Search results for "Cyanide"
showing 10 items of 180 documents
Cyanide-bridged Fe(III)–Co(II) bis double zigzag chains with a slow relaxation of the magnetisation
2003
Reaction of [FeIII(bipy)(CN)4]¯ with fully solvated MII cations [M = Co (1) and Mn (2)] produces the isostructural bis double zigzag chains [[FeIII(bipy)(CN)4]2MII(H2O)]·MeCN·1/2H2O; 1 exhibits intrachain ferromagnetic and interchain antiferromagnetic couplings, slow magnetic relaxation and hysteresis effects. Luminita Marilena, Toma, Luminita.Toma@uv.es ; Lescouezec, Alain Francois Rodri, Alain.Lescouezec@uv.es ; Lloret Pastor, Francisco, Francisco.Lloret@uv.es ; Julve Olcina, Miguel, Miguel.Julve@uv.es
Spin-Crossover and Liquid Crystal Properties in 2D Cyanide-Bridged FeII−MI/II Metalorganic Frameworks
2010
Novel two-dimensional heterometallic Fe(II)-M(Ni(II), Pd(II), Pt(II), Ag(I), and Au(I)) cyanide-bridged metalorganic frameworks exhibiting spin-crossover and liquid crystal properties, formulated as {FeL(2)[M(I/II)(CN)(x)](y)}·sH(2)O, where L are the ligands 4-(4-alkoxyphenyl)pyridine, 4-(3,4-dialkoxyphenyl)pyridine, and 4-(3,4,5-trisalkoxyphenyl)pyridine, have been synthesized and characterized. The physical characterization has been carried out by means of EXAFS, X-ray powder diffraction, magnetic susceptibility, differential scanning measurements, and Mössbauer spectroscopy. The 2D Fe(II) metallomesogens undergo incomplete and continuous thermally induced spin transition at T(1/2) ≈ 170 …
Thermal-,Pressure-, and Light-Induced Spin Transition in Novel Cyanide-Bridged FeII-AgI Bimetallic Compounds with Three-Dimensional Interpenetrating …
2002
[EN] Low-spin, high-spin and spin-transition behaviours have been observed for the doubly interpenetrating three-dimensional bimetallic compounds {Fe-II(pz)[Ag(CN)(2)](2)}.pz (pz= pyrazine), {Fe-II(4,4'-bipy)(2)[Ag(CN)(2)](2)} (4,4'-bipy-4,4'-bipyridine), and {Fe-II-(bpe)(2)[Ag(CN)(2)](2)} (bpe = bispyridylethylene), respectively. The single crystals of the bpe derivative undergo a spin transition with a large hysteresis loop at about 95 K. After several warming and cooling cycles, the single crystals become a microcrystalline powder with 50% spin transition. Influence of pressure- as well as light-induced excited spin-state trapping (LIESST) on the thermal 50% spin transition of the microc…
Evidence for the operation of a cyanide-sensitive oxidase in chlororespiration in the thylakoids of the chlorophyll c-containing alga Pleurochloris m…
1995
For characterisation of chlororespiration in the chlorophyll c-containing alga Pleurochloris meiringensis, we measured the flash-induced electrochromic absorbance changes between 470 and 545 nm and the redox changes of cytochrome f and cytochrome c553. Cytochrome c553 was shown to be present in high amounts (1 mol cytochrome c553 per 300 mol chlorophyll) in this alga and to function as the obligate electron donor for photosystem I instead of plastocyanin. Whereas salicylhydroxamic acid had no effect on the flash-induced absorbance transients, cyanide enhanced the slow-rising (t1/2≈10 ms) kinetic component of the electrochromic absorbance change. Cyanide also accelerated the re-reduction of …
Synthesis, Crystal Structure and Magnetic Properties of Three {Cr III Mn II } Heterodimetallic Complexes Based on Heteroleptic Cyanido‐Bearing Cr III…
2017
The use of the heteroleptic [CrIII(AA)(CN)4]- complex as a ligand towards the preformed [MnII(tptz)]2+ and [MnII(pyim)2]2+ species afforded the heterometallic compounds: [MnII(tptz)(H2O)(NO3)(-NC)CrIII(ampy)(CN)3]CH3CN (1), [MnII(tptz)(H2O)(NO3)(-NC)CrIII(phen)(CN)3]H2O (2) and {[MnII(pyim)2][(-NC)Cr(phen)(CN)3]2}3H2O (3) [AA = 2-aminomethylpyridine (ampy) and 1,10-phenanthroline (phen), tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine and pyim = 2-(1H-imidazol-2-yl)pyridine]. 1 and 2 are neutral heterodinuclear complexes where a [CrIII(AA)(CN)4]- building block acts as a monodentate ligand through one cyanide group towards a seven coordinate MnII ion. Compound 3 is a neutral heterotrinuclear co…
