A convenient and efficient protocol for the synthesis of 6-alkyl phenanthridines and 1-alkyl isoquinolines has been developed. The reaction relies on the coupling of 2-isocyanobiphenyls and vinyl isonitriles with alkyl radicals formed by the silver-catalyzed decarboxylation of stoichiometric aliphatic carboxylic acids, and affords diverse phenanthridine and isoquinoline derivatives under mild reaction conditions. The experiment of β-scission of cyclobutylcarbinyl radicals is used to shed light on the reaction mechanism.

A series of cationic lanthanide-based metal–organic frameworks (MOFs), {[Ln3(bcbp)3(NO3)7]·NO3·ClO4} n (Ln = Tb (1), Gd (2), Eu (3); H2bcbpCl2 = 1,1′-bis­(4-carboxyphenyl)­(4,4′-bipyridinium) dichloride), have been synthesized under solvothermal conditions and structurally characterized. Single-crystal X-ray diffraction analyses reveal that compounds 1–3 are isostructural, in which Ln3-SBUs (SBUs = secondary building units) are connected with six adjacent Ln3-SBUs by six protonated bcbp ligands, leading to cationic lanthanide-based metal–organic frameworks. In addition, the counteranions (nitrate anions and perchlorate anions) reside in the frameworks via weak C–H···O hydrogen bonds. Furthermore, Eu-MOF displays strong red luminescence, which is further proven to be a highly selective and sensitive luminescent sensor toward Cr2O7 2– with a high quenching coefficient and low detection limit. Interestingly, Eu-MOF is also sensitive to ammonia and exhibits a rapid color change from yellow to blue-gray that can be distinguished by the naked eye when it is exposed to ammonia vapor. The UV–vis, IR, Raman, and EPR data reveal that the color change can be ascribed to an electron-transfer process and the radical generation caused by the nucleophilic attack of ammonia molecules.

We report structural and physical properties of the single crystalline . The X-ray diffraction (XRD) results show that adopts the trigonal -type structure. Temperature-dependent electrical resistivity measurements indicate an insulating ground state for with activation energies of 40 meV and 0.64 meV for two distinct regions, respectively. Magnetization measurements show no apparent magnetic phase transition under 400 K. Different from other , Sr, and Ba, and , As, and Sb) compounds with the same structure, heat capacity and reveal that has a first-order transition at and the transition temperature shifts to high temperature upon increasing pressure. The emergence of plenty of new Raman modes below the transition, clearly suggests a change in symmetry accompanying the transition. The combination of the structural, transport, thermal and magnetic measurements points to an unusual origin of the transition.