Aerobic catalytic photooxidation of olefins by an electron-deficient Pacman bisiron(III) mu-oxo porphyrin.

The synthesis and oxygen atom transfer (OAT) photoreactivity of a diiron(III) mu-oxo meso-tripentafluorophenyl bisporphyrin appended to a dibenzofuran spacer are presented. Reaction of 4,6-diformyldibenzofuran under standard Lindsey conditions furnishes the parent cofacial porphyrin architecture in a single step. These cofacial porphyrins photocatalyze the oxidation of sulfides and olefins using visible light and molecular oxygen as the terminal oxidant.

Transient absorption studies of the Pacman effect in spring-loaded diiron(III) mu-oxo bisporphyrins.

Picosecond transient absorption spectroscopy of diiron(III) mu-oxo bisporphyrins appended to xanthene, (DPX)Fe2O and (DPXM)Fe2O, and dibenzofuran (DPD)Fe2O have been investigated in order to decipher the effect of a spring-loaded cleft on their photophysics and attendant oxidation photocatalysis. The tension of the cofacial pocket is systematically tuned with the bridge span and meso-substitution opposite to the bridge; the distances of the relaxed cofacial pockets and clamped Fe-O-Fe pockets are known from X-ray crystallography (Deltad(M-M)(relaxed-clamped)=4.271 A (DPD), 2.

A phototriggered molecular spring for aerobic catalytic oxidation reactions.

The first catalytic oxidation reactions with cofacial bisporphyrins using molecular oxygen as the terminal oxidant are presented. The photocatalytic reactions proceed under mild conditions (ambient temperature and pressure) without the need for a co-reductant. A systematic reactivity study of the photooxidation of dimethyl sulfide (DMS) with a homologous series of bisiron(III) mu-oxo porphyrins containing dibenzofuran, xanthene, or no bridge reveals that the facility of these processes is markedly dependent on the vertical flexibility of the catalyst to provide a phototriggered molecular spring.

Structural, spectroscopic, and reactivity comparison of xanthene- and dibenzofuran-bridged cofacial bisporphyrins.

A comparison of the structure, spectroscopy, and oxygen atom-transfer reactivity of cofacial bisporphyrins anchored by xanthene (DPX) and dibenzofuran (DPD) pillars is presented. The synthesis and characterization of dicopper(II) and dinickel(II) complexes of DPD completes a homologous series of homobimetallic zinc(II), copper(II), and nickel(II) complexes for both cofacial platforms. X-ray crystallographic analysis of the parent free-base porphyrins H(4)DPX (1) and H(4)DPD (5) confirms the face-to-face arrangement of the two porphyrin macrocycles with a large available range of vertical pocket sizes: 1 (C(80)H(92)Cl(2)N(8)O), triclinic, space group P1 macro, a = 13.