Bedeković Nikola, Piteša Tomislav, Eraković Mihael, Stilinović Vladimir, Cinčić Dominik
University of Zagreb, Faculty of Science, Department of Chemistry, Horvatovac 102a, 10000 Zagreb, Croatia.
Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
Cryst Growth Des. 2022 Apr 6;22(4):2644-2653. doi: 10.1021/acs.cgd.2c00077. Epub 2022 Mar 24.
To investigate influences on the topicity of perfluorinated halobenzenes as halogen bond (XB) donors in the solid state, we have conducted a database survey and prepared 18 novel cocrystals of potentially ditopic (, ) and tritopic () XB donors with 15 monotopic pyridines. shows high tendency to be mono- or ditopic, but with strong bases it can act as a tritopic XB donor. DFT calculations have shown that binding of a single acceptor molecule on one of the iodine atoms of the XB donor reduces the ESP on the remaining iodine atoms and dramatically decreases their potential for forming further halogen bonds, which explains both the high occurrence of crystal structures where the donors do not achieve their maximal topicity and the observed differences in halogen bond lengths. Despite the fact that this effect increases with the basicity of the acceptor, when the increase of halogen bond energy due to the basicity of the acceptor compensates its decrease due to the reduction of the acidity of the donor, it enables strong bases to form cocrystals in which a potentially polytopic XB donor achieves its maximal topicity.
为了研究全氟卤代苯作为固态卤素键（XB）供体时对主题性的影响，我们进行了数据库调查，并制备了18种新型共晶体，这些共晶体由潜在的双位（，）和三位（）XB供体与15种单位吡啶组成。显示出单或双位的强烈倾向，但与强碱结合时，它可作为三位XB供体。密度泛函理论计算表明，在XB供体的一个碘原子上结合单个受体分子会降低其余碘原子上的静电势，并显著降低它们形成进一步卤素键的潜力，这既解释了供体未达到其最大主题性的晶体结构的高发生率，也解释了观察到的卤素键长度差异。尽管这种效应随受体的碱性增强而增加，但当由于受体碱性导致的卤素键能增加补偿了由于供体酸度降低而导致的键能降低时，它使强碱能够形成共晶体，其中潜在的多位XB供体达到其最大主题性。
