19198-87-9Relevant articles and documents
Evaluation of the metal-dependent cytotoxic behaviour of coordination compounds
Grau, Jordi,Renau, Cristina,Caballero, Ana B.,Caubet, Amparo,Pockaj, Marta,Lorenzo, Julia,Gamez, Patrick
, p. 4902 - 4908 (2018)
The [Cu(L)Cl2]2 and [Pt(L)Cl2] complexes were prepared from the simple Schiff-base ligand (E)-phenyl-N-((pyridin-2-yl)methylene)methanamine (L) and respectively, CuCl2 and cis-[PtCl2(DMSO)2]. DNA-interaction studies revealed that the copper complex most likely acts as a DNA cleaver whereas the platinum complex binds to the double helix. Remarkably, cell-viability experiments with HeLa, MCF7 and PC3 cells showed that [Cu(L)Cl2]2 is an efficient cytotoxic agent whereas [Pt(L)Cl2] is not toxic, illustrating the crucial role played by the nature of the metal ion in the corresponding biological activity.
Molybdenum (VI) Complexes Containing Pyridylimine Ligands: Effect of the Imine Nitrogen Substituent in the Epoxidation Reaction
Martínez-Martínez, Daniel,Santiago, M. León,Toscano, Rubén A.,Amézquita-Valencia, Manuel
, p. 243 - 251 (2021)
A series of pyridylimine ligands with variations of the substituent at the imine nitrogen were synthesized and coordinated to the [MoCl2O2] core. The novel molecular structures of the complexes were fully characterized by 1H and 13C NMR, FT-IR, ESI, EA, and X-ray crystallography, and their catalytic activity was studied for the epoxidation of alkenes using tert-butyl hydroperoxide (TBHP) as the oxidant. The new complexes showed excellent catalytic activity and fine selectivity in the epoxidation reaction compared with similar homogeneous molybdenum complexes. The results demonstrated that there is a significant change in the catalytic performance, depending on the alkyl arm on the structure of the pyridilimine ligand. The catalytic results indicated that complex [MoCl2O2(L)] (L: N-(2-Pyridinylmethylene)-1-tert-butylimine) C5 is the best catalytic precursor in the epoxidation of cyclohexene (TON: 92920 and TOF: 30974 h?1).
Hydrogen-Bond Catalysis of Imine Exchange in Dynamic Covalent Systems
Schaufelberger, Fredrik,Seigel, Karolina,Ramstr?m, Olof
supporting information, p. 15581 - 15588 (2020/10/02)
The reversibility of imine bonds has been exploited to great effect in the field of dynamic covalent chemistry, with applications such as preparation of functional systems, dynamic materials, molecular machines, and covalent organic frameworks. However, acid catalysis is commonly needed for efficient equilibration of imine mixtures. Herein, it is demonstrated that hydrogen bond donors such as thioureas and squaramides can catalyze the equilibration of dynamic imine systems under unprecedentedly mild conditions. Catalysis occurs in a range of solvents and in the presence of many sensitive additives, showing moderate to good rate accelerations for both imine metathesis and transimination with amines, hydrazines, and hydroxylamines. Furthermore, the catalyst proved simple to immobilize, introducing both reusability and extended control of the equilibration process.
Time-Dependent Switching of Constitutional Dynamic Libraries and Networks from Kinetic to Thermodynamic Distributions
He, Meixia,Lehn, Jean-Marie
supporting information, p. 18560 - 18569 (2019/11/21)
The distribution of the constituents of a constitutional dynamic library (CDL) may undergo time-dependent changes as a function of the kinetics of the processes generating the CDL from its components. Thus, the constitutional dynamic network (CDN) representing the connections between the constituents changes from a kinetic distribution to the thermodynamic one as a function of time. We investigated the behavior of dynamic covalent libraries (DCLs) of four constituents generated by reversible formation of C═N bonds between four components, 2 aldehydes and 2 amino compounds, both in absence and in the presence of metal cations. The associated [2 × 2] networks underwent time-dependent changes from the initial kinetic distribution to the final thermodynamic one, involving an orthogonal switch from one diagonal to the other diagonal of the square [2 × 2] network leading to a very large change in distribution. The DCL constituents could be switched from kinetic products (imines) to thermodynamic products (oximes or acylhydrazones) based on the reactivities of the components and the thermodynamic stabilities of the constituents without addition of any external effector, solely on the basis of the intrinsic properties of the self-contained system. Such processes were achieved for purely organic DCLs/CDNs as well as for inorganic ones containing two metal cations, the latter changing from the silver(I) complex of an imine (kinetic product) to the zinc(II) complex of a hydrazone (thermodynamic product). The results bear relationship to out-of-equilibrium systems concerning kinetic behavior in adaptive chemistry.
