Counterion influence on dynamic spin properties in a V(iv) complex

Abstract

Studies of R3NH+ salts of [V(C6H4O2)3]2– experimentally define the distance dependence of the impact of the CH3-group on spin properties.

Metal–ligand covalency enables room temperature molecular qubit candidates

“…Specically, the role phonons and local vibrational modes play in modulating spin dynamics of electronic spin qubits is of particular importance. [13][14][15][16][17][18][19] In this study, we focus on a different parameter, modulating the covalency of the metal-ligand bond to control relaxation times. The identity of the spin-bearing orbital and its interaction with the lattice and intramolecular vibrations should guide the magnitude of T 1 .…”

Mapping Magnetic Properties and Relaxation in Vanadium(IV) Complexes with Lanthanides by Electron Paramagnetic Resonance

“…We dissolved two representative compounds (I and III) in glass-forming water/glycerol mixture (~50/50% v/v) and recorded two-pulse echo-detected (ED) EPR spectra in such frozen (glassy) solutions ( Figure 5). Note that mostly vanadium-based candidates for spin qubits were investigated in the solid crystalline state; however, a few earlier works used dissolution as well [3,4,7,13,14]. In particular, this approach allowed obtaining very long decoherence times at low temperatures, especially in nuclear spin-free solvents.…”

“…The search for molecular spin qubits with suitable physical properties is one of the main targets on the way to the implementation of quantum spin technologies and quantum computing [1,2]. Among other candidates for molecular spin qubits, vanadium-based complexes attracted special attention during the past decade due to their long decoherence times, both at cryogenic and room temperatures [3][4][5][6][7][8][9][10][11][12][13][14][15]. The vanadium(IV) ion has an electron spin S = 1/2 and a nuclear spin I = 7/2 for stable isotope 51 V of nearly 100% natural abundance.…”

“…These properties determine the intrinsically longer electron spin relaxation times compared to high-spin (S > 1/2) ions, and, at the same time, provide a set of nuclear spin states for manipulation of multiple coherences. Some previous works were concerned with the frozen solutions of vanadium(IV) complexes [3,4,7,13,14], while the others considered solid-state compounds and their relaxation properties. The longest decoherence time (also called dephasing, phase memory, sometimes transverse relaxation time) at room temperature T m~1 µs was obtained for vanadyl phthalocyanine complexes with nuclear spin-free ligands in the solid-state [6].…”

“…With this purpose, we have studied the spectroscopic and relaxation properties in a series of vanadium complexes with lanthanides using EPR spectroscopy. All these complexes include VO 6 octahedral units, which to the best of our knowledge, have not yet been considered as potential qubits at room temperatures (only low-temperature relaxation studies were performed for some complexes [13,14]). At the first step of this research, diamagnetic lanthanides in the complexes with paramagnetic vanadium ions were addressed.…”