51304-75-7Relevant academic research and scientific papers
Influence of Electronic Effects on the Reactivity of Triazolylidene-Boryl Radicals: Consequences for the use of N-Heterocyclic Carbene Boranes in Organic and Polymer Synthesis
Telitel, Sofia,Vallet, Anne-Laure,Flanigan, Darrin M.,Graff, Bernadette,Morlet-Savary, Fabrice,Rovis, Tomislav,Lalevée, Jacques,Lac?te, Emmanuel
, p. 13773 - 13777 (2015)
A small library of triazolylidene-boranes that differ only in the nature of the aryl group on the external nitrogen atom was prepared. Their reactivity as hydrogen-atom donors, as well as that of the corresponding N-heterocyclic carbene (NHC)-boryl radicals toward methyl acrylate and oxygen, was investigated by laser flash photolysis, molecular orbital calculations, and ESR spin-trapping experiments, and benchmarked relative to the already known dimethyltriazolylidene-borane. The new NHC-boranes were also used as co-initiators for the TypeI photopolymerization of acrylates. This allowed a structure-reactivity relationship with regard to the substitution pattern of the NHC to be established and the role of electronic effects in the reactivity of NHC-boryl radicals to be probed. Although their rate of addition to methyl acrylate depends on their electronegativity, the radicals are all nucleophilic and good initiators for photopolymerization reactions. Polar influence: The influence of electronic effects on the reactivity of N-heterocyclic carbene (NHC)-boryl radicals (see figure) was studied. The addition rate of the radicals to methyl acrylate depends on their electronegativity. Nevertheless, all NHC-boranes studied were good co-initiators for the TypeII photopolymerization of acrylates, which suggests that the addition rate is not the determining factor for the polymerization.
Synthesis, optical properties and in vitro cell viability of novel spiropyrans and their photostationary states
Rastogi, Shiva K.,Zhao, Zhenze,Gildner, M. Brenton,Shoulders, Ben A.,Velasquez, Tara L.,Blumenthal, Madeleine O.,Wang, Lei,Li, Xiaopeng,Hudnall, Todd W.,Betancourt, Tania,Du, Liqin,Brittain, William J.
supporting information, (2021/01/06)
A novel class of spiropyran (SP) was synthesized using a multistep process that involves three key intermediates: (a) diazonium-tetrafluoroborate, (b) hydrazine and (c) indolium iodide. Single crystal X-ray spectroscopy was used to confirm the structure of one of the analogues. The SP analogues were confirmed as being able to isomerize and attain a photostationary state (PSS) upon irradiation with ultraviolet light (UV, 365 nm) in an aqueous environment. UV–visible absorption spectra were recorded to confirm the isomerization properties. The ability of the synthesized compounds to induce growth inhibition of HeLa cervical cancer cells was assessed via the MTT assay after incubation with either the SP or their PSS. The IC50 values of two PSS (PSS-2, 4), were observed to be around 14 ± 4 fold lower (26 ± 3 μM) than their corresponding SPs. The most cytotoxic compounds SP-7 and PSS-7 showed the lowest IC50 values (12 μM). An in vitro tubulin polymerization assay showed that SP-7 and PSS-7 exhibited the greatest difference in tubulin inhibition relative to unirradiated SP-1 and SP-4.
