<sup>13</sup>C nuclear magnetic resonance spectra in the solid state of 18-crown-6•NaNCS•H<sub>2</sub>O, some dicyclohexyl-18-crown-6 ethers, and their complexes with phenoxides and phenol

Buchanan, G. W.; Khan, M. Z.; Ripmeester, John A.; Bovenkamp, John W.; Rodrigue, André

doi:10.1139/v87-426

Cited by 8 publications

(15 citation statements)

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“…The space group P21/n was unambiguously defined from the The 45.3-MHz13C CPMAS Vectra were via techniques systematic absences noted in the data set. The structure was solved by described previously (1,2). direct methods usine MULTAN (15).…”

Section: Spectramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Recent publications from these laboratories (1,2) have dealt with the observation of dynamic 13C NMR phenomena in crystalline 18-crown-6 ether (1), its KNCS complex (I), and its NaNCS . H 2 0 complex (2). In each case, the low temperature 13c chemical shift differences could be interpreted in terms of torsional angle effects, with the geometrical data being available from X-ray crystallographic results.…”

Section: Introductionmentioning

confidence: 99%

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A novel 1:1 benzenesulfonamide: 18-crown-6 complex as uncovered via ¹³C solid phase NMR spectroscopy and X-ray crystallography

Buchanan¹,

Morat²,

Charland³

et al. 1989

Can. J. Chem.

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A 1:1 complex of 18-crown-6 ether and benzenesulfonamide has been prepared, whose melting point is within 4° of the previously reported 1:2 complex. The X-ray crystallographic structure shows pseudo D3d symmetry in the crown ether portion of this complex, in contrast to the 1:2 complex, which exhibits Ci symmetry in the macrocycle. The temperature dependent 13C CPMAS NMR spectra of these complexes have two regions of broadening for the crown ether carbons. At higher temperatures, a dipolar "washout" mechanism is operative, leading to broadening when molecular motion has a correlation time approximately equal to the inverse of the decoupling field. At lower temperatures broadening occurs when the motional correlation time is equal to the inverse of the chemical shift difference. From application of the Arrhenius equation, the activation energy for the molecular motion in solid 18-crown-6 is found to be approximately 10kcal/mol. Evidence for independent anisotropic motion in the benzenesulfonamide moiety of the 1:1 complex is also presented. Keywords: crown ether, molecular motion, solid phase NMR.

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Section: Spectramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A novel 1:1 benzenesulfonamide: 18-crown-6 complex as uncovered via ¹³C solid phase NMR spectroscopy and X-ray crystallography

Buchanan¹,

Morat²,

Charland³

et al. 1989

Can. J. Chem.

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“…When the reaction was carried out and quenched at -78 °C by addition of chlorotrimethylsilane, there were obtained a series of homologous dibromides 11 with 11 { = 3) as a major product, but neither the trimethylsilylated compound nor the benzene 12 was obtained. Only when the reaction was quenched after warming to the room temperature, a small amount (4% yield) of 12 was obtained, suggesting the formation of 12 only at the ambient temperature probably by the action of excessive amount of n-BuLi. These reactions were found to proceed regardless of the presence of Ni(II) complexes such as nickelocene and Ni(PPh3)2Cl2, which we had erroneously believed to be active as a catalyst.7…”

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confidence: 99%

Generation and oligomerization of bicyclo[2.2.2]octyne and properties of tris(bicyclo[2.2.2]octeno)benzene obtained from the linear trimer

Komatsu¹,

Aonuma²,

Jinbu³

et al. 1991

J. Org. Chem.

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“…Although the dihedral angle dependence of 13C chemical shifts in these particular types of networks has not been delineated, the effects are well documented experimentally for both central and terminal atoms of related C -C -C -C and C -C -C 4 arrangements (23)(24)(25). In every instance carbons experiencing gauche interactions are shielded by ca.…”

Section: Host-guest Interactionsmentioning

confidence: 99%

Synthesis, NMR spectroscopy, and crystal structure of the 1:2 host: guest complex of 18-crown-6 with lithium phenoxide

Watson¹,

Fortier²,

Murchie³

et al. 1990

Can. J. Chem.

