Crystal Structure and Supramolecular Architecture of Inorganic Ligand-Coordinated Salen-Type Schiff Base Complex: Insights into Halogen Bond from Theoretical Analysis and 3D Energy Framework Calculations

Abstract

To identify the effects of halogen bonding in the architecture of Schiff base complex supramolecular networks, we introduced halogenated Schiff-base 3-Br-5-Cl-salen as ligand and isolated a new salen-type manganese(III) complex [MnIII(Cl)(H2O)(3-Br-5-Cl-salen)] (1) where 3-Br-5-Cl-salen = N,N’-bis(3-bromo-5-chlorosalicylidene)-1,2-diamine. The complex was investigated in the solid-state for halogen bonds (XBs) by single crystal X-ray structure analysis. Meanwhile, theoretical calculations were carried out to rationalize the formation mechanism of different types of XBs in the complex. The analysis result of electronic structure of the halogen bonds indicated that the chlorine atom coordinated to the Mn(III) center possesses the most negative potential and acts as anionic XB acceptor (electron donor) to the adjacent substituted halogens on the ligand, meanwhile the intermolecular Mn-Cl···X-C halogen bonding plays a significant role in directing the packing arrangement of adjacent molecules and linking the 2D layers into a 3D network. In order to verify the above results and acquire detailed information, the title complex was further analyzed by using the Hirshfeld surface analyses.