Synthesis, Crystal Structure, and Photophysical Properties of Novel (Monophthalocyaninato)lanthanide Complexes Stabilized by an Organometallic Tripodal Ligand

An unprecedented series of (monophthalocyaninato)lanthanide(III) complexes {[PcYb(L OMe )] ( 3 ) and [( t Bu) 4 PcLn(L OMe )] [Ln = Yb ( 4 ), Er ( 5 )]} {Pc = phthalocyaninate, L OMe – = [(cyclopentadienyl)tris(dimethylphosphito)cobaltate(III)]} were prepared by the reaction of Ln[N(SiMe 3 ) 2 ] 3 · [LiCl(THF) 3 ] x (Ln = Yb or Er) with the corresponding phthalocyanine [H 2 Pc and H 2 ( t Bu) 4 Pc] followed by Na(L OMe ). X‐ray structural analysis of 3 reveals that the Yb 3+ ion is seven‐coordinate, surrounded by four nitrogen atoms from the phthalocyaninate dianion and three oxygen atoms from the anionic tripodal L OMe – ligand. The photophysical properties of these new mixed‐metal (monophthalocyaninato)lanthanide complexes are investigated. An efficient intramolecular energy transfer from ligand‐centered states to the metal ion manifold or metal‐centered states takes place for the Er 3+ complex, but there is a significant back‐energy transfer for the Yb 3+ complex. Singlet oxygen ( 1 O 2 ) phosphorescence was detected instead of the Yb 3+ emission in the photoluminescence spectra of 3 and 4 in the NIR region, but only the Er 3+ ion emission was observed for 5 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)