Aromatic Amines:  A Comparison of Electron-Donor Strengths

Abstract

The electron-donor abilities of ten aminophenyl systems and an additional aminothienyl system are compared using density functional theory calculations. The systems studied here include those with amine nitrogen atoms bearing alkyl or aryl groups and those with amine nitrogen atoms as part of a heterocycle. Their abilities to act as donors in electron-transfer processes are assessed from calculated vertical ionization potentials for the aminobenzenes, which are in good agreement with available experimental data. Their abilities to act as intramolecular pi-electron donors in conjugated systems are inferred from the bond lengths and charge densities calculated for the corresponding 4-aminobenzaldehydes and 4-aminobenzonitriles. The computed (13)C NMR chemical shifts for the 4-aminobenzaldehydes and 4-aminobenzonitriles are in good agreement with published and new experimental data. The chemical shifts correlate well with the computed charge densities and can, to some extent, be used as an experimental probe of pi-donor strength. We find that the electron-transfer-donor strengths do not correlate well with pi-donor strengths: these differences can largely be attributed to steric effects.

Functionalization of phosphorescent emitters and their host materials by main-group elements for phosphorescent organic light-emitting devices

“…Different from triphenylamine moieties, carbazole units show a more rigid molecular structure and poorer p-electron-donating ability than triphenylamie moieties, 66,67 which makes molecules containing carbazole units usually showing higher T g than their corresponding analogues bearing triphenylamine moieties. Similar to triphenylamine moieties, carbazole-based groups also have sp 3 hybridized nitrogen atoms, indicating their HI/HT capacity.…”

Novel polythiophene derivatives functionalized with conjugated side-chain pendants comprising triphenylamine/carbazole moieties for photovoltaic cell applications

“…37 Here, the tTPA pendant polymers (PTtTPA and PBTtTPA) exhibited higher HOMO levels than tCz pendant polymers (PTtCz and PBTtCz), presumably because of the lower oxidation potential and weaker electrondonating ability of carbazole derivatives. 38 Further, PBTtTPA and PBTtCz are expected to have higher HOMO levels than PTtTPA and PTtCz because of the longer conjugation length and p-electron delocalization in BT-based polymers compared to T-based polymers. Because no reversible n-doping process was observed in the CV spectra, the LUMO levels were estimated from the HOMO levels and UV-vis absorption E g using the equation:…”

Auxiliary donor for tetrahydroquinoline-containing nonlinear optical chromophores: enhanced electro-optical activity and thermal stability

“…[11][12][13][14] Among all the materials studied, the NLO chromophores bearing 4-(dialkylamino)phenyl groups or triarylamine groups as a donating group were the most case due to their strong electrondonating ability and ease of synthesis. 18,19 However, there are few reports about additional amino groups, which are introduced into chromophore's donor part, how to infect chromophore's NLO activity and thermal stability. 16,17 Some studies have shown that by introducing additional electron-rich heteroatom group into the donor moiety could effectively enhance nonlinear optical property.…”