The Complexed Triphosphaallyl Radical, Cation, and Anion Family

Abstract

Radically complex: The photolytic reaction of [Cp*P{W(CO)(5)}(2)] (Cp* = C(5)Me(5)) with a diphosphene produces, via a radical intermediate, an air-stable complexed triphosphaallyl radical, in which the unpaired electron is evenly distributed over both terminal P atoms. Oxidation of the radical leads to a triphosphaallyl cation, which is only stable at low temperatures in solution, whereas the stable triphosphaallyl anion is formed by reduction (see picture, Mes* = 2,4,6-tri-tert-butylphenyl).

Density functional theory and ab initio studies on hyperfine coupling constants of phosphinyl radicals

“…Having a lone pair and an unpaired electron at the phosphorus atom makes them not only interesting magnetic systems but also reactive intermediates in phosphorus chemistry, for instance in the addition of phosphines to olefins . Lately, many persistent phosphinyl radicals have been reported . Usually, they owe their stability to kinetic or resonance effects and have at least one substituent bound via a heteroatom to the phosphorus atom, with the PC 2 Si 4 radical (Figure ) being an exception to this rule .…”

“…Lately, many persistent phosphinyl radicals have been reported . Usually, they owe their stability to kinetic or resonance effects and have at least one substituent bound via a heteroatom to the phosphorus atom, with the PC 2 Si 4 radical (Figure ) being an exception to this rule . The structural diversity among •PR 2 radicals brings rich variety to their electronic and magnetic properties.…”

Carbene-stabilized main group radicals and radical ions

“…40 Consequently, a few examples of structurally characterized phosphorus radicals G - K have been reported (Figure 11), all of them being stabilized by very bulky subtituents, and/or spin delocalization. 41 In addition, two phosphorus centred radical cations L and M have recently been described. 42 …”

“…41a Since carbenes can behave similarly to transition metals (both have an occupied and vacant orbital), 10i we just replaced the metal fragment of J by an NHC. Reduction of the corresponding phosphenium triflate 20 afforded the desired radical 20 · (Figure 14).…”

Insight into the Reaction of a Dinuclear Phosphinidene Complex with Nitriles

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The phosphinidene complex[ Cp*P{W(CO) 5 } 2 ]( 1; Cp* = C 5 Me 5 )r eactedw ith malononitrile to give the 1,2-dihydro-1,3,2-diazaphosphinine derivative 2.T he reactiono f 1 with 1,4-benzodinitrile gave [1,4-{{W(CO) 5 } 2 P-N = C(Cp*)} 2 (C 6 H 4 )] (3), the first example of ac umulene-like aminophosphinidene complex. Both, the Cp* radical elimination by photolysis [6] andt he migration of the Cp* substituent from the phosphorus atom to the tungsten atom, induced by thermal activation, lead to reactive intermediates. To comparet he reactivity of benzonitrile and aniline with 1,t he phosphinidene complex 1 was reactedwith three different isomers of aminobenzonitrile (2-, 3-, and 4-aminobenzonitrile).

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