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Dipole moments of polyenic oligomeric systems. Part II—molecular organic wire resistivities: polyacetylenes, allenes and polyynes
Author(s) -
Morales Raul G. E.,
GonzálezRojas Claudio
Publication year - 2005
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.931
Subject(s) - molecular wire , chemistry , dipole , molecular orbital , molecular electronics , thermal conduction , moment (physics) , conduction electron , conductance , electron acceptor , charge (physics) , electron , series (stratigraphy) , computational chemistry , molecule , condensed matter physics , thermodynamics , organic chemistry , quantum mechanics , physics , paleontology , biology
Polyacetylenic, allenic and polyynic molecular wire series, containing electron‐donor (D) and electron‐acceptor (A) groups as two terminal units of the oligomeric bridge (D–wire–A), can be well described by means of a one‐dimensional conduction model, which considers a scattering process of electrons through the charge‐transfer conduction bridge. The conduction constants (γ i ) of the oligomeric structures of the three molecular series under study were determined from the functional dependence between the dipole moment of the oligomers (μ n ) and the π‐molecular orbital bridge length ( L ). According to our one‐dimensional molecular organic wire model:$$\mu_n = \mu_{\rm o} + \mu_{\infty} (1 - {\rm e}^{-\gamma L})$$ where μ o is the dipolar moment of the first compound of the oligomeric series without a bridge unit ( n = 0) and μ ∞ is a limit value for L → ∞. By means of the Landauer theoretical expression for the conductance of a metallic one‐dimensional conductor and our molecular wire conduction constants (γ i ), we determined the intrinsic resistivities associated with the molecular resistances of these oligomeric wires. Using this approach we determined, for the first time, the linear and non‐linear contributions to the net molecular resistivity. The order of magnitudes of the linear resistivities determined in these oligomeric systems agrees very well with the expected results of experimental measurements for macroscopic wires. Copyright © 2005 John Wiley & Sons, Ltd.