Syntheses and crystal structures of (2.2.2-cryptand)potassium chloride and (2.2.2-cryptand)ammonium bromide<Subscript>(0.75)</Subscript>chloride<Subscript>(0.25)</Subscript> hydrates

Two new complexes were synthesized, namely, 7: 2 (2.2.2-cryptand)potassium chloride and (2.2.2-cryptand)ammonium bromide_(0.75)chloride_(0.25) hydrates: [M(Crypt-222)]⁺ · Hal^? · 3.5H₂O, where M = K, Hal = Cl (I) and M = NH₄, Hal = Br_0.75Cl_0.25 (II). The structures of two isomorphous crystals were studied by X-ray diffraction analysis. Trigonal (space group P \(\bar 3\), Z = 2) structures I (a = 11.763 Å, c = 11.262 Å) and II (a = 11.945 Å, c = 11.337 Å) were solved by direct methods and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.057 (I) and 0.065 (II) for all 2626 (I) and 1654 (II) independent measured reflections (CAD-4 automated diffractometer, λMoK _α). In structures I and II, the host-guest [M(Crypt-222)]⁺ complex cation lies on the threefold crystallographic axis and has the approximate D ₃ symmetry. In complex I, the coordination polyhedron of the K⁺ cation (CN = 8) is a bicapped trigonal prism somewhat distorted toward an antiprism. Complexes I and II contain H-bonded disordered cubes of the water molecules and the Cl^? or Br^? anions.     

Synthesis and crystal structures of binuclear complexes of cobalt(II) and cadmium(II) diisobutyldithiophosphinates with hexamethylenetetramine

Heteroligand complexes [Co₂(HMTA)(iso-Bu₂PS₂)₄] (I) (μ_eff = 4.67 μB) and [Cd₂(HMTA)(iso-Bu₂PS₂)₄] (II) have been synthesized. Single crystals of compounds I and II have been obtained. The crystals are monoclinic: a = 32.622(2) Å, b = 9.4891(6) Å, c = 21.7570(13) Å, β = 125.774(1)^o, V = 5464.3(6) Å,³, Z = 4, ρ_calcd = 1.331 g/cm³ for I; a = 34.6092(7) Å, b = 9.5595(2) Å, c = 22.3473(5) Å, β = 127.144(1)^o, V = 5893.5(2) Å, Z = 4, ρ_calcd = 1.355 g/cm³ for II; space group for both complexes C2/c. Structures I and II are based on discrete binuclear molecules. The coordination polyhedra of the Co and Cd atoms are distorted tetragonal pyramids NS₄, with the bases formed by four S atoms of two bidentate chelating ligand iso-Bu₂PS ₂ ^? and the axial vertices occupied by N atoms of bidentate bridging HMTA ligand. The character of interaction of the molecules in structures I and II is considered.     

Synthesis and crystal structures of tetraacetylethylenediamine and <Emphasis Type="Italic">N</Emphasis>-(2-ammoniumethyl)carbamate

Two ethylenediamine derivatives—N-(2-ammoniumethyl)carbamate HN(COO^?)CH₂CH₂N⁺H₃ (I) and tetraacetylethylenediamine (H₃CC(O))₂NCH₂CH₂N(C(O)CH₃)₂ (II) (synthesized for the first time)—have been synthesized and characterized by X-ray crystallography. Compounds I and II are isolated as minor admixtures upon an attempt to synthesize ethylenediamine complexes of lanthanum and neodymium nitrates, respectively. The crystals of I and II are monoclinic: a = 7.778 Å, b = 8.060 Å, c = 7.568 Å, β = 95.73°, Z = 4, space group P2₁/c (I); a = 5.946, b = 10.255, c = 9.343 Å, β = 95.72°, Z = 2, space group P2₁/c (II). The bond lengths and bond angles lie within the corresponding standard values. Compounds I and II have different conformations of the N-C-C-N ethylenediamine moiety: gauche in I and trans in II, and the corresponding torsion angles are equal to 66.6° and 180°, respectively.     

Synthesis and crystal structures of (2.2.2-cryptand)rubidium chloride and bromide hydrates

Two complexes, (2.2.2-cryptand)rubidium chloride and bromide hydrates [Rb(Crypt-222]Hal · 3.5H₂O (Hal = Cl (I) and Br (II)), are synthesized. The structures of isomorphic crystals of compounds I and II are studied by X-ray diffraction analysis. The crystals are trigonal: space group P \(\overline 3 \), Z = 2; I: a = 11.810 Å, c = 11.302 Å; II: a = 11.890 Å, c = 11.402 Å. The structures are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.060 (I) and 0.077 (II) for 2650 (I) and 2700 (II) independent reflections (CAD-4 automated diffractometer, λMoK _α radiation). In crystals of complexes I and II, the [Rb(Crypt-222)]⁺ cation of the host-guest type lies on the crystallographic axis 3 and has the approximate symmetry D ₃. In complexes I and II, the coordination polyhedron of the Rb⁺ cation is a two-base-centered trigonal prism somewhat distorted to an antiprism. The crystals of compounds I and II contain H-bonded disordered cubes of the water molecules and Cl^? or Br^? anions.     

