PUB - Publikationen an der Universität Bielefeld

A series of unique C2P3-ring compounds [(ADC(Ar))P-3] (ADC(Ar) = ArC{(DippN)C}(2); Dipp = 2,6-iPr(2)C(6)H(3); Ar = Ph 4a, 3-MeC(6)H(4)4b, 4-MeC(6)H(4)4c, and 4-Me(2)NC(6)H(4)4d) are readily accessible in an almost quantitative yield by the direct functionalization of white phosphorus (P-4) with appropriate anionic dicarbenes [Li(ADC(Ar))]. The formation of 1,2,3-triphosphol-2-ides (4a-4d) suggests unprecedented [3 + 1] fragmentation of P-4 into P-3(+) and P-. The P-3(+) cation is trapped by the (ADC(Ar))(-) to give 4, while the putative P- anion reacts with additional P-4 to yield the Li3P7 species, a useful reagent in the synthesis of organophosphorus compounds. Remarkably, the P-4 fragmentation is also viable with the related mesoionic carbenes (iMICs(Ar)) (iMIC(Ar) = ArC{(DippN)(2)CCH}, i stands for imidazole-based) giving rise to 4. DFT calculations reveal that both the C3N2 and C2P3-rings of 4 are 6 pi-electron aromatic systems. The natural bonding orbital (NBO) analyses indicate that compounds 4 are mesoionic species featuring a negatively polarized C2P3-ring. The HOMO-3 of 4 is mainly the lone-pair at the central phosphorus atom that undergoes sigma-bond formation with a variety of metal-electrophiles to yield complexes [{(ADC(Ar))P-3}M(CO)(n)] (M = Fe, n = 4, Ar = Ph 5a or 4-Me-C(6)H(4)5b; M = Mo, n = 5, Ar = Ph 6; M = W, n = 5, Ar = 4-Me(2)NC(6)H(4)7).