Constructing Sandwich-Type Rare Earth Double-Decker Complexes with N‑Confused Porphyrinato and Phthalocyaninato Ligands

Reaction of the half-sandwich complexes MIII(Pc)­(acac) (M = La, Eu, Y, Lu; Pc = phthalocyaninate; acac = acetylacetonate) with the metal-free N-confused 5,10,15,20-tetrakis­[(4-tert-butyl)­phenyl]­porphyrin (H2NTBPP) or its N2-position methylated analogue H­(CH3)­NTBPP in refluxing 1,2,4-trichlorobenzene (TCB) led to the isolation of MIII(Pc)­(HNTBPP) (M = La, Eu, Y, Lu) or YIII(Pc)­[(CH3)­NTBPP] in 8–15% yield. These represent the first examples of sandwich-type rare earth complexes with N-confused porphyrinato ligands. The complexes were characterized with various spectroscopic methods and elemental analysis. The molecular structures of four of these double-decker complexes were also determined by single-crystal X-ray diffraction analysis. In each of these complexes, the metal center is octa-coordinated by four isoindole nitrogen atoms of the Pc ligand, three pyrrole nitrogen atoms, and the inverted pyrrole carbon atom of the HNTBPP or (CH3)­NTBPP ligand, forming a distorted coordination square antiprism. For EuIII(Pc)­(HNTBPP), the two macrocyclic rings are further bound to a CH3OH molecule through two hydrogen bonds formed between the hydroxyl group of CH3OH and an aza nitrogen atom of the Pc ring or the inverted pyrrole nitrogen atom of the HNTBPP ring, respectively. The location of the acidic proton at the inverted pyrrole nitrogen atom (N2) of the protonated double-deckers was revealed by 1H NMR spectroscopy.