Crystallite Tuning of Magnetic Properties in S = 1/2 Ni(III) Cyclam (Bi)sulfate Complex Salts

Abstract

Molecular-level crystallographic tuning of a coordination complex structure can enable manipulation of the small energies that govern intra- and intermolecular responses toward molecular actuators. Chemically tuning of the magnetic response of S = 1/2 coordination complexes is of particular interest in recent years because these species represent the simplest electron-based quantum bits (qubits) for developing molecular quantum computers. In this report, we discuss the crystallographic tuning tools and corresponding magnetic properties of novel S = 1/2 Ni(III) cyclam complex salts: strong antiferromagnetic coupling in sulfate-bridged chain {[Ni(cyclam)(μ2-SO4)]ClO4·H2O}n (1) and field-, temperature-, and size-dependent slow magnetic relaxation in molecular [Ni(cyclam)(HSO4)2]HSO4 (2). We have reported two methods of manipulating the dynamic magnetic response of these coordination molecules: particle size selection and deuteration. We find that particle size dependency, which we attribute to the phonon bottleneck effect, for the magnetic dynamics in the parent compound 2, is removed in deuterated 2-d7, revealing only the faster molecular relaxation mode(s).