Designing molecular qubits: computational insights into first-row and group 6 transition metal complexes

Abstract

In the realm of optically addressable qubits, a previously synthesized and characterized Cr(IV) pseudo-tetrahedral complex, featuring four strongly donating ligands surrounding the chromium center, has demonstrated potential as a qubit candidate. This study proposes analogs of this complex through a metal substitution strategy, extending the investigation to different complexes based on metal centers selected from first-row and Group 6 transition metals. Computational modeling based on multiconfigurational methods CASPT2 and MC-PDFT was utilized to calculate energy gaps between ground and excited electronic spin states, and zero-field splitting parameters. Simulations were applied to each equilibrium geometry and related deformations based on vibrational modes. All results align with previous experimental findings, but also show that qubits based on V and Ti centers could be more electronically stable than the Cr one, suggesting a lower electronic features dependency from their related geometry. In some cases geometrical deformations provide changes in relative energy gaps between triplet and singlet excited state, that could potentially swap, offering a different initialization process, and some inspiration for ligand design based on such deformations. Additionally, this study identifies an unsynthesized Ti(II) compound as a promising candidate for molecular qubits. This finding highlights the role of computational multireference methods in the rational design of qubit systems.

Graphical abstract: Designing molecular qubits: computational insights into first-row and group 6 transition metal complexes

Supplementary files

Article information

Article type
Edge Article
Submitted
04 Apr 2025
Accepted
13 May 2025
First published
13 Jun 2025
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2025, Advance Article

Designing molecular qubits: computational insights into first-row and group 6 transition metal complexes

A. Sauza-de la Vega, A. Darù, S. Nofz and L. Gagliardi, Chem. Sci., 2025, Advance Article , DOI: 10.1039/D5SC02544C

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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