3d-Metal nitroprusside-4-phenylthiosemicarbazide complexes: Synthesis and properties

3d-Metal nitroprusside complexes with 4-phenylthiosemicarbazide of the composition [ML₂][Fe(CN)₅NO] and [CoL₃]₂[Fe(CN)₅NO]₃(M = Ni, Cu, Zn; L = 4-phenylthiosemicarbazide) are synthesized and their structures and physicochemical properties are studied by IR and diffuse reflection spectroscopy and DTA.     

Hydrothermal synthesis of the fist two‐dimensional folded layer formed by a cyano‐bridged one‐dimensional chain joined by Cu(I)?Cu(I) bonding

Two cyano‐bridged polymers, [Cu₃(CN)₃(phen)]_n ( 1 ) and [Cu(CN)(phen)]_n ( 2 ) (phen = 1,10‐phenphralonine), were synthesized by the hydrothermal reaction of Cu(NO₃)₂· 3H₂O, K₃[Fe(CN)₆] and phen and were characterized structurally by X‐ray, IR and ERSC methods. Compound 1 shows a two‐dimensional folded coordination network by Cu(I)? CN? Cu(I) and Cu(I)? Cu(I) interaction, while compound 2 exhibits an infinite helix chain by Cu(I)? CN linkages. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis, crystal structures and magnetic properties of single and double cyanide-bridged bimetallic Fe2(III)Cu(II) zigzag chains

The bimetallic complexes [[Fe(III)(phen)(CN)4]2Cu(II)(H2O)2].4H2O (1), [[Fe(III)(phen)(CN)4]2Cu(II)].H2O (2) and [[Fe(III)(bipy)(CN)4]2Cu(II)].2H2O (3) and [[Fe(III)(bipy)(CN)4]2Cu(II)(H2O)2].4H2O (4) (phen = 1,10-phenanthroline and bipy = 2,2'-bipyridine) have been prepared and the structures of 1-3 determined by X-ray diffraction. The structure of 1 is made up of neutral cyanide-bridged Fe(III)-Cu(II) zigzag chains of formula [[Fe(III)(phen)(CN)4]2Cu(II)(H2O)2] and uncoordinated water molecules with the [Fe(phen)(CN)4]- entity acting as a bis-monodentate bridging ligand toward two trans-diaquacopper(II) units through two of its four cyanide groups in cis positions. The structure of 2 can be viewed as the condensation of two chains of 1 connected through single cyanide-bridged Fe(III)-Cu(II) pairs after removal of the two axially coordinated water molecules of the copper atom. The structure of 3 is like that of 2, the main differences being the occurrence of bipy (phen in 2) and two (one in 2) crystallization water molecules. The crystals of 4 diffract poorly but the analysis of the limited set of diffraction data shows a chain structure like that of 1 the most important difference being the fact that elongation axis at the copper atom is defined by the two trans coordinated water molecules. 1 behaves as a ferromagnetic Fe(III)2Cu(II) trinuclear system. A metamagnetic-like behavior is observed for 2 and 3, the value of the critical field (Hc) being ca. 1100 (2) and 900 Oe (3). For H > Hc the ferromagnetic Fe(III)2Cu(II) chains exhibit frequency dependence of the out-of-phase ac susceptibility signal at T < 4.0 K. The magnetic behavior of 4 corresponds to that of a ferromagnetically coupled chain of low spin iron(III) and copper(II) ions with frequency dependence of the out-of-phase susceptibility at T < 3.0 K. Theoretical calculations using methods based on density functional theory (DFT) have been employed to analyze and substantiate the exchange pathways in this family of complexes.     

