We successfully synthesized verdazyl biradical crystals of p-BIP-V 2 [4,4′-bis(1,5-diphenylverdazyl-3-yl)biphenyl]. Two types of intermolecular interactions are deduced from the spin-density distribution and molecular packing in the crystal, and these interactions are considered to result in the formation of a honeycomb lattice. The ab initio molecular orbital calculation also indicated such an exchange network of intermolecular interactions. The intramolecular interaction acts as a diagonal bridge across the honeycomb lattice to form a square lattice. We evaluated the intramolecular antiferromagnetic (AF) interaction J1 to be about 8.8 K from an analysis of the magnetic susceptibility of isolated p-BIP-V 2 molecules in terms of an isolated S = 1/2 AF dimer. We analyzed the magnetic susceptibility of the crystals using the quantum Monte Carlo method. Consequently, two types of intermolecular AF interactions, J2 and J3, were found to be almost comparable and about 4.5 times larger than the intramolecular interaction J1. Thus, we confirmed that p-BIP-V2 has a slightly distorted S=1/2 honeycomb-like lattice.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2013 Mar 14|