Synthesis, molecular and electron transport properties of 2-alkyltrinitrofluoren-9-ones

Abstract

2-Alkyltrinitrofluoren-9-ones 2 were conveniently synthesized by controlled nitration of 2-alkylfluoren-9-ones 5 with a mixture of red fuming HNO3 and concentrated H2SO4 at 0–25 °C. The precursors 5 were derived from the corresponding 2-acylfluorenes by appropriate reduction of the acyl function, followed by base-catalysed O2-oxidation at the C-9 position. The regiochemistry of nitration was interesting: with a sterically bulky substituent in 5, nitration occurred at C-4, -5, and -7 positions, affording 2-alkyl-4,5,7-trinitrofluoren-9-one in over 35% yield; on the other hand, 5 with a primary alkyl function underwent nitration predominantly at C-3, -5, and -7 positions. By virtue of its alkyl function, 2-alkyltrinitrofluoren-9-one 2 displayed better solubility and polymer compatibility characteristics than its non-alkylated analog, TNF. However, the charge transfer interactions of 2 with electron donors were weaker than those of TNF, despite the fact that they both have the same electron affinity. Both 2 and TNF exhibited good electron transport properties in poly(N-vinylcarbazole) matrices.

Syntheses, Structures, and Photoisomerization of (E)- and (Z)-2-tert-Butyl-9-(2,2,2-triphenylethylidene)fluorene

“…2 As shown in Scheme 1, 2-tertbutylfluorene (3) was converted by air oxidation to 2-tertbutylfluorenone (4). 11 As reported for fluorenone, 12 Wittig reaction of 4 with bromomethylenetriphenylphosphorane gave the bromomethylene derivative 5, in this case as a ca. 1:1 mixture of E and Z stereoisomers.…”

Synthesis and characterization of polystyrene-block-polyisoprene functionalized with aromatic 1,3,4-oxadiazoles by metal catalyzed reaction

“…At 298 K, the electron mobilities of the polymers are of the order of 10 -4 cm 2 N V -1 N s -1 , which is both temperature and electric field dependent. These electron mobilities are comparable to some oxadiazole-doped polymers 17) and higher than trinitrofluorenone derivatives 18,19) . The majority of the charge carriers are electrons, as the hole carrier mobilities are two to three orders of magnitude smaller than that of the electron carriers.…”

Synthesis and Photoisomerization of Substituted Dibenzofulvene Molecular Rotors

“…The starting material for the synthesis shown in Scheme , 2‐iodofluorene 12 , was prepared in 77 % yield by iodination of fluorene in acetic acid . The corresponding fluorenone 13 was then obtained from 12 by air oxidation . A Wittig reaction of 13 gave bromomethylene derivative 14 as a mixture of E and Z isomers and a reaction of this mixture with trityllithium gave target compound ITEF.…”

“…Compound a 1 a 2 a 3 E-TTEF( mol 1) [c] 133.2(5)133.7(5) 121.8(5) E-TTEF( mol 2) [c] 133.6(5)134.8(5) 120.8(5) Z-TTEF( mol 1) [c] 134.1(4)133.7(4) 121.7(4) Z-TTEF( mol 2) [c] 130.8(3)132.6(3) 122.5(3) Z-NTEF 122.5(2)129.7(2) 124.3(2) E-ITEF 131.4(1)132.8(1) 122.1(1) Z-ITEF 134.8 (7)134.3 (7) 121.5(7) Z-10 131.7(1) 133.3(1) 121.8(1) Z-11 (mol 1) 134.6(1) 134.9(1) 120.5(1) Z-11 (mol 2) 134.2(1) 133.7(1) 121.1(1) TEF (mol 1) [d] 134.7(3) 134.5(3) 120.8(3) TEF (mol 2) [d] 133.5(3) 134.3(3) 121.1 (3) was then obtained from 12 by air oxidation. [19] AW ittig reaction of 13 gave bromomethylene derivative 14 as am ixture of E and Z isomersand areaction of this mixture with trityllithium gave target compound ITEF.P ure samples of E-ITEF and Z-ITEF were then obtained by crystallization of the resulting mixture of stereoisomers and unambiguously identified by X-ray crystallography (see Figure3 and Ta ble 1). The E/Z mixture was converted into CTEF by aR osenmund-von Braun reaction [20] with copper cyanidei nD MF [21] and both E-CTEF and Z-CTEF were isolated for photoisomerization studies.…”