Synthesis of rigid ethynyl-bridged polytopic picolinate ligands for MOF applications

Robust Lanthanoid Picolinate-Based Coordination Polymers for Luminescence and Sensing Applications

Picolinate-based segmented dianionic ligands L₁^2- (5-((4-carboxyphenyl)ethynyl)picolinate) and L₂^2- (5,5'-(ethyne-1,2-diyl)dipicolinate) have been used in the synthesis of the highly robust and luminescent europium(III) coordination polymers [(CH₃)₂NH₂][Eu(H₂O)₂(L₁)₂] (1) and [(CH₃)₂NH₂][Eu(L₂)₂]·H₂O·CH₃COOH (2). Both 1 and 2 exhibit high selectivity for detection of nitroaromatic compounds since they act as quenchers of the Eu³⁺ emission. Stern-Volmer plots, using nitrobenzene as a quencher, yielded values of K_SV = 150 M^-1 and 160 M^-1 for 1 and 2, respectively. Luminescence studies in the presence of different metal ions indicate a high selectivity for Fe³⁺ detection, with K_SV values of 471 M^-1 and 706 M^-1 for 1 and 2, respectively. Both 1 and 2 possess extremely robust extended structures, leading to emissive properties that are stable in a wide pH range.

Decarboxylative/Sonogashira-type cross-coupling using PdCl2(Cy*Phine)2

Expedient protocol to access a wide range of internal alkynes and symmetrical di(heteroaryl)alkynes via tandem decarboxylative–Sonogashira cross-coupling.