Synthesis and crystallography of cerium(IV) bis porphyrinates and hafnium(IV) mono porphyrinates; a tool box for supramolecular chemistry

Cerium(IV) bis tetra aryl porphyrinato "sandwich" complexes, CeP 2, were synthesized in a solvent mixture of 1,2,4 trichlorobenzene and 1-dodecanol. The porphyrin is deprotonated to the Na2P species in situ using sodium dodecanate and then metalated with cerium, under argon at 205°C reflux, using the cerium (III) tris-acetylacetonate hydrate starting complex, Ce(acac)3•H2Ox. CeP 2 complex formation is achieved in 2-4 hours in yields equal to or higher than reported preparations. Structural studies of these complexes using NMR and crystallographic techniques have displayed asymmetric distortions of the porphyrin macrocycles not previously reported.; Hafnium(IV) mono porphyrinate complexes of the type Hf(P)L2, where L = Cl-, acetate (OAc-), octinoate (oct), pentanoate (pent), para-amino benzoate (PABA), peroxo (O2-2), HPO4-2, and SO4-2 have been synthesized according to four unique methods that cater to a wide variety of porphyrins not previously reported in hafnium porphyrinate chemistry. The methods use refluxing solvent mixtures of 1-chloronapthalene, dodecanol, and o-cresol under argon to metalate porphyrins with the hafnium (IV) ion from HfCl4. A solventless method has also been developed using, hafnium (IV) bis cyclopentadienyl dichloride, Hf(cp)2Cl2, in a melt with the porphyrins at 300°C. The compounds have been purified as the Hf(P)OAc2 derivative using chromatography over silica. The other mentioned derivatives have been formed in quantitative yield by exchange of the acetate ligands and are also, in a large part, new to the field of hafnium porphyrinate chemistry. The crystal structure of the SO 4-2, HPO4-2, and the O 2-2 complexes reveal bridged dimer crystal structures that also exist as dimers in solution according to spectroscopic evidence.; Stirring solutions of the Hf(TPP)OAc2 and the Hf(TPyP)OAc 2 complexes with the Keggin lacunary polyoxometalate H3PW 11O39[TBA]4, generates the ternary complexes, (TPP)HfPW11O39[TBA]5 and (TPyP)HfPW 11O39[TBA]5, that have been isolated and characterized. The crystal structure for the TPyP ternary complex reveals that the POM draws the hafnium ion further away from the porphyrin core than its relative position in the crystal structure of the Hf(TPyP)OAc2 complex. This results in spectroscopic shifts observed in the UV-Visible absorption, 1H NMR, and 31P NMR spectra.