Die Reaktionen von Europium und Yttrium mit N‐Iod‐triphenylphosphanimin. Kristallstrukturen von [EuI2(DME)3], [Eu2I(NPPh3)5(DME)] und [Y2I(NPPh3)4(THF)4]+I3–

The Reactions of Europium and Yttrium with N‐Iodinetriphenylphosphoraneimine. Crystal Structures of [EuI₂(DME)₃], [Eu₂I(NPPh₃)₅(DME)] and [Y₂I(NPPh₃)₄(THF)₄]⁺I₃^– When treated with ultrasound, the reaction of europium metal with INPPh₃ in 1,2‐dimethoxyethane (DME) leads to the complexes [EuI₂(DME)₃] ( 1 ) and [Eu₂I(NPPh₃)₅(DME)] ( 2 ) which are separated from each other by fractional crystallization. On the other hand, the reaction of yttrium metal with INPPh₃ under similar conditions in THF gives the ionic phosphoraneiminato complex [Y₂I(NPPh₃)₄(THF)₄]⁺I₃^– ( 3 ). All complexes are characterized by crystal structure determinations. 1 : Space group P2₁, Z = 2, lattice dimensions at 188 K: a = 848.9(1); b = 1059.4(1); c = 1227.9(1) pm; β = 93.793(6)°; R = 0.0246. In the molecular structure of 1 the europium atom is eightfold coordinated with a bond angle I–Eu–I of 158.51°. 2 · 2 DME: Space group P1, Z = 2, lattice dimensions at 193 K: a = 1405.5(1); b = 1652.2(2); c = 2203.7(2) pm; α = 89.404(11)°; β = 72.958(11)°; γ = 78.657(11)°; R = 0.0391. In 2 the europium atoms are linked by the μ‐N‐atoms of two (NPPh₃^–) groups to form a planar Eu₂N₂ four‐membered ring. One of the Eu atoms is terminally coordinated by the N atoms of two (NPPh₃^–) groups, thus achieving a distorted tetrahedral surrounding. The second Eu atom is coordinated by the N atom of one (NPPh₃^–) group, by the terminally bounded iodine atom and by the oxygen atoms of the DME chelate, thus achieving a distorted octahedral surrounding. 3 · 6¹/₂ THF: Space group P1, Z = 2, lattice dimensions at 103 K: a = 1739.7(2); b = 1770.1(2); c = 2153.8(3) pm; α = 74.929(15)°; β = 84.223(14)°; γ = 64.612(12)°; R = 0.0638. In the cation [Y₂I(NPPh₃)₄(THF)₄]⁺ of 3 the yttrium atoms are linked by the μ‐N atoms of two (NPPh₃^–) groups as well as by the μ‐I atom. One (NPPh₃^–) ligand and two THF molecules complete the distorted octahedral coordination at each yttrium atom.     

Metal–π Interactions Dominate in the Solid‐State Structures of Molecular Heterobimetallic Alkali‐Metal–Europium(II) Aryloxo Complexes

Treatment of Eu metal, 2,6‐diphenylphenol (HOdpp), and MOdpp (M=Na, K) at elevated temperature in the presence of mercury afforded heterobimetallic complexes which were structurally characterized after crystallization from toluene. The structures of [MEu(Odpp)₃]?nPhMe (M=Na, n=1, 1 ; K, n=2.5, 2 ) consist solely of bridging aryloxide ligands and feature extensive π‐Ph–metal interactions. Rather than a heterobimetallic species, treatment of Eu metal and HOdpp with LiOdpp under similar conditions afforded a number of products, including a mixed‐valent europium complex, [Eu₂(Odpp)₃][Eu(Odpp)₄]?4 PhMe ( 3 ). The structural framework of the [Eu₂(Odpp)₃]⁺ cation of 3 is similar to that of the molecular heterobimetallics 1 and 2 , including the presence of π‐Ph–Eu interactions. The reluctance of the reaction to provide a Eu/Li heterobimetallic complex was exemplified by the simultaneous crystallization of [Eu₂(Odpp)₄]?PhMe ( 6 ) and the homoleptic cubane [Li₄(Odpp)₄]?2 C₆H₁₄ ( 5 ) from toluene/hexane.     

