Asymmetric reactions merging organocatalysis and metal catalysis significantly broaden the scope of organic synthesis. Nevertheless, the accomplishment of stereoselective annulations combining two ...types of dipole species, independently generated from the activations of organocatalysts and metal complexes, still remains as a challenging task. Now, Morita–Baylis–Hillman carbonates from isatins and carbamate‐functionalized allyl carbonates could be chemoselectively activated by achiral Lewis basic tertiary amines and chiral iridium complexes. The zwitterionic allylic ylides and 1,4‐π‐allyliridium dipoles formed in situ are assembled in a highly stereoselective 4+3 annulation pattern. Similar cooperative catalytic strategy could be applied for the reactions of Morita–Baylis–Hillman carbonates and vinyl aziridines, furnishing an asymmetric 3+3 annulation reaction also with excellent stereocontrol.
Morita–Baylis–Hillman carbonates from isatins and carbamate‐functionalized allylic carbonates were activated by a Lewis basic tertiary amine and chiral iridium complex. The resulting zwitterionic allylic ylides and π‐allyliridium complex‐contained 1,4‐dipoles underwent regio‐ and stereoselective 4+3 annulations. Similar π‐allyliridium complex‐containing 1,3‐dipoles from vinyl aziridines were utilized in asymmetric 3+3 annulations.
Cancer treatments which include conventional chemotherapy have not proven very successful in curing human malignancies. The failures of these treatment modalities include inherent resistance, ...systemic toxicity and severe side effects. Out of 50% patients administrated to chemotherapy, only 5% survive. For these reasons, the identification of new drug designs and therapeutic strategies that could target cancer cells while leaving normal cells unaffected still continues to be a challenge. Despite advances that have led to the development of new therapies, treatment options are still limited for many types of cancers. This review provides an overview of platinum, copper and ruthenium metal based anticancer drugs in clinical trials and in vitro/in vivo studies. Presumably, copper and ruthenium complexes have greater potential than Pt(II) complexes, showing reduced toxicity, a new mechanism of action, a different spectrum of activity and the possibility of non-cross-resistance. We focus the discussion towards past, present and future aspects.
Synthetic chemistry is built around the formation of carbon-carbon bonds. However, the development of methods for selective carbon-carbon bond cleavage is a largely unmet challenge1-6. Such methods ...will have promising applications in synthesis, coal liquefaction, petroleum cracking, polymer degradation and biomass conversion. For example, aromatic rings are ubiquitous skeletal features in inert chemical feedstocks, but are inert to many reaction conditions owing to their aromaticity and low polarity. Over the past century, only a few methods under harsh conditions have achieved direct arene-ring modifications involving the cleavage of inert aromatic carbon-carbon bonds7,8, and arene-ring-cleavage reactions using stoichiometric transition-metal complexes or enzymes in bacteria are still limited9-11. Here we report a copper-catalysed selective arene-ring-opening reaction strategy. Our aerobic oxidative copper catalyst converts anilines, arylboronic acids, aryl azides, aryl halides, aryl triflates, aryl trimethylsiloxanes, aryl hydroxamic acids and aryl diazonium salts into alkenyl nitriles through selective carbon-carbon bond cleavage of arene rings. This chemistry was applied to the modification of polycyclic aromatics and the preparation of industrially important hexamethylenediamine and adipic acid derivatives. Several examples of the late-stage modification of complex molecules and fused ring compounds further support the potential broad utility of this methodology.
The development of new and more effective antibiotic agents is necessary for human health. Herein, we have prepared the series of azo-derivatives of 1,3-indandion and metal complexes (Cu2+, Zn2+, ...Ni2+ and Mn2+) with these azo derivatives like 3-hydroxy-2-phenyldiazenyl-1H-inden-1-one (HPDIO), 3-hydroxy-2-2-methylphenyldiazenyl-1H-inden-1-one (HMPDIO),3-hydroxy-2-2-nitrophenyldiazenyl-1H-inden-1-one (HNPDIO) and 3-hydroxy2-2-chlorophenyldiazenyl-1H-inden-1-one (HCPDIO) have been successfully synthesized and screened against some bacteria. The appearance of –NN- peak at 1400-1500 cm−1 with disappearance of NH2 peak at 3500 cm−1 in FTIR spectra and chemical shift at 4.07–4.05 ppm and appearance of multiplet at 8.0–7.5 ppm for phenyl protons confirmed the synthesis of new azo derivatives. The appearance of, C–N sharp peak at 102 ppm, aromatic carbon peak in the range of 115–135 ppm, C–OH sharp peak at 192 ppm and CO peaks at 160–187 ppm and appearance of molecular ion peaks at 250 m/z, 264 m/z, 295 m/z and 284 m/z respectively further gives strong indication for the synthesis of proposed azo derivatives. Further, the XRD analysis of azo derivatives confirmed that these derivatives have cubic geometry. A relationship between anti-bacterial activities and structure of synthesized compounds have been established, the addition of electron donating group (for example methyl group) on the compound (HMPDIO) showed remarkable results which were equal to standard drug ciproxin against B. subtilis. Furthermore, the metal complexes of HCPDIO with Zn(II) and HNPDIO with Cu(II) showed more anti-bacterial activity against E.coli, P.aeruginose, B.subtilis and S.aureus than other metal complexes and azo derivatives. The compounds also screened against antioxidant as well as chymotrypsin activity and HCPDIO gives maximum inhibition against antioxidant activity than standard drug (BHA). All the ligands give good inhibition results against chymotrypsin activity except HCPDIO.
