The First Mixed‐Metal Borole Cluster; Stabilization of Formally 14e Pd Centers in the Re₂Pd₂ Electron‐Deficient [{[(η⁵‐C₄H₄BPh)(CO)₃Re]Pd}₂] Cluster

Abstract

Carbonylmetalates have long been used for the synthesis of metal cluster complexes and have proved particularly useful in mixed-metal cluster chemistry. The HOMO of 18-electron reagents such as [CpMo(CO),]-(Cp = q-C5H5) has mostly metal d orbital character, accounting for its propensity to form metal-metal bonds. For the isosteric reagent [CpMn-(CO),(CN)]-, in contrast, the HOMO is centered on the cyano nitrogen atom, which explains the tendency of this anion to form linear Mn-CN-M' arrays."] In 1990 we found that this cyanometalate is simultaneously involved in both Mn-CN-Pd and direct Mn-Pd bonding in the unprecedented octanuclear, double-helix-type cluster 1 .[21 We have begun an investigation of the reactivity of electronically related borole-containing metalates such as 2, where the negative charge is very much delocalized, and 3, where it is mostly associated with the cyano ligWe also hoped that these compounds would allow the synthesis of the first cluster complexes containing a borole ligand. This was actually achieved and we present here our first results with anion 2 and the characterization of an unprecedented Re,Pd, cluster 4.

An organometallic tetranuclear cluster with phosphine and phosphido ligands in nonclassical bonding modes: X-ray structural characterization

“…The interaction between the phosphido containing P(2) and the Pd(2) centre is very noteworthy and different to the previously proposed interaction. The Pd(2)-C(37) distance (2.391(5) Å ) is rather short [18][19][20][21][22][23][24][25], as is the Pd(2)-P(2) distance (2.272(1) Å ), in fact it is even Scheme 1. shorter than the Pd(1)-P(2) and Pt(1)-P(2) distances (2.389(1) and 2.358(1) Å , respectively). These data indicate that the P(2)-C(37) bond interacts with the Pd(2) centre giving rise to a 2e-3c bond or an agostic-like interaction of a P-C sp2 bond with an unsaturated metal atom, as it has been recently called for related phosphine complexes [26][27][28].…”

Heterometallic complexes and clusters with 2-boratanaphthalene ligands †

“…In a different context, the isolobal analogy between the 6π electron borollide dianion (C 4 H 4 BR) 2Ϫ (R = Ph) and the cyclopentadienide ion (C 5 H 5 ) Ϫ has been recently used to compare the reactivity and bonding properties of isolobal metal-centred organometallic nucleophiles of two adjacent columns of the Periodic classification, such as [WCp(CO) 3 ] Ϫ (1) and [Re(η 5 -C 4 H 4 BR)(CO) 3 ] Ϫ (2). 2,3 This led inter alia to the synthesis of heterodinuclear complexes with Re-Cu, Re-Ag, Re-Au or Re-Hg bonds in which the borole-containing carbonylmetalate behaves as a terminal, two-electron donor metalloligand. This bonding behaviour is also commonly encountered with the cyclopentadienylcontaining carbonylmetalates [MCp(CO) 3 ] Ϫ (M = Cr, Mo or W) in metal-metal bonded complexes.…”

“…5, 6 A strict analogue of these clusters does not exist in the borole series since despite its planar, triangulated metal core, the cluster [Re 2 Pd 2 (C 4 H 4 -BPh) 2 (CO) 6 ] 4 contains only 54 CVE. 3 This unusual cluster displays a unique bonding situation for the borole ligand which not only binds to rhenium in the usual η 5 manner but also to the adjacent palladium via a 2e-3c B-C ipso -Pd system. These intriguing similarities and differences led us to extend our studies with borole-containing carbonylmetalates to [HFe(η 5 -C 4 H 4 BPh)(CO) 2 ] Ϫ , 2, 7 [Fe(η 5 -C 4 H 4 BPh)-(CO) 2 CN] Ϫ , 8 and now to the 2-boratanaphthalene system.…”

Organometallic building blocks with amino-substituted cyclopentadienyl and boratabenzene ligands for the synthesis of heterometallic complexes and clusters

“…Data for Li•7•2DME. 1 H NMR ((CD 3 ) 2 CO): AA XX system d 4.76 and 4.45 (2 pseudo-t, 8H, Cp), 3.48 (s, 8H, CH 2 , DME), 3.30 (s, 12H, CH 3 , DME), 2.34 (s, 6H, N(CH 3 ) 2 ). IR (THF): m(CO): 1898s, 1799vs, 1773sh, 1709s cm −1 .…”