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Diphenylphosphine‐Oxide‐Fused and Diphenylphosphine‐Fused Porphyrins: Synthesis, Tunable Electronic Properties, and Formation of Cofacial Dimers
Author(s) -
Fujimoto Keisuke,
Kasuga Yuko,
Fukui Norihito,
Osuka Atsuhiro
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.201700909
Subject(s) - diphenylphosphine , porphyrin , diphenylphosphine oxide , chemistry , photochemistry , intramolecular force , dimethylformamide , crystallography , electron transfer , medicinal chemistry , catalysis , stereochemistry , organic chemistry , solvent , phosphine
Abstract Diphenylphosphine‐oxide‐fused Ni II porphyrin 8 was synthesized from 3,5,7‐trichloroporphyrin 5 via a reaction sequence of nucleophilic aromatic substitution with lithium diphenylphosphide, oxidation with H 2 O 2 , and palladium‐catalyzed intramolecular cyclization. Reduction of 8 with HSiCl 3 gave diphenylphosphine‐fused Ni II porphyrin 9 . The embedded P=O and P moieties serve as a strong electron‐accepting and electron‐donating group to perturb the optical and electrochemical properties of the Ni II porphyrin. Ni II porphyrin 9 is diamagnetic with a low‐spin Ni II center in solution but becomes paramagnetic with a five‐coordinated Ni II center with high‐spin ( S= 1) state in the solid state. Diphenylphosphine‐oxide‐fused Zn II porphyrin 10 was also synthesized and shown to form a face‐to‐face dimer with mutual O‐Zn bonds in the crystal and in nonpolar and moderately polar solvents. The dimerization of 10 in CDCl 3 has been revealed to be an entropy‐driven process with a large entropy gain (Δ S D =207 J K −1 mol −1 ).