sym-cis,cis,cis-1,4,7-Cyclononatriene, an Unusual Cyclic Six Pi Electron System

Untch, Karl G.

doi:10.1021/ja00886a022

Cited by 32 publications

(13 citation statements)

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“…From these two sets of results, we infer that the decomposition of benzenediazonium 2-carboxylate does (1) National Institutes of Health Predoctoral Fellow.…”

Section: Introductionmentioning

confidence: 91%

“…This is the conclusion drawn from the combined results of two types of investigation of reactions assumed to be eq. 1 and 2. C6H4N2C02(s) -X C6H4(g) + C02 + N2 (1) 2C6H4(g) ->-(C6H4)2(g) (2) The first step was the observation of the formation of biphenylene,3 (C6H4)2, in the gas, presumably from reaction 2. The biphenylene spectrum, observed as a function of time, grows in intensity while a broad continuum, previously unknown, diminishes.3 The time scale for this process is measured in tens or hundreds of microseconds.…”

Section: Introductionmentioning

confidence: 99%

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The Dimerization of Gaseous Benzyne

Schafer¹,

Berry²

1965

J. Am. Chem. Soc.

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“…From these two sets of results, we infer that the decomposition of benzenediazonium 2-carboxylate does (1) National Institutes of Health Predoctoral Fellow.…”

Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

The Dimerization of Gaseous Benzyne

Schafer¹,

Berry²

1965

J. Am. Chem. Soc.

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“…1) appears to be a little more simple. cis‐cis‐cis ‐1,4,7‐cyclononatriene ( I ) and structurally related compounds show some unusual conformational properties 5–20. The ring system can exist in either a crown (C), which is rigid and has C 3v symmetry for the parent hydrocarbon, or as a “saddle” conformation, which is more or less flexible.…”

Section: Introductionmentioning

confidence: 99%

Identification of a NCR⁺/NKG2D⁺/LFA‐1^low/CD94⁻ immature human NK cell subset

et al. 2009

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CD56bright natural killer (NK) cells, generated in vitro from CD34 1 hematopoietic progenitor cells, were characterized after a 30-day culture with flt3 ligand plus IL-15. Virtually, all CD56 bright cells expressed CD117, CD25, natural cytotoxicity receptors (NCRs), NKG2D, CD161, and CD244, while only a subset expressed CD18-CD11a (LFA-1), and CD94 molecule, defining an immature CD56 and activatory function that finely control their functional activities. In particular, they express inhibitory receptors for MHC class I (MHC-I) molecules, named killer cell immunoglobulin (Ig)-like receptors (KIRs) and C-type lectin CD94-CD159a, and many triggering molecules like NKp30, NKp44, NKp46, (called natural cytotoxicity receptors, NCRs), NKG2D, CD161, and CD244 (1-4). The majority of peripheral blood (PB) human NK cells are characterized by a phenotype with a low density expression of CD56 (CD56 dim ) and a high expression of CD16 (CD16 bright ), whereas a minority (approximately 5-10%) shows a bright expression of CD56 (CD56 bright ). This latter NK subset presents relatively high expression of some cytokine receptors (CD117 and CD25), lymph node homing receptors (CD62L and CCR7) and the CD94-CD159a heterodimeric inhibitory receptor. Moreover, differently from the well-known CD56 dim /CD16 bright cells, only a small percentage of the CD56 bright subset expresses KIR inhibitory receptors (5-10%) and CD16 dim (20-30%) while, in the majority, these antigens are not expressed (5). On the other hand, CD56bright NK cells are widely expressed in lymphoid tissues (6) and can be generated from CD34 1 cells when cultured with combinations of flt-3 ligand (FL) or stem cell factor plus IL-15 or IL-2 (7-10). During their development, NK cells sequentially acquire many different antigens and some of them allow to distinguish intermediate stages of NK cell differentiation. We had already taken advantage of CD161 antigen expression to define an immature CD161 1 /CD56 2 subset able to kill Jurkat cells via a TRAIL-dependent mechanism (3,11). When cultured with IL-12, this NK cell subset began to express CD56 molecule and became cytotoxic against K562 cells, thus suggesting a

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“…About twenty years ago, an X-ray analysis of cis,cis,cis-1,4,7-cyclononatriene was carried out (6) in order to resolve contradictory predictions of homoaromaticity in that molecule (7)(8)(9). The authors concluded that the C(sp2)-C(sp3)-C(sp2) bond angle of 108" and the C(sp2) -.-C(sp2) nonbonded distance of 2.46 A in the crown-shaped triene precluded the possibility of any meaningful homoaromaticity.…”

Section: Introductionmentioning

confidence: 99%

Crystal structure and infrared spectra of an inclusion compound of cyclotriveratrylene and water

Birnbaum¹,

Klug²,

Ripmeester³

et al. 1985

Can. J. Chem.

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. Can J. Chem. 63, 3258 (1985). A crystal grown by slow evaporation from a solution of cyclotriveratrylene (CTV) in toluene was found to be an inclusion compound with water as the only encaged guest. Its stoichiometry is C27H3006b~HZO (X = 0.16) and it belongs to the monoclinic space group C2/c, with a = 24.216(21), b = 9.636(2), c = 23.1 17(4) A, P = 118.08(5)", Z = 8. X-ray intensity data were measured with a diffractometer and the structure was solved by direct methods. Least-squares refinement, which included all hydrogen atoms of the host molecule, converged at R = 0.046 for 3986 observed reflections. The geometry of the host molecule is compared to that of analogous structures and to cyclononatriene. Significant differences are ascribed to the effects of homoaromaticity and steric strain. Both the X-ray analysis and an FTIR study of the OH stretching show that the water molecules are weakly bound to the methoxy oxygen atoms of CTV. The molecular packing of CTV clathrates is discussed on the basis of crystallographic and spectroscopic evidence.

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sym-cis,cis,cis-1,4,7-Cyclononatriene, an Unusual Cyclic Six Pi Electron System

Cited by 32 publications

References 0 publications

The Dimerization of Gaseous Benzyne

The Dimerization of Gaseous Benzyne

Identification of a NCR⁺/NKG2D⁺/LFA‐1^low/CD94⁻ immature human NK cell subset

Crystal structure and infrared spectra of an inclusion compound of cyclotriveratrylene and water

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sym-cis,cis,cis-1,4,7-Cyclononatriene, an Unusual Cyclic Six Pi Electron System

Cited by 32 publications

References 0 publications

The Dimerization of Gaseous Benzyne

The Dimerization of Gaseous Benzyne

Identification of a NCR+/NKG2D+/LFA‐1low/CD94− immature human NK cell subset

Crystal structure and infrared spectra of an inclusion compound of cyclotriveratrylene and water

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Identification of a NCR⁺/NKG2D⁺/LFA‐1^low/CD94⁻ immature human NK cell subset