Reversible P₄ Activation with Nickel(I) and an η³‐Coordinated Tetraphosphorus Ligand between Two Ni^I Centers

Abstract

P4 activation but without reduction is the most striking result of the reaction of NiI precursors (LNi) with white phosphorus. This reaction leads to the complexes 1 a and 1 b, which feature the scarce η3‐coordination of the P4 ligand between two metal centers. Remarkably, 1 a undergoes facile dissociation in solution to give the paramagnetic NiI complex 2. L=β‐diketiminate; 1 a: R=iPr2C6H3, 1 b: R=2,6‐Et2C6H3.

Metal‐Assisted Opening of Intact P4 Tetrahedra

“…In 5 m′ , the initial P 4 moiety underwent a P−P bond cleavage, resulting in a quasi‐butterfly‐type ligand, behaving as a trihapto‐coordinated ligand towards cobalt while still η 1 ‐coordinated to ruthenium. Remarkably, there are very few examples in literature of a “naked” tetraphosphorus moiety η 3 ‐coordinated to a metal center, such as the bimetallic complex [LNi(η 3 ‐P 4 )NiL] (L: L Et =CH[CMeN(2,6‐Et 2 C 6 H 3 )] 2 , L i Pr =CH[CMeN(2,6‐ i Pr 2 C 6 H 3 )] 2 ) featuring a doubly trihapto‐coordinated P 4 . The optimized structure of the intermediate shows an asymmetric coordination of the new tetraphosphorus moiety to the cobalt center with two shorter (2.20 Å) and one longer 2.27 Å Co−P distance(s), reminiscent of the iridium complex [Ir(κ 2 ‐dppm)(κ 1 ‐dppm)(η 3 ‐P 3 {P(O)H})] (dppm=(Ph 2 P) 2 CH 2 ) and the Mo complex [Cp′Mo(CO) 2 {(η 3 ‐P 4 ){Cr(CO) 5 } 4 (H)}] (Cp′=η 5 ‐C 5 H 4 t Bu), in which a naked P 3 unit (coming from P 4 as well) behaves as a stable triphosphaallyl group and possesses an asymmetric structure.…”

“…(L:L Et = CH[CMeN(2,6-Et 2 C 6 H 3 )] 2 ,L iPr = CH[CMeN(2,6-iPr 2 C 6 H 3 )] 2 )f eaturing ad oubly trihapto-coordinated P 4 . [19] The optimized structure of the intermediate shows an asymmetricc oordination of the new tetraphosphorus moiety to the cobalt center with two shorter (2.20 )a nd one longer 2.27 CoÀPd istance(s), reminiscento ft he iridium complex [Ir(k 2 -dppm)(k 1 -dppm)(h 3 -P 3 {P(O)H})] [20] (dppm = (Ph 2 P) 2 CH 2 ) and the Mo complex [Cp'Mo(CO) 2 {(h 3 -P 4 ){Cr(CO) 5 } 4 (H)}] [21] (Cp' = h 5 -C 5 H 4 tBu), in whichanaked P 3 unit (coming from P 4 as well) behaves as as table triphosphaallyl group andp ossesses an asymmetricstructure.…”

Metalate‐Mediated Functionalization of P4 by Trapping Anionic [Cp*Fe(CO)2(η1‐P4)]− with Lewis Acids

“…The challenge is to control the unpredictable reactivity of P 4 . To date, steps invoking reducing neutral metal complexes have been reported by, for example, the groups of Scheer (Fe), Driess (Fe, Co, and Ni), and Cummins (Nb) and cations by Peruzzini and co‐workers (Fe, Ru, Rh, and Ir) . However, in spite of its inherent electrophilic character, reactions of P 4 with TM anions have hardly been considered.…”

Functionalization of Pentaphosphorus Cations by Complexation

“…However, the coordination chemistry of cationic polyphosphanes has scarcely been studied thus far. In contrast to a variety of neutral compounds I – IV (Figure ) and anionic compounds V – VII , cationic polyphosphorus complexes with late transition metals (such as VIII ) are extremely rare . In particular, the direct use of cationic polyphosphanes as ligands has not been investigated.…”