146462-25-1Relevant articles and documents
Synthesis, Resolution, and Absolute Configuration of Chiral Tris(2-pyridylmethyl)amine-Based Hemicryptophane Molecular Cages
Zhang, Dawei,Bousquet, Benjamin,Mulatier, Jean-Christophe,Pitrat, Delphine,Jean, Marion,Vanthuyne, Nicolas,Guy, Laure,Dutasta, Jean-Pierre,Martinez, Alexandre
, p. 6082 - 6088 (2017)
The synthesis, characterization, and chiroptical properties of a new class of hemicryptophane cages combining a cyclotriveratrylene unit and a tris(2-pyridylmethyl)amine (TPA) moiety are reported. Changing the linkers between these two units allows for the modification of the size and shape of the cavity. The synthesis is straightforward and efficient, providing gram-scale of cage compounds. The racemic mixture of each hemicryptophane host can be readily resolved by chiral HPLC, giving an easy access to the enantiopure molecular cages of which absolute configurations have been assigned by ECD spectroscopy. These new hemicryptophanes are available chemical platforms ready to use for various purposes due to the versatile metal complexation properties of the TPA unit. A Zn(II)@hemicryptophane complex has been obtained and used as a heteroditopic host for the selective recognition of zwitterionic guests.
H2depda: An acyclic adjuvant potentiates meropenem activity in vitro against metallo-β-lactamase-producing enterobacterales
Shi, Xiu-Fang,Wang, Ming-Ming,Huang, Shu-chao,Han, Jiang-Xue,Chu, Wen-Chao,Xiao, Chunling,Zhang, En,Qin, Shangshang
, p. 367 - 376 (2019)
Metallo-β-lactamase (MBL)-producing carbapenem-resistant Enterobacterales (CRE) pose an emerging threat to public health worldwide. An effective inhibitor of MBLs is therefore urgently needed for clinical use. In this study, two acyclic pyridine-containin
Gallium Fluoride Complexes with Acyclic Bispicolinic Ligands as Potential New Fluorine-18 Labelled Imaging Agents
Donnelly, Paul S.,Haskali, Mohammad B.,Koay, HuiJing,Roselt, Peter D.,White, Jonathan M.
, p. 3378 - 3386 (2020)
The positron-emitting radionuclide, fluorine-18, is used to radiolabel molecules to develop tracers for diagnostic imaging with positron-emission tomography. There is growing interest in the potential of using strong coordinate bonds between electropositive Ga(III) and electronegative fluoride (≈ 557 kJ/mol) to provide new methods of incorporating fluorine-18 into molecules. The potential of gallium(III) complexes with acyclic pentadentate bispicolinic acid containing ligands (H2L1–3) to form ternary complexes with fluoride, [GaL1–3F] was investigated with a view to developing new methods for fluorine-18 radiolabelling. A solid-phase peptide synthesis approach was used to produce a bispicolinic acid chelator with a lysine residue. Characterisation of [GaL1X] (X = OH, Cl, F) by X-ray crystallography revealed that L1 acted as dianionic N2O2 donor to the Ga(III) with the fifth site occupied by a monodentate anion (OH–, Cl– or F–). Despite its high stability in aqueous mixture and [D6]DMSO and the straightforward synthesis of [GaL1F], it was only possible to form the radioactive analogue [18F][GaL1F] in low radiochemical yields.
Metal ion based chiral fluorescence sensor selective for dihydrogenphosphate
Goswami, Shyamaprosad,Sen, Debabrata,Das, Nirmal Kumar
, p. 6707 - 6710 (2010)
A Cu(II) based conformationally restricted chiral fluorescence sensor (receptor 2) has been designed and synthesized for selective sensing of anions. The anion recognition property of the Cu2+-complex has been studied in acetonitrile by fluorescence methods which show remarkable sensitivity toward dihydrogen phosphate via fluorescence modulation of the Cu2+-complex over the other anions examined.
