Synthesis, properties, and thermal decomposition of compounds [Co(En)3][Fe(CN)6] · 2H2O and [Co(En)3]4[Fe(CN)6]3 · 15H2O

Binary complex salts, [Co(En)₃][Fe(CN)6] · 2H₂O and [Co(En)₃]₄[Fe(CN)₆]₃ · 15H₂O, are synthesized. The properties of the salts and their thermolysis in air, dihydrogen, and argon are studied. Oxides of the central ions of the binary complex salts are found to be the thermolysis products in an oxidative atmosphere. Solid solutions (intermetallic compounds) CoFe are the thermolysis products in the reductive atmosphere, whereas intermetallides containing considerable amounts of C and N and an impurity of Co and Fe oxides are the thermolysis products in an inert atmosphere. Gaseous thermolysis products in dihydrogen and argon are NH₃, hydrocarbons, and ethylenediamine.     

Syntheses and Crystal Structures of Two Ion Pair Complexes, [Ru(bpy)3]2[Fe(CN)6]I · 7H2O and [Ru(bpy)3]- [Fe(CN)5NO]CH3OH · H2O

Two ion pair complexes, [Ru(bpy)₃]₂[Fe(CN)₆]I [sdot] 7H₃O (1) and [Ru(bpy)₃][Fe(CN)₅NO](CH₃OH) [sdot] H₂O (2) (bpy = 2,2-bipyridine) have been synthesized and structurally characterized. X-Ray crystallographic structures of 1 and 2 both show Fe(III) and Ru(II) in distorted octahedral environments. In both complexes, H-bonding interactions between an uncoordinated water molecule and the nitrogen atom of a cyano group exist.     

[Bu4N]2[Fe2(μ-S2O3)2(NO)4]: Synthesis,Structure, Redox Properties,and EPR Study

The [n-Bu₄N]₂[Fe₂(-S₂O₃)₂(NO)₄] complex was studied using X-ray diffraction analysis, cyclic voltammetry, and EPR spectroscopy, and its crystal structure was determined. The redox properties of the [Fe₂(-S₂O₃)₂(NO)₄]^2–anion in CH₃CN and CH₂Cl₂solutions were studied. An addition of excess reducer (sodium thiosulfate) to the thiosulfate complex was shown to produce an EPR signal with g= 2.03 typical of the mononuclear iron dinitrosyl complexes. The mechanism for [Fe₂(-S₂O₃)₂(NO)₄]^2–reduction was suggested.     

Synthesis and characterisation of [tris(1,3-dithiole-2-thione-4,5-dithiolato)-stannate]2−, [Q]2[Sn(dmit)3], [tris(1,3-dithiole-2-one-4,5-dithiolato)stannate]2−, [Q]2[Sn(dmio)3] and [tris(1,3-dithiole-2-thione-4,5-selenolato)stannate]2−, [Q]2[Sn(dsit)3], complexes: Analysis of the structural variations of the [Sn(dmit)3]2− and [Sn(dmio)3]2− dianions

[Tris(1,3-dithiole-2-thione-4,5-dithiolato)stannate]²⁻, [Q]₂[Sn(C₃S₅)₃], [tris(1,3-dithiole-2-one-4,5-dithiolato)stannate]²⁻, [Q]₂[Sn(C₃S₄O)₃], and [tris(1,3-dithiole-2-thione-4,5-diselenolato)stannate]²⁻ [Q]₂[Sn(C₃S₃Se₂)₃], complexes, have been synthesised and characterised. Crystal structure determinations of [Q]₂[Sn(C₃S₅)₃] (Q=1,4-dimethylpyridinium, monoclinic and orthorhombic forms; NMe₄, NEt₄, and PPh₄) and [NEt₄]₂[Sn(C₃S₄O)₃] revealed variations in the overall dianion structures. The geometry about tin in each case is essentially octahedral with the chelate bite angles in the range 80.7(5)–87.45(4)°: the range of Sn–S distances is 2.5207(18)–2.571(17) Å. A statistical analysis, carried out on the crystal structure data for the six complexes, indicated that the most critical factors in controlling the overall shape of the dianion were the distances of the Sn atom from the dithiolate ligand planes [Sn–OOP]. Interanionic S⋯S interactions, within the sum of the van der Waals’ radii for two S atoms, are affected by the size of the cation, Q; the secondary connectivity is 3-dimensional for the smallest cations, Q=1,4-dimethylpyridinium and NMe₄, in chains for the somewhat larger cation, NEt₄ and is absent for the still larger, PPh₄ cation.     