Synthesis and Properties of a Novel 3D Europium Coordination Polymer with Helical Chain and (3,6)‐Connected rtl Net

The first coordination polymer of 2,2′‐((4‐carboxymethyl‐1,3‐phenylene)bis(oxy)) diacetic acid (H₃L) with europium(III) ion, [Eu(L)(H₂O)]·3H₂O ( 1 ), has been hydrothermally synthesized and structurally characterized. Complex 1 exhibits a 3D coordination polymer with helical chain and rtl topology of the point symbol (4·6²)₂(4²·6¹⁰·8³) based on [Eu₂(COO)₄] as secondary building unit (SBU). Furthermore, the luminescent and magnetic properties of complex 1 are studied.     

Abbau von Koordinationspolymeren bis zum Monomer und Konkurrenz von Polymerisation und Chemischer Schere an Carbazolaten von Yb und Eu mit N‐Phenylpiperazin

Degradation of Coordination Polymers to the Monomer and Competition of Polymerization and Chemical Scissors on Carbazolates of Yb and Eu with N‐Phenylpiperazine The coordination polymers , Ln = Yb, Eu, Cbz⁻ = carbazolate anion, C₁₂H₈N⁻, can be degraded by the use of strong N‐donor ligands like N‐phenylpiperazine (Phpip = (C₆H₅)C₄H₈NNH) as chemical scissors. The degradation process for the ytterbium containing polymer ends in the monomeric compound [Yb(Cbz)₃(Phpip)₂]·1/2Phpip and includes an oxidation step Yb^II → Yb^III. Thus the circle of reactions of Yb metal with carbazole (CbzH) starting in liquid NH₃ to the coordination polymer and ending with its degradation by the use of chemical scissors is resolved. Transformation on europium has been started on the base of both metals leading to coordination polymers of the same chemical formula. However already the prelude of reactions differs for Eu as the electride induced reaction of Eu metal with CbzH in liquid ammonia followed by Phpip treatment gives single crystalline [Eu₂(Cbz)₄(NH₃)₂(Phpip)₄]·2Phpip. This dimeric molecule contains Eu^II and ligands of all reaction steps, NH₃, Cbz⁻, Phpip, and is thereby an interesting starting point for the resolution of polymer formation and degradation as well as a competition of these counter reactions.     

Diacetonalkohol‐Komplexe von Lanthanoid‐Trichloriden. Die Kristallstrukturen von [LnCl3(DAA)2] mit Ln = Sm und Eu

Diacetone Alcohol Complexes of Lanthanide Trichlorides. Crystal Structures of [LnCl₃(DAA)₂] with Ln = Sm and Eu The diacetone alcohol complexes [LnCl₃(DAA)₂] with Ln = samarium ( 1 ) and europium ( 2 ) are obtained from the waterfree metal trichlorides with excess diacetone alcohol (4‐hydroxy‐4‐methyl‐2‐pentanone = DAA) forming colourless ( 1 ) and pale yellow crystals ( 2 ), respectively, which are characterized by crystal structure determinations. The europium compound 2 is additionally described by its vibrational spectra (IR, Raman). 1 and 2 crystallize isotypically with one another. The metal atoms of the molecular complex units are unusually coordinated in a distorted pentagonal‐bipyramdial fashion by the three chlorine atoms and by the two alcoholic oxygen atoms of the DAA molecules in the equatorial plane. The apical positions are occupied by the carbonyl oxygen atoms of the chelating DAA molecules. The complex units [LnCl₃(DAA)₂] are associated along [100] by bifurcated —OH···Cl···HO— bridges to form chains. 1 : Space group P2₁, Z = 2, lattice dimensions at —80 °C: : a = 710.2(1), b = 1617.6(2), c = 827.3(1) pm; β = 106.36(1)°; R₁ = 0.026. 2 : Space group P2₁, Z = 2, lattice dimensions at —80 °C: a = 709.7(1), b = 1614.5(2), c = 825.7(1) pm; β = 106.40(1)°; R₁ = 0.0303.     

