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Metal Complexes of 5,15‐Porphyrinquinones: Systematic Study of Crystal Structure, Electronic Structure, and Lewis Acidity
Author(s) -
Yamashita Kenichi,
Hirano Daisuke,
Sugiura Kenichi
Publication year - 2020
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202000527
Subject(s) - chemistry , metal , porphyrin , crystal structure , inorganic chemistry , crystallography , electron transfer , quinone , absorption spectroscopy , metal ions in aqueous solution , ultraviolet visible spectroscopy , photochemistry , stereochemistry , organic chemistry , physics , quantum mechanics
We conducted the first systematic study on the synthesis, structure, and properties of various divalent metal complexes (Ni II , Cu II , Zn II , Pd II , Pt II , and Pb II ) of 5,15‐porphyrinquinone (PQ, a quinone compound of porphyrin) for diversifying the chemistry of traditional quinone‐metal complexes. Similar to electron‐accepting nature of PQ, the metal complexes studied here also exhibit it. Ni II , Pd II , and Pt II complexes favor face‐to‐face stacked structures in the crystals, thus inducing effective Pt II –Pt II interaction, which has not been observed in the porphyrin analogues to date. Ultraviolet‐visible (UV/Vis) absorption spectra of the metal complexes vary widely depending on the metal ion and owing to the effective d(metal)–π(PQ) coupling in their molecular orbitals. Quantitative analyses of the axial ligation on the central metal ions (Ni II and Cu II ) revealed significantly larger binding constants than those of the porphyrin analogues, indicating significant enhancement of their Lewis acidities due to the strong electron‐withdrawing nature of PQ.