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•Synthesis of high yield azo derivatives form indandion and metal complexes.•Antibacterial and antioxidant activity of azo compounds.•Structure activity relationship for chymotrypsin activity.
•TPMA, or TPA, complexes have increasing applications in supramolecular chemistry.•Biological sensing related to Zinc or hypoxia has been performed using this ligands.•Probes for enantiomeric excess ...determination have been developed.•Several examples of confined systems using TPMA has been reported.
tris-(2-Pyridylmethyl)amine (usually abbreviated as TPA or TPMA) are ligands which are emerging in many fields of chemistry because of their ability to form stable and catalytically active complexes with a wide variety of metals. While the applications in catalysis began soon after the synthesis of the first metal complexes, studies in supramolecular chemistry are more recent and they often take advantage from their stereodynamic nature. This review surveys TPMA applications as: i) anion sensors, ii) biochemical sensors, iii) molecular switches, iv) chiral probes and as v) building blocks in the synthesis of supramolecular cages.
•Synthesis and characterization of two novel hydroquinone chelating agents.•Synthesis and characterization of two novel Zn (II) and two novel V (V) complexes.•Anticancer activity of the tert-L1-VO ...(V) and the methyl-L2-VO (V) on MDA-MB-231 breast cancer cis-platin resistance cells.•Antibacterial activity of the methyl-L2-Zn (II) complex compound on gram-positive bacteria.
Four novel mononuclear complexes of Zn2+ and V5+ ions were synthesized by the chelation of tridentate ligands of hydroquinone derivatives in 1:1 M ratios. The synthesis of the two novel ligands and their metal complexes were identified and characterized by NMR, IR, UV–Vis, cyclic voltammetry, and conductivity measurements. Structural information was also collected using computational chemistry and density functional theory studies. The biological activity of these metal complexes was investigated by the ctDNA interaction process via UV–Vis and viscosity measurements. The synthesized compounds C1 – C4 were primarily screened for their in vitro anti-microbial activities against gram-positive, gram-negative bacteria, and their anticancer potential against MDA-MB-231 cells carried out by MTT assay. Furthermore, on the complex molecules, we performed DPPH antioxidant studies and BSA (bovine serum albumin) binding studies on the UV–Vis. Additionally, studies were performed in silico by molecular docking evaluation of the molecules against breast cancer-related proteins. The data show that complexes C1- C4, have anticancer activity even in cells that showed resistivity against cis-platin (C3 > C4 > C2, C1) and the complexes (C2 > C1), have antibacterial activity against gram-positive bacteria. Another remarkable piece of evidence is that the anticancer activity of the molecules does not occur only because of their prooxidant activity, since C4 compound resulted in antioxidant activity.
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Carboranes are a class of carbon–boron molecular clusters with unusual thermal and chemical stabilities. They have been proved as very useful building blocks in supramolecular design, ...optoelectronics, nanomaterials, boron neutron capture therapy agents and organometallic/coordination chemistry. Thus, the functionalization of o‐carboranes has received growing interests. Over the past decades, most of the works in this area have been focused on cage carbon functionalization as the weakly acidic cage C−H proton can be readily deprotonated by strong bases. In sharp contrast, selective cage B−H activation/functionalization among chemically very similar ten B−H vertices is very challenging. Considering the differences in electron density of ten cage B−H bonds in o‐carborane and the nature of transition metal complexes, we have tackled this selectivity issue by means of organometallic chemistry. Our strategy is as follows: using electron‐rich transition metal catalysts for the functionalization of the most electron‐deficient B(3,6)−H vertices (bonded to both cage CH vertices); using electron‐deficient transition‐metal catalysts for the functionalization of relatively electron‐rich B(8,9,10,12)−H vertices (with no bonding to both cage CH vertices); and using the combination of directing groups and electrophilic transition metal catalysts for the functionalization of B(4,5,7,11)−H vertices (bonded to only one cage CH vertex). Successful applications of such a strategy result in the preparation of a large variety of cage B‐functionalized carboranes in a regioselective and catalytic manner, which are inaccessible by other means. It is believed that as this field progresses, other cage B‐functionalized carboranes are expected to be synthesized, and the results detailed in this concept article will further these efforts.