Metal‐Ion Sensing Europium(III) Complexes with Bidentate Phosphine Oxide Ligands Containing a 2,2′‐Bipyridine Framework

Novel Eu^III complexes with bidentate phosphine oxide ligands containing a bipyridine framework, i.e., [3,3′‐bis(diphenylphosphoryl)‐2,2′‐bipyridine]tris(hexafluoroacetylacetonato)europium(III) ([Eu(hfa)₃(BIPYPO)]) and [3,3′‐bis(diphenylphosphoryl)‐6,6′‐dimethyl‐2,2′‐bipyridine]tris(hexafluoroacetylacetonato)europium(III) ([Eu(hfa)₃(Me‐BIPYPO)]), were synthesized for lanthanide‐based sensor materials having high emission quantum yields and effective chemosensing properties. The emission quantum yields of [Eu(hfa)₃(BIPYPO)] and [Eu(hfa)₃(Me‐BIPYPO)] were 71 and 73%, respectively. Metal‐ion sensing properties of the Eu^III complexes were also studied by measuring the emission spectra of Eu^III complexes in the presence of Zn^II or Cu^II ions. The metal‐ion sensing and the photophysical properties of luminescent Eu^III complexes with a bidentate phosphine oxide containing 2,2′‐bipyridine framework are demonstrated for the first time.     

Physical Properties of Superbulky Lanthanide Metallocenes: Synthesis and Extraordinary Luminescence of [EuII(CpBIG)2] (CpBIG=(4‐nBu‐C6H4)5‐Cyclopentadienyl)

The superbulky deca‐aryleuropocene [Eu(Cp^BIG)₂], Cp^BIG=(4‐nBu‐C₆H₄)₅‐cyclopentadienyl, was prepared by reaction of [Eu(dmat)₂(thf)₂], DMAT=2‐Me₂N‐α‐Me₃Si‐benzyl, with two equivalents of Cp^BIGH. Recrystallizyation from cold hexane gave the product with a surprisingly bright and efficient orange emission (45 % quantum yield). The crystal structure is isomorphic to those of [M(Cp^BIG)₂] (M=Sm, Yb, Ca, Ba) and shows the typical distortions that arise from Cp^BIG???Cp^BIG attraction as well as excessively large displacement parameter for the heavy Eu atom (U_eq=0.075). In order to gain information on the true oxidation state of the central metal in superbulky metallocenes [M(Cp^BIG)₂] (M=Sm, Eu, Yb), several physical analyses have been applied. Temperature‐dependent magnetic susceptibility data of [Yb(Cp^BIG)₂] show diamagnetism, indicating stable divalent ytterbium. Temperature‐dependent ¹⁵¹Eu Mössbauer effect spectroscopic examination of [Eu(Cp^BIG)₂] was examined over the temperature range 93–215 K and the hyperfine and dynamical properties of the Eu^II species are discussed in detail. The mean square amplitude of vibration of the Eu atom as a function of temperature was determined and compared to the value extracted from the single‐crystal X‐ray data at 203 K. The large difference in these two values was ascribed to the presence of static disorder and/or the presence of low‐frequency torsional and librational modes in [Eu(Cp^BIG)₂]. X‐ray absorbance near edge spectroscopy (XANES) showed that all three [Ln(Cp^BIG)₂] (Ln=Sm, Eu, Yb) compounds are divalent. The XANES white‐line spectra are at 8.3, 7.3, and 7.8 eV, for Sm, Eu, and Yb, respectively, lower than the Ln₂O₃ standards. No XANES temperature dependence was found from room temperature to 100 K. XANES also showed that the [Ln(Cp^BIG)₂] complexes had less trivalent impurity than a [EuI₂(thf)_x] standard. The complex [Eu(Cp^BIG)₂] shows already at room temperature strong orange photoluminescence (quantum yield: 45 %): excitation at 412 nm (24270 cm^?1) gives a symmetrical single band in the emission spectrum at 606 nm (ν_max=16495 cm^?1, FWHM: 2090 cm^?1, Stokes‐shift: 2140 cm^?1), which is assigned to a 4f⁶5d¹→4f⁷ transition of Eu^II. These remarkable values compare well to those for Eu^II‐doped ionic host lattices and are likely caused by the rigidity of the [Eu(Cp^BIG)₂] complex. Sharp emission signals, typical for Eu^III, are not visible.     

