Stabilization of Heteroleptic Heavier Alkaline Earth Metal Complexes with an Encapsulating Dipyrromethene Ligand
Ballmann G, Rösch B, Harder S (2019)
Publication Type: Journal article
Publication year: 2019
Journal
DOI: 10.1002/ejic.201900743
Abstract
A new dipyrromethene ligand with 9-anthracenyl substituents for steric shielding of the metal has been introduced. The ligand, AnthDPM-H (3), was directly deprotonated with MN′′2 {M = Mg, Ca, Sr, Ba, Zn; N′′ = N(SiMe3)2} to give (AnthDPM)MN′′ (4–8) in the form of highly fluorescent substances that are intensively colored from deep-red to purple. Crystal structures reveal in all cases monomeric complexes with tricoordinate metals. Also the crystal structure of (AnthDPM)K, prepared by reaction of 3 with KN′′, is presented. The metal's coordination sphere in complexes 4–8 is further saturated by anagostic M···MeSi interactions which are most important for the smaller metals Mg and Zn. For the larger metals, Ca–Ba, the anthracenyl-substituents assist in metal coordination. These secondary metal π-interactions result in very high thermal stabilities. The least stable complex (AnthDPM)BaN′′ decomposes at circa 100 °C. The dipyrromethene complexes are clearly more stable than the corresponding β-diketiminate complexes (DIPPBDI)MN′′ {DIPPBDI = CH[C(Me)N-DIPP]2, DIPP =2,6-diisopropylphenyl} which partially decompose at room temperature. These heteroleptic complexes of similar constitution, with metals ranging from Mg to Ba, form a new series that is potentially useful for investigations towards metal effects in early main group metal catalysis.
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APA:
Ballmann, G., Rösch, B., & Harder, S. (2019). Stabilization of Heteroleptic Heavier Alkaline Earth Metal Complexes with an Encapsulating Dipyrromethene Ligand. European Journal of Inorganic Chemistry. https://dx.doi.org/10.1002/ejic.201900743
MLA:
Ballmann, Gerd, Bastian Rösch, and Sjoerd Harder. "Stabilization of Heteroleptic Heavier Alkaline Earth Metal Complexes with an Encapsulating Dipyrromethene Ligand." European Journal of Inorganic Chemistry (2019).
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