Synthesis of a Heterobimetallic Rhodium−Iron Complex Containing an η³-Interaction between Rhodium and the B−C_ipso−C_ortho Unit of a Triarylborane

Abstract

Reaction of [{RhCl(CO)2}2] with a phosphine/thioether/borane ligand (TXPB) gave [Rh(μ-Cl)(CO)(TXPB)] (1), a rare example of a complex containing a M−Cl−BR3 bridging interaction. Reaction of 1 with K[CpFe(CO)2] gave [(TXPB)Rh(μ-CO)2Fe(CO)Cp] (2), which contains an unprecedented η3-interaction between rhodium and the B−C ipso −C ortho unit of a triarylborane. DFT calculations suggest a bonding description intermediate between that expected for an isolated borane/alkene complex and a fully delocalized allyl-like complex.

Hypervalent Silicon Compounds by Coordination of Diphosphine–Silanes to Gold

“…[4] The scope of s-acceptor ligands nowadays appears significantly broader than initially believed, and a great variety of complexes are in fact susceptible to such metal!Lewis acid interactions. [5] To assess to which extent the Lewis acidity of the s-acceptor site can be decreased while retaining substantial interaction with the metal, we recently became interested in the coordination of saturated compounds of heavier Group 14 elements ER 4 (E = Si, Sn, …) to transition metals. The targeted metal!ER 4 interactions would arise from donation of an occupied d orbital at the metal to a vacant low-lying s* orbital centered at silicon or tin.…”

Ambiphilic Diphosphine–Borane Ligands: Metal→Borane Interactions within Isoelectronic Complexes of Rhodium, Platinum and Palladium

“…[11b-d] In this context, we have recently initiated a research programme aimed at exploring the use of so-called ambiphilic ligands combining donor and acceptor coordination sites. [12][13][14][15] Here, the rhodium complexes 2 and 3, [12a] deriving from the diphosphine-borane (DPB) 1, provided the first evidence for M!B interactions in the absence of a s-donor in the position trans to the Lewis acid. Moreover, the gold complexes 5, [12b] deriving from related monophosphine-boranes 4, exemplify the possibility for M!B interactions to occur in 14e complexes, even when supported by only a single donor buttress (Scheme 1).…”

Coordination Chemistry of Neutral (Ln)–Z Amphoteric and Ambiphilic Ligands

“…Elegantly, the chloride can be displaced by the nucleophilic metal anion K[CpFe(CO) 2 ] to form dimetallic species 30. [38] DFT calculations and X-ray diffraction studies support the presence of a weak interaction between the boron and rhodium centres in the form of a boratabenzyl fragment [Rh-B = 2.62(2) Å], in which one of the aryl groups on the boron acts as a benzyl source.…”

“…[37] This ambiphilic framework was also used to coordinate onto a Rh I precur-sor, [RhCl(CO) 2 ] 2 , to yield complex 29. [38] In this squareplanar complex, the ambiphilic ligand is P,S-coordinated, and the chloride ligand bridges the rhodium and boron atoms. Elegantly, the chloride can be displaced by the nucleophilic metal anion K[CpFe(CO) 2 ] to form dimetallic species 30.…”