Selective functionalization of o‐carboranes has received increasing interests due to their valuable applications in medicine, materials and organometallic/coordination chemistry. However, the exceptional chemical stability and three‐dimensional structure of carboranes make selective cage B−H functionalization among chemically similar ten BH vertices very challenging. This concept article describes the strategy to achieve transition‐metal‐catalyzed regioselective and straightforward cage B−H functionalization of o‐carboranes.
Aggregation-induced electrochemiluminescence (AIECL) has attracted extensive interest due to the significant increase in ECL response by restricting free intramolecular rotation and torsion, but ...traditional AIECL emitters suffer from limited ECL efficiency, high cost, and complex synthetic steps, dramatically limiting their applications. Herein, novel Al(III)-Cbatpy metal–organic gels (Al(III)-Cbatpy-MOGs) with nanofiber morphology and ultrarapid coordination of Al3+ and 4′-carboxylic acid-2,2′:6′,2″-terpyridine (Cbatpy) are developed, which demonstrates an excellent AIECL enhancement behavior far beyond that reported in ECL supramolecular gels. In view of the strong affinity of N and O atoms in Cbatpy toward Al3+, Al(III)-Cbatpy-MOGs with high viscosity and stability can be assembled in one step within about 15 s, easily conquering the main predicaments of current AIECL emitters: complicated synthesis steps and poor film formation. Impressively, the ECL efficiency of Al(III)-Cbatpy-MOGs with superemission is about 20 times higher than that of individual Cbatpy molecules, which is attributed to the aggregation of the organic ligand Cbatpy restricting intramolecular rotation and torsion to reduce nonradiative relaxation. Furthermore, compared with traditional metal complexes, Al(III)-Cbatpy-MOGs show the benefits of remarkable biocompatibility and low cost without the involvement of any organic solvents, noble metals, and rare metals. As proof, a “signal-off” sensing platform based on an Al(III)-Cbatpy-MOGs/S2O8 2– system was constructed for the sensitive detection of dopamine (DA) with a low detection limit of 0.34 nM. This strategy provides a novel method to prepare cheap metal–organic gels as a highly efficient AIECL emitter, which is promising as a luminescent molecular device and biosensor for clinical diagnostic applications.
The complex of heavy metals and organic acids leads to high difficulty in heavy metals separation by traditional technologies. Meanwhile, alkaline precipitation commonly used in industry causes the ...great consumption of resources and extra pollution. Herein, the effective decomplexation of Cu(Ⅱ)-EDTA and synchronous recycling of Cu2+ were realized by contact-electro-catalysis (CEC) coupled with capacitive deionization (CDI) innovatively. In particular, fluorinated ethylene propylene (FEP) as dielectric powders could generate reactive oxygen species under ultrasonic stimulation, realizing continuous deaminization and decarboxylation of Cu(Ⅱ)-EDTA and accelerating the totally breakage of Cu-O and Cu-N bonds. Additionally, the degradation pathway and intermediates evolution of Cu(Ⅱ)-EDTA were investigated using various characterization methods. It was confirmed that decarboxylation predominantly governed the degradation process of Cu(Ⅱ)-EDTA in CEC. During the course of treatment, the degradation ratio of Cu(Ⅱ)-EDTA reached 86.4 % within 150 min. Impressively, this strategy had satisfactory applicability to other metal combinations and excellent cycle stability. Subsequently, the released Cu ions were captured by CuSe cathode electrode through CDI. This research elucidated the degradation mechanism of persistent organic pollutant during CEC, and provided a novel approach for efficiently treating industrial wastewater containing metal complexes and advancing the exploitation and utilization of new technologies for metal recovery.
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•The reactive oxygen species were generated in CEC without extra oxidants.•FEP as dielectric powders could effectively degrade Cu(Ⅱ)-EDTA in CEC.•CEC coupled CDI could degrade Cu(Ⅱ)-EDTA and directly capture Cu2+.•The decomplexation of Cu(Ⅱ)-EDTA in CEC was dominated by decarboxylation.
