通式LauX3(L=甲基-吡啶或二甲基-吡啶,X=Cl或Br)表示为:三-氯-(2-甲基-吡啶)-金(III),[AuCl3(C6H7N)],1(作为两种多晶型物1a和1b);三溴-(2-甲基-吡啶)-金(III),[AuBr3(C6H7N)],2;三-溴代-(3-甲基-吡啶)-金(III),[AuBr3(C6H7N)],3;三-溴代-(2,4-二-甲基-吡啶)-金(III),[AuBr3(C7H9N)],4;三-氯-(3,5-二甲基吡啶)-金(III),[AuCl3(C7H9N)],5;三-溴代-(3,5-二甲基-吡啶)-金(III),[AuBr3(C7H9N)],6和三-氯-(2,6-二甲基-吡啶)-金(III),[AuCl3(C7H9N)],7.此外,8的结构,2和6的1:1加合物,[AuBr3(C6H7N)]·[AuBr3(C7H9N)],包括在内。所有结构都无溶剂结晶,除了5和7,它们都具有Z'=1,它们显示出晶体学的双重旋转对称性,和4,其Z\'=2。图1a和2是同型的。金(III)原子的配位几何形状是,正如预期的那样,方形平面。四个晶体(1a,1b,2和8)是非摩罗大教堂双胞胎,这些结构使用“HKLF5”方法进行了细化。对于吡啶环具有2-甲基取代基的那些结构,观察到吡啶环与配位平面之间的最大平面间角度。Au-N键对Br的反式(平均2.059µ)始终比对Cl的反式(平均2.036µ)更长。在水晶包装中,一个常见的特征是偏移堆叠和近似矩形的二聚体部分(Au-X)2,在与配位平面轴向的空位上,通过Au_X触点连接的反平行Au-X键。二聚体通过进一步的二次相互作用(Au_X或X_X接触,\'弱\'C-H→X氢键)形成链,双链(\'梯子\')或层结构,在某些情况下,在第三维度中再次链接。只有1b和7不包含偏移二聚体;这些结构反而涉及C-H-Cl氢键与Cl-Cl接触(1b)或Cl-π接触(7)结合。将涉及简单吡啶的其他七个配合物LauX3的堆积模式(取自剑桥结构数据库)与1-8的堆积模式进行了比较。
The structures of seven gold(III) halide derivatives of general formula LAuX 3 (L = methyl-pyridines or di-methyl-pyridines, X = Cl or Br) are presented: tri-chlorido-(2-methyl-
pyridine)-gold(III), [AuCl3(C6H7N)], 1 (as two polymorphs 1a and 1b); tri-bromido-(2-methyl-
pyridine)-gold(III), [AuBr3(C6H7N)], 2; tri-bromido-(3-methyl-
pyridine)-gold(III), [AuBr3(C6H7N)], 3; tri-bromido-(2,4-di-meth-yl-pyridine)-gold(III), [AuBr3(C7H9N)], 4; tri-chlorido-(3,5-di-methylpyridine)-gold(III), [AuCl3(C7H9N)], 5; tri-bromido-(3,5-di-methyl-pyridine)-gold(III), [AuBr3(C7H9N)], 6, and tri-chlorido-(2,6-di-methyl-
pyridine)-gold(III), [AuCl3(C7H9N)], 7. Additionally, the structure of 8, the 1:1 adduct of 2 and 6, [AuBr3(C6H7N)]·[AuBr3(C7H9N)], is included. All the structures crystallize solvent-free, and all have Z\' = 1 except for 5 and 7, which display crystallographic twofold rotation symmetry, and 4, which has Z\' = 2. 1a and 2 are isotypic. The coordination geometry at the gold(III) atoms is, as expected, square-planar. Four of the crystals (1a, 1b, 2 and 8) were non-merohedral twins, and these structures were refined using the \'HKLF 5\' method. The largest inter-planar angles between the pyridine ring and the coordination plane are observed for those structures with a 2-methyl substituent of the
pyridine ring. The Au-N bonds are consistently longer trans to Br (average 2.059 Å) than trans to Cl (average 2.036 Å). In the crystal packing, a frequent feature is the offset-stacked and approximately rectangular dimeric moiety (Au-X)2, with anti-parallel Au-X bonds linked by Au⋯X contacts at the vacant positions axial to the coordination plane. The dimers are connected by further secondary inter-actions (Au⋯X or X⋯X contacts, \'weak\' C-H⋯X hydrogen bonds) to form chain, double chain (\'ladder\') or layer structures, and in several cases linked again in the third dimension. Only 1b and 7 contain no offset dimers; these structures instead involve C-H⋯Cl hydrogen bonds combined with Cl⋯Cl contacts (1b) or Cl⋯π contacts (7). The packing patterns of seven further complexes LAuX 3 involving simple pyridines (taken from the Cambridge Structural Database) are compared with those of 1-8.