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Organometallic Group 11 (Cu III , Ag III , Au III ) Complexes of a trans ‐Doubly N‐Confused Porphyrin: An “Expanded Imidazole” Structural Motif
Author(s) -
Yan Jiaying,
Yang Yufeng,
Ishida Masatoshi,
Mori Shigeki,
Zhang Bao,
Feng Yaqing,
Furuta Hiroyuki
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201701958
Subject(s) - chemistry , imidazole , crystallography , imine , aromaticity , porphyrin , trifluoroacetic acid , metal , group 2 organometallic chemistry , stereochemistry , inorganic chemistry , photochemistry , molecule , organic chemistry , catalysis
Complexation of group 11 metal cations with an α‐bis(phenylthio)‐substituted trans ‐doubly N‐confused porphyrin ( trans ‐ N 2 CP SPh : 4 ) afforded a series of square‐planar trivalent organometallic complexes (i.e., Cu‐H4 , Ag‐H4 , and Au‐H4 ). The X‐ray crystal structures of the complexes revealed highly planar core geometries along with the presence of peripheral amine and imine nitrogen sites of the pyrrolic moieties. NMR, UV/Vis absorption, and magnetic circular dichroism (MCD) spectroscopies suggested the 18 π‐electron aromaticity of the complexes. The aromaticity was also fully analyzed by various theoretical methodologies such as nucleus‐independent chemical shift (NICS) and anisotropic induced current density (ACID) calculations. The central metal affects the amphiprotic character of the complexes possessing both pyrrolic amino nitrogen and imino nitrogen atoms at the periphery, which was examined by the photometric titration with trifluoroacetic acid (TFA) and 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU), respectively. The inherent acidity of the complexes was followed in the order; Cu‐H4 > Au‐H4 > Ag‐H4 and that of basicity was Au‐H4 > Ag‐H4 > Cu‐H4 . The complexes could be considered as an “expanded imidazole” structural motif.