Synthesis, crystal structure, and photophysieal properties of novel (Monophthalocyaninato)lanthanide complexes stabilized by an organometallic tripodal ligand

An unprecedented series of (monophthalocyaninato)lanthanide(III) complexes {[PcYb(LOMe)] (3) and [(tBu)4PcLn(LOMe)] [Ln = Yb (4), Er (5)]} {Pc = phthalocyaninate, LOMe= [(cyclopentadienyl) tris(dimethylphosphito)cobaltate(III)]} were prepared by the reaction of Ln[N(SiMe3)2]3[LiCl(THF)3]x(Ln = Yb or Er) with the corresponding phthalocyanine [H2Pc and H2(tBu)4Pc] followed by Na(LOMe). X-ray structural analysis of 3 reveals that the Yb3+ion is seven-coordinate, surrounded by four nitrogen atoms from the phthalocyaninate dianion and three oxygen atoms from the anionic tripodal LLOMeligand. 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 Er3+complex, but there is a significant back-energy transfer for the Yb3+complex. Singlet oxygen (1O2) phosphorescence was detected instead of the Yb3+emission in the photoluminescence spectra of 3 and 4 in the NIR region, but only the Er3+ion emission was observed for 5. KGaA.