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A Zinc(II) Complex Composed of a Tridentate Ligand Bearing Podand Pyrenyl Moieties
Author(s) -
Moriuchi Toshiyuki,
Nishiyama Masahito,
Hirao Toshikazu
Publication year - 2002
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 - 10.1002/1099-0682(20022)2002:2<447::aid-ejic447>3.0.co;2-t
Subject(s) - chemistry , ligand (biochemistry) , moiety , intramolecular force , crystal structure , crystallography , square pyramid , zinc , molecule , stacking , fluorophore , stereochemistry , dimer , octahedron , quenching (fluorescence) , fluorescence , organic chemistry , receptor , biochemistry , physics , quantum mechanics
The structural characterization and function of Zn II complexes composed of a tridentate ligand bearing podand pyrenyl moieties as a fluorophore [2,6‐pyridinedicarboxaldehydebis(1‐pyrenylmethylimine) (L 1 )] are described. The tridentate podand ligand L 1 forms a 2:1 complex, [Zn(L 1 ) 2 (BF 4 ) 2 ], with Zn(BF 4 ) 2 although the 1:1 complex [Zn(L 1 )(OAc) 2 ] is obtained with Zn(OAc) 2 . The X‐ray crystal structure determination of [Zn(L 1 ) 2 (BF 4 ) 2 ] reveals that two tridentate podand ligands L 1 coordinate meridionally to Zn II ion to give an orthogonally oriented molecular turn around the approximately octahedral Zn II center. One pyridyl moiety of L 1 is sandwiched in between two podand pyrenyl moieties of another L 1 through π‐π interactions, together with an extended π‐stacking through π‐π interactions between the pyrenyl moieties in the crystal packing. [Zn(L 1 )(OAc) 2 ] serves as a fluorophore metalloreceptor possessing a two‐guest binding ability. [Zn(L 1 )(OAc) 2 ] affords the 1:2 complex [Zn(L 1 )(G 1 ) 2 ] (G = guest molecule) with 4‐nitrobenzoate ion (G 1 ). The X‐ray crystal structure of [Zn(L 1 )(G 1 ) 2 ] confirms that Zn(L 1 ) 2+ accommodates two 4‐nitrobenzoate moieties and that the coordination geometry around Zn II is a distorted square pyramid. Two independent molecules are present in the asymmetric unit to form the π‐stacked dimer by face‐to‐face overlap. Fluorescence quenching of [Zn(L 1 )(G 1 ) 2 ] is observed by intramolecular electron transfer from the pyrenyl moieties to the Zn II ‐bound 4‐nitrobenzoates.