Crystals of phospholipid analogues as plausible material for molecular electronics. I: Synthesis and investigation of the structure and physical properties of two halogen hydride derivatives of isobutyl-2-aminoethyl phosphate—phosphatidylethanolamine analogues
✍ Scribed by V. A. Karasev; N. A. Korovnikova; Y. P. Miroshkin; V. V. Luchinin; V. S. Fundamenski; I. I. Bannova; V. E. Stefanov
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 963 KB
- Volume
- 6
- Category
- Article
- ISSN
- 1616-301X
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✦ Synopsis
Synthesis and investigation of the structure and electrophysical properties of two halogen hydride derivatives of isobutyl analogues of phosphatidylethanol amine (IPE), namely IPE-HCI and IPE-HBr, were performed to offer a new material for 'molecular wires' according to the model of molecular electronics developed earlier by Karasev eta/. (Adv. Mater. Opt. Electron., 1994, 4, pp. 203-218). X-ray analysis showed that isostructural crystals of the synthesised compounds are monoclinic with the space symmetry group /2/a (C2/c). They have very similar lattice cell parameters, namely a= 21.892(8), b= 4.7747(2), c = 44.63(2) A, p = 91.83(3)", Z=16 for IPE-HCI and a=22.115(14), b=4.808(3), c=44.83(2) A, /3=91,74(5)O, Z=16 for IPE-HBr. It was found that the structure of IPE-HCI contains two symmetrically unrelated molecules of IPE. They form two bilayers within the elementary cell each of which includes three zones of hydrogen bonds. The central zone is formed by NH, groups belonging to IPE and by chloride ions. The other two zones are quasi-one-dimensional systems of HO-P=O groups generated by translationally related IPE molecules and can be considered as prospective 'molecular wires'. These two zones are located symmetrically with respect to the central zone. Electrophysical parameters (contuctance y and complex dielectric permittivity components E' and E") were determined for polycrystalline samples of IPE-HCI and IPE-HBr in the temperature range from -20 to 70°C. The permittivity E' was found to assume abnormally high values (about lo6) at low frequency and to decrease monotonically with increasing temperature in the frequency range from 50 Hz to 10 MHz. Possible mechanisms of polarisation of the synthesised IPE derivatives are analysed. The conductance of the crystals was shown to have an activation character with the activation energy equal to 0.7-1.3 eV for