Cobalt(II) Complexes of 4,6-Dimethylpyrimidine-2(1H)-one

Some cobalt(II) complexes of 4,6-dimethylpyrimidine-2(1H)-one (HL) have been prepared and studied by infrared and electronic spectra and by magneto-chemical and conductometric measurements. The ligand is coordinated through the unprotonated ring-nitrogen atom and in one case also through the carbonylic oxygen atom. The “blue” complexes [CoX₂ · 2HL] (X₂ = Cl₂, ClBr, Br₂, (NCS)₂) and [CoX₂ · 2HL] · 2HL (X = Cl, Br) have a distorted C_2v [CoX₂N₂] coordination; the thiocyanate ion is N-bonded to the metal. The “green” complexes CoX₂ · 2HL (X = Cl(4H₂O), Br) have a square-pyramidal [CoX₂N₂O] coordination. The “pink” CoX₂ · 4HL · nH₂O (X = ClO₄, n = 2; X = BF₄, n = 8; X = F₃Ac, n = 4) and “cream” CoX₂ · 4HL · 6 H₂O (X = I, ClO₄) complexes have an octahedral coordination; only the F₃Ac^? ion is coordinated. The “cyclamen” CoAcL · 2HL · 2 H₂O and Co₃Ac₄L₂ · 2HL · 2H₂O complexes have a polynuclear constitution; the Ac^? ion behaves as bidentate ligand.     

Cobalt(II) and copper(II) complexes of (2-thiophene)-(5,6-diphenyl-[1,2,4]-triazin-3-yl)hydrazone

New complexes having the formulae [L₂CoX₂] and [LCuCl₂], [LCuCl] and [LCu](ClO₄)₂ where L?=?(2-thiophene)-(5,6-diphenyl-[1,2,4]-triazin-3-yl)hydrazone TDPTH; X?=?Cl, OAc or ClO₄ have been synthesized and characterized on the basis of elemental analyses, conductance, magnetic moments and infrared, electronic and ESR spectral data. The IR spectra indicate that TDPTH is a neutral bidentate ligand, coordinating via a triazine-N and azomethine-N in [L₂CoX₂] and [LCuCl₂] with the thiophene-S not coordinated but is tridentate in [LCuCl] and [LCu](ClO₄)₂ through the same two nitrogen atoms and thiophene-S. The magnetic moment and electronic spectral data suggest a distorted octahedral structure for Co(II) complexes, a dimeric square pyramidal geometry for [LCuCl₂] through chloride bridges and a dimeric diamagnetic, four-coordinate copper in [LCu](ClO₄)₂ through thiophene-S bridges. The X-band ESR spectra of Co(II) complexes, in the solid state, are rhombic with three g values consistent with a high-spin distorted octahedral structure. The X-band ESR spectrum of the powdered sample of both [LCuCl₂]·2H₂O and [LCu](ClO₄)₂ at room temperature and at 77?K showed only one broad signal due to?ΔM _s?=?±?1 transition and a weak signal due to the forbidden?ΔM _s?=?±?2 transition, indicating an antiferromagnetic interaction between copper(II) centers whereas [LCuCl] is ESR silent, indicating a monovalent copper ion in this complex.     

Enantioselective Hydrogenation over Chiral Cobalt Complexes with (+)-(1S,2S,5R)-Neomenthyldiphenylphosphine and (-)-(R,R)-2,2-Dimethyl-4,5-bis(diphenylphosphinomethyl)-1,3-dioxolane

The optical yield in enantioselective hydrogenation of methyl -acetamidocinnamate over mono- and diphosphine cobalt(II) complexes CoX₂L₂ [where X = Cl or CF₃SO₃, L = (+)-(1S,2S,5R)-neomenthyl-diphenylphosphine or L2' = (-)-(R,R)-2,2-dimethyl-4,5-bis(diphenylphosphinomethyl)-1,3-dioxolane], which are generated in situ, in the presence of sodium tetrahydridoborate increases with rise in the phosphine-to-metal ratio and hydrogen pressure. The maximal optical yields of (+)-(S)-N-acetylphenylalanine methyl ester attain 40% (CoX₂L₂) and 42% (CoX₂L₂').     

