An experimental and theoretical exploration of supramolecular interactions and photoresponse properties of two Ni(II) complexes

Two new nickel(II) complexes, C32H2N8NiClO9 (1) and C36H28N12NiOF24P4 (2), have been synthesized where both 2,4,6-tri(pyridin-2-yl)-1,3,5-s-triazine and dipicolinic acid act as tridentate ligands for complex 1 and only 2,4,6-tri(pyridin-2-yl)-1,3,5-s-triazine is employed as a tridentate ligand for complex 2. These complexes were characterized by FT-IR spectroscopy and single-crystal X-ray diffraction. The noncovalent interactions occurring in the crystal packing of both the complexes have been well-defined focusing on pi center dot center dot center dot pi (for complex 1) and anion center dot center dot center dot pi (for complex 2) interactions, which have also been analysed using DFT calculations. Besides, noncovalent interactions such as C-H center dot center dot center dot pi, lone pair center dot center dot center dot pi, pi center dot center dot center dot pi(+), anion center dot center dot center dot pi(+), and pi(+)center dot center dot center dot pi(+) along with hydrogen bonding interactions play an important role in the stabilization of both the complexes in a solid state. We also observed that the change in auxiliary ligands exhibits significant variations in their structures, band gaps and photoresponse properties. To gain insights into the charge transport mechanism, several Schottky barrier diode (SBD) parameters like carrier mobility, transit time, carrier concentration, diffusion coefficient, diffusion length, and ideality factor were measured in the light of thermionic emission and SCLC (space charge limiting current) theory.

Automated summary

Two new nickel(II) complexes have been synthesized using different ligands, showing diverse noncovalent interactions in their crystal structures which play an important role in the stabilization of the complexes. The variation in auxiliary ligands significantly affects the structures, band gaps, and photoresponse properties of the complexes. Study of the charge transport mechanism reveals the importance of various SBD parameters.