3310-62-1Relevant articles and documents
A photoactivable fluorophore based on thiadiazolidinedione as caging group
Gramlich, Gabriela,Nau, Werner M.
, p. 603 - 605 (1999)
(Matrix presented) Photoactivable ("caged*) fluorescent dyes and probes are crucial for temporally and spatially resolved tracer experiments, e.g., in cell biology or fluid physics. The thiadiazolidinedione 1 represents a new class of caged fluorophore. Upon UV-irradiation it releases in a rapid photoreaction with high quantum yield the azoalkane 2. Longer wavelength excitation of 2 to the singlet excited state results in strong and long-lived fluorescence with maximum intensity at 425 nm. It has been demonstrated that one single uncaging laser pulse suffices for time-resolved or steady-state detection of the fluorescence.
Reactions of Bis(N,N'-bicyclic) Diazenium Dications
Nelsen, Stephen F.,Wang, Yichun
, p. 3082 - 3090 (2007/10/02)
Eleven bis(N,N'-bicyclic) diazenium dications were generated from the corresponding hydrazines by NOPF6 oxidation.Their reactivity depends greatly upon the sizes of the bicyclic rings. (We designate bicyclic ring size using the number of atoms in the two bridges in addition to the dinitrogen bridge all the compound share.) Compounds with rings alkylate acetonitrile at 240 K by opening a Cα-N(+) bond to produce a trialkyldiazenium cation, with ΔG(excit.) for the reaction increasing by at least 5.5 kcal/mol as the second bicyclic ring size increases.Compounds with an unsaturated bridge also alkylate acetonitrile; 22/u22(2+) only cleaves the bridge and reacts faster than 21/22(2+), which only cleaves the bridge.Cα-N(+) cleavage of and larger rings by acetonitrile has not been observed. 21/22(2+) is significantly more acidic than 22/22(2+), but both are β-deprotonated by pyridine to produce aminoaziridinium cations at 240 K.At least mostly the exo ring proton is lost from 21/22(2+).Dications with and bridges deprotonate at the α-carbon instead of the β-carbon, and 22/23(2+) is slightly more kinetically acidic than 21/22(2+). 22/24(2+) is deprotonated rapidly by ether at 235 K.
Tetraalkyl-p-urazines and Their Cation Radicals
Nelsen, Stephen F.,Kim, Yaesil,Neugebauer, Franz A.,Krieger, Claus,Siegel, Rolf,Kaftory, Menahem
, p. 1045 - 1051 (2007/10/02)
X-ray strucures for tetramethyl-p-urazine 1 and its dithia derivative 3 show these compounds to exist in significantly twisted boat structures with nearly planar nitrogens.The X-ray structure of the fused bicyclooctyl derivative cation radical 4.+ is consistent with a delocalized structure having equivalent N-N bonds and planar nitrogens.ESR and ENDOR data are consistent with delocalized cation radicals in solution.Cyclic voltammetry and cation radical optical absorption data are reported.Differences between the solvent dependence of the optical absorption maximum for 4.+ and for a bisalkoxyurea which is known to have the positive charge localized (5.+) are discussed.
