Electronic Structure of Manganese Complexes of the Redox‐Non‐innocent Tetrazene Ligand and Evidence for the Metal‐Azide/Imido Cycloaddition Intermediate. Issue 30 (24th June 2016)

• Record Type: Journal Article
• Authors: Vaddypally, Shivaiah; McKendry, Ian G.; Tomlinson, Warren; Hooper, Joseph P.; Zdilla, Michael J.
• Is Part Of: Chemistry. Volume 22:Issue 30(2016)
• Page Start: 10548
• Page End: 10557
• Publication Date: 2016-06-24
• Subjects: density functional calculations -- energetic materials -- non-innocence -- tetrazene -- valence tautomerism; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201600531
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The first synthetic manganese tetrazene complexes are described as a redox pair comprising anionic [Mn(N4 Ad2 )2 ] − (1 ) and neutral Mn(N4 Ad2 )2 (2 ) complexes (N4 Ad2 =[Ad‐N−N=N−N‐Ad] 2− ). Compound 1 is obtained in two forms as lithium salts, one as a cationic Li2 Mn cluster, and one as a Mn–Li 1D ionic polymer. Compound 1 is electronically described as a Mn III center with two [N4 Ad2 ] 2− ligands. The one‐electron oxidized 2 is crystalized in two morphologies, one as pure 2 and one as an acetonitrile adduct. Despite similar composition, the behavior of 2 differs in the two morphologies. Compound 2 ‐MeCN is relatively air and temperature stable. Crystalline 2, on the other hand, exhibits a compositional, dynamic disorder wherein the tetrazene metallacycle ring‐opens into a metal imide/azide complex detectable by X‐ray crystallography and FTIR spectroscopy. Electronic structure of 2 was examined by EPR and XPS spectroscopies and DFT calculations, which indicate 2 is best described as a Mn III ion with an anion radical delocalized across the two ligands through spin‐polarization effects. Abstract : With opened arms : The first synthetic manganese tetrazene complexes are described as a redox pair comprising anionic [Mn(N4 Ad2 )2 ] − (1 ) and neutral Mn(N4 Ad2 )2 (2 ) complexes (N4 Ad2 = [Ad‐N−N=N−N‐Ad] 2− ). Despite similar composition, the behavior of 2 differs in the two morphologies (see figure). EPR and XPS spectroscopies and DFT calculations indicate that 2 is best described as a Mn III ion with an anion radical delocalized across the two ligands through spin‐polarization effects.