Molecules 1999, 4(1), 28-51; doi:10.3390/40100028
Article

Polarization by the effect of a small torsional change in the benzothiazole (A)-benzobisthiazole (B) oligomer A-B13-A

1 Department of Chemistry and Biochemistry, South Dakota State University, Box 2202, Brookings, South Dakota 57007, USA 2 Departament de Química Física, Facultat de Química, Universitat de València, Dr. Moliner 50, E-46100-Burjassot (València), Spain
* Author to whom correspondence should be addressed.
Received: 30 September 1998; Accepted: 5 January 1999 / Published: 12 February 1999
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Abstract: We use a method for the calculation of the molecular dipole ( μ ) and quadrupole (θ ) moments and dipole-dipole (α ), dipole-quadrupole ( A) and quadrupole-quadrupole (C ) polarizabilities which we have successfully applied to the benzothiazole (A)-benzobisthiazole (B) linear oligomer A-B13-A. Two model rotational isomers have been characterized: (1) the fully-planar (000) conformation; and (2) a rotational isomer with each unit rotated in the range 1 - 10° in the same direction (+++). For isomer 000, μ is smaller than for +++. The calculation of α, A and C has been carried out by the interacting induced dipoles polarization model that calculates tensor effective anisotropic point polarizabilities (method of Applequist et al.). The values of A are specially sensitive to μ which varies under rotation. This fact explains the great values of Ax,xx for the +++ polar isomer. It is found that small torsional changes can enhance solubility by a clear increasing of the hydrophilic accessible surface area. However, the torsion of the oligomer varies the value of μ and so modifies α, C , and, specially, A. For conformer +++, polarization effects occur even when each unit is rotated only f = 1°. The observed effect is an increase in μ and, hence, in α , C , and, specially, A.
Keywords: multipole moments; polarization; polarizability; geometric descriptors; fractal dimension

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MDPI and ACS Style

Torrens, F.; Sánchez-Marín, J.; Nebot-Gil, I. Polarization by the effect of a small torsional change in the benzothiazole (A)-benzobisthiazole (B) oligomer A-B13-A. Molecules 1999, 4, 28-51.

AMA Style

Torrens F, Sánchez-Marín J, Nebot-Gil I. Polarization by the effect of a small torsional change in the benzothiazole (A)-benzobisthiazole (B) oligomer A-B13-A. Molecules. 1999; 4(1):28-51.

Chicago/Turabian Style

Torrens, Francisco; Sánchez-Marín, José; Nebot-Gil, Ignacio. 1999. "Polarization by the effect of a small torsional change in the benzothiazole (A)-benzobisthiazole (B) oligomer A-B13-A." Molecules 4, no. 1: 28-51.

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