Qin, Chuanxiang et al. published their research in Optical Materials (Amsterdam, Netherlands) in 2008 | CAS: 65350-59-6

1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6) belongs to pyridine derivatives. Pyridine has a dipole moment and a weaker resonant stabilization than benzene (resonance energy 117 kJ·mol−1 in pyridine vs. 150 kJ·mol−1 in benzene). Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C–H in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Recommanded Product: 65350-59-6

Optical properties of stilbene-type dyes containing various terminal donor and acceptor groups was written by Qin, Chuanxiang;Zhang, Weizhou;Wang, Zhiming;Zhou, Maoyi;Wang, Xiaomei;Chen, Guoqiang. And the article was included in Optical Materials (Amsterdam, Netherlands) in 2008.Recommanded Product: 65350-59-6 This article mentions the following:

A series of “D-π-A” stilbene-type dyes, named as trans-4-[p-(N,N-hydroxyethyl) aminino-styryl]-N-methylpyridinium iodide (DHEASPI-C1), trans-4-[p-(N,N-hydroxyethyl) aminino-styryl]-N-butylpyridinium bromide (DHEASPBr-C4), trans-4-[p-(N,N-hydroxyethyl) aminino-styryl]-N-octylpyridinium bromide (DHEASPBr-C8) and trans-4-[p-(N,N-hydroxyethyl) aminino-styryl]-N-dodecylpyridinium bromide (DHEASPBr-C12), resp., have been synthesized and their optical properties have been exptl. investigated. When DHEASPI-C1 are compared with trans-4-[p-(N,N-diethylamino) styryl]-N-methylpyridinium iodide (DEASPI) and trans-4-[p-(N-hydroxyethyl-N-ethylamino) styryl]-N-methylpyridinium iodide (HEASPI), both the electronegativity of two hydroxyl and intra-mol. hydrogen bond decrease the donor ability of the Et chain, there are obvious blue shifts both in single-photon absorption spectra, fluorescence spectra and two-photon excited fluorescence spectra. Interestingly, fluorescence intensity of DHEASPI-C1 is the biggest. There are little shifts from DHEASPBr-C4 to DHEASPBr-C8 and to DHEASPBr-C12 in their spectra. As dyes’ two-photon excited fluorescence spectra were concerned, pumped by 1064 nm, <130 fs mode-locked Nd:YAG laser, their peak locations were between 613 and 623 nm. In the experiment, the researchers used many compounds, for example, 1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6Recommanded Product: 65350-59-6).

1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6) belongs to pyridine derivatives. Pyridine has a dipole moment and a weaker resonant stabilization than benzene (resonance energy 117 kJ·mol−1 in pyridine vs. 150 kJ·mol−1 in benzene). Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C–H in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Recommanded Product: 65350-59-6

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem