bis(N-neopentyl-3-t-butyl-5-methyl-salicylaldiminato)nickel(II) | 165881-78-7

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 苯并三唑类
• 英文名称: bis(N-neopentyl-3-t-butyl-5-methyl-salicylaldiminato)nickel(II)
• CAS: 165881-78-7
• 化学式: C₃₄H₅₂N₂NiO₂
• 分子量: 579.489
• InChiKey: KHOOLNIEAKKWNY-BWZRFINISA-L

反应信息

• 作为产物：
  描述：

  、 nickel dibromide 在 Et₃N 作用下， 以 乙腈 为溶剂， 生成 bis(N-neopentyl-3-t-butyl-5-methyl-salicylaldiminato)nickel(II)
  参考文献：
  名称：

  Configurational Isomerism in Bis(N-alkylsalicylaldiminato)nickel(II) Complexes: The Equilibrium Planar .dblharw. Tetrahedral and Its Effect on the Kinetics and Mechanism of Ligand Substitution

  摘要：

  A series of bis(N-alkylsalicylaldiminato)nickel(II) complexes Ni(XYsal-R) = NiA(2) with different combinations of substituents X (= tert-butyl, isopropyl, isobutyl, NO2, Br), Y (= methyl, H), and alkyl groups R (= H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl) were prepared and characterized by their vis/near-IR absorption spectra and magnetic moments (XYsal-R = anion of N-alkyl-3-X-5-Y-salicylaldimine). X-ray structure analysis of Ni(3-tert-butyl-5-methylsal-Et)(2) (= C28H40N2O2Ni; monoclinic, P2(1)/c; alpha = 12.188(4), b = 11.455(4), and c = 18.852(6) Angstrom, beta = 97.66(1)degrees; Z = 4; R(w) = 0.0367) and of the corresponding Zn(II) complex (= C28H40N2O2Zn; monoclinic, C2/c; alpha = 27.14(2), b = 13.17(1), and c = 18.30(2) Angstrom, beta = 120.64(2)degrees; Z = 8; R(w) = 0.0357) confirms a distorted planar geometry of the NiN2O2 coordination core and tetrahedral coordination of the zinc. The equilibrium constants K-1 and K-2 for the formation of the various pyridine adducts NiA(2) . py and NiA(2) . 2py, respectively, were determined by spectrophotometric titration in acetone. Variable-temperature H-1 NMR measurements led to the equilibrium constants K-p,K-r for the fast configurational isomerization of complexes NiA(2) in organic solution according to NiA(2) (planar) reversible arrow NiA(2) (tetrahedral). Conventional and stopped-flow spectrophotometries were used to study the kinetics of displacement of the two bidentate ligands in NiA(2) by tetradentate ligands H2B = H(2)salen (= N,N' -disalicylidene-1,2-diaminoethane-), H(2)salpren (= N,N' -disalicylidene 1,3-diaminopropane), and H(2)sal(Me)(2)en (= N,N' -disalicylidene-1,2-diamino-2-methylpropane) in acetone solution. Ligand displacement follows second-order kinetics, rate = k(H2B)[NiA(2)][H2B] For complexes Ni(3-tert-butyl-5-methylsal-R)(2) and H2B = H(2)salen, late constant k(H2B) spans from 3.75 x 10(4) M(-1) s(-1) for R = methyl to 4.4 x 10(-3) M(-1) s(-1) for R = tert-butyl at 298 K. The activation entropy ranges from -52.5 J mol(-1) K-1 for Ni(3-isobutylsal-ethyl)(2) to - 138 J mol(-1) K-1 for Ni(3-nitro-5-methylsal-isopropyl)(2). The parameters K-1, K-2, K-p,K-t and k(H2B) are governed by the bulkiness and specific combination of the various substituents X and alkyl groups R. The size of these parameters allows meaningful conclusions concerning the associatively controlled mechanism of ligand displacement.

  DOI：

  10.1021/ic00120a005