A High-Spin Cyanide-Bridged Mn9W6 Cluster (S = 39/2) with a Full-Capped Cubane Structure

Structures of high coordination complexes

EPR detection of a cryogenically photogenerated intermediate in photosynthetic oxygen evolution

Supramolecular coordination networks based on octacyanometalates: From structure to function

Nonconventional heptacoordination in combination with efficient magnetic exchange coupling is shown to yield a 1-D heteronuclear {FeIINbIV} compound with remarkable magnetic features when compared to other Fe(II)-based single chain magnets (SCM). Cyano-bridged heterometallic {3d-4d} and {3d-5d} chains are formed upon assembling Fe(II) bearing a pentadentate macrocycle as the blocking ligand with octacyano metallates, [M(CN)8]4− (M = NbIV, MoIV, WIV). X-ray diffraction (single-crystal and powder) measurements reveal that the [{(H2O)Fe(L1)}{M(CN)8}{Fe(L1)}]∞ architectures consist of isomorphous 1-D polymeric structures based on the alternation of {Fe(L1)}2+ and {M(CN)8}4− units (L1 stands for the pentadentate macrocycle). Analysis of the magnetic susceptibility behavior revealed cyano-bridged {Fe−Nb} exchange interaction to be antiferromagnetic with J = −20 cm−1 deduced from fitting an Ising model taking into account the noncollinear spin arrangement. For this ferrimagnetic chain a slow relaxation of its ma...

Enhanced Ion Anisotropy by Nonconventional Coordination Geometry: Single-Chain Magnet Behavior for a [{FeIIL}2{NbIV(CN)8}] Helical Chain Compound Designed with Heptacoordinate FeII

K4W(CN)8 · 2 H2O was prepared by the reduction of WO (in potassium cyanide medium) by KBH4. The reduction proceeds on the slow, drop-by-drop addition of concentrated acetic acid. The synthesis is simple and efficient because the reduction and complexation are accomplished at the same time.



Darstellung von K4W(CN)8 · 2 H2O



K4W(CN)8 · 2 H2O ist hergestellt worden durch Reduktion von WO mit KBH4 in Gegenwart von KCN. Die Reduktion findet wahrend langsamer Zugabe von Essigsaure statt. Reduktion und Komplexbildung finden gleichzeitig statt, daher wird eine gute Ausbeute erhalten.

The preparation of potassium octacyanotungstate(IV) dihydrate

[HN(n-C4H9)3]3M(CN)8 4 H2O, where M = Mo or W, is formed as a light yellow or white water insoluble precipitate by adding tri-n-butylammonium ions to M(CN), obtained by oxidation of K4Mo(CN)8· 2H2O or K4W(CN)8·2H2O with concentrated nitric acid. The precipitates are soluble in methyl and ethyl alcohol, benzene and acetonitrile. Crystal data were determined for crystals of the Wv compound. The tri-n-butylammonium compound can be nearly quantitatively converted to Cs3M(CN)8· 2H2O with CsCl, which is fairly soluble in methyl alcohol. Crystal data were determined for light yellow crystals obtained by recrystallization. The potassium complex of Wv can be prepared by using potassium acetate instead of CsCl.



Darstellung von Cs3Mo(CN)8·3H2O und Cs3W(CN)8·2H2O



[HN(n-C4H9)3]3M(CN8)·4H2O, mit M = Mo oder W, entsteht als hellgelber oder weiser Niederschlag, wenn Tri-n-butylammonium-Ionen zu einer M(CN)-Losung erhalten durch Oxydation von K4Mo(CN)8·2H2O oder K4W(CN)8·2H2O mit konzentrierter Salpetersaure, gegeben werden. Die Niederschlage sind loslich in Methyl- und Athylalkohol, Benzol und Acetonitril. Kristalldaten fur Kristalle der Wv-Verbindung wurden bestimmt. Die Tri-n-butylammonium-Verbindung kann fast quantitativ in Cs3M(CN)8· 2H2O mit CsCl, das einigermasen loslich in Methylalkohol ist, umgewandelt werden. Fur die hellgelben Kristalle dieser Verbindung, durch Umkristallisation erhalten, wurden Kristalldaten ermittelt. Die Wolfram(V)-Kalium-Verbindung kann mittels Kaliumacetat statt CsCl hergestellt werden.

The preparation of Cs3Mo(CN)8·2H2O and Cs3W(CN)8·2H2O

The crystal structure of the compound C8Cl4H32N8O12W has been determined by means of three-dimensional X-ray analysis. The space group is C2/c and the cell dimensions are a = 18.01, b = 19.42, c = 12.51 A; β = 111.23°, Z = 4. The corresponding Mo compound is isomorphous with the W compound. The W(CN) ion has only C2 symmetry whilst the coordination polyhedron is an approximate square antiprism. The average dimensions for the octacyanotungstate(IV) ion are: W—C = 2.176, C—N = 1.151 W—N = 3.323 A and the angle W—C—N = 175.3°. The W—C bonds form an averaged angle of 56.1° with the theoretical 8 axis of the anion.



Die quadratisch-antiprismatische Konfiguration des Oktacyanowolframat-(IV)-Ions. Die Kristallstruktur des H4W(CN)8 · 4 HCl · 12 H2O



Die Kristallstruktur der Verbindung C8Cl4H32N8O12W wurde aus dreidimensionalen Rontgenbeugungsdaten bestimmt. Die Kristalle sind monoklin — Raumgruppe C2/c — mit vier Formeleinheiten in der Elementarzelle. Die Zellkonstanten sind: a = 18,01, b = 19,42, c = 12,51 A, β = 111,23°. Die entsprechende Mo-Verbindung ist isomorph mit der W-Verbindung. Das W(CN)-Ion hat nur C2-Symmetrie, wahrend das Koordinationspolyeder annahernd ein viereckiges Antiprisma ist. Die mittleren Abmessungen fur das Oktacyanowolframat(IV)-Ion sind: W—C = 2,176 A, C—N = 1,151 A, W—N = 3,323 A und der Winkel W—C—N = 175,3°. Die W—C-Bindungen haben einen mittleren Winkel von 56,1° mit der theoretischen 8 Achse des Anions.

