Premium
meso ‐Aryl Phenanthroporphyrins: Synthesis and Spectroscopic Properties
Author(s) -
Xu HaiJun,
Mack John,
Descalzo Ana B.,
Shen Zhen,
Kobayashi Nagao,
You XiaoZeng,
Rurack Knut
Publication year - 2011
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.201002596
Subject(s) - aryl , chemistry , crystallography , protonation , spectroscopy , steric effects , absorption (acoustics) , redshift , circular dichroism , ring (chemistry) , helicene , photochemistry , stereochemistry , materials science , molecule , organic chemistry , alkyl , physics , ion , quantum mechanics , galaxy , composite material
The successful synthesis of tetraphenyltetraphenanthroporphyrin (TPTPhenP; 5 a ) in 2006 under modified Rothemund–Lindsey conditions yielded a tetraphenyl porphyrinoid with a B band redshifted to an unprecedented 576 nm. Radially symmetric fused‐ring expansion of tetraphenylporphyrin with phenanthrene moieties results in very deep saddling due to steric crowding and very marked redshifts of the Q and B (or Soret) porphyrinoid absorption bands. The extent to which the TPTPhenP structure can be further modified is explored, and the optical properties of TPTPhenPs are analyzed based on a perimeter model approach that makes use of time‐dependent DFT calculations and magnetic circular dichroism spectroscopy and also based on a detailed analysis of the fluorescence emission. Attempts to introduce substituents at the ortho and meta positions of the meso ‐phenyl groups and to insert a central metal proved unsuccessful. The synthesis of a series of TPTPhenPs with strong electron‐withdrawing (CN, NO 2 ) and ‐donating (CH 3 , N(CH 3 ) 2 ) substituents at the para positions of the meso ‐phenyl rings is reported. Marked redshifts of the main spectral bands were consistently observed. The most pronounced spectral changes were observed with N(CH 3 ) 2 groups ( 5 i ) due to a marked destabilization of the HOMO, which has large MO coefficients on the meso ‐carbon atoms. Protonation of 5 i at both the ligand core and at the N(CH 3 ) 2 groups resulted in unprecedented Q 00 band absorption at wavelengths greater than 1200 nm.