Single Crystal X-ray Diffraction Studies of Two Polymorphic Modifications of the Dicarbonyl- o-Semiquinonato Rhodium Complex at Different Temperatures. Destruction Stimulated by Cooling Versus Stability

Roman V Rumyantcev; Georgy K Fukin; Galina V Romanenko; Irina A Teplova; Michael P Bubnov; Vladimir K Cherkasov

doi:10.1021/acsomega.0c05344

Single Crystal X-ray Diffraction Studies of Two Polymorphic Modifications of the Dicarbonyl- o-Semiquinonato Rhodium Complex at Different Temperatures. Destruction Stimulated by Cooling Versus Stability

ACS Omega. 2020 Dec 9;5(50):32792-32799. doi: 10.1021/acsomega.0c05344. eCollection 2020 Dec 22.

Authors

Roman V Rumyantcev¹, Georgy K Fukin¹, Galina V Romanenko², Irina A Teplova¹, Michael P Bubnov¹, Vladimir K Cherkasov¹

Affiliations

¹ G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, 49 Tropinina str., GSP-445, Nizhniy Novgorod 603950, Russia.
² International Tomography Center of Siberian Branch of Russian Academy of Sciences, Institutskaya, 3a, Novosibirsk 630090, Russia.

Abstract

It was found that the dicarbonyl-rhodium-o-semiquinonate complex (which thread-like crystals can bend reversibly under light/warm activation) can form two polymorphic modifications: isometric prisms (1) and sticks (2). 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 1 are destructed after cooling to 110 K as opposed to crystals 2. In turn, the reversible phase transition is detected in 2. 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 1 in the adjacent stacks are shifted relative to each other along the stack, in contrast to crystal 2. It was found that different packing of stacks leads to different anisotropic compression of crystals 1 and 2 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.