Synthesis and structural characterization of ruthenium carbonyl clusters containing acetylenic fluorene moieties derived from 9-ethynylfluoren-9-ol

Abstract

Five new ruthenium fluorene clusters, [Ru 3(CO) 9(μ-H){μ 3-η 1:η 2:η 2-CC(C 13H 9)}] 1 (8%), [Ru 3(CO) 7(μ-CO){μ 3-η 1:η 2:η 4-(HOC 13H 8)CCHC(C 13H 8OH)CH}] 2 (15%), [Ru 4(CO) 10(μ-CO)(μ 3-OH)(μ 3-η 1:η 2:η 2-C 13H 8CCH)] 3 (12%), [Ru 5(CO) 11(μ-H)(μ-CO)(μ 3-OH)(μ 5-η 1:η 1:η 2:η 2:η 6-C 13H 7CHC)] 4 (10%) and [Ru 6(CO) 15(μ 5-η 1:η 1:η 2:η 3:η 6-C 13H 7CHC)] 5 (9%), have been synthesized by a reaction of 9-ethynylfluoren-9-ol with triruthenium dodecacarbonyl in tetrahydrofuran under reflux. All these compounds have been fully characterized by spectroscopic and X-ray diffraction methods. The structure of 1 consists of a fluorene ring bound to the triruthenium cluster unit via a typical μ 3-( η 2-⊥) co-ordination mode. Cluster 2 is based on a Ru 3 triangle containing a C 4 chain which arises from the coupling of two ligand molecules with the formation of a metallacyclopentadiene ring. An interesting structural feature observed in cluster 3 is the formation of a Ru 4O square pyramidal framework in which the hydroxy group, originating from the ligand, is bound to the cluster in a triply bridging manner. The bonding modes of the organic fragments in 4 and 5 are very similar. They both interact with five ruthenium metal centres but with a novel Ru 5 bent chain in 4 and a spiked butterfly in 5.