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Introduction to Nanosensors
Published in Vinod Kumar Khanna, Nanosensors, 2021
An alkyl group (symbol R) is a group formed from an alkane by removal of a single atom of hydrogen (–CH3, methyl group; –CH3CH2, ethyl group, etc.). An aryl group is a group formed from an aromatic compound by removing a single hydrogen atom, such as the C6H5– group from benzene.
Synthesis and evaluation of Zn(II) dithiocarbamate complexes as potential antibacterial, antibiofilm, and antitumor agents
Published in Journal of Coordination Chemistry, 2019
Vinay Kumar Maurya, Ashish Kumar Singh, Ravi Pratap Singh, Shivangi Yadav, Krishna Kumar, Pradyot Prakash, Lal Bahadur Prasad
1H NMR spectra of the ligands and complexes were recorded in CDCl3. The chemical shifts of the different types of the protons observed in the 1H NMR spectra of the ligands were compared with their Zn(II) complexes. 1H NMR spectra of the ligands show proton signals at between δ 7.34–6.79, 3.66, and 5.32–4.42 ppm due to benzene protons, –OCH3 and methylene protons of aryl group, respectively [31, 32]. The methylene protons (adjacent to nitrogen atom) of alkyl chain are observed at δ 3.91 ppm and alkyl chain of methyl proton are observed around δ 2.05–1.05 ppm [33]. It is noticed that signals due to benzene, –OCH3, aromatic and aliphatic methylene protons and methyl protons do not show significant shift upon complexation.
Electronically varied manganese tris-arylacetamide tripodal complexes
Published in Journal of Coordination Chemistry, 2019
Anthony F. Cannella, Roshaan Surendhran, Samantha N. MacMillan, Rupal Gupta, David C. Lacy
Six new Mn(II) complexes were synthesized with a systematically varied ligand set and were characterized as the [Me4N]2[MnLR(OAc)] salts. The nitro variant, LNO2, of the ligand series that we have prepared has furnished four crystallographically_characterized M(II) complexes MnNO2, FeNO2, CoNO2, and ZnNO2; this report details the synthesis and characterization of MnNO2 and CoNO2. By comparing the results from XRD studies, we found that the bond metrics trend well with the metal ion’s respective ionic crystal radii. The trends manifest with the acetato ligand in MNO2 binding in a bidentate fashion for M = Mn, but monodentate in the remaining complexes (M = Fe, Co, Zn). Electrochemical characterization of the MnR and FeR complexes follow the expected trend wherein the more electron-withdrawing substituents render the complex more oxidizing. For each set, a quasi-reversible oxidation event was observed for the II/III oxidation event in DMA in the presence of acetate ion. A Hammett plot was constructed using the quasi reversible waves for Mn and Fe and moderately good correlations were obtained with ρ ≈ 0.07. These ρ values (slopes) are somewhat small compared to other comparable systems. We rationalized this based on poor electronic communication between the amidate nitrogen and aryl substituent that arises from a twisting of the aryl group.
Metal- and nonmetal-catalyzed synthesis of five-membered S,N-heterocycles
Published in Journal of Sulfur Chemistry, 2018
Navjeet Kaur, Nirmala Kumari Jangid, Vivek Sharma
The direct C–H functionalization/C–S bond formation with the help of iron catalyst under mild conditions was reported. Moderate to excellent yields of benzothiazoles were obtained from several substrates (Scheme 38). Pyridine played an important role for the high selectivities and yields as suggested by preliminary mechanistic aspects. Under optimal conditions, the substrate scope of this reaction was investigated. The substituent on the aryl group of the thiobenzoyl part (Ar) does not influence this transformation. Good to excellent yields (72–95%) were observed with either steric or electronic property. Halo substituents (Br, I) can be well tolerated under the reaction conditions. The reaction did not get affected when the electron-donating group was present at either the ortho- or para-position. Excellent yields (84–93%) were obtained. The cyclization product was obtained in excellent yields (97%) from the reaction of N-naphthalene-substituted benzothioamide. However, the yields decreased dramatically with electron-withdrawing groups. When the NO2 group was present only moderate yield was obtained [12].