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Maria Helena Garcia Pedro Florindo Maria de Fátima M. Piedade Stefano Maiorana Emanuela Licandro 《Polyhedron》2009
A series of organometallic complexes possessing new tetrathia-[7]-helicene nitrile derivative ligands [TH-7] as chromophores, of general formula [MCp(P–P)(NC{TH-[7]-Y}Z)][PF6] (M = Ru, Fe, P–P = DPPE, Y = H, NO2, Z = H, C≡N; M = Ru, L–L = 2PPh3, Y = H, Z = H) has been synthesized and fully characterized. 1H NMR, FT-IR and UV–Vis. spectroscopic data were analyzed with in order to evaluate the existence of electronic delocalization from the metal centre to the coordinated ligand to have some insight on the potentialities of these new compounds as non-linear optical molecular materials. Slow crystallization of compound [RuCp(PPh3)2(NC{TH-[7]-H}H)][PF6] 2Ru revealed an interesting isomerization of the helical ligand with formation of two carbon-carbon bonds between the two terminal thiophenes, leading to the total closure of the helix (2*Ru). 相似文献
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Yusuke Matsuo Dr. Chihiro Maeda Dr. Yusuke Tsutsui Dr. Takayuki Tanaka Prof. Dr. Shu Seki 《Angewandte Chemie (International ed. in English)》2023,62(50):e202314968
Oxidative fusion reaction of cyclic heteroaromatic pentads consisting of pyrrole and thiophene gave closed-heterohelicene monomers and dimers depending on the oxidation conditions. Specifically, oxidation with [bis(trifluoroacetoxy)iodo]benzene (PIFA) gave closed-[7]helicene dimers connected at the β-position of one of the pyrrole units with remarkably elongated C−C bonds of about 1.60 Å. Although this bond was intact against thermal and physical activations, homolytic bond dissociation took place in DMSO upon irradiation with UV light to give the corresponding monomers. Thus, interconversion between the closed-helicene monomer and dimer was achieved. The optically pure dimer was photo-dissociated into the monomers associated with a turn-on of circularly polarized luminescence (CPL). 相似文献
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