Langmuir-Blodgett films of donor-urethane-TCNQ and related molecules

Abstract

New molecules of the type D-have been shown to form Pockels-Langmuir monolayers at the air-water interface and Langmuir-Blodgett films over glass or A1 substrates (D, one-electron donor; , covalent bridge (urethane); A, strong one-electron acceptor BHTCNQ or weak two-electron acceptor HMTCAQ). Assemblies 1| --| 2 (Mb M2, conventional metallic thin films; D, strong one-electron donor; A, strong one-electron acceptor) had been predicted in 1973 to be one-molecule-thick rectifiers of electrical current. When A is BHTCNQ, monolayers are formed if D is either pyrene (strong donor) (area per molecule at film collapse, Ac = 53 Á2/molecule; differential surface tension at collapse, IIC = 28.2 mN/m), (dodecyloxy)phenyl (weak donor) (Ac = 50 Á2, Ilc = 20.2 mN/m), or (bis(dodecyl)amino)phenyl (medium donor) (Ac = 54 A2, IIC = 45.9 mN/m). When A is HMTCAQ, monolayers are formed if D is (bis(dodecyl)amino)phenyl (Ac = 58 Á2, IIC = 22.3 mN/m). Thus, greasy tails are found to be generally helpful in orienting D-molecules in monolayers (even though they may slow down electron conduction through the molecules).

The first two decades of a versatile electron acceptor building block: 11,11,12,12-tetracyano-9,10-anthraquinodimethane (TCAQ)

“…These derivatives were prepared by the treatment of 13 with 1-pyrenyl isocyanate (25) and differently substituted 4-(dialkylamino)phenyl isocyanates 26, respectively (Scheme 4). [31][32][33][34] The presence of long alkyl chains in 28b,c allows them to form Pockels-Langmuir (PL) films at the air-water interface which can be mostly transferred as LB films onto solid substrates. 35 Following this seminal approach by Panetta and Metzger, other TCAQ-based donor-s-acceptor derivatives (30, 22 31, 22 33, 26 34, 26 35, 26 Scheme 5) were reported by Bryce and coworkers containing stronger donor moieties such as the well known tetrathiafulvalene system.…”

Synthesis of Thiadiazine, Imidazothiadiazole, Diazospiroundecatetraene and Spirothiadiazolopyrimidinocyclohexadiene Derivatives from 2,5-Dithiobiureas

“…1 H NMR spectrum of 11b in DMSO- 21 which has been successfully used for the preparation of electrically conducting salts and CT-complexes. 22 The interest of TCNQ has focused on its potential applications on material rectifiers, 23 nonlinear optical materials, 24 organoferromagnets 25 and organic chromophores. 26 Recently, it has been reported that the addition of 1,8diaminonaphthalene to TCNQ (16) afforded 2-(4-(1H,3Hpyrimidin-2-ylidene)cyclohexa-2,5-dienylidene)malononitrile.…”

Indenoxadiazine, Indenopyrazole and Spiro Triazole Derivatives from (substituted ylidene)-N-phenylhydrazine Carbothioamides

“…Such an attempts was made for the synthesis of 7,7',8,8'tetracynoquinodimethane (3). The interest of 3 has focused on its potential applications on molecular rectifiers 26 , nonlinear optical materials 27 and electron accepting properties. 28 Mixture of two-fold molar amounts of 3 with one mole each of the donors 1a-e in dry pyridine.…”