Structure and stability of aqua(bis-β-picoline)copper(II)-benzoate

Pseudochalcogeno Compounds. XI. On a New Type of Pseudochalcogeno-Modified Phosphates The preparation of pseudochalcogenophosphates of the general formulas [PO₃Y]^3? and [P₂O_7-nY_n]^4? (Y = C(CN)₂, n = 1, 2) is described. Chromatography of sodium salts, the formation of silver and calcium salts, characteristic IR and ³¹P-NMR data are discussed.     

4-amino-2,6-dimethyl-5-oxo-3-thioxo-2,3,4,5-tetrahydro-l,2,4-triazine cobalt(II) complexes

Summary Cobalt(II) complexes of 4-amino-2,6-dimethyl-5-oxo-3-thioxo-2,3,4,5-tetrahydro-1,2,4-triazine (taz) were prepared by reacting the triazine with the corresponding cobalt salt. The isolated compounds were of the types: [CoCl₂(taz)], [CoX₂(taz)₂(H₂O)₂] (X = Br or I), [CoX₂(taz)₂] (X = Br, SCN or NO₃) and [Co(taz)₂(H₂O)₂]X₂(X = C1O₄, BF₄ or NO₃). Conductance, magnetic and spectroscopic (i.r. and vis.) data were used for structural assignments. Pseudooctahedral and pseudotetrahedral structures are proposed for the complexes, with the triazine molecule acting either as a monodentate nitrogen-donor or a bidentate nitrogen-sulphur-donor ligand.     

Pseudoelementverbindungen. II. Quantenchemische Untersuchungen an pseudoelementmodifizierten Nitrit-Ionen [EO2−nYn]− (E = N,C(CN); Y = C(CN)2)

Pseudoelement Compounds. II. Quantum Chemical Studies on Pseudoelement Modified Nitrite Ions [EO_2?nY_n]^? (E = N, C(CN); Y = C(CN)₂) The electronic structure and the ambidence of pseudochalcogen modified nitrite ions are discussed on the basis of a quantum chemical MNDO study in connection with structural, ESCA and ¹³C NMR data.     

Some transition metal complexes of new terdentate ligands: Bis[2-(diphenylphosphino)ethyl]benzylamine and bis[2-(diphenylarsino)ethyl)benzylamine

Complexes of the terdentate ligands bis[2-diphenylphosphino)ethyl]benzylamine (DPBA) and bis[2-(diphenylarsino)ethyl]benzylamine (DABA) with Co(II), Ni(II), Pd(II), Pt(II), Rh(III), Ir(III), Rh(I) and Ir(I) are reported. The ligand DPBA reacts with Co(II) ion to form two types of complexes: a high-spin, paramagnetic, tetrahedral Co(II) complex of composition [CoCl(DPBA)]Cl and a low-spin, paramagnetic, square-planar complex of composition [CoBr(DPBA)]B(C₆H₅)₄. The reaction of DPBA with Ni(II) ion in methanol yields low-spin, diamagnetic, square-planar complexes of type [NiX(DPBA)]Y [X = Cl, Br or I; Y = Cl or B(C₆H₅)₄]. Four-coordinate, square-planar, cationic complexes of type [MY(L⁺[M = Pd(II), Pt(II), Rh(I) or Ir(I); Y = Cl or P(C₆H₅)₃; L = DPBA or DABA], were obtained on reaction of L with various starting materials containing these metal ions. Reaction of DPBA and DABA with rhodium and iridium trichlorides gave octahedral, neutral complexes of general formula [MCl₃(L)] (M = Rh or Ir, L = DPBA or DABA). All the complexes were characterized on the basis of their elemental analysis, molarconductance data, magnetic susceptibilities, electronic spectra, IR spectral measurements, and¹H and³¹P-{¹H} NMR spectral data.     

