Department of Chemistry, Wichita State University, Wichita, Kansas 67260, USA.
J Phys Chem A. 2010 Jul 1;114(25):6766-75. doi: 10.1021/jp103749b.
Two new derivatives of all-trans retinal, one containing a pyridine and a cyanide substituent, all-trans-15-cyano-15'-pyridylretinal (2), and the other containing two cyanide substituents, all-trans-15,15'-dicyanoretinal (3), have been synthesized from all-trans-retinal (1) by the Knoevenagel reaction. Compound 2 crystallizes in the space group P1; compound 3 crystallizes in the space group P2(1)/n. The polyene chains are bowed. The compounds exhibit C[triple bond]N vibrations in the infrared and Raman regions and undergo irreversible oxidations. Compounds 2 and 3 display electronic absorptions with maxima located at 442 and 487 nm and emission peaks located at 583 and 500 nm, respectively. Density Functional Theory and Time Dependent Density Functional Theory calculations reveal that the electronic transition from the HOMO to the LUMO can be associated with the A(g) --> B(u) electronic transition and a peak corresponding to the HOMO --> LUMO+1 transition can be associated with the "cis-peak".
两个全反式视黄醛的新衍生物，一个含有吡啶和氰基取代基，全反式-15-氰基-15'-吡啶基视黄醛（2），另一个含有两个氰基取代基，全反式-15,15'-二氰基视黄醛（3），已经通过克诺文格尔反应从全反式视黄醛（1）合成得到。化合物 2 在空间群 P1 中结晶；化合物 3 在空间群 P2(1)/n 中结晶。多烯链呈拱形。这些化合物在红外和拉曼区域显示出 C[三重键]N 振动，并经历不可逆氧化。化合物 2 和 3 显示出最大位于 442nm 和 487nm 的电子吸收峰，以及分别位于 583nm 和 500nm 的发射峰。密度泛函理论和时间相关密度泛函理论计算表明，从 HOMO 到 LUMO 的电子跃迁可以与 A(g) --> B(u) 电子跃迁相关联，与 HOMO --> LUMO+1 跃迁对应的峰可以与“顺式峰”相关联。
