Phosphine complexes of lone pair bearing Lewis acceptors

Abstract

An overview of the synthesis, structures and reaction chemistry of coordination complexes featuring an acceptor with at least one lone pair and at least one phosphine donor is presented. One or more examples of complexes have been structurally-characterized for the majority of p-block elements but few are known for most elements. The unusual condition of a p-block element centre accommodating a lone pair of electrons and offering a low energy LUMO gives the element centre the potential to behave as both a Lewis acid and a Lewis Base. The structural diversity and reactivity of the phosphine complexes highlights new directions in main group chemistry and by comparison with transition metal coordination chemistry, the featured complexes demonstrate significant configurational and stereochemical flexibility. Ligand exchange, oxidation and reduction chemistry at the lone pair bearing acceptor centre reveals unusual reactivity and an interesting class of ligands and inorganic reagents, with new possibilities for catalysis or small molecule activation.

Synthetic and Structural Study of peri-Substituted Phosphine-Arsines

“…The stability of these and related dative species is likely to be driven by the difference in the Lewis acidity and basicity of the donor and acceptor (i.e., the strength of the dative bond), combined with the redox properties of the two components (i.e., the reducing and oxidising power of these). Comprehensive accounts on neutral [ 12 ] and related cationic species [ 13 , 14 ] have been published recently, encompassing the variety of the structural modes adopted by main group pnictine complexes.…”

Synthesis and reactivity of cyclo-tetra(stibinophosphonium) tetracations: redox and coordination chemistry of phosphine–antimony complexes

“…While the chemistry of p-block elements is primarily dened by covalent bonding as typied by organic frameworks, an array of phosphine adducts has also been characterized for main group element acceptors. [1][2][3][4][5] Beyond their versatile ligand properties as neutral, two-electron donors (L-type), 6 phosphines also exhibit redox reactivity within the coordination sphere of an acceptor. For example, reductive elimination of tetraorgano-or halotriorganophosphonium cations (Scheme 1a), 7 and oxidative addition of PR-X bonds (Scheme 1b), 8 or P-R bonds (Scheme 1c) 9 are all known pathways of tertiary phosphine activation in transition metal chemistry.…”

“…14 Examples of cationic homocycles for p-block metalloids are limited to unsupported selenium and tellurium dications 15 and heavily substituted silicon 16 or germanium 17 monocations. For antimony, a number of acyclic catenated monocations ( [1] 1+ and [2] 1+ ) [18][19][20] and dications ([3] 2+ , [4] 2+ , [5] 2+ and [6] 2+ ) 19,[21][22][23] have recently been isolated (Chart 1), but generally on small scales, precluding further reactivity studies of these interesting species. Enabled by a rational and large scale synthetic protocol for cations [10(R)] 4+ , we now report the reaction chemistry of the prototypical derivative, [10(Me)] 4+ , debuting the coordination chemistry of a new catenaelement framework.…”

Phosphorus–Bismuth Peri-Substituted Acenaphthenes: A Synthetic, Structural, and Computational Study

“…[7][8] Nevertheless, a number of R3E→E'R'3 dative species have been either isolated or observed spectroscopically and they have been treated in several reviews. [9][10][11][12][13][14] Structural and spectroscopic data indicate these complexes adopt a variety of structural forms, including one, 15 two 16 and even three 17 pnictine ligands being coordinated to the Lewis acidic pnictine centre. This results in the general molecular formulae R3E→E'R'3, (R3E→)2E'R'3 and (R3E→)3E'R'3.…”