The reaction of [Ru(bpy)2(NO)Cl]2+ and [Fe(CN)5NO]2− with benzylamine: coordinated nitrosyl as an oxidizing agent

[Fe(CN)₅NO]^2–, (1) and [Ru(bpy)₂(NO)Cl]²⁺, (2) react with PhCH₂NH₂ to produce mainly N-benzylphenyl-methanimine and PhCN as oxidation products. (PhCH₂)₂NH, PhCH₂Cl and PhCH₂OH are formed as diazotization products. Products derived from the benzyl radical (such as PhMe), are also formed. Since oxidation products are generated even in the absence of oxygen, a mechanism in which the nitrosyl ligand acts as an oxidant is proposed.     

Double sandwich polyoxometalate and its Fe(III) substituted derivative, [As2Fe5Mo21O82]17– and [As2Fe6Mo20O80(H2O)2]16–

A double sandwich polyoxometalate and its Fe(III) substituted derivative, [As(2)Fe(5)Mo(21)O(82)](17-) (1) and [As(2)Fe(6)Mo(20)O(80)(H(2)O)(2)](16-) (2), were synthesized and characterized by single-crystal X-ray diffraction, infrared spectroscopy, fluorescent spectroscopy, UV spectra, thermogravimetry-differential scanning calorimetry analyses, electrospray ionization mass spectrometry, and magnetism measurements. The polyoxoanion is composed of a central fragment FeMo(7)O(28) for 1 (Fe(2)Mo(6)O(26)(H(2)O)(2) for 2) and two external AsMo(7)O(27) fragments linked together by two distinct edge-sharing dimeric clusters Fe(2)O(10) to lead to a C(2v) molecular symmetry. The central FeMo(7)O(28) fragment and external AsMo(7)O(27) fragment have a similar structure, and both of them can be viewed as a monocapped hexavacant α-Keggin subunit with a central FeO(4) group or a central AsO(3) group. Both of the polyoxoanions contain a oxo-bridged Fe(III)(5) magnetic core with the angles of Fe-O-Fe in the range of 96.4(4)-125.7(5)°, and magnetism measurements show an overall ferromagnetic interactions among the five-nuclearity cluster Fe(5) with the spin ground state S = 15/2.     

Synthesis and mononuclear complexes of the bis-bidentate ligand 2,5-di(2-pyridyl)-1,3,4-thiadiazole (dptd): spin crossover in [Fe(II)(dptd)2(NCSe)2] and [Fe(II)(dptd)2(NCBH3)2]·H2O

A simple and convenient protocol for the synthesis of the ligand 2,5-di(2-pyridyl)-1,3,4-thiadiazole (dptd) has been developed. Five new 2?:?1-type iron(II), cobalt(II), nickel(II) and copper(II) complexes have been prepared and structurally characterised, all of which feature the mononuclear trans-(N',N(1))(2) coordination mode. Spin crossover behaviour has been found for [Fe(II)(dptd)(2)(NCSe)(2)] (2) and [Fe(II)(dptd)(2)(NCBH(3))(2)]·H(2)O (3·H(2)O) with T(1/2) = 192 and 285 K, respectively, reflecting the increasing ligand field strength of the respective co-ligands and showing that the [Fe(II)(dptd)(2)L(2)] unit is suitable for the investigation of the co-ligand field effects on T(1/2). In addition, the 3?:?1-type low-spin complexes [Fe(II)(dptd)(3)]{B(CN)(4)}(2)·3MeOH (4·3MeOH) and [Fe(II)(dptd)(3)](OTf)(2)·1.25DCM·0.5H(2)O (5·1.25DCM·0.5H(2)O) have been studied by X-ray diffraction and have been found to exist exclusively as the mer or fac stereoisomer, respectively, in the solid state. In MeCN-d(3) solution the latter two complexes, as well as [Fe(II)(dptd)(3)](ClO(4))(2)·H(2)O (6·H(2)O), show counterion-independent stereoisomerisation, each yielding a ca. 3?:?1 mixture of mer and fac stereoisomers as identified by (1)H NMR spectroscopy.     

