Review: Properties and chemical reactivity of metallo phthalocyanine and tetramethylbenzoannulene complexes grafted into a polymer backbone

Abstract

The properties of coordination complexes grafted to a polymer backbone are reviewed in this article. The focus is on complexes of phthalocyanine and tetraazaannulene (5,7,12,14-tetramethyldibenzo[b,i] [1,4,8,11]tetraazacyclotetradecine, also abbreviated tmdbztaa) with various transition metal ions and Al(III). In addition to the morphological characteristics of the materials, their thermal and photochemical reactions are reviewed. Processes such as catalysis of the lignin degrading process and the reduction of CO 2 are presented as examples of these materials potential applications. tmdbztaa = 5,7,12,14-tetramethyldibenzo[b,i]-1,4,8,11-tetraaza[14]annulene tspc = phthalocyaninetetrasulfonate trspc = phthalocyaninetrisulfonate pc = phthalocyanine TEM = transmission electron microscope AFM = atomic force microscope eaq = solvated electron in aqueous solutions esol = solvated electron in organic medium k ob = experimentally determined pseudo-first order rate constant k/ε = ratio of the second order rate constant to the extinction coefficient at the wavelength of the probe Downloaded by [New York University] at 03:51 14 October 2014 2 λ ex = wavelength of the light used for the irradiation of the light absorbing compound (HOMO-6) 1 (LUMO) 1 -dd 3 ππ* = triplet excited state resulting in an electronic transition between low energy π and higher energy π* orbitals 3 LF = triplet metal-centered excited state Abbreviated names of the polymers with their corresponding structures can be seen in figure 1. Abbreviations used in the text IntroductionThe extensive and diverse chemistry of transition metal coordination complexes can be modified when the complexes are grafted into a polymer backbone. This extends the chemistry to different conditions that can be used for practical applications [1][2][3][4][5][6][7][8][9]. There has been an increasing interest in the design, synthesis and use of diverse macrocyclic receptors capable of selective recognition of metal ions, anions and neutral molecules [10 -24]. Such macrocyclic receptors are readily incorporated in polymer matrices. In this role, polyazamacrocycles have been extensively studied [11][12][13][14][15][16] because they are able to coordinate divalent metal cations, such as Ni 2+ or Cu 2+ , by displacing the amide protons. The complexes have many applications in catalysis [23], molecular machines, oxygen uptake [18, 19], medicine [18], as antiviral agents [25][26][27], and can also be studied as biological models for metalloproteins [28] in a polymeric environment. For example, the structural features of the macrocycles and the unique radiophysical properties of copper radioisotopes have led to their potential usefulness in diagnostic and/or therapeutic applications [29].Among the metal complexes that can be grafted into a polymer, the annuleno and phthalocyanine ligands are of a particular interest because they can catalyze thermal and photochemical reactions. In addition to other applications, these complexes are competent in the photoinduced oxidative degradation of...

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