Synthese und Struktur der Kronenetherkomplexe von Kaliumhexachlorodipalladat(II) und -diplatinat(II)

Synthesis and Structure of Crown Ether Complexes of Potassium Hexachlorodipalladate(II) and -diplatinate(II) K₂[MCl₄] (M ? Pd, Pt) reacts with an excess of crown ether 18-crown-6 in water to give the crown ether complexes of potassium hexachlorodipalladate(II) and -diplatinate(II) [K(18-cr-6)]₂[M₂Cl₆] (M ? Pd, 1 ; M ? Pt, 3 ), respectively, and in methylene chloride to give those of potassium tetrachloropalladate(II) and -platinate(II) [K(18-cr-6)]₂[MCl₄] ( 1 ) (M ? Pd, 2 ; M ? Pt, 4 ), respectively. 1 - 4 are characterized by microanalysis, NMR (¹H, ¹³C), and vibrational spectroscopy. The X-ray structure analyses of the isotypic complexes 1 (P2₁/c; a = 10,9678(8), b = 8,2991(7), c = 22,469(2) Å, β = 98,523(5)°; Z = 2) and 3 (P2₁/c; a = 10,934(3), b = 8.376(3), c = 22,410(5) Å, β = 98,77(3)°; Z = 2) reveal [M₂Cl₆]^2? anions of nearly D_2h symmetry and [K(18-cr-6)]⁺ cations, in which the distance of K⁺ to the mean plane of the crown ether defined by its six oxygen atoms amounts to 0,830(4) Å in 1 and 0,821(2) Å in 3 , respectively. There are tight contacts between cations and anions (d(K-Cl): 3,341(2)/3,260(2) Å ( 1 ); 3,348(4)/3,259(4) Å ( 3 )).     

Synthesis and reactivity of new methylallylpalladium(II) complexes with bidentate 2-(methylthio-N-benzylidene)anilines

This work describes the synthesis, characterisation and reactivity of new methylallyl Pd(II) complexes that contain bidentate 2-(methylthio-N-benzylidene)anilines as ligands. The reaction of the binuclear complex [(η³-Me-allyl)Pd(μ-Cl)₂] with AgBF₄ causes the total abstraction of the chloride bridges, with the subsequent formation of an intermediary fragment of Pd(II). This fragment in turn reacts with neutral bidentate 2-(methylthio-N-benzylidene)anilines to give cationic complexes of Pd(II) of general formula [(η³-Me-allyl)Pd(η²-S,N-MeSC₆H₄NCHC₆H₄(X)Y)]BF₄ [X=H, Y=H (1); X=F, Y=H (2); X=Me, Y=H (3); X=H, Y=Cl (4); X=H, Y=Me₂N (5); X=H, Y=NO₂ (6)]. The new complexes were characterised by means of elemental analysis, IR, NMR [¹H, ¹⁹F{¹H}, ¹³C{¹H}, ³¹P{¹H}, Dept, ¹H-¹H-COSY, HSQC, HMBC] and mass spectroscopies. The reaction of the Pd(II) complexes with nucleophiles such as NaI, (EtO)₂PS₂K, KCN, KSCN or NaH lead to the deco-ordination of the bidentate ligands to give dimeric or polymeric complexes of Pd(II). The reactivity pattern observed is discussed by a theoretical analysis based on Fukui functions.     

Osmium(II)-Phthalocyanine: Darstellung und Eigenschaften von Di(acido)phthalocyaninatoosmaten(II)

