Halogen···Halogen and π–Hole Interactions in Supramolecular Aggregates and Electrical Conductivity Properties of Cu(II)-Based 1D Coordination Polymers
Sanobar Naaz, Pubali Das, Antonio Frontera, Basudeb Dutta, Samim Khan, Partha Pratim Ray, Mohammad Hedayetullah Mir
Abstract
The two isostructural one-dimensional coordination polymers (1D CPs) [Cu(5-nip)(3-Clpy)2]n (1) and [Cu(5-nip)(3-Brpy)2]n (2) have been synthesized using a 5-nitroisophthalic acid (H25-nip) linker and the meta-substituted 3-chloropyridine (3-Clpy)/3-bromopyridine (3-Brpy) auxiliary ligands. The structural architectures and supramolecular interactions of the CPs have been investigated by single-crystal X-ray diffraction (SCXRD) and density functional theory (DFT) studies, respectively. The SCXRD study reveals that CPs 1 and 2 form a 1D double-chain structure with carboxylato-bridged cyclic secondary building units (SBUs). Interestingly, both CPs involve type I halogen···halogen (X···X) interactions combined with π···π stacking interactions to generate a three-dimensional (3D) supramolecular network. Moreover, both CPs exhibit interesting X···N π-hole interactions involving a nitro group as the electron acceptor. Both CPs show electrical conductivity in the semiconducting regime and behave as Schottky diodes. However, CP 1 has a higher electrical conductivity in comparison to CP 2.