Lambert Ethan C, Stratton Benjamin W, Hammer Nathan I
Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38655, United States.
ACS Omega. 2022 Apr 8;7(15):13189-13195. doi: 10.1021/acsomega.2c00636. eCollection 2022 Apr 19.
The pyridine-borane (PyBH) complex was analyzed by Raman vibrational spectroscopy and density functional theory to elucidate its structural and vibrational properties and to compare these with those for neat pyridine (Py). The borane-nitrogen (BN) bond length, the BN dative bond stretching frequency, and the effects of dative-bonded complex formation on Py are presented. Rather than having a single isolated stretching motion, the complex exhibits multiple BN dative bond stretches that are coupled to Py's vibrations. These modes exhibit large shifts that are higher in energy relative to neat Py, similar to previous observations of Py/water mixtures. However, significantly higher charge transfer was observed in the dative-bonded complex when compared to the hydrogen-bonded complex with water. A linear relationship between charge transfer and shifts to higher frequencies of pyridine's vibrational modes agrees well with earlier observations. The present work is of interest to those seeking a stronger relationship between charge-transfer events and concomitant changes in molecular properties.
通过拉曼振动光谱和密度泛函理论对吡啶 - 硼烷（PyBH）配合物进行了分析，以阐明其结构和振动特性，并将这些特性与纯吡啶（Py）的特性进行比较。给出了硼烷 - 氮（BN）键长、BN配位键伸缩频率以及配位键合配合物形成对Py的影响。该配合物并非具有单一孤立的伸缩运动，而是表现出多个与Py振动耦合的BN配位键伸缩。这些模式表现出较大的位移，相对于纯Py，其能量更高，这与之前对Py/水混合物的观察结果相似。然而，与与水形成的氢键配合物相比，在配位键合配合物中观察到了明显更高的电荷转移。电荷转移与吡啶振动模式向更高频率的位移之间的线性关系与早期观察结果非常吻合。本研究对于那些寻求电荷转移事件与分子性质伴随变化之间更强关系的人具有重要意义。
