Synthesis of 9,9′-Spirobifluorenes and 4,5-Diaza-9,9′-spirobifluorenes and Their Application as Affinity Materials for Quartz Crystal Microbalances
Two different classes of aza analogues of 9,9′-spirobifluorenes have been synthesized. These were obtained by either furnishing the spirobifluorene with additional pyridyl moieties or by installing the aza function directly into the spirobifluorene core. These structurally rigid compounds were then evaluated as affinity materials for quartz crystal microbalances and proved to be highly potent for the detection of volatile organic compounds.
Stobe, Caroline,Pyka, Isabella,Linke, Alexander,Müller, Sarah,Schnakenburg, Gregor,Waldvogel, Siegfried R.,Lützen, Arne
p. 758 - 769
(2017/06/06)
Multiple Paths for Photo-alkylation and -alkoxylation of 3-Pyridinecarboxylic Ester in Alcohol. Simultaneous Contribution of Several Kinds of Excited States
UV-irradiation of methyl 3-pyridinecarboxylate (1) in acidic alcoholic solutions brings about the alkoxylation and alkylation at the pyridine ring.Photoalkylation occurs in several paths: 1) alkylation initiated by the triplet ?-?* state, 2) alkylation initiated by the triplet n-?* state of the carbonyl moiety of the ester group, 3) alkylation initiated by exciplex between a free base form of 1 and a pyridinium form of 1, and 4) alkylation promoted by chloride ions.Photoalkoxylation originates from a singlet excited state of 1.In the photoreactions of 1 in strongly a cidic methanolic solutions acidified with H2SO4, three kinds of excited states (two kinds of triplet states for alkylation and a singlet state for alkoxylation) contribute simultaneously.
Sugimori, Akira,Tobita, Etsuo,Kumagai, Yasuyuki,Sato, Gen P.
p. 1761 - 1766
(2007/10/02)
MULTIPLE PATHS FOR PHOTOALKYLATION OF PYRIDINECARBOXYLIC ESTERS IN ALCOHOLS
Photochemical substitution of ring hydrogen of pyridinecarboxylic esters by alkyl groups derived from solvent alcohols occurs in several paths: 1) alkylation initiated by excited carbonyl moiety of the ester group and 2) alkylation initiated by the excitation of the ?-electronic system of the pyridine ring.In the photoreaction of methyl 3-pyridinecarboxylate in acidic methanol, three types of excited state (two triplet states for alkylation and a singlet state for alkoxylation) contribute simultaneously.