Synthesis of cyclohexadienyl ruthenium complexes by replacement of the naphthalene ligand in [(η5-C6H3Me4)Ru(η6-C10H8)]+

•Cyclohexadienyl ruthenium complexes were synthesized by naphthalene replacement.•The mechanism of naphthalene replacement was studied by DFT calculations.•Cyclohexadienyl ruthenium naphthalene complex catalyzes cyclotrimerization of alkynes.

Reactions of the cyclohexadienyl ruthenium complex [(η5-C6H3Me4)Ru(C10H8)]+ (1) with 2-electron ligands L lead to replacement of the naphthalene ligand with formation of the half–sandwich complexes [(η5-C6H3Me4)RuL3]+ (L = MeCN, tBuNC, P(OEt)3, 1,3,5-triaza-7-phosphaadamantane). Similar reactions with P(OMe)3 or dppe in the presence of Cl− give the neutral complexes (η5-C6H3Me4)Ru(P(OMe)3)2Cl or (η5-C6H3Me4)Ru(dppe)Cl, respectively. Cation 1 also exchanges the naphthalene ligand for other arenes producing the corresponding sandwich compounds [(η5-C6H3Me4)Ru(arene)]+ (arene = C6H6, 1,4-C6H4(OMe)2). Complex 1 catalyzes cyclotrimerization of N,N-di(propargyl)tosylamide with 1-octyne or 4-pentynol, but less effectively than [CpRu(C10H8)]+. The mechanism of the naphthalene replacement in 1 was studied by DFT calculations.

Graphical abstractHalf-sandwich cyclohexadienyl ruthenium complexes were synthesized by replacement of the naphthalene ligand in the readily available complex [(η5-C6H3Me4)Ru(η6-C10H8)]+.Figure optionsDownload full-size imageDownload as PowerPoint slide