Showing papers by "Georgina M. Rosair published in 2012"

Copper(II) Complexes of Salicylic Acid Combining Superoxide Dismutase Mimetic Properties with DNA Binding and Cleaving Capabilities Display Promising Chemotherapeutic Potential with Fast Acting in Vitro Cytotoxicity against Cisplatin Sensitive and Resistant Cancer Cell Lines

Abstract: The complexes [Cu(salH)(2)(H(2)O)] (1), [Cu(dipsH)(2)(H(2)O)] (2), {Cu(3-MeOsal)(H(2)O)(0.75)}(n) (3), [Cu(dipsH)(2)(BZDH)(2)] (4), [Cu(dipsH)(2)(2-MeOHBZDH)(2)]·EtOH (5), [Cu(sal)(phen)] (6), [Cu(dips)(phen)]·H(2)O (7), and [Cu(3-MeOsal)(phen)]·H(2)O (8) (salH(2) = salicylic acid; dipsH(2) = 3,5-diisopropylsalicylic acid; 3-MeOsalH(2) = 3-methoxysalicylic acid; BZDH = benzimidazole; 2-MeOHBZDH = 2 methanolbenzimidazole and phen =1,10-phenanthroline) were prepared and characterized. Structures of 4, 5, and 8 were determined by X-ray crystallography. Compounds 1-8 are potent superoxide dismutase mimetics, and they are inactive as inhibitors of COX-2 activity. Compounds 1, 4, and 5 exhibit moderate inhibition of COX-1. Complexes 6-8 display rapid micromolar cytotoxicity against cisplatin sensitive (breast (MCF-7), prostate (DU145), and colon (HT29)) and cisplatin resistant (ovarian (SK-OV-3)) cell lines compared to 1-5, and they exhibit potent in vitro DNA binding and cleavage capabilities.

Untethered 4,1,2-MC2B10 supraicosahedral metallacarboranes, their C,C'-dimethyl 4,1,6-, 4,1,8- and 4,1,12-MC2B10 analogues, and DFT study of the (4,)1,2- to (4,)1,6-isomerisations of C2B11 carboranes and MC2B10 metallacarboranes.

Abstract: Reduction of the tethered carborane 1,2-μ-(CH2SiMe2CH2)-1,2-closo-C2B10H10 followed by metallation with {CpCo} or {(p-cymene)Ru} fragments affords both C,C′-dimethyl 4,1,2-MC2B10 and 4,1,6-MC2B10 species. DFT calculations indicate that the barriers to isomerisation of both 4-Cp-4,1,2-closo-CoC2B10H12 and 4-(η-C6H6)-4,1,2-closo-RuC2B10H12 to their respective 4,1,6-isomers are too high for this to be the origin of the unexpected formation of 4,1,6-MC2B10 products (in marked contrast to the related isomerisation of 1,2-closo-C2B11H13 to 1,6-closo-C2B11H13), and, indeed, the 4,1,2-species are recovered unchanged from refluxing toluene. Equally, the DFT-calculated profile for the isomerisation of [7,8-nido-C2B10H12]2− to [7,9-nido-C2B10H12]2− suggests that the unexpected formation of 4,1,6-metallacarboranes is unlikely to result from isomerisation of a reduced (nido) carborane following desilylation. Instead, the source of the 4,1,6-MC2B10 compounds is traced to desilylation of 1,2-μ-(CH2SiMe2CH2)-1,2-closo-C2B10H10 by Li or Na prior to reduction. The supraicosahedral metallacarboranes 1,8-Me2-4-Cp-4,1,8-closo-CoC2B10H10, 1,12-Me2-4-Cp-4,1,12-closo-CoC2B10H10 and 1,12-Me2-4-(p-cymene)-4,1,12-closo-RuC2B10H10 are also reported with all new species characterised both spectroscopically and crystallographically.