Osmium(II) Phthalocyanines: Preparation and Properties of Di(acido)phthalocyaninatoosmates(II) “H[Os(X)₂Pc^2?]” (X = Br, Cl) reacts in basic medium or in the melt with (ⁿBu₄N)X forming less stable, diamagnetic, darkgreen (ⁿBu₄N)₂[Os(X)₂Pc^2?]. Similar dicyano and diimidazolido(Im) complexes are formed by the reaction of “H[Os(Cl)₂Pc^2?]” with excess ligand in the presence of [BH₄]^?. The cyclic voltammograms show up to three quasireversible redoxprocesses: E_1/2(I) = 0.13 V (X = CN), ?0.03 V (Im), ?0.13 V (Br) resp. ?0.18 V (Cl) is metal directed (Os^II/III), E_1/2(II) = 0.69 V (Cl), 0.71 V (Br), 0.83 V (CN), 1.02 V (Im) is ligand directed (Pc^2?/?) and E_1/2(III) = 1.17 V (Cl) resp. 1.23 V (Br) is again metal directed (Os^III/IV). Between the typical “B” (～16.2 kK) and “Q” (～29.4 kK), “N regions” (～34.1 kK) up to seven strong “extra bands” of the phthalocyanine dianion (Pc^2?) are observed in the uv-vis spectrum. Within the row CN > Im > Br > Cl, most of the bands are shifted slightly, the “extra bands” considerably more to lower energy in correlation with E_1/2(I). The vibrational spectra are typical for the Pc^2? ligand with D_4h symmetry. M.i.r. bands at 514, 909, 1 173 and 1 331 cm^?1 are specific for hexa-coordinated low spin Os^II phthalocyanines. In the resonance Raman (r.r.) spectra polarized, depolarized or anomalously polarized deformation and stretching vibrations of the Pc^2? ligand will be selectively enhanced, if the excitation frequency coincides with “extra bands”. With excitation at ～19.5 kK the intensity of the symmetrical Os? X stretching vibration at 295 cm^?1 (X = Cl), 252 cm^?1 (X = Im) and 181 cm^?1 (X = Br) is r.r. enhanced, too. The asymmetrical Os? X stretching vibration is observed in the f.i.r. spectrum at 345 cm^?1 (X = CN), 274 cm^?1 (X = Cl), 261 cm^?1 (X = Im) and 200 cm^?1 (X = Br).     

Manganese(II) Silylamides

Mn[N(SiMe₃)₂]₂(THF) ( I ) (Me = methyl, THF = tetrahydrofuran) was obtained on large scale from “active” MnCl₂ and LiN(SiMe₃)₂ in THE in 85–93% yield. The novel, theoretically interesting tetra-coordinated Mn[N(SiMe₃)₂]₂L₂ series was derived from I , where L = THF, pyridine and t-butyleyanide. All these species are quite stable thermally and exhibit exteme oxygen sensitivity. Preparation, properties, and reactions of unsymmetrically substituted (“hemi”) X? Mn? Y type compounds are presented also, where X = ? Cl, ? NO₃ and n = butyl, and Y = ? N(SiMe₃)₂ and ? OR. From Cl? Mn? N(SiMe₃)₂, with or without coordinated THF being present, the unusual (Mn{SiMe₃)₂, was isolated as yellow crystals. The “hemi” Mn(II)-system exhibits only moderate thermal stability and tends to disproportionate. Many derivatives are photosensitive, especially with UV light.     

Ruthenium(II)-Phthalocyaninate(1–): Darstellung und Eigenschaften von (Halogeno)(carbonyl)phthalocyaninato(1–)ruthenium(II)

Ruthenium(II)-Phthalocyaninates(1–): Synthesis and Properties of (Halo)(carbonyl)phthalocyaninato(1–)ruthenium(II) Brown-violet (halo)(carbonyl)phthalocyaninato(1–)ruthenium(II), [Ru(X)(CO)Pc^?] (X = Cl, Br) is prepared by oxidation of [Ru(X)(CO)Pc^2?]^? with the corresponding halogen or dibenzoylperoxide. The eff. magnetic moment μ_eff = 1.74 (X = Cl), 1.68 μ_B (Br) confirms the presence of a low-spin Ru^II complex of the Pc^? radical. Accordingly, only the first ring oxidation at ～0.64 V and the first ring reduction at ～ ?1.19 V is observed in the cyclovoltammogram of [Ru(X)(CO)Pc^2?]^?. The UV-VIS-NIR spectra characterizing a monomeric Pc^? radical with intense π-π* transitions at 14500, 19800, 25100 and 33900 cm^?1 are compared with those of [Ru(Cl)₂Pc^?] and of monomeric as well as dimeric [Zn(Cl)Pc^?]. The IR and resonance Raman(RR) spectra are characteristic for a Pc^? radical, too. Diagnostic in-plane vibrations of the Pc^? ligand are in the IR spectrum at 1071, 1359, 1445 cm^?1 and in the RR spectrum (λ₀ = 488.0 nm) at 567, 1597 cm^?1. v(C? O) at 1950 cm^?1 and v(Ru? X) at 260 (X = Cl) resp. 184 cm^?1 (X = Br) are observed only in the IR spectrum.     

