Acetylene Polymers: Preparation, Physical Properties, Infrared and Ultraviolet. Spectra<sup>1</sup>

Georgieff, K. K.; Cave, W. T.; Blaikie, K. G.

doi:10.1021/ja01650a070

Cited by 32 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Characteristic chemical shifts, such as upfield values for C2 (δ 116), C9 (δ 112) and those for equivalent two methylenes (H 2 5 and H 2 6 δ 2.47, C5 and C6 δ 21), could be accounted for by a bis-conjugated enyne system. The triconjugated yne-diene system from C7 to C12 was supported by the UV maxima data 244, 267, 278 nm . The section from C1 to C5 was supported by comparable chemical shifts and coupling constants reported for a similar structure …”

Section: Resultssupporting

confidence: 59%

Structures and Partial Stereochemical Assignments for Prymnesin-1 and Prymnesin-2: Potent Hemolytic and Ichthyotoxic Glycosides Isolated from the Red Tide Alga Prymnesium parvum

1999

View full text Add to dashboard Cite

Two glycosidic toxins, prymnesin-1 (PRM1) and prymnesin-2 (PRM2) have been isolated from cultured cells of the red tide phytoflagellate Prymnesium parvum, and the gross structure of PRM2 C96H136Cl3NO35 has been reported in a previous contribution. The molecule possesses unique structural features: a C90 unbranched carbon chain except for a single methyl, five contiguous ether rings (6/6/6/7/6), four distinct 1,6-dioxadecalin units, conjugated double and triple bonds, chlorine and nitrogen atoms, and an uncommon l-xylose. Potent ichthyotoxic and hemolytic properties of the two toxins were also demonstrated. However, the stereochemistry of PRM2 and the structure of PRM1 remained unknown. In the present paper the relative stereochemistry of the polycyclic ether moiety of PRM2 and the structure of PRM1 C107H154Cl3NO44 are reported. Structural elucidation was carried out by extensive analysis of NMR data. Difficulties arising from the poor solubility of the toxins in NMR solvents were overcome by preparing N-acetyl, peracetyl, perhydro, and dehydrochlorinated derivatives of the toxins. These derivatives were also effective in improving the precision of signal assignments. 13C NMR measurements were facilitated by a 13C-enriched N-acetate from cultures of the flagellate in the presence of Na13CO3. Comparison of the NMR data between N-acetylprymnesin-1 and N-acetylprymnesin-2 and chiral GC analysis of the glycosidic residues indicated that PRM1 possessed α-d-ribofuranosyl, α-l-arabinopyranosyl, and β-d-galactofuranosyl residues at C77, C78, and C82 positions, respectively, on the same aglycone structure as PRM2. In the polycyclic parts (C20−C74) of both toxins, all ring fusions were trans and all rings took a chair conformation. The stereochemistry at C14 and C76−C85 remains unknown.

show abstract

Section: Resultssupporting

confidence: 59%

Structures and Partial Stereochemical Assignments for Prymnesin-1 and Prymnesin-2: Potent Hemolytic and Ichthyotoxic Glycosides Isolated from the Red Tide Alga Prymnesium parvum

1999

View full text Add to dashboard Cite

show abstract

“…The observed absorptions have a complex shape because of the possible formation of a mixture of cis and trans isomers of 1,3-hexadien-5-yne and the possible presence of different conformations of molecules and trapping sites (detailed analysis is out of the scope of this work). We also observed a number of weak radiation-induced absorptions (Table and Figure S4 in Supporting Information), which are in agreement with previously published IR spectra of 1,3-hexadien-5-yne in the gas phase and in para -hydrogen matrix. , A number of even weaker IR features in the region between 1200 and 3150 cm –1 observed in the gas phase was not found in the matrix experiments, neither in para -H 2 nor in noble-gas matrices, probably, because of low concentrations of the generated alkyne. In additional experiments involving radiolysis of benzene- d 6 in noble-gas matrices, we observed radiation-induced absorptions in 2580–2620 cm –1 (Figure S5, Supporting Information).…”

Section: Resultssupporting

confidence: 92%

“… a This work. b Reference . c Reference . d A multiplet with a complex structure due to different isomers and trapping sites (see text). …”

Section: Resultsmentioning

confidence: 99%

Radiation-Induced Transformations of C₆H₆ Molecules in Solid Noble-Gas Matrices: Is Benzene Intrinsically Resistant in Condensed Media?

