• P Venugopalan

      Articles written in Journal of Chemical Sciences

    • Synthesis of novel spiro-𝛽-lactams

      Renu Arora P Venugopalan S S Bari

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      A new synthetic approach for spiro-𝛽-lactams by cyclization of cis-3-allyl-3-benzylthio-𝛽-lactams is presented. The reaction involves step-wise electrophilic addition-dealkylation sequence giving stereospecific synthesis of C-3-spiro-𝛽-lactams.

    • Weak C-H$\cdots$F-C interactions in carboxylate anion binding: Synthesis, spectroscopic and X-ray structural studies of [Co(phen)2CO3]2 (C7H3O2FCl)Cl$\cdots$11H2O and [Co(phen)2CO3](C7H3NO4Cl)$\cdot$6H2O

      A Singh R P Sharma T Aree P Venugopalan

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      Two new complex salts containing 2,5-substituted benzoate ions, [Co(phen)2CO3]2 (C7H3O2FCl)Cl$\cdot$11H2O (1) and [Co(phen)2CO3](C7H3NO4Cl)$\cdot$6H2O (2) (where phen = 1,10-phenanthroline, C7H3O2FCl = 2-chloro-5-fluorobenzoate (cfbz) and C7H3NO4Cl = 2-chloro-5-nitrobenzoate(cnbz)) were synthesized by reacting carbonatobis(1,10-phenanthroline)cobalt(III) chloride with appropriate salts in aqueous medium. A detailed packing analysis has been undertaken to delineate the role of second sphere C-H$\cdots$F and C-H$\cdots$O interactions amid other heteroatom interactions. The complex salts have been characterized by elemental analyses, spectroscopic studies (IR, UV/Visible, multinuclear NMR), conductance and solubility product measurements. Single crystal X-ray structure determination revealed ionic structures of both the complex salts having discrete ions along with lattice water molecules. Crystal lattice is stabilized by a variety of hydrogen bonding interactions, i.e. O-H$\cdots$O, C-H$\cdots$O and C-H$\cdots$F involving second sphere coordination besides 𝜋-𝜋 interaction. Furthermore, packing analyses reveal that C-H…F interactions can manifest even in the presence of a large number of heteroatom interactions.

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