Mixed-Metal Cluster Chemistry. 31. Reactions of Dimolybdenum–Diiridium Clusters with Alkylidyne Complexes

Abstract

Reactions of the tetrahedral clusters Mo 2 Ir 2 (μ-CO) 3 (CO) 7 (η 5 -L) 2 (L = C 5 H 5 , C 5 HMe 4 ) with the molybdenum alkylidyne complex Mo(CC 6 H 4 OMe-4)(CO) 2 {(N 2 C 3 H 3 ) 3 BH-κ 3 N,N′,N″} afford the pentanuclear clusters Mo 3 Ir 2 (μ 4 -C)(μ 3 -CC 6 H 4 OMe-4)(μ-O)(CO) 6 {(N 2 C 3 H 3 ) 3 BH-κ 3 N,N′,N″}(η 5 -C 5 H 5 ) 2 (1; 62%) and Mo 3 Ir 2 (μ 3 -CC 6 H 4 OMe-4)(μ 3 -η 2 -CO)(μ-CO)(CO) 6 {(N 2 C 3 H 3 ) 3 BH-κ 3 N,N′,N″}(η 5 -C 5 Me 4 H) 2 (2; 65%), respectively, while the reaction of Mo 2 Ir 2 (μ-CO) 3 (CO) 7 (η-C 5 H 5 ) 2 with W(CCCSiMe 3 )(CO) 2 {(N 2 C 3 H 3 ) 3 BH-κ 3 N,N′,N″} yields the butterfly cluster Mo 2 Ir 2 (μ 4 -η 2 -SiMe 3 C 2 CW(CO) 2 {(N 2 C 3 H 3 ) 3 BH-κ 3 N,N′,N″})(μ-CO) 4 (CO) 4 (η 5 -C 5 H 5 ) 2 (3; 60%). The identities of 1−3 have been confirmed by single-crystal X-ray diffraction studies. Cluster 1 contains μ 4carbido and μ-oxido ligands resulting from CO cleavage. Cluster 2, with sterically more encumbering tetramethylcyclopentadienyl ligands that arrest CO cleavage, possesses a μ 3 -η 2 -CO ligand with a weak CO bond (1.272(7), 1.257(7) Å). Cluster 2 could not be converted into an analogue of cluster 1. The reaction with alkyne is more facile than the reaction with alkylidyne; cluster 3 results from addition of the CC bond (rather than the WC bond) across the Mo−Mo vector.

Mixed-metal cluster chemistry. 35. Syntheses and structural studies of Mo 3 Ir 3 (μ 3 -O)(μ-CO) 3 (CO) 8 ( η 5 -C 5 H 5 ) 3 , Mo 4 Ir 4 (μ-CO) 4 (CO) 9 ( η 5 -C 5 H 5 ) 4 and Mo 3 Ir 5 (μ-CO) 3 (Cl)(CO) 6 ( η 5 -C 5 H 5 ) 3 ( η 5 -C 5 HMe 4 )

“…We have reported comprehensive studies of the syntheses and chemistry of tetranuclear mixed molybdenum/tungsteneiridium carbonyl clusters [5] and have recently extended these studies to embrace pentanuclear examples [6]. On modifying the reaction conditions employed for the syntheses of one of the pentanuclear clusters, we observed the unexpected formation of several highernuclearity species, the syntheses and structural characterization of which are reported herein.…”

Phosphorescent Cyclometalated Iridium(III) Complexes Based on Amidate Ancillary Ligands: Their Synthesis and Photophysical Properties

“…Neutral complexes (especially heteroleptic complexes) are of particular interest, because they typically exhibit good optical properties. Recently, a number of contributions in the literature described ancillary ligands, such as acetylacetonate (acac), functionalized β-diketonate, picolinate, triazolate, and others …”