A trichloro‐bridged binuclear ruthenium complex with 1,1,1‐tris(diphenylphosphinomethyl)ethane

The tri­chloro‐bridged dinuclear Ru^II complex tri‐μ‐chloro‐bis{[1,1,1‐tris­(di­phenyl­phosphino­methyl)­ethane‐κ³P,P′,P′′]ruthenium(II)} hexa­fluoro­phosphate ethanol solvate, [Ru₂Cl₃(tripod)₂]PF₆·C₂H₆O, containing the tripod [1,1,1‐tris­(di­phenyl­phosphino­methyl)­ethane, C₄₁H₃₉P₃] ligand, was unexpectedly obtained from the reaction of [Ru^IIICl₃(tripod)] with 1,4‐bis­(di­phenyl­phosphino)­butane (dppb), followed by pre­cipitation with NH₄PF₆. The magnetic moment of the compound at room temperature indicates that the dinuclear [Ru₂(μ‐Cl)₃(tripod)₂]⁺ cation is diamagnetic. A single‐crystal X‐ray structure determination revealed that the two Ru atoms are bridged by the three Cl atoms. The coordination sphere of each Ru atom is completed by the three P atoms of a tripod ligand. The two P₃Ru units are exactly eclipsed, while the bridging Cl atoms are staggered with respect to the six P atoms. The Ru⋯Ru distance is 3.3997 (7) Å and the mean Cl—Ru—Cl bond angle is 77.7°.     

Phenylimidorhenium(V) Complexes with 1,3‐Diethyl‐4,5‐dimethylimidazole‐2‐ ylidene Ligands

The phenylimidorhenium(V) complexes [Re(NPh)X₃(PPh₃)₂] (X = Cl, Br) react with the N‐heterocyclic carbene (NHC) 1,3‐diethyl‐4,5‐dimethylimidazole‐2‐ylidene (L^Et) under formation of the stable rhenium(V) complex cations [Re(NPh)X(L^Et)₄]²⁺ (X = Cl, Br), which can be isolated as their chloride or [PF₆]^? salts. The compounds are remarkably stable against air, moisture and ligand exchange. The hydroxo species [Re(NPh)(OH)(L^Et)₄]²⁺ is formed when moist solvents are used during the synthesis. The rhenium atoms in all three complexes are coordinated in a distorted octahedral fashion with the four NHC ligands in equatorial planes of the molecules. The Re–C(carbene) bond lengths between 2.171(8) and 2.221(3) Å indicate mainly σ‐bonding between the NHC ligand and the electron deficient d² metal atoms. Attempts to prepare analogous phenylimido complexes from [Re(NPh)Cl₃(PPh₃)₂] and 1,3‐diisopropyl‐4,5‐dimethylimidazole‐2‐ylidene (L^i?Pr) led to a cleavage of the rhenium‐nitrogen multiple bond and the formation of the dioxo complex [ReO₂(L^i?Pr)₄]⁺.     

A Highly Triflated Rare‐Earth Ion in [Eu(O3SCF3)8]5−

The reaction of Eu₂O₃ with fuming nitric acid, trifluormethanesulfonic acid, and its anhydride in torch‐sealed glass ampoules at 120 °C gave the europium compound (NO)₅[Eu(O₃SCF₃)₈] (orthorhombic, Fddd, Z=16, a=1932.69(4), b=2878.44(7), c=2955.12(7) pm, V=16439.7(7) ų). The compound exhibits the [Eu(O₃SCF₃)₈]^5? anion showing for the first time a lanthanide ion that is exclusively coordinated by eight triflate anions. The anion has been further investigated by DFT calculations, which also allowed clear assignment of the vibrational spectra. Moreover, magnetochemical and luminescence measurements gave additional insight into the properties of this complex. The luminescence spectra revealed that the Eu³⁺ ions are in a pseudo D_4d symmetric environment.     

