Roger Guilard

Handbook of porphyrin science : with applications to chemistry, physics, materials science, engineering, biology and medicine

Volumes in Preparation (Volume 31 - 35): Bioinspired Systems Applications II Electrochemistry Solar Fuels Materials.

Synthesis, spectroscopic and electrochemical properties of tetrazolatomanganese(III) porphyrins

Abstract The synthesis, spectroscopic characterization and electrochemical properties of four tetrazolatomanganese(III) porphyrins are reported. The investigated compounds are represented by (TPP)Mn[N 4 C(R)], where TPP is the dianion of tetraphenylporphyrin and R is CH 2 CH 3 , C 6 H 5 , CHCH 2 or CHCHCN. Each complex was characterized by IR, UV-vis and 1 H NMR spectroscopy, as well as by mass spectrometry. Variable-temperature 1 H NMR data demonstrate that the electron-withdrawing effect of the tetrazolato ligand in (TPP)Mn[N 4 C(R)] is higher than that of the azido axial ligand in (TPP)MnN 3 . The reductions of each σ-bonded (TPP)Mn[N 4 C(R)] derivative were also examined in four non-aqueous solvents (dichloromethane, benzonitrile, tetrahydrofuran and pyridine) and the resulting data compared with data in the literature for manganese(III) porphyrins containing an ionic axial ligand such as Cl − or ClO 4 − .

Electrochemical and spectroelectrochemical studies of bis(diketonate) thorium(IV) and uranium(IV) porphyrins

The synthesis, characterization and chemical properties of actinide and lanthanide metalloporphyrin complexes have been the subject of several recent reports [l-6]. A combination of the coordination properties of actinide metals [7] with the ligation properties of metalloporphyrins has resulted in the generation of several distinct sets of molecular structures. These include monomeric species, trimeric species and triple decker type species. The monomeric [2-41 complexes are represented by dichloro and bis(acetylacetonato) porphyrins of the form (P)MC12L2 and (P)M(acac)* where L is the solvent molecule, acac is acetylacetonate, P is the dianion of a given porphyrin macrocycle and M is Th or U. Other structures include ‘triple decker’ complexes of the form (P),M, [5], where M is one of 12 different metal ions and a trimeric complex of the form [(P)Th(OH)*] a [6]. In each case, crystallographic determinations [4-61 have been reported. have recently been reported [6]. All electrode reactions of the porphyrin or phthalocyanine species were found to occur on the macrocyclic ligand and, for the case of trimeric [(P)Th(OH),],, up to six electrons could be either reversibly abstracted or added to the molecular unit at low temperature on the electrochemical time scale. A three electron oxidation step was also observed for this trimeric complex.