Ylid-Komplexe von Alkali-und Erdalkalimetallen, VI [1] Neutrale und anionische Ferrocenylmethylide und Fluorenylide

Coordination properties of phosphorus ylides towards electropositive metals are greatly improved in systems, where the carbanionic charge can be delocalized into the aromatic rings of substituents. as illustrated in the title compounds. The ferrocenyl-substituted ylide 2, synthesized from bis(diphenylphosphino)methane and (ferrocenyl)trimethyl-ammonium iodide via the phosphonium salt intermediate 1. is thus easily converted into the alkali complexes 3a, b on treatment with NaNH₂ or KH in tetrahydrofuran, respectively. The intensely coloured products are soluble in a number of organic solvents. NMR spectra of these solutions provide evidence for an interaction between alkali cations and the ferrocenyl rings. - From (C₆H₅)₂CH₂P(C₆H₅)₂ and ferrocenylmethyl chloride a diquaternary salt 4 is obtained, which yields a double-ylido mixture 5a, b on treatment with base. Hydrolysis of this product affords the ylidic phosphine oxide 6. - The reaction of the ylides 7 and 9 (described previously) with NaNH₂, KH or barium metal (in liquid ammonia) leads to the (earth) alkali complexes 8a-c and 10a, b, respectively. With the exception of 8c, but similar to 3a, these materials contain tetrahydrofuran solvate molecules. The ²³Na NMR spectrum of 8a and the pronounced quadrupole broadening of the P(III) signals by the alkali cations in the ³¹P NMR spectra of 8a, b allow structural suggestions for the solution state as proposed in the formulae. Further treatment of 10b with KH yields a potassium complex 11. characterized, i.a., via a corresponding diquaternary salt 12.