Pseudoelementverbindungen. IV. Modifizierung der Ionen Sulfit [SOY2]2−, Sulfat [SO4−nYn]2− und Sulfonat [RSO2Y]− durch Einführung der Pseudochalkogengruppen NCN und C(CN)2

Pseudoelement Compounds. IV. Modification of the Ions Sulfite [SO₂Y]^2?, Sulfate [SO_4?nY_n]^2?, and Sulfonate [RSO₂Y]^? by Introducing Pseudochalcogen Groups NCN and C(CN)₂ . Described is the synthesis of pseudochalcogen modified sulfites M₂[SOY₂], sulfates M₂[SO_4?nY_n] (Y = NCN), and arylsulfonates M[RSO₂Y] (Y = NCN, C(CN)₂). The ¹³C-NMR and IR spectra of the new compounds are discussed.     

4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]-hexacosane tetrachloromanganese(II) and tetrachlorozinc(II) hydrates: Synthesis and crystal structures

Two complex salts, i.e., 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane tetrachloromanganese(II) and tetrachlorozinc(II) hydrates, [H₂(Crypt-222)][MnCl₄] · 1.5H₂O (I) and [H₂(Crypt-222)][ZnCl₄] · 2H₂O (II) were synthesized and their crystal structures were studied by X-ray diffraction. Crystals I and II are trigonal (space group R \(\bar 3\) c, Z = 12); I: a = 11.033, c = 77.775 Å; II: a = 11.046, c = 77.555 Å (the structures were solved by the direct method and refined by the full-matrix least-squares method in anisotropic approximation to R = 0.056 (I) and 0.065 (II) for all 2634 (I) and 2636 (II) independent reflections; CAD-4 automated diffractometer, λMoK _α). The [MnCl₄]^2? or [ZnCl₄]^2? anion in structures I or II and the 2.2.2-cryptand dication (with two protonated N atoms) lie on crystal axis 3. The dication contains trifurcate hydrogen bonds N⁺-H(…O)₃. The bond lengths and bond angles in tetrahedral anions [MnCl₄]^2? or [ZnCl₄]^2? are disproportional, probably, due to the Jahn-Teller effect. The molecules of water of crystallization in crystals I, II are disordered over two positions.     

Ag/CuI-Mischbesetzung in den Kristallstrukturen der Kupfer(II)-cyanoargentate Cu(NH3)(py)Ag3-xCux(CN)5 · py

Ag/Cu^I Mixed Occupancy in the Crystal Structures of the Copper(II) Cyanoargentates Cu(NH₃)(py)Ag_3?xCu_x(CN)₅ · py From pyridine and ammonia containing Cu^II solutions, to which K[Ag(CN)₂] and in part KCu(CN)₂/KCN has been added, we obtained single crystals of mixed-valent copper compounds of variable composition Cu(NH₃)-(py)Ag_3-xCu_x(CN)₅ · py. The phases corresponding to x = 0.39(1) ( I ) and to x = 1.243(6) ( II ) were characterized by X-ray structure analysis. They are isomorphous and crystallize with Z = 4 in the monoclinic space group P2₁/c. The lattice constants for I [and II , resp.] are: a = 923.8(2) [901.4(2)], b = 1226.8(2) [1227.3(2)], c = 1809.8(4) [1783.5(2)] pm, β = 91.41(3) [91.02(1)]°. The Cu^II cation shows trigonal bipyramidal [CuN₅] coordination, with the neutral ligands in axial positions (mean value Cu? N for II : 201 pm), three N atoms of cyano bridges in equatorial ones (Cu? N: 206 pm). One of these bridges stems from a trigonal unit [AgCN(NC)₂], the central atom of which is substituted by Cu^I to an extent of 39% in I , and completely in II . The two other bridges originate from two [Ag(CN)₂]^? groups, of which the more bent one may be partially occupied by Cu^I as well (24% in II ). The units mentioned are connected into meshes of elongated hexagons and further into puckered layers within the (010) plane, interpenetrating each other in pairs. A threedimensional linking of layers occurs by the trigonal Ag/Cu^I species forming centrosymmetric dimers, in which the metal coordination is completed to tetrahedral by a C-atom of the corresponding neighbouring group and short metal-metal distances of 279.1(3) pm in I and 264.1(1) pm in II appear. Details and relations are discussed.     

