Programmable Nuclear-Spin Dynamics in Ti(IV) Coordination Complexes

Autor: Spencer H. Johnson, Cassidy E. Jackson, Joseph M. Zadrozny
Rok vydání: 2020
Předmět:
Zdroj: Inorg Chem
ISSN: 1520-510X
0020-1669
DOI: 10.1021/acs.inorgchem.0c00244
Popis: Interstitial patterning of nuclear spins is a nascent design principle for controlling electron spin superposition lifetimes in open-shell complexes and solid-state defects. Herein we report the first test of the impact of the patterning principle on ligand-based nuclear spin dynamics. We test how substitutional patterning of (1)H and (79/81)Br nuclear spins on ligands modulates proton nuclear spin dynamics in the ligand shell of metal complexes. To do so, we studied the (1)H nuclear magnetic resonance relaxation times (T(1) and T(2)) of a series of eight polybrominated catechol ligands and six complexes formed by coordination of the ligands to a Ti(IV) ion. These studies reveal that (1)H T(1) values can be enhanced in the individual ligands by a factor of 4 (from 10.8(3) to 43(5) s) as a function of substitution pattern, reaching the maximum value for 3,4,6-tribromocatechol. The T(2) for (1)H is also enhanced by a factor of 4, varying by ∼14 s across the series. When complexed, the impact of the patterning design strategy on nuclear spin dynamics is amplified and (1)H T(1) and T(2) values vary by over an order of magnitude. Importantly, the general trends observed in the ligands also match those when complexed. Hence, these results demonstrate a new design principle to control (1)H spin dynamics in metal complexes through pattern-based design strategies in the ligand shell.
Databáze: OpenAIRE