The Square Antiprismatic Configuration for the Octacyanotungstate(IV) Ion. The Crystal Structure of H4W(CN)8 · 4HCI · 12H2O

β-Diketonkomplexe vom Typ M(LL)4, worin M = Zr, Hf, Th sowie U und LL = β-Diketone verschiedener Saurestarken, d. h. Acetylaceton, Dibenzoylmethan, Thenoyltrifluoroaceton, Trifluoroacetylaceton, und Hexafluoroacetylaceton bedeuten, wurden fur die Darstellung von Addukten des Typs M(LL)4 · S, verwendet. Darin bedeutet S die neutralen Phosphorester TBP, TOPO, TPPO, und TPP (vgl. Abstract). Es zeigte sich, das mit den Zr-, Hf-, und U-Komplexen keine Addukte entstehen. Addukte der Th-Komplexe bildeten sich nur, wenn die β-Diketone relativ starke Sauren waren, d. h. Thenoyltrifluoroaceton, Trifluoroacetylaceton und Hexafluoroacetylaceton. Aus den Versuchen geht hervor, das die Moglichkeit zur Bildung von Addukten zwischen β-Diketons, die Basizitat des Phosphoresters, die Ionenradien und die Elektronenkonfiguration des Metalles beeinflust wird.



β-diketone complexes of the type M(LL)4, where M = Zr(IV), Hf(IV), Th(IV) and U(IV), and LL = β-diketone with different acid strengths, viz. acetylacetone, dibenzoylmethane, thenoyltrifluoroacetone, trifluoroacetylacetone and hexafluoroacetylacetone were used to prepare adducts of the type M(LL)4 · S, where represents the neutral phosphorus esters with various basicities, viz. tributylphosphate, trioctylphosphine oxide, triphenylphosphine oxide and triphenylphosphate. It was found that no adducts of the Zr(IV), Hf(IV) and U(IV) complexes were formed Adducts of the Th(IV) complexes were formed only if the β-diketones were relatively strong acids, e. g. thenoyltrifluoroacetone, trifluoroacetylacetone and hexafluoroacetylacetone. Results of the attempted preparations showed that the possibility of adduct formation between β-diketone complexes and phosphorus esters in influenced by the acid strength od the β-diketone, the basicity of the phosphorus ester, the ionic radii, and the electron configuration of the metal.

Synergism in the Solvent Extraction of Tetravalent Metal Ions. A Study of the Formation of the Synergistic Adducts

The crystal structure of the title compound has been determined from three dimensional x-ray data obtained by the multiple film method. The space group is P2l/n and the cell dimensions are: a = 14.90, b = 16.84, c = 8.38 A; β = 93.5° Z = 4. The structure is formed by discrete Co (en) and Fe(CN) ions, both of which have an octahedral configuration. The Fe(CN) ions are approximately octahedrally surrounded by the Co (en) ions while arrangement of Fe (CN) ions around the Co(en) ions completely differs from an octahedron. The mean FeC and CoC dustances are 1.91 and 2.01 A, respectively. The water molecules do not play an important role in the structure and all distances between oxygen and other atoms indicate the presence of very weak hydrogen bonds. The salts M (en)3 Q(CN)6 · H2O, where M = Co and Cr and Q = Cr, Mn, Fe and Co, are all isomorphous.



Die Kristallstruktur von Co(en)3 Fe(CN)6 · 2H2O ist mittels dreidimensionalen Rontgenstrahldaten, die mit der multiplen Filmmethode erhalten wurden, bestimmt worden. Raumgruppe P21/n; Zelldimensionen a = 14,90 A, b = 16,84 A, c = 8,38 A, β = 93,5° Z = 4. Die Struktur besteht aus diskreten, oktaedrischen Co(en)- und Fe (CN) -Ionen. Die Fe(CN)-Ionen werden oktaedrisch von Co(en)-Ionen umgeben, dagegen sind die Fe(CN)Ionen um die Co(en)-Ionen nicht oktaedrisch angeordnet. Die mittlere FeC- und CoC-Abstande sind mit 1,91 A und 2,01 A unterschiedlich. Die Wassermolekeln spielen keine wichtige Rolle, und alle Abstande zwischen Sauerstoff und anderen Atomen deuten auf sehr schwache Wasserstoffbindungen hin. Die Salze M(en)3 Q(CN)6 ·2H2O mit M = Co und Cr und Q = Cr, Mn, Fe und Co sind isomorph.

J. G. Leipoldt

Papers

The preparation of potassium octacyanotungstate(IV) dihydrate

The preparation of Cs3Mo(CN)8·2H2O and Cs3W(CN)8·2H2O

The Square Antiprismatic Configuration for the Octacyanotungstate(IV) Ion. The Crystal Structure of H4W(CN)8 · 4HCI · 12H2O

Synergism in the Solvent Extraction of Tetravalent Metal Ions. A Study of the Formation of the Synergistic Adducts

The crystal structure of tris (ethylenediamine), cobalt(III) hexacyanoferrate(III)dihydrate, Co(C2H8N2)3[Fe(CN)6] · 2H2O