A Class of Trinuclear Clusters with Carbonyl Bridging

✍ Scribed by Allan R. Pinhas; Thomas A. Albright; Peter Hofmann; Roald Hoffmann

• Book ID: 102858448
• Publisher: John Wiley and Sons
• Year: 1980
• Tongue: German
• Weight: 958 KB
• Volume: 63
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19800630105

✦ Synopsis

The impetus for this work was the structure of a trinuclear complex with two carbonyl groups showing incipient triple bridging -Cp,Rh,(CO);. Its structure, barrier to rotation of one Rh (CO), piece vs. the rest of the molecule, and the nature of the bridging carbonyl interaction are analyzed. Isolobal analogies form an interesting connection between this complex and a bridged isomer of the recently synthesized carbene complexes, C P ~R ~, ( C O ) ~C R ~, one isomer of Cp2Rh3(C0),, and hypothetical carbyne complexes Cp2Rh2(C0),CH+.-. A general bonding model for Cp2Rh2(p-CO),X complexes is constructed. The model, rich in geometrical detail, allows minima for the bridging carbonyl groups bending toward and away from the bonded ligand X.

Introduction. -Interest and expediency, two of the motive forces of science, lay behind the initiation of this work. The interest was provided by the preparation and structure determination of Cp2Rh,(CO)y (1) by Bergman el al. [1J2). We were intrigued by the semi-triply bridging disposition of two carbonyl groups in 1. In transition metal clusters there exists a spectrum of terminally bonded, doubly bridging, semi-doubly bridging, and triply bridging carbonyl groups [2] [3]. The complex 1 is a so far unique example of a molecule caught between the doubly 1