0000000000776695
AUTHOR
Anthony L. Spek
A new 3-D polymeric spin transition compound: [tris(1,4-bis(tetrazol-1-yl)butane-N1,N 1′)iron(II)] bis(perchlorate)
A series of novel polymeric compounds of formula [M(btzb)3][ClO4]2 (Mll = Fe, Ni or Cu) with btzb = 1,4-bis-(tetrazol-1-yl)butane have been prepared and their physical properties investigated. The btzb ligand has been prepared and its crystal structure determined, together with a tentative crystal structure of the 3-D compound [Fe(btzb)3][ClO4]2. The model of the latter shows two symmetry-related, interpenetrating Fe-btzb networks in which the iron(II) ions approach each other as close as 8.3 and 9.1 A. This supramolecular catenane undergoes a sharp thermal spin transition around 160 K with hysteresis (20 K) along with a pronounced thermochromic effect. The spin crossover behaviour has been…
Dimetallic complexes derived from a novel dinucleating chelating symmetric triazole ligand; crystal structure, magnetic properties and ESR study of bis[μ-3,5-diacetylamino-1,2,4-triazolato-O ′,N 1,N 2,O ″]bis[(nitrato)(aqua)copper(II)] ‡
Reaction of 3,5-diacetylamino-1,2,4-triazole (Hdaat) with copper(II), nickel(II) and cobalt(II) salts yields dinuclear co-ordination compounds, which were spectroscopically characterized. The crystal and molecular structure of one of the compounds, bis[µ-3,5-diacetylamino-1,2,4-triazolato-O′,N 1,N 2,O″]bis[(nitrato)(aqua)copper(II)] 1, was determined by single-crystal X-ray diffraction. Complex 1 consists of dinuclear units with an inversion center at the midpoint of the Cu–Cu vector. The most remarkable feature of this structure is that the daat ligand forms a six-membered chelate ring [Cu–N3–C3–N1–C2–O1; Cua–N4–C4–N5–C5–O2], in contrast with the five-membered chelate rings always found in…
Synthesis, Structure, and Magnetic Properties of a Tris[3-(2-pyridyl)-1,2,4-triazole]iron(II) Spin-Crossover Complex
The synthesis and characterization of tris[3-(pyridin-2-yl)-1,2,4-triazole]iron(II) bis(tetrafluoroborate), obtained from the reaction of 3-(pyridin-2-yl)-1,2,4-triazole (Hpt) and hexaaquairon(II) tetrafluoroborate, [Fe(H2O)6](BF4)2, is described, together with its crystal structures at two temperatures. X-ray crystallographic parameters are as follows: [Fe(Hpt)3](BF4)2·nH2O (n ≈ 2) at 250 K: orthorhombic space group Pbam, a = 15.8068(18) A, b = 17.2800(14) A, c = 21.215(2) A, V = 5794.7(10) A3, and Z = 8. [Fe(Hpt)3](BF4)2·nH2O (n ≈ 2) at 95 K: orthorhombic space group Pbam, a = 15.7080(12) A, b = 17.1023(16) A, c = 21.006(2) A, V = 5643.1(9) A3, and Z = 8. The FeII ions are (at both temper…
Synthesis, Structure and Properties of a Mixed Mononuclear/Dinuclear Iron(II) Spin-Crossover Compound with the Ligand 4-(p-Tolyl)-1,2,4-triazole
A new iron(II) compound with the formula [Fe2(L)5(NCS)4]2[Fe(L)2(NCS)2(H2O)2] (I) [where L = 4-(p-tolyl)-1,2,4-triazole] has been synthesized and subjected to X-ray structure determination. Compound I crystallizes in the triclinic space group P–1 (no. 2) with a = 14.5785(11), b = 16.1253(11), c = 16.1963(8) A, α = 80.930(5), β = 85.796(5), γ = 78.132(6)°, V = 3676.2(4) A3. The structure refinement converged to wR2 = 0.172, RF = 0.084. The structure was found to consist of two types of iron-containing structural units, a mononuclear unit and a dinuclear one. The mononuclear unit has a crystallographic inversion centre, and is coordinated by two NCS anions, two triazole N1 nitrogen atoms, and…