Systematic Structural Elucidation for the Protonated Form of Rare Earth Bis(porphyrinato) Double-Decker Complexes: Direct Structural Evidence of the Location of the Attached Proton

Direct structural
evidence of the presence and location of the attached proton in the
protonated form of rare earth bis­(porphyrinato) double-decker complexes
is obtained from an X-ray diffraction study of single crystals for
a series of protonated forms of bis­(tetraphenylporphyrinato) complexes
[MIII(tpp)­(tppH)] (M = Tb, Y, Sm, Nd, and La). When CHCl3 is used as a solvent for crystallization of the complexes,
their nondisordered molecular structures are obtained and the attached
proton is identified on one of the eight nitrogen atoms. Use of other
solvents affords another type of crystal, in which the position of
the proton is disordered and thus the molecular structure is averaged.
La complex also affords the disordered average structure even when
CHCl3 is used for crystallization. A variable-temperature
diffraction study for the Tb complex reveals that the dynamics of
the proton in the nondisordered crystal is restricted.