Copper(II) cyanido-bridged bimetallic nitroprusside-based complexes: Syntheses, X-ray structures, magnetic properties, Fe Mössbauer spectroscopy and thermal studies

Three heterobimetallic cyanido-bridged copper(II) nitroprusside-based complexes of the compositions [Cu(tet)Fe(CN)₅NO]·H₂O (1), where tet=N,N′‐bis(3-aminopropyl)ethylenediamine, [Cu(hto)Fe(CN)₅NO]·2H₂O (2), where hto=1,3,6,9,11,14-hexaazatricyclo[12.2.1.1^6,9]octadecane and [Cu(nme)₂Fe(CN)₅NO]·H₂O (3), where nme=N-methylethylenediamine, were synthesized and characterized by elemental analyses, ⁵⁷Fe Mössbauer and FTIR spectroscopies, thermal analysis, magnetic measurements and single-crystal X-ray analysis. The products of thermal degradation processes of 2 and 3 were studied by XRD, ⁵⁷Fe Mössbauer spectroscopy, SEM and EDS, and they were identified as mixtures of CuFe₂O₄ and CuO.     

3d-Metal Nitroprusside–Thiosemicarbazide Complexes: Synthesis and Properties

The following complexes were synthesized from 3d-metal nitroprussides and thiosemicarbazide: [CrL₃][Fe(CN)₅H₂O] · 6H₂O, [FeL₃]₂[Fe(CN)₅NO]₃ · 14H₂O, [CoL₃]₂[Fe(CN)₅NO]₃ · 4H₂O, [NiL₂][Fe(CN)₅NO], [CuL₂][Fe(CN)₅NO] · 5H₂O, and [[ZnL₂][Fe(CN)₅NO], where L is thiosemicarbazide. Their structures and properties were studied by IR and diffuse reflection spectroscopies and DTA.     

Synthesis, Characterization and Crystal Structure of the First Tri-nuclear MFe2（M = Cu and Ni） Complexes Based on Nitroprusside

IntroductionSince 184 8,whenPlayfairpublishedthefirstpaperrelatedtonitroprussides ,1thetransitionmetalpenta cyanonitrosylmetallatehydrateshavebeenwidelystudiedbecauseoftheirimportantrolesinmolecularsieves ,cationexchangers,electronscavengersandradionuclidesor bents .2 4 Thenitroprussides ,regardlessofthecationicmetal,arecurrentlyemployedasreversibleinhibitorsofagroupofenzymesknownassuperoxidedismutases .5Recently ,using [Fe(CN ) 5(NO) ]2 - asabuildingblock ,somenitroprusside bridgedpolymeri…     

Synthesis,structure, DNA-binding,and nuclease activity of a 3d–4f mixed metal nitrosyl complex, [Pr(phen)2(MeOH)(H2O)2][Fe(CN)5(NO)] · (Phen)(DMF)(MeOH)(H2O)

A cyano-bridged heterometallic lanthanide-transition metal nitrosyl complex, [Pr(phen)₂(MeOH)(H₂O)₂][Fe(CN)₅(NO)]?·?(Phen)(DMF)(MeOH)(H₂O) (Phen?=?1,10-phenanthroline and DMF?=?dimethylformamide), has been synthesized from reaction of PrCl₃?·?6H₂O with 1,10-phenanthroline in methanol and sodium nitroprusside followed by crystallization from DMF. The crystal structure shows that the complex is a 1-D chain, stabilized by coordination, hydrogen-bonding, and π–π stacking interactions. The complex shows nuclease activity with pUC19 supercoiled DNA in DMF/Tris-HCl buffer in the presence of H₂O₂.     

Cyanonitrosylferrate und Cyanocarbonylnitrosylferrate niedriger Oxydationsstufen

Cyanonitrosylferrates and Cyanocarbonylnitrosylferrates of Low Oxidation States By the reduction of sodium nitroprusside with alkali metals in liquid ammonia the cyanonitrosylferrates [Fe[CN]₅, NO]^3?, [Fe(CN)₄, NO]^2?, [Fe(CN)₄N0]^3? and [Fe(CN)₃N0]^4? are formed. Preparation and properties of these reduction products (Table 1) and of the cyanocarbonylnitrosylferrates still missing within the series [Fe(CN)_n(CO)_3?nNO]^(n+l)? (n = 1 and 2) are described. Structure and bonding of these complexes are discussed with respect to their magnetic properties and their i.r. spectra.     

