The synthesis and structure of the alkaline earth metal organic compounds [M(OAr) 2 (thf) n ][M = Ca, n= 3 (1) or 0; M = Ba, n= 4] and [{Ca(NR 2 )(µNR 2 )(thf)} 2 ], and the X-ray structure of (1)(Ar = C 6 H 2 Bu t 2 -2,6-Me-4; R = SiMe 3 ; thf - OC 4 H 8 )

Treatment of highly reactive, pyrophoric calcium or barium (obtained by co-condensation of the appropriate metal vapour and toluene) in tetrahydrofuran with (i) ArOH (Ca more reactive than Ba) affords the phenoxide [M(OAr)2(thf)n][M = Ca and n= 3 (1), or n= 0 after heating at 80°C and 10–2 Torr; M = Ba, n= 4], or (ii) R2NH (for M = Ca) yields [{Ca(NR2)(µ-NR2)(thf)}2][also obtained from (1)+ 2LiNR2 in n-C6H14; Ar = C6H2But2-2,6-Me-4; R = SiMe3)]; the X-ray structure of crystalline (1) shows a distorted trigonal bipyramidal Ca environment with the thf ligands in apical sites.