Preda A M, Schneider W B, Schaarschmidt D, Lang H, Mertens L, Auer A A, Mehring M
Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Chemie, Professur Koordinationschemie, 09107 Chemnitz, Germany.
Dalton Trans. 2017 Oct 10;46(39):13492-13501. doi: 10.1039/c7dt02567j.
Two polymorphs of tris(thienyl)bismuthine Bi(2-CHS) (1) were isolated upon crystallization from n-hexane at different temperatures. The high temperature form 1-HT crystallized at 269 K in the trigonal space group R3[combining macron], whereas the low temperature form 1-LT crystallized at 245 K in the triclinic space group P1[combining macron]. An enantiotropic phase transition was observed at 250 K showing a transition energy of 1.4 kJ mol. Both polymorphs reveal the formation of centrosymmetric dimers that are based on London dispersion type bismuthπ heteroarene interactions. These primary building units show additional dispersion type interactions between neighbouring dimers and as a result 2D networks are formed. DFT calculations on the model systems BiXπ thiophene (X = Cl, Me) verify the hypothesis of a soft and shallow binding potential of the London dispersion type bismuthπ heteroarene interaction, providing an explanation for the reversibility of the phase transition.
在不同温度下从正己烷中结晶时，分离得到了三（噻吩基）铋Bi(2-CHS)（1）的两种多晶型物。高温形式1-HT在269 K下结晶于三方空间群R3[上加横线]，而低温形式1-LT在245 K下结晶于三斜空间群P1[上加横线]。在250 K观察到一个互变的相变，其转变能为1.4 kJ/mol。两种多晶型物都显示出基于伦敦色散型铋-π-杂芳烃相互作用形成的中心对称二聚体。这些主要构建单元在相邻二聚体之间还显示出额外的色散型相互作用，结果形成了二维网络。对模型体系BiX-π-噻吩（X = Cl，Me）的密度泛函理论计算验证了伦敦色散型铋-π-杂芳烃相互作用具有软且浅的结合势这一假设，为相变的可逆性提供了解释。
