- The synthesis of "apo-proteinic" multidentate, N2SS* and N2S, ligands to model type I trigonal and trigonal-pyramidal copper protein sites
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The syntheses of the novel sterically highly hindered asymmetric tripodal tridentate N2S and "distended" tripodal tetradentate N2SS* (S: thiolate; S*: thioether donor) ligands, 2-[bis(3′-isopropylpyrazol-1′-yl)methyl] -6-tert-butyl-4-methylbenzenethiol (11) and 3-{2′-[bis(3″-isopropylpyrazol-1″-yl) methyl]phenylsulfanyl}-1,1-diphenylpropane-1-thiol (28) are reported. These molecules possess the atom donor arrays of "trigonal" and "trigonal-pyramidal" type I "blue" copper proteins respectively. The success of the synthesis has transpired from the development of an effective flexible route to achieving the functional group interconversion of the phenolic group of the N2O heteroscorpionate ligands based upon the already known 2-[bis(pyrazol-1′-yl)methyl]phenol framework to their benzenethiol analogs. This has been effected using the Newman-Kwart rearrangement of the thiocarbamic acid O-ester of the N2O-phenol by a "Direct Insertion Vapour Phase Flash Vacuum Pyrolysis" (DIVPFVP) protocol which is highly effective despite the high involatility of the N2O precursors/N2S products. This process has been illustrated crystallographically for the sequence of conversions of 2-[bis(pyrazol-1′-yl)methyl]-6-tert-butyl-4-methylphenol (3) to O-{2-[bis(pyrazol-1′-yl)methyl]-6-tert-butyl-4-methylphenyl}-N, N-dimethylthiocarbamate (4) to S-{2-[bis(pyrazol-1′-yl)methyl]-6-tert-butyl-4-methylphenyl}-N, N-dimethylthiocarbamate (5). These "all-in-one" ligands represent a new strategy to modeling "blue" copper proteins and should be capable of complementing recent significant developments in the field since they are sterically somewhat less bulky than pre-existing ligands whilst maintaining viable coordination vectors and thus allow for the adoption of more "open" metal coordination environments. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Higgs, Timothy C.,Carrano, Carl J.
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p. 3632 - 3645
(2007/10/03)
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