作者:Wolfram Sander、Michael Exner
DOI:10.1039/a905189i
日期:——
The UV photolysis of [2.2]metaparacyclophanediones 4b and 4c leads to α-cleavage and formation of CO, p-xylylene 5, and m-benzynes 2b and c with a fluorine or methyl substituent in the 5-position, respectively. The IR spectra of 2b and 2c were assigned by comparison with that of the parent m-benzyne 2a and with spectra calculated at the BLYP/6-311G(d,p) level of theory. Both band positions and intensities of the experimental spectra are in excellent agreement with the DFT calculations. This method thus provides a reliable tool for the investigation of ground state properties of m-benzynes. The benzynes 2 exhibit a very strong IR absorption at 545 ± 2 cmâ1 which is almost not affected by the substituents and therefore can be used to identify m-benzynes in product mixtures.
[2.2]间对环芳二酮 4b 和 4c 的 UV 光解导致 α-裂解并形成 CO、对二甲苯 5 和间苯炔 2b 和 c,分别在 5 位具有氟或甲基取代基。 2b 和 2c 的红外光谱是通过与母体间苯炔 2a 的红外光谱比较以及在 BLYP/6-311G(d,p) 理论水平上计算的光谱来确定的。实验光谱的能带位置和强度都与 DFT 计算非常一致。因此,该方法为研究间苯炔的基态性质提供了可靠的工具。苯炔2在545±2 cm-1处表现出非常强的红外吸收,几乎不受取代基的影响,因此可用于鉴定产品混合物中的间苯炔。