Rumyantcev Roman V, Fukin Georgy K, Romanenko Galina V, Teplova Irina A, Bubnov Michael P, Cherkasov Vladimir K
G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, 49 Tropinina str., GSP-445, Nizhniy Novgorod 603950, Russia.
International Tomography Center of Siberian Branch of Russian Academy of Sciences, Institutskaya, 3a, Novosibirsk 630090, Russia.
ACS Omega. 2020 Dec 9;5(50):32792-32799. doi: 10.1021/acsomega.0c05344. eCollection 2020 Dec 22.
It was found that the dicarbonyl-rhodium--semiquinonate complex (which thread-like crystals can bend reversibly under light/warm activation) can form two polymorphic modifications: isometric prisms () and sticks (). Some thin sticks can bend as mentioned above. X-ray diffraction studies of polymorphic modifications at different temperatures were carried out. It was found that crystals are destructed after cooling to 110 K as opposed to crystals . In turn, the reversible phase transition is detected in . In both polymorphic modifications, stack packaging motifs through the direct Rh-Rh bond are observed. The principal difference between packages of polymorphic modifications is that molecules in the adjacent stacks are shifted relative to each other along the stack, in contrast to crystal . It was found that different packing of stacks leads to different anisotropic compression of crystals and during cooling, which is a key factor of their stability. Using the molecular invariom approach, the nature of the chemical bonds and charge distribution was investigated; the energy of the Rh-Rh bonds was estimated.
研究发现，二羰基铑 - 半醌配合物（其丝状晶体在光/热激活下可可逆弯曲）可形成两种多晶型变体：等轴棱柱体（）和棒状体（）。一些细棒状体可如上述那样弯曲。对不同温度下的多晶型变体进行了X射线衍射研究。结果发现，与晶体相比，晶体在冷却至110 K后会被破坏。反过来，在中检测到可逆相变。在两种多晶型变体中，均观察到通过直接Rh - Rh键的堆积包装模式。多晶型变体包装之间的主要区别在于，与晶体相比，相邻堆积中的分子沿堆积方向彼此相对移动。研究发现，不同的堆积排列导致晶体和在冷却过程中产生不同的各向异性压缩，这是它们稳定性的关键因素。使用分子不变量方法，研究了化学键的性质和电荷分布；估计了Rh - Rh键的能量。