Preparation of cationic chelate ylide complexes of palladium(II) and platinum(II)

Cationic palladium(II) and platinum(II) complexes with chelate ylides and neutral ligands of the type, [MCl (Y) (L)]⁺BPh₄^? (M  Pd or Pt; Y  bdep or bdmp*; L = 4-methylpyridine, 3,5-dimethylpyrazole, PPh₃, PCy₃, PMePh₂, P(OMe)₃, AsPh₃ or SbPh₃) and [M(bdep) (4-methylpyridine)₂] (BPh₄)₂ (M = Pd or Pt) were prepared and characterized by means of infrared and ¹H NMR spectra.     

New biimidazole and bibenzimidazole derivatives: mono and binuclear palladium(II) or platinum(II) complexes and heterobinuclear palladium(II)-rhodium(I) or platinum(II)-rhodium(I) complexes

Novel neutral biimidazolate or bibenzimidazolate palladium(II) and platinum(II) complexes of the type M(NN)₂(dpe) [M = Pd, Pt; (NN)₂^2? = BiIm^2?, BiBzIm^2?. dpe = 1,2-bis(diphenylphosphino) ethane] have been obtained by reacting MCl₂(dpe) with TI₂(NN)₂. Complexes M(NN)₂(dpe) which are Lewis bases react with HClO₄ or [M(dpe)(Me₂CO)₂](ClO₄)₂ to yield, respectively, mononuclear cationic complexes of general formula [M{H₂(NN)₂](dpe) (M = Pd, Pt; H₂(NN)₂ = H₂BiIm, H₂BiBzIm) and homobinuclear palladium(II) or platinum(II) cationic complexes of the type [M₂{μ - (NN)₂}(dpe)₂](ClO₄)₂. Reactions of M(BiBzIm)(dpe) with [Rh(COD) (Me₂CO)_X](ClO₄) render similar heterobinuclear palladium(II)-rhodium(I) and platinum(II)-rhodium(I) cationic complexes, of general formula [(dpe)M(μ-BiBzIm)Rh(COD)](ClO₄) (M = Pd, Pt; COD = 1,5-cyclooctadiene). Di- and mono-carbonyl derivatives [(dpe)M(μ-BiBzIm)Rh(CO)L](ClO₄) (M = Pd, Pt; L = CO, PPh₃) have also been prepared. The structures of the resulting complexes have been elucidated by conductance studies and IR spectroscopy.     

Die Quecksilber(II)-Ionen induzierte Hydrolyse gemischter Hexahalogenoosmate(IV)

Mercury(II)-Induced Hydrolysis of Mixed Hexahalo-Osmates(IV) The strong hydrolytic activity of Hg²⁺ ions on complexes [OsX_nI_6?n]^2?, X = Cl or Br; n = 1 – 5, is due to electrophilic attack at the I ligands. Small amounts of Hg²⁺ remove only one I. The very stable [HgI]⁺ and [HgI₂] are formed along with the corresponding pentahalo-monaquo-osmates(IV). In cis-[OsCl₄I₂]^2? and fac-[OsCl₃I₃]^2? ligands rearrange during hydrolysis giving the thermodynamically favoured I? Os? H₂O axis. Other mono- and bivalent cations have only a slight catalytic effect on the aquation, increasing with the size from Mg²⁺ to Ba²⁺.     

