Some phenylberyllium complexes

Abstract

Monomeric diphenylberyllium complexes Ph₂Be,L (L = tetramethylethylenediamine, tetramethyl-o-phenylenediamine, 1,2-dimethoxyethane, and 2,5-dithiahexane) are described. Reactions between diphenylberyllium and dimethyl ether, diethyl ether, dimethyl sulphide, trimethylamine, and trimethylphosphine have been followed tensimetrically. Whereas compositions Ph₂BeL_n have negligible dissociation pressures at 0° up to n= 2 when L = Me₂O, Me₂S, and Me₃P, the diethyl ether system has a dissociation pressure of 16 mm. in most of the range from n= 1 to n= 2 and the trimethylamine system has a smaller but appreciable dissociation pressure in the same range of composition. Both Ph₂BeL₂(L = Me₂S or Me₃P), which were prepared from solutions of diphenylberyllium in diethyl ether, are partly dissociated in benzene as measured cryoscopically.

Diphenylberyllium eliminates benzene on reaction with NNN′-trimethylethylenediamine giving (PhBeNMe·C₂H₄·NMe₂)₂. With dimethylamine it gives (PhBeNMe₂)₃, with diphenylamine (PhBeNPh₂)₂, and with methanol (PhBeOMe)₄.