2019

View full text Add to dashboard Cite

The radiation resistance of aromatic compounds is one of the key concepts of basic and applied radiation chemistry in condensed phases. Usually, it is attributed to the intrinsic radiation stability of the benzene ring. In this work, we have demonstrated for the first time that the isolated benzene molecules undergo rather efficient radiation-induced degradation in rigid inert media at cryogenic temperatures (comparable to that of aliphatic hydrocarbons), and their stability is essentially determined by the intermolecular relaxation correlating with matrix polarizability. The principal primary products of benzene radiolysis in matrices are phenyl radicals and fulvene. The matrix environment strongly affects the proportion of these species because of external heavy atom effect on the intersystem crossing, which may trigger further reaction pathways. The obtained results may have important implications for the prediction of radiation stability of complex organic systems and polymers. Furthermore, they may contribute to a better understanding of the radiation-induced evolution of aromatic species in cold interstellar media.

show abstract

“…(1)], since weak and slowly depleting slowest photolytic progress was observed with the ArF laser absorption bands of this compound at 219 and 227 nm (ref. 30) irradiation of tellurophene and the fastest with the KrF laser were observed during all the photolytic runs. irradiation of R 2 Te compounds, the depletion of all the organotelluriums with the different lasers (ArF, KrF and XeCl ) are very similar.…”

Section: Introduction Experimentalmentioning

confidence: 91%

Deposition of nanostructured Te and Te/C particles by excimer laser-induced photolysis of organotelluriums in the liquid phase

Ouchi¹,

Yamamoto²,

Koga³

et al. 1999

J. Mater. Chem.

View full text Add to dashboard Cite

Acetylene Polymers: Preparation, Physical Properties, Infrared and Ultraviolet. Spectra¹

Cited by 32 publications

References 0 publications

Structures and Partial Stereochemical Assignments for Prymnesin-1 and Prymnesin-2: Potent Hemolytic and Ichthyotoxic Glycosides Isolated from the Red Tide Alga Prymnesium parvum

Structures and Partial Stereochemical Assignments for Prymnesin-1 and Prymnesin-2: Potent Hemolytic and Ichthyotoxic Glycosides Isolated from the Red Tide Alga Prymnesium parvum

Radiation-Induced Transformations of C₆H₆ Molecules in Solid Noble-Gas Matrices: Is Benzene Intrinsically Resistant in Condensed Media?

Deposition of nanostructured Te and Te/C particles by excimer laser-induced photolysis of organotelluriums in the liquid phase

Contact Info

Product

Resources

About

Acetylene Polymers: Preparation, Physical Properties, Infrared and Ultraviolet. Spectra1

Cited by 32 publications

References 0 publications

Structures and Partial Stereochemical Assignments for Prymnesin-1 and Prymnesin-2: Potent Hemolytic and Ichthyotoxic Glycosides Isolated from the Red Tide Alga Prymnesium parvum

Structures and Partial Stereochemical Assignments for Prymnesin-1 and Prymnesin-2: Potent Hemolytic and Ichthyotoxic Glycosides Isolated from the Red Tide Alga Prymnesium parvum

Radiation-Induced Transformations of C6H6 Molecules in Solid Noble-Gas Matrices: Is Benzene Intrinsically Resistant in Condensed Media?

Deposition of nanostructured Te and Te/C particles by excimer laser-induced photolysis of organotelluriums in the liquid phase

Contact Info

Product

Resources

About

Acetylene Polymers: Preparation, Physical Properties, Infrared and Ultraviolet. Spectra¹

Radiation-Induced Transformations of C₆H₆ Molecules in Solid Noble-Gas Matrices: Is Benzene Intrinsically Resistant in Condensed Media?