Crystal structure of the bis-pocket porphyrin aquo(tetramesitylporphinato)zinc(II)

Abstract The crystal structure of aquo(tetramesitylporphinato) zinc(II) ([Zn(TMP)(OH 2 )]) is reported. Crystal data for [Zn(TMP)(OH 2 )]· 1 21 H 2 O: ZnO 1.5 - N 4 C 56 H 55 , tetragonal, space group I 4/ m , a = 18.392(10), c =8.804(3) A Z =2. The crystal packing of [Zn(TMP)(OH 2 )] is compared to that of the tetraphenylporphyrin (TPP) analogue which has the same solid state arrangement (space group I 4/ m , M. D. Glick, G. H. Cohen and J. L. Hoard, J. Am. Chem. Soc., 89 (1967) 1996). [Zn(TMP)- (OH 2 )] packs with a substantially lower density than [Zn(TPP)(OH 2 )]. 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.