Treatment of calcium or strontium with 2.0 equivalents of N,Nâ²-bis(o-methylphenyl)formamidine (o-TolFormH), N,Nâ²-bis(2,6-dimethylphenyl)formamidine (XylFormH) or N,Nâ²-bis(o-phenylphenyl)formamidine (o-PhPhFormH) in the presence of 1.0 equivalent of Hg(C6F5)2 in tetrahydrofuran (thf) affords the bis(formamidinate) complexes [Ca(o-TolForm)2(thf)2] (1), [Ca(XylForm)2(thf)2] (2), [Ca(o-PhPhForm)2(thf)2]·thf (3), [Sr(o-TolForm)2(thf)3] (4), [Sr(XylForm)2(thf)3]·3thf (5) and [Sr(o-PhPhForm)2(thf)3]·2thf (6). Analogous reactions with barium were generally unsatisfactory but [Ba(o-PhPhForm)2(thf)3]·2thf (7) was successfully prepared. Compounds 1â7 have been characterised by various spectroscopic methods (1H, 13C1H} NMR and IR), elemental analyses and, for 1, 2 and 4â6, X-ray crystallography. The calcium complexes are monomeric and six-coordinate with either transoid octahedral or trigonal prismatic geometry, whilst the larger radius of strontium accommodates an additional thf solvent donor to give seven-coordinate structures with two types of coordination polyhedra.
将
钙或
锶与 2.0 等量的 N,Nâ²-双(邻甲基苯基)
甲脒 (o-TolFormH)、N,Nâ²-双(2,6-二甲基苯基)
甲脒 (XylFormH) 或 N,Nâ²-双(邻苯基苯基)
甲脒 (o-PhPhFormH)在 1.0当量的 Hg(
C6F5)2 在
四氢呋喃(thf)中生成双(
甲脒)络合物 [Ca(o-TolForm)2(thf)2] (1)、[Ca(XylForm)2(thf)2] (2)、[3)、[Sr(o-TolForm)2(thf)3](4)、[Sr(XylForm)2(thf)3]Â-3thf(5)和[Sr(o-PhPhForm)2(thf)3]Â-2thf(6)。与
钡的类似反应通常并不令人满意,但[Ba(o-PhPhForm)2(thf)3]Â-2thf (7) 已成功制备。化合物 1â7 已通过各种光谱方法(1H、13C1H} NMR 和 IR)、元素分析以及 X 射线晶体学(对于 1、2 和 4â6 而言)进行了表征。
钙配合物是单体,具有横八面体或三棱柱的六配位几何形状,而
锶的半径较大,可以容纳额外的thf溶剂供体,从而产生具有两种配位多面体的七配位结构。