Ruthenium(II) pentamethylcyclopentadienyl half-sandwich carbene complexes with polypyridyl ligands

Polypyridyl complexes [RuCl(eta(5)-C5Me5)(NeN)] (1-4) [NeN] 2,2'-bipyridine (bpy) (1), 4,4'-dimethyl2,2'-bipyridine (4,4'-Me2bpy) (2), 1,10-phenanthroline (phen) (3) and 4,7-dimethyl-1,10-phenanthroline (4,7-Me2phen) (4)] were prepared by reacting [RuCl2(eta(5)-C5Me5)](2) with Zn dust in the presence of polypyridyl ligands. Unlike the related [RuCl(eta(5)-C5Me5)(L1)(L2)](+) [L1, L2 = P(OR)(3), PPh3] derivatives with Pdonor ligands, treatment of chloro compounds 1-4 with diazoalkanes Ar1Ar2CN(2) afforded polypyridyl carbene complexes [Ru(eta(5)-C5Me5)(] CAr1Ar2)(NeN)] BPh4 (5-8) [Ar1 = Ar2 = Ph (a), Ar1 = Ph, Ar2 = p-tolyl (b)]. Comparative DFT studies of the formation of metallacarbenes from aromatic diazoalkanes are reported. Phosphite complex [Ru(eta(5)-C5Me5)(bpy){P(OEt)(3)}] BPh4 (9) and acetylide derivatives [Ru(eta(C5Me5)-C-5)(C=CAr)(bpy)] (10, 11) [Ar = Ph (10), p-tolyl (11)] were also obtained by substitution of the carbene in 5e8. Unstable vinylidene cations [Ru(eta(5)-C5Me5){] C] C(H) Ar](bpy)](+) (12, 13) were formed by protonation with HBF4 center dot Et2O of acetylide species 10, 11. The complexes were characterized spectroscopically (IR and H-1, C-13, P-31 NMR) and by X-ray crystal structure determination of [Ru(eta(5)-C5Me5){= C(Ph)(p-tolyl)}(bpy)] BPh4 (5b). (C) 2017 Elsevier B.V. All rights reserved.