The conformation of six-membered rings

Boeyens, Jan C. A.

doi:10.1007/bf01200485

Cited by 368 publications

(236 citation statements)

References 6 publications

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“…The octahedral coordination sphere around the central atom is composed of three carbonyl ligands in fac con guration, one chlorido ligand as well as one molecule of bis(2-pyridylmethanone), the latter coordinating via its two nitrogen atoms to the central atom. A puckering analysis of the six-membered chelate ring according to Cremer & Pople [4] shows the latter to adopt a B4,1 conformation on carbon and rhenium (B C1,Re1 ) [5]. Re-C bond lengths cover a narrow range of 1.904 (7) [6], the values found in the present study are among the most comon ones reported so far.…”

Section: Atom Sitesupporting

confidence: 65%

Crystal structure of chlorido-tricarbonyl-bis(2-pyridylmethanone-N,N′)-rhenium(I), C14H8ClN2O4Re

Mukiza

Gerber

Hosten

2015

Zeitschrift Für Kristallographie - New Crystal Structures

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C14H 8 ClN 2 O4Re, triclinic, P¯ (no. 2), a = 7.5566(3) Å, b = 8.3079(3) Å, c = 12.0017(6) Å, α = 83.583(1)°, β = 88.746(2)°, CCDC no.: 1267/4339 Source of materialThe compound was obtained upon reacting the Schi base derived from 2,6-diazaaniline and bis(2-pyridylmethanone) with Re(CO)5Cl in toluene. Crystals suitable for the di raction study were obtained upon free evaporation of the solvent at ambient conditions.

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Section: Atom Sitesupporting

confidence: 65%

Crystal structure of chlorido-tricarbonyl-bis(2-pyridylmethanone-N,N′)-rhenium(I), C14H8ClN2O4Re

Mukiza

Gerber

Hosten

2015

Zeitschrift Für Kristallographie - New Crystal Structures

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“…No data is available from the electron diffraction studies for the intracyclic distance between the two sulfur atoms. Apuckering analysis [10]shows thesix-membered ringtoadopt a 1 C 4 chair conformation according to [11].The latter finding is Z corroborated by projections of the structure along the C-S bonds showing nearly ideal staggered conformations for all methylene groups, the relevant C-S-C-C dihedral angles measuring 59.23(9) and 59.34 (9)°. An investigation of intra-and intermoleculari nteractions in the crystal structureo ft he title compound revealed an interesting picture.…”

supporting

confidence: 52%

Redetermination of the crystal structure of 1,4-dithiane, at 200 K – Analysis of intermolecular forces, C4H8S2

Hosten

Betz

2014

Zeitschrift Für Kristallographie - New Crystal Structures

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“…The flap atom in both cases is carbon atom C7. For the six-membered ring, a B 2,5 (B C2,C5 )conformation was found [6]. The C-O bond lengths were measured at 1.2130(14) Åa nd 1.3206 (14) Åf or the doublebonded and the single-bonded oxygen atom.The latter two values are in good agreement with other values reported for carboxylic acidsw hose metrical parameters have been deposited with the Cambridge Structural Database [7].Inthe crystal, classical hydrogen bondso ft he O-H×××Ot ype arep redominant.…”

Section: Discussionmentioning

confidence: 99%

Redetermination of the crystal structure of endo-2-carboxy-bicyclo[2.2.1]- heptane, C8H12O2

Schalekamp

Hosten

Betz

2015

Zeitschrift Für Kristallographie - New Crystal Structures

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Source of materialThec ompoundw as obtained commercially (Frinton Laboratories). Crystals suitable for the diffraction study were obtained upon sublimation of the product at room temperature. Experimental detailsCarbon-bound Hatomswere placed in calculated positions (C-H 0.99 Åfor methylene groups and C-H 1.00 Åfor methine groups) and were included in the refinement in the riding model approximation, with U iso (H) setto1.2U eq (C). The Hatom of the carboxyl group was allowed to rotate with afixed angle around the C-O bond to best fit the experimental electron density (HFIX 147 in the SHELX program suite [11]), with U iso (H) sett o1 .5U eq (O). Due to very low residual electron densities after refinement of givenstructuralmodel,nodisorder model could be set up. DiscussionThe bicycloheptane scaffold has been afocusofresearch in organic chemistry for many decades. Especially questions centered around classicala nd non-classicalc arbocationsf ocusedo nt his keystructure andonlyveryrecentlythe existenceofpenta-coordinate carboncould be proven experimentally on grounds of diffraction experiments based on single crystals [1,2].T he latter finding motivated us to include bicycloheptane-derived ligands into our research efforts in synthesizing novel coordination compounds of transition metals. As aconvenient starting point for our studies, the title compound was chosen as it is commercially available. The molecular and crystal structure of endonorbornane-2-carboxylic acid have been mentioned in the literature once, however, no 3D coordinates have been provided [3]. As the structures of envisioned target molecules shall be elucidated by means of diffraction experiments on single crystals, the structure of the title compound was redetermined. The title compound is the endo-configured carboxylic acid of norbornane. A puckering analysis according to Cremer &Pople [4]showed the five-membered rings in the norbornane scaffold to adopt an E 3 and an E 5 conformation, respectively [5]. The flap atom in both cases is carbon atom C7. For the six-membered ring, a B 2,5 (B C2,C5 )conformation was found [6]. The C-O bond lengths were measured at 1.2130(14) Åa nd 1.3206(14) Åf or the doublebonded and the single-bonded oxygen atom.The latter two values are in good agreement with other values reported for carboxylic acidsw hose metrical parameters have been deposited with the Cambridge Structural Database [7].Inthe crystal, classical hydrogen bondso ft he O-H×××Ot ype arep redominant. There are C-H×××Oc ontacts whose range falls below the sum of van-derWaals radii of the atomsparticipating in them.While the hydrogen bonds give rise to the formation of centrosymmetric dimers as often observed for carboxylic acids [8], the C-H×××Ocontacts extend thesed imeric unitst os trands along the crystallographic a axis. The latter contacts are supported by one of the hydrogen atomsatabridge-head position of the norbornane scaffold and employ the carbonylic oxygen atom as acceptor thus giving rise to two anti-dromic C-H×××Oc ontact chains. In terms...

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The conformation of six-membered rings

Cited by 368 publications

References 6 publications

Crystal structure of chlorido-tricarbonyl-bis(2-pyridylmethanone-N,N′)-rhenium(I), C14H8ClN2O4Re

Crystal structure of chlorido-tricarbonyl-bis(2-pyridylmethanone-N,N′)-rhenium(I), C14H8ClN2O4Re

Redetermination of the crystal structure of 1,4-dithiane, at 200 K – Analysis of intermolecular forces, C4H8S2

Redetermination of the crystal structure of endo-2-carboxy-bicyclo[2.2.1]- heptane, C8H12O2

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