title: Next generation PhotoCORMs: polynuclear tricarbonylmanganese(I)-functionalized polypyridyl metallodendrimers.
abstract: The first CO-releasing metallodendrimers, based on polypyridyl dendritic scaffolds functionalized with Mn(CO)3 moieties, of the general formula [DAB-PPI-{MnBr(bpy(CH3,CH═N))(CO)3}n], where DAB = 1,4-diaminobutane, PPI = poly(propyleneimine), bpy = bipyridyl, and n = 4 for first- or n = 8 for second-generation dendrimers, were synthesized and comprehensively characterized by analytical (HR-ESI mass spectrometry and elemental analysis) and spectroscopic ((1)H, (13)C{(1)H}-NMR, infrared, and UV/vis spectroscopy) methods. The CO-release properties of these compounds were investigated in pure buffer and using the myoglobin assay. Both metallodendrimer generations are stable in the dark in aqueous buffer for up to 16 h but show photoactivated CO release upon excitation at 410 nm, representing a novel class of macromolecular photoactivatable CO-releasing molecules (PhotoCORMs). No scaling effects were observed since both metallodendrimers release ∼65% of the total number of CO ligands per molecule, regardless of the generation number. In addition, the mononuclear model complex [MnBr(bpy(CH3,CH═NCH2CH2CH3))(CO)3] was prepared and comprehensively studied, including DFT/TDDFT calculations. These metallodendrimer-based PhotoCORMs afford new methods of targeted delivery of large amounts of carbon monoxide to cellular systems.
authors.affiliation: Department of Chemistry, University of Cape Town, Rondebosch, 7701, Cape Town, South Africa.
authors.forename: Preshendren
authors.initials: P
authors.lastname: Govender
authors.forename: Sandesh
authors.initials: S
authors.lastname: Pai
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schatzschneider
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Smith
mesh_terms: D000818:Animals; D002248:Carbon Monoxide / Q000008:administration & dosage*; D002254:Carbonates / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000737:chemistry*; D050091:Dendrimers / Q000737:chemistry*; D006736:Horses; D008345:Manganese / Q000737:chemistry*; D008958:Models, Molecular; D009211:Myoglobin / Q000378:metabolism; D011126:Polypropylenes / Q000737:chemistry; D011700:Putrescine / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry*
chemical_list: D002254:Carbonates; D003692:Delayed-Action Preparations; D050091:Dendrimers; D009211:Myoglobin; D011126:Polypropylenes; D011725:Pyridines; C443641:poly(propyleneimine); D008345:Manganese; D002248:Carbon Monoxide; C045327:manganese carbonate; D011700:Putrescine