Synthesis and characterization of phosphorus complexes of meso-tetraphenylporphyrin (tpp), and X-ray crystal structure of [P(tpp)(OCH(CH 3) 2) 2] +Cl −

Abstract

Three cationic phosphorus(V) porphyrin complexes of the type [P(ttp)(L) 2] + [tpp = meso-tetraphenylphorphyrin; the axial ligand L = OCH(CH 3) 2, O(CH 2) 4OH, O- p-C 6H 4OH] have been prepared. All compounds were characterized by 1H and 13C NMR and mass spectrometry. The structure of the new compound di(2-propanolato)( meso-tetraphenylporphyrinato)phosphorus(V) chloride, [P(tpp)(OCH(CH 3) 2) 2] +Cl −, was determined by a single-crystal X-ray structure analysis. The cation of [P(tpp)(OCH(CH 3) 2) 2] +Cl − displays an octahedral coordination about the phosphorus atom and exhibits a ruffled porphyrin geometry with a core size of 1.866 Å. The displacement of the phosphorus atom from the porphyrin mean plane is 0.016 Å. The geometry around the phosphorus centre of the [P(tpp)(OCH(CH 3) 2) 2] +Cl − molecule has P(1)— O(1) = 1.650(3) A ̊ , P(1)— O(2) = 1.622(3) A ̊ and PNp = 1.866(4) A ̊ . NMR spectroscopy provides a convenient method for investigating the ring current effect (Δσ) between di(1,4-butanediolato) ( meso-tetraphenylporphyrinato)phosphorus(V) chloride, [P(tpp)(OCH 2CH 2CH 2CH 2OH) 2] +Cl −, with fluxional 1,4-butanediolate ligands, and di(1,4-hydroxy-benzeneato)( meso-tetraphenylporpyrinato)phosphorus(V) chloride, [P(tpp)(O- p-C 6H 4OH) 2] +Cl −, with rigid 1,4-hydroxybenzeneate ligands. It also differentiates the ring current effect for the diolate ligands of [P(tpp)(O(CH 2) n OH) 2] +Cl − with different chain lengths by increasing n from 2 to 4.