Syntheses, characterisation and some ligand substitution chemistry of Ru(II)-diphosphine triflate complexes

摘要

The complexes cis-[Ru(OTf)_2(L-L)_2]{L-KL = Ph_2PCH_2PPh_2, dppm (1a); (Ph_2P)_2C=CH_2, dppen (1b)} react with halide ions, with retention of stereochemistry, to give cis-[RuX_2(L-L)_2] [L-L]_2] {L-L = dppm, dppen; X = Br (2), I (3)}. With MeCN, 1a, b yield cis-[Ru(L-L)_2(MeCN)_2](OTf)_2(4a, b), but cis-[Ru(OTf)_2(dppe)_2](1c; dppe = Ph_2PCH_2CH_2PPh_2) reacts to give trans-[Ru(dppe)_2(MeCN)_2](OTf)_2 (4c). Whereas 1a reacts readily with 1,2-diaminoethane (en) to give [Ru(dppm)_2(en)](OTf)_2 (5a) cleanly, 1a, b only react under forcing conditions with 2,2'-bipyridine (bipy) to provide [Ru(L-L)_2(bipy)](OTf)_2 (6a, b); in addition to 6a(L-L = dppm), some [Ru(dppm)(bipy)_2](OTf)_2 is also formed via diphosphine displacement. Attempts to obtain [Ru(dppe)_2(bipy)](OTf)_2 (6c) by this route were unsuccessful. The outcome of reactions of 1a, b with phosphorus donors is governed by steric considerations. For example, while reaction of 1a, b with PMe_3 failed to provide [Ru(L-L)_2(PMe_3)_2](OTf)_2 complexes, P(OMe)_3 reacted readily to yield [Ru(L-L)_2{P(OMe)_3}_2](OTf)_2(7a, b). The reaction of 1a with one equivalent of Me_2PCH_2CH_2PMe_2 (dmpe) gave [Ru(dppm)_2(dmpe)](OTf)_2 (8a) and [Ru(dppm)(dmpe)_2](OTf)_2 (9a) in a 5:1 ratio, although [Ru(dppen)_2(dmpe)](OTf)_2(8b) was the only product from an analogous reaction with 1b. However, with one equivalent of Me_2PCH_2PMe_2 (dmpm), 1a reacted to form exclusively [Ru(dppm)(dmpm)_2](OTf)_2 (10a). The complexes have been characterised by ~(31)P{~1H} and ~1H NMR spectroscopy, FAB mass spectrometry, and X-ray crystallography in the case of 4a and 7b.