Thiosilicate der Selten‐Erd‐Elemente: I. Die isotypen Verbindungen KCe[SiS4] und Eu2[SiS4]

Thiosili‐Thiosilicates of the Rare‐Earth Elements: I. The Isotypic Compounds KCe[SiS₄] and Eu₂[SiS₄] Both isotypic thiosilicates KCe[SiS₄] (a = 649.15(6), b = 656.18(6), c = 863.96(8) pm, β = 107.531(9)°) and Eu₂[SiS₄] (a = 651.71(6), b = 659.54(6), c = 821.93(8) pm, β = 108.437(9)°) crystallize monoclinically in the space group P2₁/m and Z = 2. By the reaction of KCl, Ce₂S₃ and SiS₂ in the ratio 1 : 1 : 1 using a sixfold molar amount of KCl as flux in evacuated silica tubes (7 d, 850°C) brownish yellow, plate‐shaped single crystals, resistant both to air and water are obtained. The conversion of Eu, S and SiS₂ in molar ratios of 2 : 2 : 1 with an excess of CsCl as flux in evacuated silica tubes (7 d, 850°C) leads to deep red, plate‐shaped single crystals, which remain air‐ and water‐stable for a few days. The crystal structure contains isolated ortho‐thiosilicate units, that together with the Ce³⁺ or (Eu2)²⁺ cations build corrugated anionic layers parallel (001) according to {(Ce[SiS₄])^—} and {(Eu2[SiS₄])^2—}, respectively. These layers are alternatingly piled with cationic layers consisting solely of K⁺ or (Eu1)²⁺ cations. The latter show coordination numbers of eight in the shape of a bicapped trigonal prism, whereas the cations of the position Ce³⁺ and (Eu2)²⁺ have a (2+1)‐fold capped trigonal prismatic environment with a coordination number of 8+1. The comparison of both compounds KCe[SiS₄] and Eu₂[SiS₄] (≡ EuEu[SiS₄]) demonstrates, that Eu²⁺ is able to substitute both K⁺ and Ce³⁺ isomorphically.     

First Characterization of an Extended Ammonium‐Ammonia Complex [{NH4(NH3)4}+(μ‐NH3)2] in the Crystal Structure of [NH4(NH3)4][Co(C2B9H11)2] · 2 NH3

The compound [NH₄(NH₃)₄][Co(C₂B₉H₁₁)₂] · 2 NH₃ ( 1 ) was prepared by the reaction of Na[Co(C₂B₉H₁₁)₂] with a proton‐charged ion‐exchange resin in liquid ammonia. The ammoniate 1 was characterized by low temperature single‐crystal X‐ray structure analysis. The anionic part of the structure consists of [Co(C₂B₉H₁₁)₂]^‐ complexes, which are connected via C‐H···H‐B dihydrogen bonds. Furthermore, 1 contains an infinite equation/tex2gif-stack-2.gif[{NH₄(NH₃)₄}⁺(μ‐NH₃)₂] cationic chain, which is formed by [NH₄(NH₃)₄]⁺ ions linked by two ammonia molecules. The N‐H···N hydrogen bonds range from 1.92 to 2.71Å (DHA = Donor···Acceptor angles: 136‐176°). Additional N‐H···H‐B dihydrogen bonds are observed (H···H: 2.3‐2.4Å).     

Coordination Compounds of Palladium(II) and 4‐Amino‐1,2,4‐triazole

Mononuclear coordination compounds of the type [Pd(NH₂trz)₄]²⁺ with the counterions chloride, nitrate, trifluoromethanesulfonate, and methanesulfonate were synthesized and their structures identified with single‐crystal X‐ray diffraction. In case of the synthesis with methanesulfonate as the counterion the dominant product was of the generic formula [Pd₂(NH₂trz)₃](CH₃SO₃)₄, and the complex [Pd(NH₂trz)₄](CH₃SO₃)₂ only emerged as a byproduct. While the structure of the byproduct could be analyzed by single‐crystal X‐ray diffraction, suitable crystals of the main product [Pd₂(NH₂trz)₃](CH₃SO₃)₄ could not be obtained. However, stoichiometry implies a polynuclear nature with NH₂trz present in the rare μ₃‐η¹:η¹:η¹ coordination type, i.e. with NH₂trz molecules coordinating to three palladium atoms. Accordingly, identification of solids by single‐crystal analysis alone can be misleading in particular with NH₂trz as a ligand due to its versatile coordination behavior. Finally, analysis by differential scanning calorimetry (DSC) revealed that the complexes were thermally stable (the onset of decomposition well above 100 °C), with [Pd₂(NH₂trz)₃](CH₃SO₃)₄ being the most stable compound (onset of decomposition at 204 °C).     

