Origin of the temperature dependence of ¹³C pNMR shifts for copper paddlewheel MOFs.

ABSTRACT: An efficient protocol for the calculation of ¹³C pNMR shifts in metal-organic frameworks based on Cu(ii) paddlewheel dimers is proposed, which involves simplified structural models, optimised using GFN2-xTB for the high-spin state, and CAM-B3LYP-computed NMR and EPR parameters. Models for hydrated and activated HKUST-1 and hydrated STAM MOFs with one, two and three Cu dimers have been used. The electronic ground states are low-spin and diamagnetic, with pNMR shifts arising from thermal population of intermediate- and high-spin excited states. Treating individual spin configurations in a broken symmetry (BS) approach, and selecting two or more of these to describe individual excited states, the magnetic shieldings of these paramagnetic states are evaluated using the approach by H

SUBMITTER: Ke Z 

PROVIDER: S-EPMC8890090 | biostudies-literature | 2022 Mar

REPOSITORIES: biostudies-literature