• Catalysts
  • Due to the activated nature of the cyclic carbon-carbon triple bond, many alkyne addition-type reactions such as the Diels-Alder, 1,3-dipolar cycloadditions and halogenation may be performed using very mild conditions and in the absence of the catalysts frequently required to accelerate the transformation in a non-cyclic system. (wikipedia.org)
  • phosphorus
  • The first phosphirenium ion characterized by X-ray Crystallography has the following structural formula: In the refined crystal structure, average phosphorus-cyclic carbon distance has been found to be 1.731(12) Å, roughly corresponding to a bond order of 1.5. (wikipedia.org)
  • With the presence of an alkyne: With the presence of water or alcohol: Electrophilic B(C6F5)3 readily reacts with phosphinylalkynes at room temperature to give phosphirenium-borate zwitterions as intermediates, which then generate carbon-phosphorus σ bond activation products at higher temperature. (wikipedia.org)
  • Similar to the aromatic cyclopropenium ion, the phosphorus analog shows a resonance between the structure with carbon-carbon double bond (1, 72.02%) and the ones with carbon-phosphorus double bond (3a and 3b, 7.88% combined). (wikipedia.org)
  • alcohols
  • When water is eliminated from cyclic tertiary alcohols by an E1 route, three major products are formed. (wikipedia.org)
  • Rather than reacting with additional alcohol, they may disproportionate to give the desired carbonate diesters and one equivalent of phosgene: PhOH + COCl2 → PhOCOCl + HCl 2 PhOCOCl → PhOCO2Ph + COCl2 With an appropriate catalyst, alcohols can react with carbon monoxide and an oxidant (e.g. oxygen gas). (wikipedia.org)
  • C2O4
  • Notable examples of unstable or metastable oxides that were detected only in extreme situations are dicarbon monoxide radical (:C=C=O), carbon trioxide (CO3), carbon tetroxide (CO 4), carbon pentoxide (CO 5), carbon hexoxide (CO 6) and 1,2-dioxetanedione (C2O4). (wikipedia.org)
  • Alkyne
  • In organic chemistry, a cycloalkyne is the cyclic analog of an alkyne. (wikipedia.org)
  • Analysis by photoelectron spectroscopy has indicated that the alkyne bond in small cyclic systems is composed of two non-degenerate π bonds - a highly reactive strained bond perpendicular to a lower-energy π bond. (wikipedia.org)
  • monoxide
  • Carbon monoxide may occur in combustion, too, and was used (though not recognized) since antiquity for the smelting of iron from its ores. (wikipedia.org)
  • Loss or gain of electrons can result in monovalent negative oxygen (-O− ), trivalent positive oxygen (≡O+ ), or trivalent negative carbon (≡C− ). The last two are found in carbon monoxide, −C≡O+. (wikipedia.org)
  • carbons
  • Moreover, while carbon can connect to other carbons to form arbitrarily large chains or networks, chains of three or more oxygens are rarely if ever observed. (wikipedia.org)
  • consist
  • Thus the known electrically neutral oxocarbons generally consist of one or more carbon skeletons (including cyclic and aromatic structures) connected and terminated by oxide (-O-, =O) or peroxide (-O-O-) groups. (wikipedia.org)
  • Typical electrodes consist of small carbon fiber needles that are micrometers in diameter and able to be noninvasively inserted into live tissues. (wikipedia.org)
  • atom
  • The ring spontaneously opens and closes, allowing rotation to occur about the bond between the carbonyl group and the neighbouring carbon atom, yielding two distinct configurations (α and β). (wikipedia.org)
  • pathways
  • In addition to the elimination-type pathways described, cycloalkynes can also be obtained through the oxidation of cyclic bis-hydrozones with mercury oxide as well as through the thermal decomposition of selenadiazole. (wikipedia.org)
  • microelectrodes
  • This unit describes the isolation of several cell types known for their exocytotic properties, the fabrication and calibration of carbon fiber microelectrodes, as well as some of the equipment and software requirements for obtaining electrochemically generated data. (currentprotocols.com)
  • FSCV in combination with carbon-fiber microelectrodes became a very popular method for detection of neurotransmitters, hormones and metabolites in biological systems. (wikipedia.org)
  • oxides
  • Many other stable (practically if not thermodynamically) or metastable oxides of carbon are known, but they are rarely encountered, such as carbon suboxide (C3O2 or O=C=C=C=O) and mellitic anhydride (C12O9). (wikipedia.org)
  • Some of these reactive carbon oxides were detected within molecular clouds in the interstellar medium by rotational spectroscopy. (wikipedia.org)
  • Chemistry
  • The low-polydispersity cyclic PCL samples (C-PCLs) were synthesized by click chemistry with a number-average molecular weight (M n) of 22 kg/mol. (upc.edu)
  • alternate
  • When drawn in this order, the Fischer projections of the D-aldohexoses follow a pattern: beginning with allose having all four hydroxyl groups on the right, going through the mnemonic at carbon 2 the hydroxyl groups alternate right-left with each different sugar (allose left, altrose right, glucose left, etc. (wikipedia.org)
  • Calvin
  • Calvin, M., and Benson, A. A. "The Path of Carbon in Photosynthesis" , Ernest Orlando Lawrence Berkeley National Laboratory, University of California Radiation Laboratory-Berkeley, United States Department of Energy (through predecessor agency the Atomic Energy Commission ), (March 8, 1948). (wikipedia.org)
  • Results
  • Results on linear and cyclic PCL blends are also presented here, and they support our explanation of the unexpected antinucleation effect reported for C-PCL/MWNT-g-PCL nanocomposites. (upc.edu)
  • The results demonstrate that cAMP is crucial for catabolic flexibility during slow, carbon-limited growth, whereas RpoS is primarily involved in the regulation of stress response systems necessary for the survival of this bacterium under hunger conditions. (duhnnae.com)
  • systems
  • The inability to synthesize cAMP exerted a strong negative influence on the expression of alternative carbon source uptake and degradation systems. (duhnnae.com)
  • effect
  • When these linear chains come into contact with cyclic PCL chains, a threading effect is produced that dramatically affects chain dynamics by forming a transient entanglement network. (upc.edu)
  • energy
  • For heterotrophic microbes, limited availability of carbon and energy sources is one of the major nutritional factors restricting the rate of growth in most ecosystems. (duhnnae.com)
  • growth
  • As a consequence, cyclic molecules relax and diffuse more slowly than anticipated, decreasing both nucleation and growth kinetics. (upc.edu)
  • Therefore, during growth of E. coli in carbon-limited chemostat culture at different dilution rates, the transcriptomes, expression of periplasmic proteins and catabolomes of strains lacking one of these global regulators, either rpoS or adenylate cyclase cya, were compared to those of the wild-type strain. (duhnnae.com)
  • ability
  • Phenotypical analysis confirmed this observation: The ability to respire alternative carbon substrates and to express periplasmic high-affinity binding proteins was eliminated in cya and crp mutants, while these properties were not affected in the rpoS mutant. (duhnnae.com)