Scorpionates are effective facial chelates with predictable bonding patterns involving almost every metal ion on the periodic table. Heteroscorpionates (where one nitrogen-donor group is varied) exhibit unique asymmetry in the compounds produced. The ligand Tp’ was created in our lab through simple triazole-for-pyrazole substitution. Here, with the first ever reported use of microwave heating, reaction time for this ligand has been drastically reduced. Tp’ represents the monoanion scorpionate hydrobenzotriazolyl-bis(3,5-dimethylpyrazolyl) borate. The present work describes M(Tp’)2 complexes (M = Mn, Fe, Co). The orange iron(II) form has been oxidized to the deep purple iron(III) form. The structure of the cis-Fe(Tp’)2 was confirmed by single crystal XRD. These reactions demonstrate the utility of this scorpionate with a variety of first row transition metals. The Fe(Tp’)2 and the Co(Tp’)2 cases were separated into cis and trans isomers through column chromatography. All were characterized by 11B NMR, Infrared, MALDI, and UV-Vis spectroscopy. The Fe(Tp’)2 was unique in showing an intense MLCT in the visible region. This series allows variations in magnetic properties across the {Mn, Fe, Co, Ni} series to be investigated, including spin-crossover behavior in the iron(II) case and trends in 11B paramagnetic NMR shifts. Now, with an improved Tp' synthesis through microwave heating, we plan to use a similar ring substitution approach to anchor this scorpionate to cellulose, furthur increasing the utility of this ligand system.

Metal complexes of a heteroscorpionate with unique symmetries, optical, and magnetic properties

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.