Dinuclear complexes with a μ-cyano ligand. XII [1]. synthesis and characterization of cis-[(aa)2FCr–NC–Fe(CN)4NO] (aa = 1,3-propanediamine and 1,2-cyclohexanediamine) kinetics of the anation in the solid state

The new mixed complex salts trans-[CrF(aa)₂(H₂O)][Fe(CN)₅NO] · nH₂O (aa = ethylenediamine, 1,3-propanediamine, and 1,2-cyclohexanediamine) have been synthesized. From solid state heating of these complexes, the two new dinuclear compounds, cis-[(aa)₂FCr? NC? Fe(CN)₄NO] (aa = 1,3-propanediamine and 1,2-cyclohexanediamine) have also been synthesized. All the attempts to prepare the cis or trans-[(en)₂FCr? NC? Fe(CN)₄NO] failed. All the new complexes have been characterized by means of chemical analysis, electronic and infrared spectra, and TG measurements. The kinetics of the solid state dehydration-anation has been investigated in the case of trans-[CrF(chxn)₂(H₂O)][Fe(CN)₅(NO)] by means of isothermal thermogravimetry. From the Activation Energy found (ca. 40 kcal/mol) and by comparison with other data, a chemical mechanism for the dehydration reaction is proposed.     

Reductive nitrosylation of tetraoxometallates. part V1. single pot and A virtually single step synthesis of chromium(l) cyanonitrosyl derivatives directly from chromate(VI) in aqueous-aerobic media.

Cyanonitrosyl complexes and their derivatives of the types [Cr(NO)(CN)₄]^2?, [Cr(NO)(CN)₃H₂O]^? and [Cr(NO)(CN)₂ LL] [LL = 2,2′ bipyridine (bipy) or 1, 10-Phenanthroline (phen)] are synthesised directly from CrO₄^2? using NH₂OH.HCl, OH^? and CN^? and other appropriate ligands, virtually in a single step process in an aqueous aerobic medium. The compounds are characterised by IR, molar conductance, magnetic susceptibility, e.s.r, electronic spectra and thermoanalytical data.     

Equilibria in complexes of N-heterocyclic molecules,part 44. The thermogravimetric behaviour of a Schilt-Barbieri compound dicyanobis-(1,10-phenanthroline) iron(II) dihydrate,Fe(phen)2(CN)2 · 2H2O

Summary The thermogravimetric behaviour of Fe(phen)₂(CN)₂ · 2H₂O (phen = 1,10-phenanthroline) is discussed by comparison with that of phen · H₂O. It is shown that the crystal water of the Schilt-Barbieri compound is released only at 323.5 °C. After water loss, the complex decomposes immediately.Covalent hydrate formation for diimines or their complexes was discussed recently⁽¹⁾. In general, formation of covalent hydrates, containing moieties like, should be favoured by electron-withdrawing substituents while true hydrates, containing essentially intact molecules of water, are easily formed by electron-releasing substituents.Although no covalent hydrate has yet been established in a coordinated N-heterocycle by x-ray structural analysis, there are some cases which could involve covalent hydrate formation for diimines. One such is the strange claim that Fe(phen)₂(NCS)₂ · H₂O is diamagnetic at room temperature whereas anhydrous Fe(phen)₂(NCS)₂ is paramagnetic⁽²⁾, though this apparently well-studied system is almost certainly complicated by the existence⁽³⁾ of several distinct solid phases of composition Fephen₂(NCS)₂ · nH₂O. The differences in the n.m.r. spectra of the compounds [Fe(LL)(CN)₄]^2– (LL = phen, bipy and 5,5-Me₂-bipy) in D₂O are equally interesting. While the last two display the two-fold symmetry expected of the diimine ligand LL, the former shows⁽⁴⁾ an unexpected corresponding inequivalence.Moreover, the circular dichroism spectrum of optically active Fe(phen)₂(CN)₂ in acid solution shows the surprising feature that a c.d. band is observed in the visible region but the absorption in the u.v. region disappears⁽⁴⁾ completely. We have reconfirmed this finding. Despite the apparent ease of obtaining attractive crystals of the dihydrate Fe(phen)₂(CN)₂ · 2H₂O, there have been crystallographic problems that have so far prevented the solution of this problem by x-ray diffraction methods⁽⁵⁾, although we have been able to obtain the structure of the adduct (±)cis-[Fe(phen)₂(CN)₂]2Hg(CN)₂.In 1,10-phenanthroline monohydrate, despite crystallographic difficulties, there is now no doubt that the unit of structure is the hydrogen-bonded true hydrate. 1,10-Phenanthroline, despite being a substituted quinoline, seems not to form a classical Reissert compound, but the evidence for the (invariably assumed) simple structure of the Schilt-Barbieri compounds [Fe(LL)₂(CN)₂] is not strong. For example, there seems to be no report of an unsolvated solid.We therefore decided to compare the thermogravimetric behaviour of phen · H₂O and Fe(phen)₂(CN)₂ · 2H₂O.The compound phen · H₂O is commercially available (BDH Chemicals Ltd. Poole, England) while Fe(phen)₂(CN)₂ · 2H₂O was obtained by the method of Schilt⁽⁶⁾.On continuous heating under a atmosphere of dinitrogen, the water of phen · H₂O is released at 93 °C. The resulting anhydrous 1,10-phenanthroline is still stable, m.p. 117 °C (see Figure 2). The water molecules (one-step mechanism) of Fe(phen)₂(CN)₂ · 2H₂O are, however, released at the remarkably high temperature of 323.5 °C followed by an immediate decomposition of the anhydrous phase (see Figure 3).Other than the possibility of very strong hydrogen bonds being present in the structure of Fe(phen)₂(CN)₂ · 2H₂O, covalent hydrate formation could account for this unexpected behaviour. Further investigations on these Schilt-Barbieri compounds are in progress.     

