Search results for "Mesoionic"
showing 4 items of 4 documents
Polymeric mesoions, 4. Synthesis of polymerizable mesoionic 4,6-dioxo-1,3-diazines derived from vinylbenzylmalonic acid
2000
Vinylbenzylmalonic acid (4) was condensed with N,N'-diphenylformamidine (5a), N,N'-diphenylacetamidene (5b), S-propyl-1,3-diphenylisothiourea (6) and anilinopyridine (7) in the presence of dicyclohexylcarbodiimide (DDC). The resulting new mesoionic monomers 8a-d were polymerized with 2,2'-azoisobutyronitrile (AIBN) as an initiator and dodecanethiol as a chain transfer agent. The low molecular weight model compounds 5-benzyl-pyrido[1,2-a]pyrimidine-2,4-dione (9a) and 5-hexadecyl-4,6-dioxo-1,3-diphenyl-2-hexadecylthio-1,3-diazine (9b) were prepared for X-ray diffraction analysis and comparison of spectrospical data.
A study of the behaviour of 2,4-substituted thiosemicarbazides toward orthoesters: Formation of mesoionic compounds
1997
The reactions beetwen 2,4-disubstituted thiosemicarbazides and orthoesters in refluxing xylene led to the formation of the 1,2,4-triazoline-5-thione ring and to the 1,2,4-triazolium-5-thiolate ring. The formation of the mesoionic componds is due to rearrangement of the easily available 2,4-disubstituted thiosemicarbazides to 1,4-disubstituted thiosemicarbazides under the reaction conditions adopted. This method can be usefully used for the synthesis of mesoionic compounds, especially in the case of the 2-methyl-4-phenylthiosemicarbazide.
Distinct photodynamics of κ-N and κ-C pseudoisomeric iron(ii) complexes
2021
Two closely related FeII complexes with 2,6-bis(1-ethyl-1H-1,2,3-triazol-4yl)pyridine and 2,6-bis(1,2,3-triazol-5-ylidene)pyridine ligands are presented to gain new insights into the photophysics of bis(tridentate) iron(II) complexes. The [Fe(N^N^N)2]2+ pseudoisomer sensitizes singlet oxygen through a MC state with nanosecond lifetime after MLCT excitation, while the bis(tridentate) [Fe(C^N^C)2]2+ pseudoisomer possesses a similar 3MLCT lifetime as the tris(bidentate) [Fe(C^C)2(N^N)]2+ complexes with four mesoionic carbenes. Financial support from the Deutsche Forschungsge-meinschaft [DFG, Priority Program SPP 2102] "Light-controlled reactivity of metal complexes" (BA 4467/7-1, LO 714/11-1, …
Synthesis and radical polymerization of novel methacrylates with mesoionic 6-oxo-1,6-dihydropyrimidin-3-ium-4-olates as photosensitive components
2001
New polymerizable mesoionic 6-oxo-1,6-dihydropyrimidin-3-ium-4-olates 5a-f have been synthesized using tosylated 2-hydroxymethyl methacrylate and various thioureas and malonic acids. Radical polymerization of the mesoionic derivatives 5a, c, d, e with AIBN as initiator resulted in soluble polymers, which were used for the preparation of photosensitive films.