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通过反 -1 ,2 -双 ( 2 -苯并唑基 )乙烯 ( BBE)和反 -1 -( 2 -苯并咪唑基 ) -2 -( 2 -苯并唑基 )乙烯 ( BME)的光二聚反应合成了 r-1 ,c-2 ,t-3 ,t-4 -四 ( 2 -苯并唑基 )环丁烷 ( BBC)和 r-1 ,c-2 ,t-3 ,t-4 -1 ,3 -双 ( 2 -苯并咪唑基 ) -2 ,4 -双 ( 2 -苯并唑基 )环丁烷 ( BMC) .用元素分析、红外、紫外、核磁共振谱、质谱及 X射线衍射表征了二聚体的结构 .BBC晶体属三斜晶系 ,空间群为 P1 .晶胞参数 :a =0 .64 684 ( 1 3 ) nm,b=1 .3 2 4 2 ( 3 ) nm,c=1 .62 4 5( 3 ) nm;α=74 .66( 3 )°,β=78.77( 3 )°,γ=76.0 6( 3 )°,Z=2 .BBC晶胞中分子有两种取向 ,两种取向不同分子的苯并唑平面间存在着 π-堆积现象 .π-堆积面间的距离在 0 .3 3 0～ 0 .3 76nm之间 ,与石墨晶体中分子平面片层间的距离非常接近 .BBC和 BMC都具有中心对称性 ,光二聚反应的高度立体选择性以及 BBE和 BME的光二聚反应不受空气中氧的影响的事实表明它们是经激发单线态历程以面对面的方式进行二聚反应的 ,本文检测到了 BBE和 BME在高浓度溶液中的激基缔合物荧光
(2 - benzimidazolyl) ethylene (BME) and trans - 1, 2 - bis (2 - (BBC), r-1, c-2, t-3 (2 - benzimidazolyl) -2,4 - bis (2 - benzoxazolyl) cyclobutane (BMC) was determined by elemental analysis, infrared, ultraviolet and nuclear magnetic resonance The structure of the dimer was characterized by spectroscopy, mass spectrometry and X-ray diffraction. The BBC crystal belongs to the triclinic system with space group P1. Cell parameters: a = 0.64 684 (13) nm, b = 1.332 4 2 (3) nm, c = 1.62 4 5 (3) nm; α = 74.66 (3) °, β = 78.77 (3) °, γ = 76.0 6 (3) °, Z = 2. There are two kinds of orientations of molecules in BBC unit cell, π-stacking phenomenon exists between the two benzimidazole planes with different molecular orientation. The distance between the stacking planes is between 0.33 and 0.766, Is very close to the distance between molecular planar layers in the graphite crystal.Because both BBC and BMC have central symmetry, the high stereoselectivity of photodimerization and the photodimerization of BBE and BME are unaffected by the oxygen in the air, Process excited singlet state by a face to face manner dimerization, and this paper detected BBE BME excimer fluorescence in a high concentration in the solution