Extended hydrocarbon chain

The c axis corresponds to both the short axis of the crystal and the axis along the molecular chain. The observed repeat distance in the c direction is what would be expected between successive substituents on a fully extended hydrocarbon chain with normal bond lengths and angles (see Sec. 1.2). 

The phase transitions in bilayers can be recognized in many ways. Differential scanning colorimetry has already been mentioned. Another approach is to measure the spacing between molecules by X-ray diffraction. The cross-sectional area occupied by a phospholipid in a bilayer is always greater than the 0.40 nm2 expected for closest packing of a pair of extended hydrocarbon chains.39 85... 

As far as the biocide properties are concerned, 0-Mannich bases containing extended hydrocarbon chains and used for their combined detcrgent/gcrmicidc action are worth mentioning. A good preserving function is also performed by plywood adhesives, based on urea, melamine, and formaldehyde, which are fixed by suitable iodo-derivatives presumably by amino- and amidomethylation reactions. 

The low-temperature gel phase corresponds closely to that of the crystalline dihydrate and is thus denoted the Lc/ phase. The detailed stmcture of this phase and the other phases discussed below is treated in detail elsewhere (see article Lipids, Phase Transitions of). The Lg/ phase is characterized by extended hydrocarbon chains that are tilted slightly with respect to the bilayer normal. These chains are packed very tightly, and rotation about their long axes is very severely restricted. The polar headgroup contains only a few bound water molecules, and its motion is also severely restricted. 

Additional increases in temperature result in a marked increase in the long-axis rotational rates of the hydrocarbon chains, and at the pretransition temperature, the Lp/ phase converts to the so-called ripple or Pp/ phase. In the Pp/ phase, the extended hydrocarbon chains seem to remain tilted with respect to the normal to the local bilayer plane but behave as if they... 

The value obtained for the maximally extended hydrocarbon length of 17.5 A is more difficult to compare with experimental values. In section 5 we found that 80-100 % of the fully extended hydrocarbon chain appears to be a reasonable estimate of 4 of saturated chains (see also Tanford Since egg PC is mainly... 

Distance between alternate C atoms in fully extended hydrocarbon chain... 

The starting point for an analysis of the structure of linear polymers is the C-C backbone of an extended hydrocarbon chain, the simplest member of which is polyethylene. The... 

The formation of the liquid-expanded phase at compression of a monolayer means that condensation from a gaseous phase to a coherent film in the liquid state takes place. Further compression can give phases with extended hydrocarbon chains tilted in relation to the surface. Such phases are called liquid-condensed (L2) phases and a consequence of this misleading term is that the formation from a liquid-expanded phase is described as a condensation. 

The most commonly held view of a surfactant micelle is not much different than that published by Hartley in 1936 [41, 42] (see Figure 1). At surfactant concentrations slightly above the cmc value, surfactants tend to associate into spherical micelles, of about 50-100 monomers, with a radius similar to that of the length of an extended hydrocarbon chain. The micellar interior, being composed essentially of hydrocarbon chains, has properties closely related to the liquid hydrocarbon. 

Methylene also engages in external vibrations where the group, as an effectively rigid unit, oscillates with respect to other atoms to which it is connected. One such mode, called a rock , is shown below, and where more than four adjacent CH2 groups form an extended hydrocarbon chain, a characteristic band appears in the IR spectrum near to 725 cm k The band is essentially due to a mode where all the CH2 groups are rocking in phase, see [2]. 

SAMs on Copper. Like its congeners, copper also adsorbs alkanethiols that form oriented SAMs attached to the surface as thiolates (75). These samples are especially difficult to obtain in high quality, and the samples that we have examined always contained copper(I) oxide. We find this system to be extremely sensitive to the details of preparation, particularly the extent of exposure of the metal film to dioxygen (formation of a thick copper oxide) or to solution (formation of copper sulfi ). Optimization of the procedure produced high-quality samples with PIERS spectra indistinguishable from those obtained on SAMs on silver (75). The structure of the SAMs on copper is, therefore, probably the same as that on silver The axis of the trans-extend hydrocarbon chain is oriented close to the surface normal. Since the SAMs we characterized formed on an oxidized suiface, we are hesitant to make claims... 

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