Zur Leitfähigkeitstitration von Nitrosylkomplexen mit Alkalimetallen in flüssigem Ammoniak

On the Conductometric Titration of Nitrosyl Complexes with Alkali Metals in Liquid Ammonia The conductometric titration has been found to be a convenient method for studying the reduction of nitrosyl complexes. The results of such titrations can easily be transferred to a preparative scale. For example, the reduction of [Mn(CN)₅NO]^3? to [Mn(CN)₄NO]^4?, of [Cr(CN)₅NO]^3? leading to NO bridged cyanonitrosyl-dichromates (?II), and of [Fe(CO)₃NO]^? to [Fe(CO)₃NO]^5?, in which the reduction takes place on the ligands, are described.     

Synthesis,crystal structure and magnetic properties of the first dinuclear copper(II)–iron(II) complex [Cu(L)Fe(CN)5NO] based on nitroprusside

The nitrosyl cyanide [Cu(L)Fe(CN)₅NO] was prepared by the reaction of [Cu(L)]Cl₂ [L = 3, 10-bis(2-hydroxymethyl)-1,3,5,8,10,12-hexaazacyclotetradecane] with Na₂[Fe(CN)₅NO]·2H₂O in aqueous solution. Single-crystal analysis revealed that the title complex is the first structurally characterized dinuclear copper(II)–iron(II) complex based on the nitroprusside. Variable temperature magnetic susceptibility measurements (4.0–180.0 K) show the occurrence of very weak antiferromagnetic interactions between the copper(II) ions with zJ = –0.410 cm^–1.     

Synthesis, crystal structures, and magnetic properties of cyano-bridged heterobimetallic chains based on [(Tp)Fe(CN)3]-

