Radical-Mediated Thiol-Ene Strategy: Photoactivation of Thiol-Containing Drugs in Cancer Cells.
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ABSTRACT:
SUBMITTER: Sun S
PROVIDER: S-EPMC6391964 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Thiol-ene click reaction was successfully employed for chemical modification of graphene oxide (GO) by one-step synthesis. Herein, 2,2-azobis(2-methylpropionitrile) (AIBN) was used as thermal catalyst and cysteamine hydrochloride (HS-(CH2 )2 -NH2 HCl) was used as thiol-containing compound, which is incorporated to GO surface upon reaction with the C=C bonds. The hydrochloride acts as protecting group for the amine, which is finally eliminated by adding sodium hydroxide. The modified GO contains both S- and N-containing groups (NS-GO). We found that NS-GO sheets form good dispersion in water, ethanol, and ethylene glycol. These graphene dispersions can be processed into functionalized graphene film. Besides, it was demonstrated that NS-GO was proved to be an excellent host matrix for platinum nanoparticles. The developed method paves a new way for graphene modification and its functional nanocomposites.
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Project description:Two coordination compounds containing tetra-n-butyl-ammonium cations and bis-tfd-chelated molybdenum(IV) [tfd2- = S2C2(CF3)22-] and oxalate (ox2-, C2O42-) in complex anions are reported, namely bis-(tetra-n-butyl-ammonium) bis-(1,1,1,4,4,4-hexa-fluoro-but-2-ene-2,3-di-thiol-ato)oxalatomolybdate(IV)-chloro-form-oxalic acid (1/1/1), (C16H36N)2[Mo(C4F6S2)2(C2O4)]·CHCl3·C2H2O4 or (N n Bu4)2[Mo(tfd)2(ox)]·CHCl3·C2H2O4, and bis-(tetra-n-butyl-ammonium) μ-oxalato-bis-[bis-(1,1,1,4,4,4-hexa-fluoro-but-2-ene-2,3-di-thiol-ato)molybdate(IV)], (C16H36N)2[Mo2(C4F6S2)4(C2O4)] or (N n Bu4)2[(tfd)2Mo(μ-ox)Mo(tfd)2]. They contain a terminal oxalate ligand in the first compound and a bridging oxalate ligand in the second compound. Anion 12- is [Mo(tfd)2(ox)]2- and anion 22-, formally generated by adding a Mo(tfd)2 fragment onto 12-, is [(tfd)2Mo(μ-ox)Mo(tfd)2]2-. The crystalline material containing 12- is (N n Bu4)2-1·CHCl3·oxH2, while the material containing 22- is (N n Bu4)2-2. Anion 22- lies across an inversion centre. The complex anions afford a rare opportunity to compare terminal oxalate with bridging oxalate, coordinated to the same metal fragment, here (tfd)2MoIV. C-O bond-length alternation is observed for the terminal oxalate ligand in 12-: the difference between the C-O bond length involving the metal-coordinating O atom and the C-O bond length involving the uncoordinating O atom is 0.044 (12) Å. This bond-length alternation is significant but is smaller than the bond-length alternation observed for oxalic acid in the co-crystallized oxalic acid in (N n Bu4)2-1·CHCl3·oxH2, where a difference (for C=O versus C-OH) of 0.117 (14) Å was observed. In the bridging oxalate ligand in 22-, the C-O bond lengths are equalized, within the error margin of one bond-length determination (0.006 Å). It is concluded that oxalic acid contains a localized π-system in its carb-oxy-lic acid groups, that the bridging oxalate ligand in 22- contains a delocalized π-system and that the terminal oxalate ligand in 12- contains an only partially localized π-system. In (N n Bu4)2-1·CHCl3·oxH2, the F atoms of two of the -CF3 groups in 12- are disordered over two sets of sites, as are the N and eight of the C atoms of one of the N n Bu4 cations. In (N n Bu4)2-2, the whole of the unique N n Bu4+ cation is disordered over two sets of sites. Also, in (N n Bu4)2-2, a region of disordered electron density was treated with the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18].
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