[Co(NioxH)2(PPh3)2]SiF5and [Co(NioxH)2(Thio)2]2SiF6· 3H2O Complexes: Synthesis and Structure

Compounds that form in the CoSiF₆· 6H₂O–NioxH₂–A–water–alcohol system, where A is thiourea (Thio) or triphenylphosphine (PPh₃) and NioxH₂is 1,2-cyclohexanedione dioxime, were synthesized and characterized by X-ray diffraction analysis. Crystal structures of the [Co(NioxH)₂(PPh₃)₂]SiF₅and [Co(NioxH)₂(Thio)₂]₂SiF₆· 3H₂O complexes were established. In octahedral Co(III) complexes, two radicals of 1,2-cyclohexanedione dioxime are bound by a hydrogen bond and are located in the equatorial plane. The intramolecular (– and H bonds) and intermolecular (C–H···F and H bonds) interactions in the crystal are discussed.     

The unusual stability of [NpO2Cl4]2−: Synthesis and characterisation of [NpO2(DPPMO2)2Cl]2[NpO2Cl4] and [Ph3PNH2]2[NpO2Cl4]

The [NpO₂(DPPMO₂)₂Cl][NpO₂Cl₄] complex (where DPPMO₂ = bis(diphenylphosphino)methanedioxide) contains the linear neptunyl group, {NpO₂}²⁺, with two bidentate P=O donor ligands. Coordinating anion Cl^? fills the fifth equatorial coordination site yielding a complex of general formula [NpO₂(DPPMO₂)₂X]₂[Y] (1) (where X = Cl^? and Y = [NpO₂Cl₄]^2?. Reaction between our newly prepared neptunium starting material [NpO₂Cl₂(thf)]_n and phosphinimine ligand produced crystals of [Ph₃PNH₂]₂[NpO₂Cl₄] (2). Compounds 1 and 2 have been structurally characterised.     

Iron salts with the tetracyanidoborate anion: [Fe(III)(H2O)6][B(CN)4]3, coordination polymer [Fe(II)(H2O)2{κ2N[B(CN)4]}2], and [Fe(II)(DMF)6][B(CN)4]2

The reaction of Fe(OH)(3) with tetracyanidoboronic acid, H[B(CN)(4)]·xH(2)O, in water leads to the first examples of tetracyanidoborates with a triply charged metal cation, [Fe(III)(H(2)O)(6)][B(CN)(4)](3) (1). Using elemental iron powder as starting material, [Fe(II)(H(2)O)(2){κ(2)ΝB(CN)(4)]}(2)] (2) is obtained. Anhydrous iron(II) tetracyanidoborate, which is synthesized by heating of 2, is soluble in dry dimethylformamide. After evaporation of the DMF solvent, single crystals of the third title compound, [Fe(II)(DMF)(6)][B(CN)(4)](2) (3), are obtained. Compound 3 is the first metal tetracyanidoborate soluble in nonpolar solvents. The title compounds have been characterized by single-crystal X-ray diffraction (1 rhombohedral, R3c (no. 167), a = 14.9017(7) ?, c = 20.486(1) ?, Z = 6; 2 tetragonal, I42d (no. 122), a = 12.3662(3) ?, c = 9.2066(4) ?, Z = 4; 3 triclinic, P1 (no. 2), a = 8.6255(3) ?, b = 11.0544(4) ?, c = 12.2377(5) ?, Z = 1). The metal ions in all three compounds are octahedrally coordinated. Whereas 1 and 3 are built up from isolated complex ions, 2 comprises a coordination polymer, in which the Fe(II) ion is coordinated by two oxygen atoms of two water molecules in a trans orientation and four nitrogen donor atoms of the [B(CN)(4)](-) groups, which bridge between neighboring iron ions. The iron(III) ion in 3 is in a perfect octahedral environment, which is formed by the O atoms of 6 molecules of water. The single-crystal X-ray structures, vibrational spectra, thermal properties, solubilities, and electrochemical characteristics are reported and compared with those of other known tetracyanidoborates.     

