Some phenylberyllium complexes

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 Ph2BeLn 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.