A comparison of the pentaammine(pyridyl)ruthenium(ii) and 4-(dimethylamino)phenyl groups as electron donors for quadratic non-linear optics

Abstract

Hyper-Rayleigh scattering and Stark spectroscopic studies show that the complex salts [1-4]PF6 have larger static first hyperpolarizabilities beta 0 than [5-8]PF6, because the higher HOMO energy of a (RuII(NH3)5)2+ centre more than offsets the superior pi-orbital overlap in the purely organic chromophores.

Linear Multinuclear RuII Photosensitizers

“…[27] The current-scan rate dependence was evaluated for each sample to check the reversibility, and ferrocene was added at the end of each run as an internal reference (ϩ0.425 V vs. SCE in CH 3 CN). [28] Photochemical data were obtained using the apparatus and data treatment described earlier, [4] [12] , with its identity verified by ESI-MS [m/z (%) ϭ 531 (100)]. Thinlayer chromatography was used to monitor reactions and chromatography and was carried out on MachereyϪNagel Polygram Sil G/UV silica gel plates and Alox N/UV alumina plates.…”

Quadratic Optical Nonlinearities of N‐Methyl and N‐Aryl Pyridinium Salts

“…The HRS b and b 0 values (derived by application of the twostate model) [16] in acetonitrile for all of the salts except for [15]PF 6 and [16]PF 6 have been published previously in separate reports, [7,9,10] but are collected together in Table 1 for purposes of comparison both internally and with the Stark-derived data (see later). Because they show multi-photon fluorescence, [1±16]PF 6 were studied via femtosecond (fs) HRS with a 1300 nm laser, incorporating high-frequency fluorescence demodulation.…”

“…The precursor to [10±12]PF 6 , trans-4-(4-dimethylaminophenyl-4-buta-1,3-dienyl)pyridine, was synthesized via standard Wittig±Horner chemistry. The syntheses of [10±12]PF 6 were originally attempted via Knoevenagel condensations of the appropriate picolinium salts with 4-(dimethylamino)cinnamaldehyde, in analogous fashion to the synthesis of [9]PF 6 . However, only the stilbazolium salts [6±8]PF 6 were isolated from these reactions, due to carbanion attack at the b-vinyl carbon, rather than at the carbonyl group.…”

π-Conjugated derivatives containing phosphole rings: synthesis, properties and coordination chemistry

“…However, dipolar phospholes 3g, h (Scheme 4) exhibit rather low b values (ca. 30 × 10 -30 esu), probably due to the weak accepting properties of the pyridine moieties [21].…”