[Co7(μ4‐O)2(O2C–CH3)8(NCO)2(HNPEt3)4] · 2 OEt2, ein siebenkerniger Komplex mit vier‐, fünf‐ und sechsfach koordinierten Cobalt‐Atomen

[Co₇(μ₄‐O)₂(O₂C–CH₃)₈(NCO)₂(HNPEt₃)₄] · 2 OEt₂, a Seven Nuclearity Complex with Four, Five, and Sixfold Coordinated Cobalt Atoms The title compound was prepared from cobalt(II) acetate with Me₃SiNPEt₃ at 180 °C and subsequent crystallization from diethylether to give blue, moisture sensitive single crystals, which were characterized by a crystal structure determination. Space group P2₁/n, Z = 2, lattice dimensions at –80 °C: a = 1544.0(1), b = 1522.1(2), c = 1702.0(1) pm, β = 103.911(10)°, R = 0.0490. [Co₇(μ₄‐O)₂(O₂C–CH₃)₈(NCO)₂ · (HNPEt₃)₄] has a centrosymmetric cluster‐like structure in which the octahedrally coordinated central cobalt atom is connected with the remaining six cobalt atoms via two μ₄‐oxygen atoms as well as via four bridging acetato groups to form a Co(Co)₆ octahedral skeleton. Four of the peripheric cobalt atoms have a distorted trigonal‐bipyramidal coordination sphere, the other two cobalt atoms are tetrahedrally coordinated. The latter are connected with the nitrogen atoms of the cyanato groups.     

catena‐Poly­[[di­aqua­(isonicotinato‐O,O′)­europium(III)]‐di‐μ‐isonicotin­ato‐O:O′]

The title complex, [Eu(C₆H₄O₂)₃(H₂O)₂], has a double carboxyl­ate‐bridged infinite‐chain structure, with one chelating carboxyl­ate group on each Eu ion centre, which also binds to two water mol­ecules to yield an eight‐coordinate square‐antiprismatic geometry, with Eu—O bond lengths in the range 2.338 (3)–2.594 (3) Å. The pyridine N atoms of the isonicotinate groups do not coordinate to the Eu ions; instead, they direct the formation of Eu^III coordination polymers via hydrogen bonding with coordinated water mol­ecules.     

catena‐Poly­[europium‐tri‐μ‐4‐methyl­benzoato]

Each Eu³⁺ ion in the title compound, catena‐poly­[europium(III)‐tri‐μ‐4‐methyl­benzoato‐O:O,O′;O:O,O′;O,O′:O′], {[Eu(C₈H₇O₂)₃]₃}_n, is coordinated by nine O atoms, and three Eu atoms form a trimeric unit. These trimeric units are linked by bridging–chelating carboxyl­ates to form an infinite one‐dimensional polymer chain.     

Lanthanide(III) (Eu,Gd, Tb,Dy) Complexes Derived from 4‐(Pyridin‐2‐yl)methyleneamino‐1,2,4‐triazole: Crystal Structure,Magnetic Properties,and Photoluminescence

The reaction of lanthanide(III) nitrates with 4‐(pyridin‐2‐yl)methyleneamino‐1,2,4‐triazole (L) was studied. The compounds [Ln(NO₃)₃(H₂O)₃] ? 2 L, in which Ln=Eu ( 1 ), Gd ( 2 ), Tb ( 3 ), or Dy ( 4 ), obtained in a mixture of MeCN/EtOH have the same structure, as shown by XRD. In the crystals of these compounds, the mononuclear complex units [Ln(NO₃)₃(H₂O)₃] are linked to L molecules through intermolecular hydrogen‐bonding interactions to form a 2D polymeric supramolecular architecture. An investigation into the optical characteristics of the Eu³⁺‐, Tb³⁺‐, and Dy³⁺‐containing compounds ( 1 , 3 , and 4 ) showed that these complexes displayed metal‐centered luminescence. According to magnetic measurements, compound 4 exhibits single‐ion magnet behavior, with ΔE_eff/k_B=86 K in a field of 1500 Oe.     