Untersuchungen an Polyhalogeniden III. Tetrammin-kupfer(II)-tetraiodid, [Cu(NH3)4I2 · I2], und Tetrammin-kupfer(II)-hexaiodid, [Cu(NH3)4I3]I3

Studies on Polyhalides. III. Crystal Structures of [Cu(NH₃)₄I₂ · I₂] and [Cu(NH₃)₄I₃]I₃ Tetramminecopper(II)tetraiodide [Cu(NH₃)₄I₂ · I₂] (I) crystallizes monoclinically in the space group C2/m with a = 1 185.9 pm, b = 892.8 pm, c = 656.8 pm, β = 111.10° and Z = 2 formula units. Tetramminecopper(II)hexaiodide [Cu(NH₃)₄I₃]I₃ (II) crystallizes orthorhombically in the space group Pnnm with a = 874.9 pm, b = 1 089.8 pm, c = 885.3 pm, and Z = 2 formula units. A special feature of these structures are coordinated polyiodide ions I₄^2? (I) or I₃^? (II). In both compounds four coplanar nitrogen atoms and two axial iodine atoms form a quasi-octahedral coordination around copper with the usual (4+2)-tetragonal distortion. The copper ions are connected by linear, centrosymmetric polyiodide ions I₄^2? (I) or I₃^? (II). Therefore infinite planar zigzag chains of units [Cu(NH₃)₄I₄] (I) or [Cu(NH₃)₄I₃]⁺(II) are resulting. The counterion I₃^? (II) is intercalated between these chains.     

Chloro- und Polyselenoselenate(II) Darstellung,Struktur und Eigenschaften von [Ph3(C2H4OH)P]2[SeCl4] · MeCN, [Ph4P]2[Se2Cl6] und [Ph4P]2[Se(Se5)2]

Chloro- and Polyselenoselenates(II): Synthesis, Structure, and Properties of [Ph₃(C₂H₄OH)P]₂[SeCl₄] · MeCN, [Ph₄P]₂[Se₂Cl₆], and [Ph₄P]₂[Se(Se₅)₂] By symproportionation of elemental selenium and SeCl₄ in polar protic solvents the novel chloroselenates(+II), [SeCl₄]^2? and [Se₂Cl₆]^2?, could be stabilized; they were crystallized with voluminous organic cations. They were characterized from complete X-ray structure analysis. Yellow-orange [Ph₃(C₂H₄OH)P]₂[SeCl₄] · MeCN (space group P1 , a = 10.535(4), b = 12.204(5), c = 16.845(6) Å, α = 77.09(3)°, β = 76.40(3)°, γ = 82.75(3)° at 140 K) contains in its crystal structure monomeric [SeCl₄]^2? anions with square-planar coordination of Se(+II). The mean Se? Cl bond length is 2.441 Å. In yellow [Ph₄P]₂[Se₂Cl₆] (space group P1 , a = 10.269(3), b = 10.836(4), c = 10.872(3) Å, α = 80.26(3)°, β = 79.84(2)°, γ = 72.21(3)° at 140 K) a dinuclear centrosymmetric [Se₂Cl₆]^2? anion, also with square-planar coordinated Se(+II), is observed. The average terminal and bridging Se? Cl bond distances are 2.273 and 2.680 Å, respectively. From redox reactions of elemental Se with boranate/thiolate in ethanol/DMF the bis(pentaselenido)selenate(+II) anion [Se(Se₅)₂]^2? was prepared as a novel type of a mixed-valent chalcogenide. In dark-red-brown [Ph₄P]₂[Se(Se₅)₂] (space group P2₁/n, a = 12.748(4), b = 14.659(5), c = 14.036(5) Å, β = 108.53(3)° at 140 K) centrosymmetric molecular [Se(Se₅)₂]^2? anions with square-planar coordination of the central Se(+II) by two bidentate pentaselenide ligands is observed (mean Se? Se bond lengths: 2.658 Å at Se(+II), 2.322 Å in [Se₅]_2?). The resulting six-membered chelate rings with chair conformation are spirocyclically linked through the central Se(+II). The vibrational spectra of the new anions are reported.