Packing polymorphism of dicarbonyl-[2-(phenylamino)pent-3-en-4-onato]rhodium(I)

Abstract

Depending on the crystallization conditions, the interaction between the rhodium metal centres of the separate [Rh(CH3COCHCN(Ph)CH3)(CO)2] molecular units, as described by the interplanar separation and lateral shift of two of the units, leads to packing polymorphism of [Rh(CH3COCHCN(Ph)CH3)(CO)2], which means the same molecule crystallises in different fashions, resulting in different polymorphs (α and β), with a difference in crystal packing. Six different sets of solid state single crystal data of [Rh(CH3COCHCN(Ph)CH3)(CO)2], show that this complex is polymorphic, forming dinuclear units that either stack in wire-like chains with weak metallophilic rhodium-rhodium interactions (β-polymorph), or with packing of the dinuclear units that does not result in rhodium-rhodium chains (α-polymorph). A DFT study on the inter-molecular interactions in different dinuclear [Rh(CH3COCHCN(Ph)CH3)(CO)2]2 models, using different DFT methods, provides an understanding on a molecular level of the rhodium-rhodium and other inter-molecular interactions between the two separate [Rh(CH3COCHCN(Ph)CH3)(CO)2] molecules in the dinuclear unit.