Observation of Slow Relaxation and Single-Molecule Toroidal Behavior in a Family of Butterfly-Shaped Ln4Complexes
Biswas, Sourav,Das, Sourav,Gupta, Tulika,Singh, Saurabh Kumar,Pissas, Michael,Rajaraman, Gopalan,Chandrasekhar, Vadapalli
, p. 18532 - 18550 (2016)
A family of five isostructural butterfly complexes with a tetranuclear [Ln4] core of the general formula [Ln4(LH)2(μ2-η1η1Piv)(η2-Piv)(μ3-OH)2]?x H2O?y MeOH?z CHCl3(1: Ln=DyIII, x=2, y=2, z=0; 2: Ln=TbIII, x=0, y=0, z=6; 3: Ln=ErIII, x=2, y=2, z=0; 4: Ln=HoIII, x=2, y=2, z=0; 5: Ln=YbIII, x=2, y=2, z=0; LH4=6-{[bis(2-hydroxyethyl)amino]methyl}-N′-(2-hydroxy-3-methoxybenzylidene)picolinohydrazide; PivH=pivalic acid) was isolated and characterized both structurally and magnetically. Complexes 1–5 were probed by direct and alternating current (dc and ac) magnetic susceptibility measurements and, except for 1, they did not display single-molecule magnetism (SMM) behavior. The ac magnetic susceptibility measurements show frequency-dependent out-of-phase signals with one relaxation process for complex 1 and the estimated effective energy barrier for the relaxation process was found to be 49 K. We have carried out extensive ab initio (CASSCF+RASSI-SO+SINGLE_ANISO+POLY_ANISO) calculations on all the five complexes to gain deeper insights into the nature of magnetic anisotropy and the presence and absence of slow relaxation in these complexes. Our calculations yield three different exchange coupling for these Ln4complexes and all the extracted J values are found to be weakly ferro/antiferromagentic in nature (J1=+2.35, J2=?0.58, and J3=?0.29 cm?1for 1; J1=+0.45, J2=?0.68, and J3=?0.29 cm?1for 2; J1=+0.03, J2=?0.98, and J3=?0.19 cm?1for 3; J1=+4.15, J2=?0.23, and J3=?0.54 cm?1for 4 and J1=+0.15, J2=?0.28, and J3=?1.18 cm?1for 5). Our calculations reveal the presence of very large mixed toroidal moment in complex 1 and this is essentially due to the specific exchange topology present in this cluster. Our calculations also suggest presence of single-molecule toroics (SMTs) in complex 2. For complexes 3–5 on the other hand, the transverse anisotropy was computed to be large, leading to the absence of slow relaxation of magnetization. As the magnetic field produced by SMTs decays faster than the normal spin moments, the concept of SMTs can be exploited to build qubits in which less interference and dense packing are possible. Our systematic study on these series of Ln4complexes suggest how the ligand design can help to bring forth such SMT characteristics in lanthanide complexes.
Electron transfer pathways in photoexcited lanthanide(iii) complexes of picolinate ligands
Kovacs, Daniel,Kocsi, Daniel,Wells, Jordann A. L.,Kiraev, Salauat R.,Borbas, K. Eszter
, p. 4244 - 4254 (2021/04/06)
A series of luminescent lanthanide(iii) complexes consisting of 1,4,7-triazacyclononane frameworks and three secondary amide-linked carbostyril antennae were synthesised. The metal binding sites were augmented with two pyridylcarboxylate donors yielding octadentate ligands. The antennae carried methyl, methoxymethyl or trifluoromethyl substituents in their 4-positions, allowing for a range of excited state energies and antenna electronic properties. The1H NMR spectra of the Eu(iii) complexes were found to be analogous to each other. Similar results were obtained in the solid-state by single-crystal X-ray crystallography, which showed the structures to have nine-coordinate metal ions with heavily distorted tricapped trigonal prismatic geometries. Steady-state and time-resolved luminescence spectroscopy showed that the antennae could sensitize both Tb(iii) and Eu(iii), however, quantum yields were lower than in other octadentate complexes lacking pyridylcarboxylate. Complexes with more electron-poor pyridines were less emissive even when equipped with the same antenna. The oxidation and reduction potentials of the antennae and the pyridinecarboxylates, respectively, were determined by cyclic voltammetry. The obtained values were consistent with electron transfer from the excited antenna to the pyridine providing a previously unexplored quenching pathway that could efficiently compete with energy transfer to the lanthanide. These results show the crucial impact that photophysically innocent ligand binding sites can have on lanthanide luminescence.
Reductive N-methylation of alkanolamines with paraformaldehyde in the presence of cobalt catalysts
Dindar, Sara,Janczak, Jan,Nemati Kharat, Ali,Zamanian, Sara
, (2021/11/11)
Herein a simple method for N-methylation of ethanolamines with paraformaldehyde as a dual methylation and reducing agent has been investigated. Two new cobalt complexes, Co[Methyl 6-(morpoline methyl) picolinate]2Cl2 and Co(2,6 bis morpholine methyl pyridine)Cl2 were prepared and applied as homogeneous catalyst in reductive methylation reaction. All experiments have progressed with excellent conversion and selectivity toward N,N dimethyl ethanolamine. On the other hand, Pyrolysis of prepared cobalt complexes on activated carbon at 550 °C leads to the formation of cobalt oxide nano-particles. These heterogeneous catalysts were shown similar activities in this reaction. Single-crystal X-ray crystallography, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used for characterization of prepared catalysts.
