=C(OMe)CH3}(P-2,N-iPr(2)PXPy)][BPh4] [X = NH (5a), S (5b)] were isolated from the reactions of 1a and 1b with acetylene gas in the presence of NaBAr4F in methanol. The deprotonation of the cationic vinylidenes derived from 1b with KtBuO affords the corresponding neutral acetylide complexes, which undergo facile protonation with CF3SO3H to reproduce the cationic vinylidenes quantitatively.