Electrochemical and spectroelectrochemical studies of (i) actinide double-decker porphyrins and phthalocyanines, (ii) monomeric europium(III) porphyrins, (iii) tin(II) binuclear porphyrins, and (iv) buckminsterfullerene

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7267123

Moninot, G

The redox properties of metalloporphyrins, metallophthalocyanines and Buckminsterfullerene, C[sub 60], were investigated by electrochemistry and/or spectroelectrochemistry in non-aqueous media. The investigated macrocyclic compounds include double-decker metalloporphyrins and metallophthalocyanines containing actinide metal ions, monomeric europium porphyrins and metal-metal bonded Sn(II) porphyrins. The homoleptic and hereoleptic actinide double-decker complexes are represented as M(P)[sub 2], M(Pc)[sub 2], M(P)(P[prime]) and M(P)(Pc), where M is U or Th, P and P[prime] are the dianions of two different porphyrins and Pc is the phthalocyanine dianion. These compounds undergo up to three reversible one-electron oxidations and up to four reversible one-electron reductions in non-aqueous media. Spectroscopic and electrochemical criteria demonstrated the existence of mixed or separate sets of orbitals depending upon the nature of the two macrocycles and the specific oxidation state of the sandwich species. This is discussed in this dissertation in terms of ring/ring interactions, porphyrin substituent effects and data in literature on other double-decker complexes. Monomeric europium tetraphenylporphyrins containing a [beta]-diketonate axial ligand can be stepwise oxidized in two one-electron abstractions or stepwise reduced in four half-an-electron additions. The data is consistent with dimerization in solution upon electroreduction. Sn(II) five-coordinate porphyrins containing a carbenoid Sn-Fe bond and a single hydrophobic chain attached to one of the four phenyl groups of the macrocycle are also reduced via two one-electron additions to the [pi]-ring system. They can also be electrooxidized. Finally, the effect of solvent molecular features on the thermodynamics and kinetics of the sequential one-electron electroreduction of C[sub 60] was investigated in aprotic solvents of different polarity, polarizability and viscosity.

• Research Organization: Houston Univ., TX (United States)
• OSTI ID: 7267123
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ACTINIDE COMPLEXES
CARBON
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
COMPLEXES
DYES
ELEMENTS
EUROPIUM COMPLEXES
FULLERENES
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
NONMETALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHTHALOCYANINES
PORPHYRINS
RARE EARTH COMPLEXES
REDOX REACTIONS
SOLVENT PROPERTIES
THORIUM COMPLEXES
TIN CHLORIDES
TIN COMPLEXES
TIN COMPOUNDS
TIN HALIDES
URANIUM COMPLEXES