Modulation of π-electron conjugation in oligo(triacetylene) chromophores by incorporation of a central spacer was written by Martin, Rainer E.;Wytko, Jennifer A.;Diederich, Francois;Boudon, Corinne;Gisselbrecht, Jean-Paul;Gross, Maurice. And the article was included in Helvetica Chimica Acta in 1999.Synthetic Route of C10H12I2 This article mentions the following:
A series of trimeric hybrid oligomers was prepared by insertion of different hetero-spacers between two (E)-hex-3-ene-1,5-diyne (E = 1,2-diethynylethene, DEE) moieties, and the optical and electrochem. properties of the resulting π-conjugated materials were compared to those of the DEE dimer and trimer, which formally contain a DEE moiety as homo-spacer. The hetero-spacers were: benzenoid (phenylene, naphthalene, biphenylene, anthracene), π-electron-deficient (pyrazine, pyridine) and π-electron-rich (thiophene, furan) aromatic rings, and trans-Pt(PEt3)2. The hybrid oligomers were synthesized using the method of K. Sonogashira et al. (1978), i.e., cross-coupling between mono-deprotected DEE and the appropriately bis-functionalized spacer. UV/VIS data revealed that the majority of the hetero-spacers were less effective than the homo-spacer DEE in facilitating π-electron delocalization along the linearly conjugated oligomeric backbone. With increasing degree of benzenoid aromaticity in the hetero-spacer, the electronic communication between the terminal DEE moieties in the hybrid oligomers was reduced. As a remarkable exception, a large bathochromic shift of the longest-wavelength absorption maximum, which is indicative of enhanced π-electron delocalization, was obtained upon introducing an anthracene-9,10-diyl moiety as hetero-spacer. Electrochem. studies by cyclic and steady-state voltammetry confirmed the limited extent of π-electron delocalization in the majority of the hybrid oligomers. The fluorescence properties of many of the DEE hybrid materials were dramatically enhanced upon incorporation of the heterospacers. The heterocyclic derivatives containing pyridine, pyrazine, or thiophene spacers, resp., displayed a strong fluorescence emission, demonstrating the value of combining repeat units to modulate oligomeric and polymeric properties. The pyridine derivative provided an interesting example of a mol. system, in which both the electronic absorption and emission characteristics can be reversibly switched as a function of pH. In the experiment, the researchers used many compounds, for example, 1,4-Diiodo-2,3,5,6-tetramethylbenzene (cas: 3268-21-1Synthetic Route of C10H12I2).
1,4-Diiodo-2,3,5,6-tetramethylbenzene (cas: 3268-21-1) belongs to iodide derivatives. In general, organic iodides are light-sensitive and turn yellow during storage, owing to the formation of iodine. Alkyl iodides react at a faster rate than alkyl fluorides due to the weak C-I bond.Synthetic Route of C10H12I2
Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com