Oshita, Hiromi; Suzuki, Takashi; Kawashima, Kyohei; Abe, Hitoshi; Tani, Fumito; Mori, Seiji; Yajima, Tatsuo; Shimazaki, Yuichi published the article 《π-π Stacking interaction in an oxidized CuII-Salen complex with a side-chain indole ring: An approach to the function of the tryptophan in the active site of galactose oxidase》. Keywords: galactose oxidase active site mimic copper salen complex tryptophan; copper; heterocycles; oxidation; pi interactions; radicals.They researched the compound: (S)-Propane-1,2-diamine dihydrochloride( cas:19777-66-3 ).Formula: C3H12Cl2N2. Aromatic heterocyclic compounds can be divided into two categories: single heterocyclic and fused heterocyclic. In addition, there is a lot of other information about this compound (cas:19777-66-3) here.
In order to gain new insights into the effect of the π-π stacking interaction of the indole ring with the CuII-phenoxyl radical as seen in the active form of galactose oxidase, we have prepared a CuII complex of a methoxy-substituted salen-type ligand, containing a pendent indole ring on the dinitrogen chelate backbone, and characterized its one-electron-oxidized forms. The X-ray crystal structures of the oxidized CuII complex exhibited the π-π stacking interaction of the indole ring mainly with one of the two phenolate moieties. The phenolate moiety in close contact with the indole moiety showed the characteristic phenoxyl radical structural features, indicating that the indole ring favors the π-π stacking interaction with the phenoxyl radical. The UV/Vis/NIR spectra of the oxidized CuII complex with the pendent indole ring was significantly different from those of the complex without the side-chain indole ring, and the absorption and CD spectra exhibited a solvent dependence, which is in line with the phenoxyl radical-indole stacking interaction in solution The other physicochem. results and theor. calculations strongly support that the indole ring, as an electron donor, stabilizes the phenoxyl radical by the π-π stacking interaction.
There are many compounds similar to this compound(19777-66-3)Formula: C3H12Cl2N2. if you want to know more, you can check out my other articles. I hope it will help you，maybe you’ll find some useful information.
Reference:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider