A Zwitterionic Tetrastanna(II) Cyclic Crown

A 12-membered zwitterionic tetrastanna(II) cycle 1 having a crown ether-like topology has been isolated from the deprotonation of 1,1′-methylenediimidazole ( B ) with two equivalents of Sn[N(SiMe₃)₂]₂ ( A ). The solid-state structure and NMR analysis confirms the tetrastanna(II) cycle 1 to be comprised of two stannate(II) and two stannyliumylidene ion pairs in alternating positions of the heterocycle. Computational analysis shows greater nucleophilicity at the proximally located stannate(II) centers. Nonetheless, the tetrastanna(II) cycle 1 remains poorly reactive due to engagement of Sn^II lone pair electrons in intramolecular donor-acceptor interactions. Simple deprotonation reaction between Sn[N(SiMe₃)₂]₂ ( A ) and N-(diisopropylphenyl)imidazole ( C ) in equimolar ratio has led to a stannylene 2 , involving the formation of a Sn−C covalent bond with the anionic imidazol-2-yl carbon center along with the release of NH(SiMe₃)₂. Compound 2 exists as a dimer, where the unsubstituted ring nitrogen atom coordinated intermolecularly to the other stannylene center.     

Vibrational spectroscopic studies and DFT calculations of 4‐fluoro‐N‐(2‐hydroxy‐4‐nitrophenyl)benzamide

Fourier transform infrared (FT‐IR) and FT‐Raman spectra of 4‐fluoro‐N‐(2‐hydroxy‐4‐nitrophenyl)benzamide were recorded and analyzed. The vibrational wavenumbers and corresponding vibrational assignments were examined theoretically using the Gaussian03 set of quantum chemistry codes. The red‐shift of the NH‐stretching wavenumber in the infrared (IR) spectrum from the computed wavenumber indicates the weakening of the NH bond resulting in proton transfer to the neighboring oxygen atom. The simultaneous IR and Raman activation of the CO‐stretching mode gives the charge transfer interaction through a π‐conjugated path. Copyright © 2008 John Wiley & Sons, Ltd.     

An efficient microwave-assisted synthesis of novel quinolone–triazole and conazole–triazole hybrid derivatives as antimicrobial and anticancer agents

1,2,4-Triazole-fluoroquinolone and 1,2,4-triazole–conazole hybrids are designed, synthesized, and investigated in vitro against a variety of common diseases. The structure of the newly synthesized compounds are characterized from spectral data (IR, ¹H NMR, ¹³C NMR, and LC–MS). The antibacterial activity against both Gram-positive and Gram-negative bacteria is shown to be enhanced by many of the produced compounds. Also, some of the products are found to have strong antiproliferative effects aganist HeLa cervical cancer cells, whilst demonstrating cytotoxic effects toward normal cells.