Electronic and Geometric Structures of Paramagnetic Diazadiene Complexes of Lithium and Sodium

Haleh H Haeri; Ramesh Duraisamy; Nicole Harmgarth; Phil Liebing; Volker Lorenz; Dariush Hinderberger; Frank T Edelmann

doi:10.1002/open.201800114

Electronic and Geometric Structures of Paramagnetic Diazadiene Complexes of Lithium and Sodium

ChemistryOpen. 2018 Sep 5;7(9):701-708. doi: 10.1002/open.201800114. eCollection 2018 Sep.

Authors

Haleh H Haeri¹, Ramesh Duraisamy², Nicole Harmgarth², Phil Liebing³, Volker Lorenz², Dariush Hinderberger¹, Frank T Edelmann²

Affiliations

¹ Institute of Chemistry Martin Luther University Halle-Wittenberg Von-Danckelmann-Platz 4 06120 Halle Germany.
² Institute of Chemistry Otto-von-Guericke University Magdeburg 39106 Germany.
³ Laboratory for Inorganic Chemistry ETH Zürich Vladimir-Prelog-Weg 2 8093 Zürich Switzerland.

Abstract

The electronic and molecular structures of the lithium and sodium complexes of 1,4-bis(2,6-diisopropylphenyl)-2,3-dimethyl-1,4-diazabutadiene (^Me2DAD^Dipp) were fully characterized by using a multi-frequency electron paramagnetic resonance (EPR) spectroscopy approach and crystallography, together with density functional theory (DFT) calculations. EPR measurements, using T₁ relaxation-time-filtered pulse EPR spectroscopy, revealed the diagonal elements of the A and g tensors for the metal and ligand sites. It was found that the central metals in the lithium complexes had sizable contributions to the SOMO, whereas this contribution was less strongly observed for the sodium complex. Such strong contributions were attributed to structural specifications (e.g. geometrical data and atomic size) rather than electronic effects.

Keywords: EPR spectroscopy; alkali metals; diazadiene ligands; relaxation filters; spin population.