78529-71-2Relevant academic research and scientific papers
Reaction of lithium alkyls and aryls with 1,1′-diphosphaferrocenes. Synthesis and structure of a stable bis(diene)iron(-I) species
Deschamps, Bernard,Fischer, Jean,Mathey, Fran?ois,Mitschler, André
, p. 3252 - 3259 (1981)
The reaction of 2 equiv of alkyllithium and 3 equiv of alkyl halide with 1,1′-diphosphaferrocene yields a stable green paramagnetic bis(η4-phospholium)iron halide in which iron bears formally 17 electrons. The stability of these species increases with the bulkiness of the alkyl chains. The product with tert-butyl and methyl P substituents was studied by X-ray. The two most striking characteristics of its structure are the absence of a phosphorus-iron bond and the impressive folding of the phospholium nucleus around the Cα-Cα′ axis (?31°). Crystal data for FeP2IC22H40 are a = 10.640 (1) A?, b = 10.865 (2) A?, c = 24.908 (4) A?, α = 90.14 (1)°, β = 95.06 (1)°, γ = 112.24 (1)°, V = 2653 A?3, Z = 4, dcalcd = 1.37 g cm-3, and space group P1. The mechanism of formation of these products probably includes the nucleophilic attack of alkyllithium onto one of the phosphorus atoms of 1,1′-diphosphaferrocene followed by the electrophilic attack of the alkyl halide onto the same phosphorus giving a transient (phospholium)(phospholyl)iron species. When phenyllithium was used, this transient species was spontaneously oxidized and gave a stable (η4-phospholium)(η 5-1-hydroxy-1-oxophospholato)iron diamagnetic zwitterion, the structure of which was also established by X-ray. The existence of such a compound demonstrates that the phosphole P(O)OH acids are able to chelate a metal between their phosphinate function and their dienic system. Crystal data for FeP2O3C19H26 are a = 9.822 (1) A?, b = 9.845 (1) A?, c = 10.913 (1) A?, α = 74.64 (1)°, β = 67.02 (1)°, γ = 80.74 (1)°, V = 935 A?3, Z = 2, dcalcd = 1.49 g cm-3, and space group P1.