Polymethylated [Fe(η6-arene)2]2+ dications: methyl-group rearrangements and application of the EINS mechanism

Reactions between the methylated arenes ArMe(n) [where ArMe(n) = C(6)Me(n)H((6-n)), and n = 1-6] and FeCl(2) in heptane at 90 °C in the presence of anhydrous AlCl(3) give, for the arenes with n = 1-5, extensive isomerisations and disproportionations involving the methyl groups on the arene rings, and the formation of mixtures of [Fe(ArMe(n))(2)](2+) dications that defy separation into pure species. GC-MS studies of AlCl(3)/mesitylene and AlCl(3)/durene reactions in the absence of FeCl(2) (90 °C, 2 h) allow quantitative assessments of the rearrangements, and the EINS mechanism (electrophile-induced nucleophilic substitution) is applied to rationalise the phenomena. By contrast, ArMe(n) / FeCl(2) /AlCl(3) reactions in heptane for 24-36 h at room-temperature proceed with no rearrangements, allowing the synthesis of the complete series of pure [Fe(ArMen)](2+) cations in yields of 48-71%. The pure compounds are characterised by (1)H NMR spectroscopy and electrospray-ionization mass-spectrometry (ESI-MS), and the structures of [Fe(m-xylene)(2)][PF(6)](2) and [Fe(durene)(2)][PF(6)](2) are established by single-crystal X-ray diffraction analyses.     

Reaction of 2-(diphenylphosphino)-pyridine and -thiazole organoiron(0) polydentate ligands with iron(III) salts: X-ray structures of [η2-Ph2P(O)py]2Fe(μ-Cl)2FeCl2 and Fe(NCS)2[η2-Ph2P(O)taz]2 (taz=thiazole)

The reaction of trans-Fe(CO)₂(CS₂)(Ph₂Ppy-P)₂ (Ph₂Ppy=2-(diphenylphosphino)pyridine) with FeCl₃ resulted in the formation of the binuclear complex [η²-Ph₂P(O)py]₂Fe(μ-Cl)₂FeCl₂ (1), while the reaction of trans-Fe(CO)₃(Ph₂Ptaz-P)₂ (Ph₂Ptaz=2-(diphenylphosphino)thiazole) with Fe(NCS)₃ gave Fe(NCS)₂[η²-Ph₂P(O)taz]₂ (2). The crystal structures of (1) and (2)·C₆H₆ have been determined using X-ray crystallography.     

121Sb and57Fe Mössbauer spectra of antimony-containing iron carbonyl complexes: [HSb{Fe(CO)4}3]2− and [Sb{Fe(CO)4}4]3−

¹²¹Sb Mössbauer spectra of the title complexes, whose isomer shifts are intermediate between the organoantimony(III) and organoantimony(V) compounds, suggest that considerable electrons are donated from hydrido ligand and Fe(CO)₄ fragments to the antimony atom.     

[2Fe2S]铁硫蛋白活性中心模型[Fe2S2(SR)4]2-(R=-H,-CH3)的局部自旋探讨

为了检验Davidson和Clark的局部自旋原理对铁硫蛋白簇合物的可行性,[Fe2S2(SR)4]2-(R=-H,-CH3)模型被选为研究对象.该目的可通过计算这些体系的局部自旋期望值〈SA.SB〉,〈S2A〉和mA,并讨论它们与Heisenberg自旋模型(HSM)和Noodleman对称破缺理论之间的联系来实现.在具体的计算中采用了自旋非限制Hartree-Fock(UHF)和自旋极化密度泛函(Spin-polarized DFT)方法,同时比较它们的计算质量.此外,采用多种方案计算了它们的交换耦合常数,并同前人的结果作了比较.     

