Gardinier James R, Pellechia Perry J, Smith Mark D
Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, USA.
J Am Chem Soc. 2005 Sep 14;127(36):12448-9. doi: 10.1021/ja053256j.
The reaction between p-(LiC2)2C6H4 (generated in situ from butyllithium and dialkynylbenzene) and 2 equiv of BPh3 affords high yields of [Li(THF)4]2[p-(Ph3BC2)2C6H4], a heretofore missing member of the isoelectronic [p-(Ph3EC2)2C6H4] (E = groups 13-15 element) series. The central phenylene linker is free to rotate in the solid state, as determined by a variable-temperature solid-state 2D spin-echo NMR spectroscopic study. At room temperature, the rate of rotation is at least 20 times faster than that of its carbon-based analogue, presumably a result of Coulombic repulsions minimizing noncovalent interactions between rotating units in the borate salt.
对二乙炔基苯原位生成的对-（LiC₂）₂C₆H₄与2当量的BPh₃反应，能高产率地得到[Li(THF)₄]₂[p-(Ph₃BC₂)₂C₆H₄]，它是等电子体[p-(Ph₃EC₂)₂C₆H₄]（E = 第13 - 15族元素）系列中此前缺失的一员。通过变温固态二维自旋回波核磁共振光谱研究确定，中心亚苯基连接基团在固态中可自由旋转。在室温下，其旋转速率至少比碳基类似物快20倍，这可能是由于库仑排斥作用使硼酸盐中旋转单元间的非共价相互作用最小化的结果。
