Imine bond transformation of a dynamic Sm(III) macrocycle-based chemosensor: The indirect approach for detecting cyanuric chloride

Herein, we report our strategy to develop the efficient chemosensor and real-time monitoring technique for cyanuric chloride (TCT) detection. A luminescent macrocyclic mononuclear Sm(III) complex Sm-2_k bearing with two dynamic imine bonds has been constructed via the template synthesis between dialdehyde H₂Q_k and matched diamine 1,2-bis(2-aminoethoxy)ethane. Sensing experiments reveal that complex Sm-2_k exhibits the turn-off fluorescent and colorimetric response for TCT in CH₃OH. It is especially encouraging that this optical sensing process is not only rapid within 60 s but also high-efficient in the presence of TCT analogues as well as sensitive with the low limit of detection (LOD, 1.74 μM) and wide linear sensing range. Mechanism studies demonstrate that TCT sensing is mainly based on the imine bond transformation of probe Sm-2_k, which is due to the increased acidity induced by TCT. Meanwhile, a smartphone-based analytical method was developed to make complex Sm-2_k accessible for the real-time TCT detection by RGB value outputs. It is believed that this work can shed some constructive lights on design of chemosensors and convenient detection technique for highly reactive analytes.

NHC-based pincer ligands: carbenes with a bite

In this frontier article we overview the emergence and scope of NHC-based CCC and CNC pincer systems, i.e. complexes containing mer-tridentate ligands bearing two NHC donor groups, comment on their effectiveness in applications, and highlight areas for future development and exploitation.

Highly water-dispersible magnetite nanoparticle supported-palladium–β-cyclodextrin as an efficient catalyst for Suzuki–Miyaura and Sonogashira coupling reactions

A novel highly water-dispersible and recoverable magnetite supported palladium–β-cyclodextrin complex as efficient catalyst in Suzuki–Miyaura and Sonogashira carbon–carbon coupling reactions.

Recent developments in the Suzuki-Miyaura reaction: 2010-2014

The Suzuki-Miyaura reaction (SMR), involving the coupling of an organoboron reagent and an organic halide or pseudo-halide in the presence of a palladium or nickel catalyst and a base, has arguably become one of most utilized tools for the construction of a C-C bond. This review intends to be general account of all types of catalytic systems, new coupling partners and applications, including the literature between September 2010 and December 2014.

Synthesis, structure and dynamics of NHC-based palladium macrocycles

A series of macrocyclic CNC pincer pro-ligands based on bis(imidazolium)lutidine salts with octa-, deca- and dodecamethylene spacers have been prepared and their coordination chemistry investigated. Using a Ag2O based transmetallation strategy, cationic palladium(II) chloride complexes [PdCl{CNC-(CH2)n}][BAr(F)4] (n = 8, 10, 12; Ar(F) = 3,5-C6H3(CF3)2) were prepared and fully characterised in solution, by NMR spectroscopy and ESI-MS, and in the solid-state, by X-ray crystallography. The smaller macrocyclic complexes (n = 8 and 10) exhibit dynamic behaviour in solution, involving ring flipping of the alkyl spacer across the Pd-Cl bond, which was interrogated by variable temperature NMR spectroscopy. In the solid-state, distorted coordination geometries are observed with the spacer skewed to one side of the Pd-Cl bond. In contrast, a static C2 symmetric structure is observed for the dodecamethylene based macrocycle. For comparison, palladium(II) fluoride analogues [PdF{CNC-(CH2)n}][BAr(F)4] (n = 8, 10, 12) were also prepared and their solution and solid-state structures contrasted with those of the chlorides. Notably, these complexes exhibit very low frequency (19)F chemical shifts (ca. -400 ppm) and the presence of C-H···F interactions ((2h)J(FC) coupling observed by (13)C NMR spectroscopy). The dynamic behaviour of the fluoride complexes is largely consistent with the smaller ancillary ligand; [PdF{CNC-(CH2)8}][BAr(F)4] exceptionally shows C(2v) time averaged symmetry in solution at room temperature (CD2Cl2, 500 MHz) as a consequence of dual fluxional processes of the pincer backbone and alkyl spacer.