Yazar "Hökelek, T" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • Küçük Resim Yok
    Öğe
    1,1?,3,3?-tetraalkyl-2,2?-biperimidinylidenes
    (John Wiley & Sons Inc, 2003) Alici, B; Hökelek, T; Çetinkaya, E; Çetinkaya, B
    C-2 deprotonation of 1,3-dibutylperimidinium bromide (1a) with sodium hydride and a catalytic amount of potassium tert-butoxide in dry THF led to the formation of the exceptionally inert tetraaminoalkene 2a. In contrast, isostructural tetrakis(2-methoxyethyl)-tetraaminoalkene (2b) instantaneously reacted with O-2 to yield urea 3b, and silver nitrate was readily reduced with 2b to form a silver mirror. Compound 2a has been characterized by X-ray diffraction studies; the naphtho-pyrimidine skeleton imposes structural constraints and some rigidity to the C=C bonding. (C) 2003 Wiley Periodicals, Inc.
  • Küçük Resim Yok
    Öğe
    2,4,4,6,6-Pentachloro-2-(2,6-di-tert-butyl-4-methylphenoxy)cyclo-2?5,4?5,6?5-triphosphazatriene
    (Munksgaard Int Publ Ltd, 1999) Hökelek, T; Kiliç, A; Begeç, S; Kiliç, Z
    The title compound, C15H23Cl5N3OP3, consists of a non-planar trimeric phosphazene ring and a bulky 2,6-di-tert-butyl-4-methylphenoxy side group in which the phenyl ring shows a small but significant distortion from planarity. The bulky group predominantly determines the molecular shape. The endocyclic angle about the P atom bonded to the substituent is decreased, while the exocyclic angle is increased. The situation is not similar to that of tetrameric phosphazene derivatives.
  • Küçük Resim Yok
    Öğe
    Crystal structure of 2,4,4,6,6-pentachloro-2-(2,4,6-trimethylphenoxy)cyclo-2?5,4?5,6?5-triphosphazatriene
    (Japan Soc Analytical Chem, 2000) Hökelek, T; Akduran, N; Kiliç, A; Begeç, S; Kiliç, Z
    [Abstract Not Available]
  • Küçük Resim Yok
    Öğe
    Phosphorus-nitrogen compounds
    (Elsevier Science Bv, 2000) Kiliç, A; Begeç, S; Kiliç, Z; Hökelek, T
    The reactions of Cl3P=N-P(O)Cl-2 (1) with Sodium 2,4,6-tert-butylphenoxide and sodium 2,6-di-tert-butyl-4-methylphenoxide give geminal bis products (2) and (3), respectively. Compounds (2) and (3) have been characterised by elemental analysis, IR, H-1-, C-13 and P-31-NMR and the structure of compound (2) has been examined crystallographically. It crystallizes in the monoclinic space group P2(1)/n with a = 10.056(1), b = 25.986(1), c = 15.533(1)Angstrom, beta = 95.9(1)degrees, V = 4037.6(1)Angstrom(3), Z = 4 and D-x = 1.19 g cm(-3). The bulky substituents are instrumental in determining the molecular geometry. The P-N bonds have neither single-nor double-bond character and are substantially shorter than the ideal P-N single bond. The P=O double bond is abnormally long and it has a single bond character. The P-N-P angle [158.0(3)degrees] is the largest one for the reported acyclic phosphazene derivatives in the literature. (C) 2000 Elsevier Science B.V. All rights reserved.