Abstract
We successfully synthesized verdazyl biradical crystals of -BIP-V [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 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 to be about 8.8 K from an analysis of the magnetic susceptibility of isolated -BIP-V molecules in terms of an isolated 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, and , were found to be almost comparable and about 4.5 times larger than the intramolecular interaction . Thus, we confirmed that -BIP-V has a slightly distorted honeycomb-like lattice.
- Received 1 October 2012
DOI:https://doi.org/10.1103/PhysRevB.87.125120
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