A Study on Thermal Decomposition of K_3[Fe(CN)_6] and KFe[Fe(CN)_6] in Helium

K3 [Fe(CN)6] and KFe[Fe(CN)6] are classical coordination compounds. However, the mechanism of decomposition reactions has not been well expounded. The gas products of thermal decomposition were examined by gas chroma tography (GC) , and the structure of the solid products by Mossbauer spectroscopy(MS) and X-ray diffraction(XRD). The findings are explained in terms of the theory of coordination chemistry and a decomposition mechanism is proposed in this study. On the basis of various experimental results, the first stage of the decomposition of K3[Fe(CN)6] in He was found to be the evolution of(CN)2 resulting in the reduction of Fe(Ⅲ)12K3 [Fe(CN)6]→9K4[Fe(CN)6] + Fe2 [Fe(CN)6] + 6 ( CN )For KFe [Fe(CN) 6 ], the first stage of decomposition man be represented as6KFe[Fe(CN)6]→3K2Fe[Fe(CN)6] + 2Fe2[Fe(CN)6 + 3(CN)2At higher temperatures, the decomposition of both K3[Fe(CN)6) andKFe[Fe(CN)6] to form KCN and Fe2C was accomplished by the release of(CN)2 and N2.     

The reactions of [Fe2(η-Cp)2(CNAr)4] complexes with halogens and tin(II) halides

Summary [Fe₂(-Cp)₂(CNAr)₄] (2) (540-01, C₆H₄Me-2, C₆H₄Et-2, C₆H₃Me₂-2,4, C₆H₃Me₂-2,6, C₆H₃(Me)Et-2,6, C₆H₃Et₂-2,6 or C₆H₃ i-Pr₂-2,6) react with I₂ to give [Fe(-Cp)(CNAr)₂I], but with Br₂[Fe(-Cp) (CNAr)₃]⁺ salts are the only products; IBr gives a mixture of the two. With SnX₂ (X = F, Cl, Br or I) in refluxing n-butanol, (2) gives isolable [{Fe(-Cp)(CNAr)₂}₂SnX₂] only when the CNAr ligands have two ortho substituents, otherwise decomposition occurred. When X = F, [Fe(-Cp) (CNAr)₂SnF₃] was also obtained from this reaction. Attempts to prepare [Fe(-Cp)(CNAr)₂X] (X = Cl or Br) by reaction of (2) with HX in the presence of air gave rather unstable products which with SnX₂ formed [Fe(-C₅H₅)-(CNAr)₂SnX₃]. Similar compounds, [Fe(-Cp) (CNAr)₂ SnX₂I], were obtained from [Fe(-Cp)-(CNAr)₂I] and SnX₂ (X = Cl or Br but not I). All of these complexes are much less stable than their Fe(-Cp)(CO)₂ counterparts; all decompose in solution to [Fe(-Cp)(CNAr)₃]⁺ which then break down to unidentified species. X-ray diffraction studies show that in [Fe(-Cp)(CNC₆H₃-i-Pr₂-2,6)₂I] and [{Fe(-Cp)(CNC₆H₃Me₂-2,6)₂}₂SnBr₂] there is pseudo-octahedral coordination about Fe. In the latter there is also distorted tetrahedral coordination about Sn so that its structure is very similar to that of [{Fe(-Cp)(CO)₂}₂SnCl₂]. Spectroscopic studies show that in all complexes rotation of the aryl rings of the CNAr ligands cannot be slowed in solution, and that there is free rotation about all 540-02 bonds.     

Synthesis and structure of novel dinitrosyl iron complexes [Fe2(μ-SCH2CH2NHR)2(NO)4]

Two novel dinitrosyl iron complexes with thiolate bridging ligands [Fe₂(μ-SCH₂CH₂NHR)₂(NO)₄] (R = Ac, Boc), derived from the cysteamine complex [Fe₂(μ-SCH₂CH₂NH₃)₂(NO)₄]²⁺ are described. The complex with acylated cysteamine is characterized by X-ray diffraction analysis. The cysteamine complex is a convenient precursor for modification of the bridging ligand.