With the use of the tailored cyanometalate precursor, (Bu4N)[(Tp)Fe(CN)3] (Tp = Tris(pyrazolyl)hydroborate) as the building block to react with fully solvated Cu(II), Co(II), and Ni(II) cations, four one-dimensional (1D) heterobimetallic cyano-bridged chain complexes of squares, [(Tp)2Fe(III)2(CN)6Cu(CH3OH).2CH3OH]n (1), [(Tp)2Fe(III)2(CN)6Cu(DMF).DMF]n (2), [(Tp)2Fe(III)2(CN)6M(CH3OH)2.2CH3OH]n (M = Co (3) and Ni (4)), have been prepared. In complexes 1 and 2, the Cu(II) ions are pentacoordinated in the form of a slightly distorted square-based pyramid, and they are linked by distorted octahedrons of [(Tp)Fe(CN)3]- to form 1D chains of squares. In complexes 3 and 4, both the central Co(II) and Ni(II) ions have a slightly distorted octahedral coordination geometry, and they are bridged by [(Tp)Fe(CN)3]- to form similar 1D chains of squares. There are weak interchain pi-pi stacking interactions through the pyrazolyl groups of the Tp ligands for complexes 3 and 4. The crystal structures and magnetic studies demonstrate that complexes 1 and 2 exhibit intrachain ferromagnetic coupling and single-chain magnets behavior, and the blocking temperature is ca. 6 K for complex 1 and ca. 3 K for complex 2. Complexes 3 and 4 show significant metamagnetic behavior, where the cyanides mediate the intrachain ferromagnetic coupling between Fe(III) and Co(II) or Ni(II) ions and the interchain pi-pi stacking interactions lead to antiferromagnetic couplings. The field dependence of the magnetization measurements shows that the critical field is around 1 kOe for complex 3 and 0.8 kOe for complex 4 at 1.8 K.     

Metal complexes as color indicators for the determination of acid-base properties of solid catalysts

The Lewis acid-basicity of a solid catalyst was determinated by using solution of Cu(tmen) (acac) (NO₃) and Fe(phen)₂ (CN)₂ as Lewis acid-base indicators.     

Low‐dimensional compounds containing cyano groups. XVI. (Dicyanamido‐κN1)bis(1,10‐phenanthroline‐κ2N,N′)copper(II) tetrafluoridoborate

The title compound, [Cu{N(CN)₂}(C₁₂H₈N₂)₂]BF₄, was prepared as part of our study of the shape of coordination polyhedra in five‐coordinated copper(II) complexes. Single‐crystal X‐ray analysis reveals that the structure consists of [Cu{N(CN)₂}(phen)₂]⁺ cations (phen is 1,10‐phenanthroline) and BF₄⁻ anions. The Cu centre is five‐coordinated in a distorted trigonal bipyramidal manner by four N atoms of two phen ligands and one N atom of a dicyanamide anion, which is coordinated in the equatorial plane at a distance of 1.996 (2) Å. The two axial Cu—N_phen distances have similar values [average 1.994 (6) Å] and are shorter than the two equatorial Cu—N_phen bonds [average 2.09 (6) Å]. This work demonstrates the effect of ligand rigidity on the shape of coordination polyhedra in five‐coordinated copper(II) complexes.     

Über Metall-Stickoxid-Komplexe. XXV. Zur Kenntnis von Nitrosylcyano-Komplexen der Metalle der Eisengruppe

The binuclear nitrosylhalides of iron and cobalt react with cyanide to anionic complexes [M(NO)₂(CN)₂]^? (M = Fe, Co). Substituted monomeric compounds M(NO)₂LBr and Ni(NO)L₂Br lead primarily under replacement of bromide to nonionic complexes M(NO)₂LCN and Ni(NO)L₂CN. In general these complexes react with more cyanide yielding anions [M(NO)₂(CN)₂]^?, [Ni(NO)L(CN)₂]^? and [Ni(NO)(CN)₃]^2?. The paramagnetic dinitrosyliron compounds can be reduced to diamagnetic complexes by Na/Hg. A disproportion reaction of Co(NO)₂P(C₆H₅)₃CN forms a salt [Co(NO)₂ · (P(C₆H₅)₃)₂][Co(NO)₂(CN)₂], a similar salt can be made by the reaction of Na[Co(NO)₂(CN)₂] with [Co(NO)₂(NHP(C₆H₅)₃₂]Br. The IR spectra are discussed.     

