CRYSTAL-STRUCTURE OF THE BIS-POCKET PORPHYRIN AQUO(TETRAMESITYLPORPHINATO)ZINC(II)

The crystal structure of aquo(tetramesitylporphinato) zinc(II) ([Zn(TMP)(OH2)]) is reported. Crystal data for [Zn(TMP)(OH2)]· 1 21H2O: ZnO1.5- N4C56H55, tetragonal, space group I4/m, a = 18.392(10), c=8.804(3) Å Z=2. The crystal packing of [Zn(TMP)(OH2)] is compared to that of the tetraphenylporphyrin (TPP) analogue which has the same solid state arrangement (space group I4/m, M. D. Glick, G. H. Cohen and J. L. Hoard, J. Am. Chem. Soc., 89 (1967) 1996). [Zn(TMP)- (OH2)] packs with a substantially lower density than [Zn(TPP)(OH2)]. The effect of the bulky mesityl-methyl groups on crystal packing is discussed. Analysis of various assumed arrangements of molecules having only the needed bulky 2- and 6-methyl groups show that the intermolecular contacts are dominated by these substituents. This study suggests that any porphyrin system with o-methyl substituted ligands is not likely to form a high-density packing arrangement. © 1990.