First-Principles Study of Two Dimensional Transition Metal Phthalocyanine-Based Metal-Organic Frameworks in Kagome Lattice

Transition metal phthalocyanines (TMPc) and relevant derivatives can act as pervasive molecules for their electronic, magnetic, and optical applications. Numerous researches based on TMPc are carried out, attempting to synthesize novel two-dimensional (2D) metal-organic frameworks. Recently, some 2D poly-TMPc frameworks including FePc J. Am. Chem. Soc. 133, 1203 (2011), CoPc Chem. Commun. 51, 2836 (2015), and Ni-NiPc J. Mater. Chem. A 6, 1188 (2018) frameworks have been successfully synthesized experimentally. Meanwhile, potential applications in catalysis, gas storage, and spintronics were predicted by theoretical studies. Here, we propose a new kind of 2D poly-TMPc frameworks with kagome lattice (denoted as kag-TMPc) and systematically investigate their electronic and magnetic properties by employing first-principles calculations. We have demonstrated that the 2D kag-MnPc framework displays quite stable ferromagnetic ordering with Curie temperature about 125 K as indicated by Monte Carlo simulations based on Heisenberg model and prefers out-of-plane easy-magnetization axis. The 2D kag-CrPc framework is an ideal candidate for S=2 kagome antiferromagnet with RT3 magnetic order. Particularly, the investigations on optical absorption suggest that when the TMPc molecules are self-assembled into 2D kag-TMPc frameworks, their absorption wave bands are broadened, especially in visible region.