Construction of alkyl-substituted pentaphosphido ligands in the coordination sphere of cobalt

Abstract

P–P condensation reactions in the coordination sphere of cobalt give access to unique organyl-substituted pentaphosphido complexes.

[3+2] Fragmentation of a Pentaphosphido Ligand by Cyanide

“…Complexes 4‐R are isostructural and resemble those of the recently reported species [( Mes BIAN)Co(η 4 ‐P 5 R 2 )] ( B , R= i Pr, t Bu, Cy; see Scheme a) . The molecular structure of 4‐ t Bu is shown as an example in Figure a; the remaining structures with R=Cy, Ph, Mes, and N i Pr 2 are given in the Supporting Information.…”

“…Filtration and crystallization from THF/ n ‐hexane afforded analytically pure, dark‐green crystals of [K(18c‐6)] 1 in good yield. The NMR spectra of 1 compare well with those of the related 1,2‐bis(arylimino)acenaphthene ( Ar BIAN) complexes K[Co(η 4 ‐1,5‐cod)( Ar BIAN)] (Ar=Dipp, Mes) …”

“…The η 4 ‐ cyclo ‐P 5 R 2 ligands show an envelope conformation with P−P bond lengths ranging from 2.1197(2) to 2.182(1) Å, which indicates some delocalized character . The C−C and C−N distances in 4‐R suggest the presence of PHDI .− radical anions . The 31 P{ 1 H} NMR spectra recorded in C 6 D 6 show an AMM′XX′ spin system in each case (see Figure b for the spectrum of 4‐ t Bu as an example) .…”

“…Rare examples of successful electrophilic functionalization reactions are shown in Scheme a. Peruzzini, Stoppioni, and co‐workers reported the methylation of a cyclo ‐P 3 ligand at Group 9 metal cations, Cummins and co‐workers described the remarkable synthesis of EP 3 (E=As, Sb) molecules from [Nb(ODipp) 3 (η 3 ‐P 3 )] − (Dipp=2,6‐ i Pr 2 C 6 H 3 ) and ECl 3 , and quite recently Scheer and co‐workers disclosed the synthesis of a phosphorus‐silicon analogue of benzene from a tetraphosphidozirconium complex . Recent studies from our groups have shown that the heterodinuclear cobalt‐gallium species A can be successfully applied for the construction of novel alkyl‐substituted pentaphosphido complexes B . However, the synthesis of A is cumbersome, and the reaction properties of B ‐type species have, therefore, not been explored.…”

Functionalization of Pentaphosphorus Cations by Complexation

“…[12] Recent studies clearly show the substantial influence of cationic substituents,f or example,N HCs [13] and phosphanes, [14] on their stability and reactivity. In contrast to avariety of neutral compounds I-IV [16][17][18][19] (Figure 1) and anionic compounds V-VII, [10,19] cationic polyphosphorus complexes with late transition metals (such as VIII)a re extremely rare. In contrast to avariety of neutral compounds I-IV [16][17][18][19] (Figure 1) and anionic compounds V-VII, [10,19] cationic polyphosphorus complexes with late transition metals (such as VIII)a re extremely rare.…”