4 results for Albrett, AM

  • Diboron porphyrins and corroles: unexpected chemistry for both boron and the ligands

    Brothers, Penelope; Albrett, AM; Mlodzianowska, A; Boyd, Peter; Clark, George; Gonzalez, E; Ghosh, A (2010)

    Conference item
    The University of Auckland Library

    Over recent years we have investigated the chemistry of boron porphyrins, which are unique in containing two boron atoms per porphyrin ligand. Highlights have been the development of a series of complexes, a diboryl porphyrin, a diboranyl porphyrin containing a B-B bond which forms through spontaneous reductive coupling of the diboryl under certain conditions, and a further diboranyl complex which is an unusual example of an isophlorin in which the porphyrin ligand has been reduced. A number of complexes containing oxygen-bridged BOB units have also been prepared. Our most recent work extends the coordination chemistry of boron to the corrole ligand. Although corroles and porphyrins are closely related, we observe some significant differences in the boron chemistry. The more constrained hole size of corrole leads to cisoid stereochemistry in the FBOBF corrole anion (Figure), compared to transoid for the related FBOBF porphyrin. We have also isolated boron hydride corrole complexes, including an unusual example of a complex containing a B-H-B group coordinated to the cavity in the corrole. The experimental work for the boron porphyrin and corrole work has been supported by extensive DFT calculations. Recent experimental results will be described, along with potential applications of the boron porphyrin complexes.

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  • Corrole as a binucleating ligand: Preparation, molecular structure and density functional theory study of diboron corroles

    Albrett, AM; Conradie, J; Boyd, Peter; Clark, George; Ghosh, A; Brothers, Penelope (2008)

    Journal article
    The University of Auckland Library

    The reactions of BF3 center dot OEt2 with four triaryl corroles (H3Cor) give the complexes [(B2OF2)(Cor)]- in which the corrole acts as a binucleating ligand. The new complexes were fully characterized, including an X-ray crystal structure of the triphenylcorrole complex. Density functional theory calculations support the observation that the boron atoms coordinate in two dipyrromethene sites in a cisoid geometry on one face of the macrocycle rather than in the alternative dipyrromethene/bipyrrole sites. The UV-visible spectra are insensitive to the corrole substituents, consistent with the lack of low-lying orbitals associated with the coordinated boron atoms.

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  • Mono- and diboron corroles: Factors controlling stoichiometry and hydrolytic reactivity

    Albrett, AM; Thomas, KE; Maslek, S; M??odzianowska, A; Conradie, J; Beavers, CM; Ghosh, A; Brothers, Penelope (2014-06-02)

    Journal article
    The University of Auckland Library

    The first example of a diboryl corrole complex, [(BF2)2(Br8T(4-F-P)C)](-) (Br8T(4-F-P)C = trianion of 2,3,7,8,12,13,17,18-octabromo-5,10,15-tris(4-fluorophenyl)corrole), has been isolated using the strongly electron-withdrawing and sterically crowded triaryl octabromocorrole ligand. Density functional theory (DFT) calculations show that the hydrolysis reaction producing the partially hydrolyzed complexes [B2OF2(Cor)](-) is more favored for the less sterically crowded triaryl corrole complexes. Monoboryl complexes BF2(H2Cor) (Cor = trianions of 5,10,15-triphenylcorrole (TPC), 5,10,15-tris(4-methylphenyl)corrole (T(4-CH3-P)C), 5,10,15-tris(4-trifluoromethylphenyl)corrole (T(4-CF3-P)C), and 5,10,15-tris(pentafluorophenyl)corrole (TPFPC)) were prepared and characterized. The experimental data are consistent with an out-of-plane dipyrrin coordination mode for these complexes, and DFT optimizations suggest that internal BF??????HN hydrogen bonding may be significant in stabilizing these complexes. Further examples of the anionic diboron corrole [B2OF2(Cor)](-) containing the electron-withdrawing 5,10,15-tris(pentafluorophenyl)corrole (TPFPC) and the sterically hindered 10-(4-methoxyphenyl)-5,15-dimesitylcorrole (Mes2(4-MeOP)C) trianions are reported.

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  • Reductive coupling and protonation leading to diboron corroles with a B-H-B bridge

    Albrett, AM; Boyd, Peter; Clark, George; Gonzalez, E; Ghosh, A; Brothers, Penelope (2010)

    Journal article
    The University of Auckland Library

    The reaction of PhBCl2 with free base triarylcorroles results in a spontaneous reduction to give diboron corrole complexes (PhBHBPh)(Cor) in which a proton has been captured to forma bridgingB-H-B group encapsulated within the corrole ligand. The proposed mechanism is supported by the reaction of PhBF2 with H(3)Cor to give (PhBF)(BPh)(Cor) in which no reduction has occurred.

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