Unprecedented Coordination of 4,4′,5,5′-Tetramethyl-2,2′-biphosphinine Doubly Bridging over an Open Triosmium Core

Abstract

The crystal structure of the novel cluster [Os 3 (CO) 10 (4,4Ј,5,5Јtetramethyl-2,2Ј-biphosphinine)] reveals an unprecedented coordination mode of the biphosphinine ligand that occupies a doubly-bridging position spanning the open osmium tri- [a]

The tmbp Dianion in the Contact Ion Pair [(tmbp)Na2(dme)1.5]n and in the Solvent-Separated Ion Pair [tmbp][(2.2.1)Li]2 This work was supported by the CNRS and the Ecole Polytechnique; tmbp=4,4′,5,5′-tetramethyl-2,2′-biphosphinine, DME=1,2-dimethoxyethane.

“…As a consequence of the loss of aromaticity in each phosphinine subunit, the ligand adopts a curved shape. A similar distorsion was observed upon coordination of 1 to a triosmium core 10. Intramolecular bond lengths are dramatically affected and the connection between the two rings is short (1.401(4) vs 1.49 Å in 1 )7b as are the C3−C4 and C7−C8 bonds (1.363(4) Å).…”

“…In 3 , the ligand adopts a transoid configuration (Figure 2). The overall geometry of 3 is highly distorted and the C5−C5′ connection deviates out of the plane defined by the other carbon atoms of the ring (C1‐C2‐C3‐C4) and the phosphorus atom ( Θ =11°) 10. Except for this distorsion, bond lengths and bond angles are very similar to those of compound 2 .…”

The tmbp Dianion in the Contact Ion Pair [(tmbp)Na2(dme)1.5]n and in the Solvent-Separated Ion Pair [tmbp][(2.2.1)Li]2

“…[5] Recently, we have shown that 2,2'-biphosphinine dianions [6a] could be used efficiently to synthesize highly reduced transitions metal complexes through their reactions with various metal precursors; [6] herein we shed some light on their very peculiar geometrical and electronic structures. [10] Intramolecular bond lengths are dramatically affected and the connection between the two rings is short (1.401(4) vs 1.49 ä in 1) [7b] as are the C3ÀC4 and C7ÀC8 bonds (1.363(4) ä). From dimethoxyethane (DME), a polymeric structure of general formula [(tmbp)Na 2 (dme) 1.5 ] n (2) crystallized, [8] whereas reaction with lithium in THF in the presence of cryptand ( The structure of 2 is highly unusual (Figure 1).…”

“…From dimethoxyethane (DME), a polymeric structure of general formula [(tmbp)Na 2 (dme) 1.5 ] n (2) crystallized, [8] whereas reaction with lithium in THF in the presence of cryptand ( The structure of 2 is highly unusual (Figure 1). [10] Except for this distorsion, bond lengths and bond angles are very similar to those of compound 2. These two units are stacked to columns by Na1 cations.…”

Halide‐Substituted Phosphacyclohexadienyl Iron Complexes: Covalent Structures vs. Ion Pairs

“…Both the lone pair on phosphorus and the conjugated π‐system may interact with metal‐based orbitals, resulting in ambidentate ligand properties evident in numerous transition metal complexes , . In such complexes, phosphinines can adopt various coordination modes such as η 1 , η 2 , η 4 , η 5 , and η 6 ‐coordination (Figure ) to single metal atoms and bridging coordination between two metal atoms , . This highly versatile coordination behavior forms the basis for successful applications in homogeneous catalysis .…”