title: Energy transfers in monomers, dimers, and trimers of zinc(II) and palladium(II) porphyrins bridged by rigid Pt-containing conjugated organometallic spacers.
abstract: A series of linear monomers (spacer-M(P)), dimers (M(P)-spacer-M'(P)), and trimers (M(P)-spacer-M'(P)-spacer-M(P)) of spacer/metalloporphyrin systems (M' = Zn, M = Zn, Pd, P = porphyrin, and spacer = trans-C(6)H(4)C[triple bond]CPtL(2)C[triple bond]CC(6)H(4)- (L = PEt(3))) including mixed metalloporphyrin compounds, were synthesized and characterized. The S(1) and T(1) energy transfers Pd(P)*-->Zn(P) occur with rates of approximately 2 x 10(9) s(-1), S(1), and 0.15 x 10(3) (slow component) and 4.3 x 10(3) s(-1) (fast component), T(1). On the basis of a literature comparison with a related dyad, the Pt atom in the conjugated chain slows down the transfers. The excitation in the absorption band of the trans-C(6)H(4)C[triple bond]CPtL(2)C[triple bond]CC(6)H(4)- spacer in the 300-360 nm range also leads to T(1) energy transfer (spacer* --> M(P); M = Zn, Pd) with rates of 10(4) s(-1).
authors.affiliation: Departement de chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Diana
authors.initials: D
authors.lastname: Bellows
authors.forename: Shawkat M
authors.initials: SM
authors.lastname: Aly
authors.forename: Claude P
authors.initials: CP
authors.lastname: Gros
authors.forename: Maya
authors.initials: M
authors.lastname: El Ojaimi
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Barbe
authors.forename: Roger
authors.initials: R
authors.lastname: Guilard
authors.forename: Pierre D
authors.initials: PD
authors.lastname: Harvey
mesh_terms: D000042:Absorption; D019281:Dimerization; D004735:Energy Transfer; D008024:Ligands; D008163:Luminescent Measurements; D008665:Metalloporphyrins / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009944:Organoplatinum Compounds / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D013057:Spectrum Analysis; D013997:Time Factors; D015032:Zinc / Q000737:chemistry*
chemical_list: D008024:Ligands; D008665:Metalloporphyrins; D009944:Organoplatinum Compounds; D010165:Palladium; D015032:Zinc