IV Dodekaedrische [Mo(CN)8]‐Koordination in den cyanoverbrückten Cobalt‐ und Nickel‐Amminkomplexen MII2(NH3)8[Mo(CN)8] · 1,5 H2O (MII = Co,Ni) und Ni2(NH3)9[Mo(CN)8] · 2 H2O

Crystal Structures of Octacyanomolybdates(IV). IV Dodecahedral [Mo(CN)₈] Coordination of the Cyano‐Bridged Cobalt and Nickel Ammin Complexes M^II₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (M^II = Co, Ni) and Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O At single crystals of the hydrated cyano complexes Co₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 910.0(4), b = 1671(2), c = 1501(1) pm, β = 93.76(6)°) and Ni₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 899.9(9), b = 1654.7(4), c = 1488(1) pm, β = 94.01°), isostructurally crystallizing in space group P2₁/c, Z = 4, and of trigonal Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O (a = 955.1(1), c = 2326.7(7) pm, P3₁, Z = 3), X‐ray structure determinations were performed at 168 resp. 153 K. The [Mo(CN)₈]^4– groups of the three compounds, prepared at about 275 K and easily decomposing, show but slightly distorted dodecahedral coordination (mean distances Mo–C: 216.3, 215.4 and 216.1 pm). Within the monoclinic complexes the anions twodimensionally form cyano bridges to the ammin cations [M(NH₃)₄]²⁺ and are connected with the resulting [MN₆] octahedra (Co–N: 215.1 pm, Ni–N: 209.8 pm) into strongly puckered layers. The trigonal complex exhibits a chain structure, as one [Ni(NH₃)₅]²⁺ cation is only bound as terminal octahedron (Ni–N: 212.0 pm). Details and the influence of hydrogen bridges are discussed.     

Second‐sphere coordination in anion binding: sodium hexa­ammine­cobalt(III) tetra­kis­(4‐fluoro­benzoate) monohydrate

In sodium hexa­amminecobalt(III) tetra­kis­(4‐fluoro­benzoate) monohydrate, Na[Co(NH₃)₆](C₇H₄FO₂)₄·H₂O, determined at 180 K, [Co(NH₃)₆]³⁺ cations lie on centres of inversion and form layers in which their C₄ axes lie perpendicular to the layer planes. 4‐Fluoro­benzoate anions lie on twofold axes and general positions and adopt near‐planar geometries. Na⁺ cations and water mol­ecules lie on twofold axes, forming [NaO₅] square pyramids that lie between the [Co(NH₃)₆]³⁺ cations. The second‐sphere inter­actions between [Co(NH₃)₆]³⁺ cations and 4‐fluorobenzoate anions comprise edge‐to‐face and vertex‐to‐face arrangements. The structure is closely comparable with that of the benzoic acid salt, demonstrating that fluorination of the anion in the para position has no significant influence on the second‐sphere inter­actions and minimal influence on the gross crystal structure.     

UF6 and UF4 in Liquid Ammonia: [UF7(NH3)]3− and [UF4(NH3)4]

From the reaction of uranium hexafluoride UF₆ with dry liquid ammonia, the [UF₇(NH₃)]^3? anion and the [UF₄(NH₃)₄] molecule were isolated and identified for the first time. They are found in signal‐green crystals of trisammonium monoammine heptafluorouranate(IV) ammonia (1:1; [NH₄]₃[UF₇(NH₃)] ? NH₃) and emerald‐green crystals of tetraammine tetrafluorouranium(IV) ammonia (1:1; [UF₄(NH₃)₄] ? NH₃). [NH₄]₃[UF₇(NH₃)] ? NH₃ features discrete [UF₇(NH₃)]^3? anions with a coordination geometry similar to a bicapped trigonal prism, hitherto unknown for U^IV compounds. The emerald‐green [UF₄(NH₃)₄] ? NH₃ contains discrete tetraammine tetrafluorouranium(IV) [UF₄(NH₃)₄] molecules. [UF₄(NH₃)₄] ? NH₃ is not stable at room temperature and forms pastel‐green [UF₄(NH₃)₄] as a powder that is surprisingly stable up to 147 °C. The compounds are the first structurally characterized ammonia complexes of uranium fluorides.