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The title complex crystallizes in the space group Pcab with a = 16.019(7), b = 19.62(1), c = 15.847(5) A, and Z = 8. The structure was solved by direct methods and refined by full matrix least-quares calculations to a residual, R , of 0.083. The monomeric structure lacks a true centre of symmetry although the two lithiums have similar chemical environments. Each lithium cation is coordinated to three different oxygens of the hexaether and to both phenoxide oxygens. The hexaether is slightly elongated allowing both Li(1) and Li(2) to lie in the cavity formed by the crown with values of -0.077 and0.074 A, respectively, out of the plane approximated by the six oxygens. Both cations are stron ly associated with the phenol moieties. The distances between the lithium and the phenoxide oxygens range from 1.859-1.893 ! , while distances of 1.940-2.420 A are found with the ether oxygens. The L i ( l t L i ( 2 ) distance is found to be relatively short at 2.35 (2) A.Evidence for motion in the 18-crown-6 portion of the solid complex has been obtained from I3C CPMAS NMR spectroscopy. At 298 K, a dipolar washout phenomenon occurs since the motional correlation times are of the order of the inverse of the 'H decoupling field amplitude. At lower temperatures, the motion becomes slow enough to permit resolution of the chemical shift differences of unique carbon sites of the crown ether. Consistent with the X-ray analysis, only five resonances are evident for the phenoxide carbons, indicating that the two aromatic rings are nearly equivalent in their crystallographic environment. The solution 13C spectrum shows only five resonances in total down to 188 K indicative of rapid conformational averaging of all the 18-crown-6 carbon resonances and rapid rotation about the 0-phenyl bond. A et Z = 8. On a rCsolu la structure par des mCthodes directes et on l'a affinCe par la mCthode des moindres carrts jusqu'h une valeur de R = 0,083. La structure monomkre ne posskde pas de vrai centre de symCtrie m&me si les deux atomes de lithium se trouvent dans des environnement chimiques semblables. Chaque cation lithium est coordonnC 5 trois oxygknes difftrents de I'hexaCther et aux deux groupements hCnolates. L'hexatther est partiellement allonge et les deux Li (1) En se basant sur des donnies de spectroscopie rrnn CPMAS due 13c, on a pu mettre en evidence un mouvement de 1'Cther 18-couronne-6. A 298 K, il se produit un phCnomkne d'annulation dipolaire qui rtsulte du fait que les temps de corrClation des mouvements sont du m&me ordre de grandeur que l'inverse de l'amplitude du champ de decouplage du 'H. A des temperatures plus basses, le mouvement devient suffisamrnent lent pour permettre la rksolution des differences dans les diplacements chimiques des sites uniques des carbones de 1'Cther couronne. En accord avec l'analyse des rayons-X, on n'obsewe que cinq bandes de resonance pour les carbones du phCnolate; ces rtsultats indiquent que les deux cycles aromatiques sont pratiquement Cquivalents dans leur environnement cristallographique. Au tota...

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¹³C nuclear magnetic resonance spectra in the solid state of 18-crown-6•NaNCS•H₂O, some dicyclohexyl-18-crown-6 ethers, and their complexes with phenoxides and phenol

Cited by 8 publications

References 0 publications

A novel 1:1 benzenesulfonamide: 18-crown-6 complex as uncovered via ¹³C solid phase NMR spectroscopy and X-ray crystallography

A novel 1:1 benzenesulfonamide: 18-crown-6 complex as uncovered via ¹³C solid phase NMR spectroscopy and X-ray crystallography

Generation and oligomerization of bicyclo[2.2.2]octyne and properties of tris(bicyclo[2.2.2]octeno)benzene obtained from the linear trimer

Synthesis, NMR spectroscopy, and crystal structure of the 1:2 host: guest complex of 18-crown-6 with lithium phenoxide

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13C nuclear magnetic resonance spectra in the solid state of 18-crown-6•NaNCS•H2O, some dicyclohexyl-18-crown-6 ethers, and their complexes with phenoxides and phenol

Cited by 8 publications

References 0 publications

A novel 1:1 benzenesulfonamide: 18-crown-6 complex as uncovered via 13C solid phase NMR spectroscopy and X-ray crystallography

A novel 1:1 benzenesulfonamide: 18-crown-6 complex as uncovered via 13C solid phase NMR spectroscopy and X-ray crystallography

Generation and oligomerization of bicyclo[2.2.2]octyne and properties of tris(bicyclo[2.2.2]octeno)benzene obtained from the linear trimer

Synthesis, NMR spectroscopy, and crystal structure of the 1:2 host: guest complex of 18-crown-6 with lithium phenoxide

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¹³C nuclear magnetic resonance spectra in the solid state of 18-crown-6•NaNCS•H₂O, some dicyclohexyl-18-crown-6 ethers, and their complexes with phenoxides and phenol

A novel 1:1 benzenesulfonamide: 18-crown-6 complex as uncovered via ¹³C solid phase NMR spectroscopy and X-ray crystallography

A novel 1:1 benzenesulfonamide: 18-crown-6 complex as uncovered via ¹³C solid phase NMR spectroscopy and X-ray crystallography