Synthesis, characterization, and fluorescent properties of two Pb(II) complexes: {[Pb(hca)2·DMF]·DMF}∞ and [Pb(hca)2(phen)·DMF]2

Two novel Pb(II) complexes, {[Pb(hca)₂·DMF]·DMF}_∞ and [Pb(hca)₂(phen)·DMF]₂ (hca=trans-4-hydroxycinnamic group), were obtained by solid-phase reactions of PbAc₂ and Hhca and PbAc₂, Hhca, and phen, respectively, and characterized by spectroscopy. X-ray crystallography analysis reveals that complex 1, {[Pb(hca)₂·DMF]·DMF}_∞, adopts a 2-dimensional structure through the weak interactions of Pb and O atoms and that complex 2, [Pb(hca)₂(phen)·DMF]₂, shows a discrete dimeric structure, in which hydrogen bonds link the dimers into a 2D network. Both complexes 1 and 2 show visible fluorescence and the intensity is stronger than that of the ligand. More interestingly, the intensity of emission was increased at least fivefolds when the pH of the solution was adjusted to alkalinity. This can be attributed to that the deprotonization of phenolic group enhancing the conjugation of the ligand hca. These results indicate that this method may be an effective way to increase the emission intensity of similar complexes.     

Darstellung und Eigenschaften von Vanadyl(IV)-Pentacyanonitrosylferrat(II), VO[Fe(CN)5NO] · 2 H2O

Preparation and Properties of Vanadyl(IV) Pentacyanonitrosylferrate(II), VO[Fe(CN)₅NO] · 2 H₂O The preparation of VO[Fe(CN)₅NO] · 2 H₂O is described for the first time. Its electronic, infrared, and ⁵⁷Fe-Mössbauer spectra were recorded and discussed. The thermal degradation was investigated by means of TG and DTA measurements and shows a very complex behaviour. A new preparative method for (VO)₂[Fe(CN)₆] · 10 H₂O is also described and some of its spectroscopic properties were investigated and compared with those of VO[Fe(CN)₅NO] · 2 H₂O.     

Cyano-bridged FeIII2CuII3 and FeIII4NiII4 complexes: syntheses, structures, and magnetic properties

Two tricyanometallate precursors, (Bu4N)[(Tp4Bo)Fe(CN)3].H2O.2MeCN (1) and (Bu4N)[(pzTp)Fe(CN)3] (2) [Bu4N+ = tetrabutylammonium cation; Tp4Bo = tris(indazolyl)hydroborate; pzTp = tetrakis(pyrazolyl)borate], with a low-spin FeIII center have been synthesized and characterized. The reactions of 1 or 2 with [Cu(Me3tacn)(H2O)2](ClO4)2 (Me3tacn = N,N',N' '-trimethyl-1,4,7-triazacyclononane) afford two pentanuclear cyano-bridged clusters, [(Tp4Bo)2(Me3tacn)3Cu3Fe2(CN)6](ClO4)4.5H2O (3) and [(pzTp)2(Me3tacn)3Cu3Fe2(CN)6](ClO4)4.4H2O (4), respectively. Assembly reactions between 2 and [Ni(phen)(CH3OH)4](ClO4)2 (phen = 1,10-phenanthroline) or Zn(OAc)2.2H2O afford a molecular box [(pzTp)4(phen)4Ni4Fe4(CH3OH)4(CN)12](ClO4)4.4H2O (5) and a rectangular cluster [(pzTp)2Zn2Fe2(OAc)2(H2O)2(CN)6] (6). Their molecular structures were determined by single-crystal X-ray diffraction. In complexes 1 and 2, the central FeIII ions are coordinated by three cyanide carbon atoms and three nitrogen atoms of Tp4Bo- or pzTp-. Both complexes 3 and 4 show a trigonal-bipyramidal geometry, in which [(L)Fe(CN)3]- units occupy the apical positions and are linked through cyanide to [Cu(Me3tacn)]2+ units situated in the equatorial plane. Complex 5 possesses a cubic arrangement of eight metal irons linked through edge-spanning cyanide bridges, while complex 6 shows Zn2Fe2(CN)4 rectangular structure, in which FeIII and ZnII ions are alternately bridged by the cyanide groups. Intramolecular ferromagnetic couplings are observed for complexes 3-5, and they have S = 5/2, 5/2, and 6 ground states and appreciable magnetic anisotropies with negative D values equal to -0.49, -2.39, and -0.39 cm-1, respectively.