Synthesis, crystal structure and magnetic properties of a new cyanide-bridged iron(III)–nickel(II) ferromagnetic chain
2008
Abstract The reaction of the iron(III) unit fac-[Fe{HB(pz)3}(CN)3]− [ HB ( pz ) 3 - = hydrotris ( 1 - pyrazolyl ) borate ] as the lithium salt (1) with the nickel(II) complex mer-[Ni(dpt)(H2O)3](ClO4)2 [dpt = dipropylenetriamine] in water affords the heterometallic compound of formula {[FeIII{HB(pz)3}(CN)3]2[NiII(dpt)]}n · 3nH2O (2). The structure of 2 has been determined by X-ray diffraction on single crystals and their magnetic properties have been investigated in the temperature range 1.9–300 K. Compound 2 is a zigzag chain compound with regular alternating bis-monodentate [Fe(1){HB(pz)3}(CN)3]− units and [Ni(dpt)]2+ cations, the six coordination around the nickel atom being achieved by …
New cyanide-bridged Mn(III)-M(III) heterometallic dinuclear complexes constructed from [M(III)(AA)(CN)4]- building blocks (M = Cr and Fe): synthesis,…
2011
Three Mn(III)-M(III) (M = Cr and Fe) dinuclear complexes have been obtained by assembling [Mn(III)(SB)(H(2)O)](+) and [M(III)(AA)(CN)(4)](-) ions, where SB is the dianion of the Schiff-base resulting from the condensation of 3-methoxysalicylaldehyde with ethylenediamine (3-MeOsalen(2-)) or 1,2-cyclohexanediamine (3-MeOsalcyen(2-)): [Mn(3-MeOsalen)(H(2)O)(µ-NC)Cr(bipy)(CN)(3)]·2H(2)O (1), [Mn(3-MeOsalen)(H(2)O)(µ-NC)Cr(ampy)(CN)(3)][Mn(3-MeOsalen)(H(2)O)(2)]ClO(4)·2H(2)O (2) and [Mn(3-MeOsalcyen)(H(2)O)(µ-NC)Fe(bpym)(CN)(3)]·3H(2)O (3) (bipy = 2,2'-bipyridine, ampy = 2-aminomethylpyridine and bpym = 2,2'-bipyrimidine). The [M(AA)(CN)(4)](-) unit in 1-3 acts as a monodentate ligand towards th…
Ligand dynamics of tert-butyl isocyanide oxido complexes of molybdenum(IV).
2014
The six-coordinate molybdenum(IV) oxido isocyanide complex 1 [Δ,Λ-OC-6-2-3-[MoO(N(p)∩N(i))2(CN(t)Bu)]; N(p)∩N(i) = 4-tert-butylphenyl(pyrrolato-2-ylmethylene)amine] is obtained in diastereomerically pure form in the solid state, as revealed by single-crystal X-ray diffraction. In solution, this stereoisomer equilibrates with the Δ,Λ-OC-6-2-4 diastereomer 2 at ambient temperature. The stereochemistry of both isomers has been elucidated by NMR, IR, and UV/vis spectroscopy in combination with density functional theory (DFT)/polarizable continuum model and time-dependent DFT calculations. The isomerization 1 → 2 is suggested to proceed via a dissociative trigonal twist with dissociation of the …
Ferromagnetic Coupling between Low- and High-Spin Iron(III) Ions in the Tetranuclear Complex fac-{[FeIII{HB(pz)3}(CN)2(μ-CN)]3FeIII(H2O)3}· 6H2O ([HB…
2002
The novel mononuclear PPh4-fac-[FeIII{HB(pz)3}(CN)3]·H2O (1) [PPh4+= tetraphenylphosphonium cation; (HB(pz)3)- = hydrotris(1-pyrazolyl)borate] and tetranuclear fac-{[FeIII{HB(pz)3}(CN)2(μ-CN)]3FeIII(H2O)3}·6H2O (2) have been prepared and characterized by X-ray diffraction analysis. Crystal data for compound 1: monoclinic, space group P21/c, a = 9.575(3) A, b = 21.984(4) A, c = 16.863(3) A, β = 100.34(2)°, U = 3486(1) A3, Z = 4. Crystal data for compound 2: orthorhombic, space group Pnam, a = 14.084(3) A, b = 14.799(4) A, c = 25.725(5) A, U = 5362(2) A3, Z = 4. Compound 1 is a low-spin iron(III) compound with three cyanide ligands in fac arrangement and a tridentate pyrazolylborate ligand …
Cyanido‐Bearing Cobalt(II/III) Metalloligands – Synthesis, Crystal Structure, and Magnetic Properties
2014
New examples of cyanido-bearing cobalt(III/II) complexes have been obtained by treatment of CoCl2·6H2O with bidentate nitrogen donors and potassium cyanide in a methanol/water mixture. Depending on the chelating ligand, the cobalt(III) complexes PPh4[Co(en)(CN)4] (1, en = ethylenediamine), PPh4[Co(ampy)(CN)4]·1.5H2O [2, ampy = 2-(aminomethyl)pyridine], and PPh4[Co(phen)(CN)4]·CH3OH·0.25H2O (3, phen = 1,10-phenanthroline) and the cobalt(II) complex PPh4[Co(dmphen)(CN)3]·3H2O (4, dmphen = 2,9-dimethyl-1,10-phenanthroline) were obtained. The complexes were characterized by single-crystal X-ray diffraction and variable-temperature magnetic measurements. They are all mononuclear species with six…