The crystal structure of octamethyl cyclotetrasiloxane

Steinfink, H.; Post, B.; Fankuchen, I.

doi:10.1107/s0365110x55001333

Cited by 113 publications

(48 citation statements)

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“…The local geometry of O-SiðCH 3 Þ 2 -O in linear and cyclic dimethylsiloxane oligomers is usually close to tetrahedral [56] ða % 109:58Þ; so our result for a supports the hypothesis of a well-defined rotation or a three-site jump of the OSiðCH 3 Þ 3 -units in Q8M8.…”

Section: Spinning-sideband Analysis Using Reredorsupporting

confidence: 84%

REDOR-Based Heteronuclear Dipolar Correlation Experiments in Multi-Spin Systems: Rotor-Encoding, Directing, and Multiple Distance and Angle Determination

Saalwächter

Schnell

2002

Solid State Nuclear Magnetic Resonance

126

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Section: Spinning-sideband Analysis Using Reredorsupporting

confidence: 84%

REDOR-Based Heteronuclear Dipolar Correlation Experiments in Multi-Spin Systems: Rotor-Encoding, Directing, and Multiple Distance and Angle Determination

Saalwächter

Schnell

2002

Solid State Nuclear Magnetic Resonance

126

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“…The differences in non-equivalent Si-O distances, Si-C distances and Si-O-Si bond angle would probably not be significant, the mean values being 1.63A, agree well with those reported by other investigators. [1][2][3][4][5][6] The mean Si-C distance agrees with those found for II and spirosiloxane.…”

Section: Structure Determinationsupporting

confidence: 77%

The Crystal and Molecular Structure of the Dehydrated Tetramer of 1,2-Dimethyldisilanetetraol, (CH3)8Si8O8

Higuchi¹,

Shimada²

1966

Bulletin of the Chemical Society of Japan

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The crystal and molecular structure of (CH3)8Si8O8 has been determined by means of the Patterson projections and refined by the two-dimensional Fourier technique and the least-squares method. The space group is P4/nnc, with four molecules per unit cell. The unit cell constants are a=11.73±0.02 Å, and c=17.17±0.02 Å. The skeleton of a molecule consists of two “crown-shaped” (–Si–O–)4 rings which are crystallographically independent of each other and are connected by four Si–Si bonds along the c axis. The four six-membered (–Si–Si–O–)2 rings thus formed have boat forms. Hence, a molecule forms a cage-like conformation with an approximate symmetry of 4/mmm. Each molecule in the unit cell is surrounded by four adjacent molecules related with centers of symmetry; these molecules form, in a sense, a layer perpendicular to the c axis.

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“…l, which also shows the atom numbering. The Si-O and Si-C lengths are in good agreement with values found in other cyclotetrasiloxanes (Steinfink, Post & Fankuchen, 1955;Shklover, Kalinin, Gusev, Bokii, Struchkov, Andrianov & Petrova, 1973;Carlstr6m & Falkenberg, 1973;S6derholm & Carlstr6m, 1977;S6derholm, 1978). In addition the angles around Si are close to expected tetrahedral values but with the C-Si-C angles consistently a few degrees larger.…”

Section: Introductionsupporting

confidence: 75%

Octaphenylcyclotetrasiloxane: the monoclinic form

Hossain¹,

Hursthouse²,

Malik³

1979

Acta Crystallogr Sect B

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Introduction.Previous work has shown that octaphenylcyclotetrasiloxane is polymorphic, occurring in monoclinic and triclinic forms and also as a benzene solvate (Hyde, Frevel, Nutting, Petrie & Purcell, 1947). As part of an investigation of the structure and conformation of cyclosiloxanes and related species, we have begun a crystallographic study of this system. Here we report the analysis of the monoclinic form.The compound was prepared by the condensation of phenylsilanediol in alkaline medium and recrystallized from benzene-95% ethanol to obtain colourless needles. The cell parameters were initially determined from photographs and subsequently refined on a Nonius CAD-4 diffractometer from the setting angles for 25 reflections. The intensities of 7191 reflections (3 < 0 < 60 °) were recorded on the diffractometer with Ni-filtered Cu K~ radiation, an 09--20 scan technique and a crystal 0.40 x 0.15 x 0.12 mm. Two reference reflections, measured periodically, showed only minor fluctuations. The intensities were corrected for Lp factors but not for absorption. 4009 unique reflections with F o > 3a(Fo) were considered observed and used in the analysis.The structure was determined by direct methods and refined by a full-matrix least-squares procedure to a

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The crystal structure of octamethyl cyclotetrasiloxane

Cited by 113 publications

References 1 publication

REDOR-Based Heteronuclear Dipolar Correlation Experiments in Multi-Spin Systems: Rotor-Encoding, Directing, and Multiple Distance and Angle Determination

REDOR-Based Heteronuclear Dipolar Correlation Experiments in Multi-Spin Systems: Rotor-Encoding, Directing, and Multiple Distance and Angle Determination

The Crystal and Molecular Structure of the Dehydrated Tetramer of 1,2-Dimethyldisilanetetraol, (CH3)8Si8O8

Octaphenylcyclotetrasiloxane: the monoclinic form

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