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401.
Recent synthesis of sp-hybridized cyclo[18]carbon allotrope has attracted immense curiosity. Since then, a generous amount of theoretical studies concerning aromaticity, adsorption, and spectra of the molecule have been performed. However, very few stuides have been carried out concerning its reactivities and catalytic behaviour. In this article, a DFT-based inquisition has been reported regarding the reactivity of Si substituted cyclo[18]carbon molecule towards molecular N2. Results show that the Si substituted derivative is effective in producing adducts with molecular nitrogen. Charge calculations and IRC trapping methods indicate that only the Si center of C17Si and its (HOMO-1) level participate in N2 addition. The N-adduct so formed, is then found to spontaneously react with molecular H2. The addition of two H2 molecules to the activated nitrogen molecule to give respective amine derivatives have also been studied. The successful generation of the precursor of NH3 by C17Si lays a clear emphasis on its potentiality. 相似文献
402.
403.
Polyaniline (PANI) forms thermoreversible gels in different sulphonic acids e.g. dinonyl napthalene sulphonic acid (DNNSA), dinonylnapthalene disulphonic acid (DNNDSA), ± camphor ‐ 10 ‐ sulphonic acid (CSA) and dodecyl sulphonic acid (DSA) when processed from the formic acid medium. The surfactant concentration has been varied from weight fraction of PANI (WPANI)=0.05−0.60. In most cases at WPANI=0.05−0.40 compositions fibrillar network structures are observed from SEM study. They also exhibit reversible first order phase transition during both heating and cooling in DSC. The melting temperature and the gelation temperature increases with increase in surfactant concentration of the gel. From the WAXS pattern it is concluded that crystallization of the surfactant tails anchored from the nitrogen atom of PANI through its SO3 H head group is responsible for gelation. The conductivity of all the gels with increase in PANI concentration showed a maximum with composition. The maximum conductivity is ∼0.01 S/cm, for WPANI=0.22. The conductivity variation has been explained by considering it as a function of both interchain and intrachain contributions. 相似文献
404.
Bimetallic palladium(II) complexes containing classical NHC donor ligands are becoming increasingly popular owing to their various catalytic applications. However, examples of the aforementioned complexes with mixed NHC/PPh3 ligands are still rare. Bimetallic palladium(II) complexes possessing these mixed ligands are described starting from a C2-symmetric bis-imidazolium salt containing 4,4′-substituted central biphenyl ring. All the palladium(II) complexes have been tested as precatalysts in α-arylation of oxindole and Suzuki–Miyaura coupling reactions. The complex composed of mixed NHC/PPh3 donor ligands shows superior catalytic activity compared with the corresponding PEPPSI type complexes when applied in α-arylation of oxindole. The dinuclear complexes display better activity compared with the mononuclear complexes. The preliminary electrochemical measurements show the facile oxidation of PdII in the presence of combined NHC/PPh3 ligands compared with a combination of NHC/Py ligands. 相似文献