Crystal structure of adducts of copper(II) acetylacetonate and hexafluoroacetylacetonate with 4-aminopyridine

Single crystal X-ray diffraction is used to investigate two synthesized β-diketonate complexes of copper(II) with aminopyridine: Cu(4-NH₂Py)(aa)₂ (I) and Cu(4-NH₂Py)(hfa)₂ (II). The crystals of I and II have a monoclinic system; the unit cell parameters of I are: P2₁/n space group, a = 8.2921(3) Å, b = 14.7243(5) Å, c = 13.4970(4) Å, β = 102.426(1)°, V = 1609.32(9) ų, Z = 4; for II: C2/c space group, a = 23.5704(5) Å, b = 11.4977(2) Å, c = 16.0285(3) Å, β = 109.265(1)°, V = 4100.6(1) ų, Z = 8. The structures of I and II are molecular; they are composed of isolated molecules. The coordination polyhedron of the copper atom is formed by the O atoms of two acetylacetonate ligands (Cu-O 1.940(2)–2.171(2) I and the O atoms of two hexafluoroacetylacetonate ligands (Cu-O 1.940(2)–2.215(3) Å) in II. The molecules of 4-NH₂Py are bonded to the copper atom via the nitrogen atom of the aromatic ring (Cu-N 2.008(2) Å in I and Cu-N 1.978(3) Å in II). Noncoordinated amino groups join the molecules of the complexes together by means of N-H…O hydrogen bonds.     

Synthesis and structure of diethylenetriammonium tetrachloroaurates(III)

The (DienH₃)[AuCl₄]₃ · H₂O (I) and (DienH₃)₂[AuCl₄]Cl₅ (II) compounds were obtained by the reaction of HAuCl₄ with diethylenetriamine trihydrochloride (DienH₃Cl₃) in hydrochloric acid. The compounds were characterized by elemental analysis, X-ray diffraction, thermogravimetry, and IR spectroscopy. Crystals of I and II are monoclinic with space group P2₁/n. For I, a = 12.2314(3) Å, b = 14.6077(5) Å, c = 13.2680(5) Å, β = 106.7350(10)°, V = 2270.22(13) ų, Z = 8. For II, a = 6.62990(10) Å, b = 17.9026(5) Å, c = 10.3661(3) Å, β = 101.9230(10)°, V = 1203.83(5) ų, Z = 2. Both structures are ionic. The gold atoms in I and II have a 4 + 2 coordination environment. The Au-Cl bond lengths are within 2.276–2.294 Å, and the axial Au…Cl contacts are within 3.315–3.405 Å. The diethylenetriammonium cation in I and II has different conformations.     

Novel germanium(IV) catecholate complexes

The interaction of germanium(II) chloride dioxanate with 3,6-di-tert-butyl-o-benzoquinone or with its mono-and dianion derivatives is attended by the redox transformations. The novel germanium bis-catecholate complexes were synthesized that contained coordinated ether molecules (THF (I), Et₂O (II)) irrespective of the initial redox form of o-quinone. The germanium complex was also synthesized by the exchange reaction between GeCl₄ and sodium catecholate. Complexes (I), (II) were characterized by NMR and IR spectroscopies, elemental and X-ray diffraction analyses.     

Synthesis and structural properties of thiapyridinophane and its complex with Ni(II) and Ag(I)

The 2,11-dithia[3.3](3,5)pyrdinophane (L¹) has been synthesized by a new method and characterized by ¹H NMR, which is used to form coordination complexes C₁₄H₁₄N₄O₆S₂Ni (I) by addition of Ni²⁺ cation and C₁₄H₁₄N₃O₃S₂Ag (II) by addition of Ag⁺ cation. 2,11,20-Trithia[3.3.3](3,5)pyridinophane (L²) and 2,11,20,29-tetrathia[3.3.3.3](3,5)pyridinophane (L³) have also been synthesized as by-products. Single-crystal X-ray analysis reveals that the conformation of the L¹ is syn(boat-chair), complexes I and II also adopt syn(boat-chair) (CIF files CCDC nos. 1400332 (I) and 700724 (II)). While in I, Ni(II) is coordinated with L¹ with two nitrogen and four oxygen atoms, in II, Ag(^I) is coordinated with L¹ by two nitrogen and two sulfur atoms came from four ligands. In complexes I and II, the formation of three-dimensional structure depends on π???π stacking and hydrogen bonds.     

Palladium clusters Pd<Subscript>4</Subscript>(SR)<Subscript>4</Subscript>(OAc)<Subscript>4</Subscript> and Pd<Subscript>6</Subscript>(SR)<Subscript>12</Subscript> (R = Bu,Ph): Structure and properties

The structures of the Pd₄(SBu)₄(OAc)₄ (I) and Pd₆ (SBu)₁₂ (II) palladium clusters are determined by the X-ray diffraction method. For cluster I: a = 8.650(2), b = 12.314(2), c = 17.659(4) Å, α = 78.03(3)°, β = 86.71(2)°, γ = 78.13(3)°, V = 1800.8(7) ų, ρcalcd = 1.878 g/cm³, space group P \(\bar 1\), Z = 4, N = 3403, R = 0.0468; for structure II: a = 10.748(2), b = 12.840(3), c = 15.233(3) Å, α = 65.31(3)°, β = 70.10(3)°, γ = 72.91(3)°, V = 1767.4(6) ų, ρ calcd = 1.605 g/cm³, space group P \(\bar 1\), Z = 1, N = 3498, R = 0.0729. In cluster I, four Pd atoms form a planar cycle. The neighboring Pd atoms are bound by two acetate or two mercaptide bridges (Pd…Pd 2.95–3.23 Å, Pd…Pd angles 87.15°–92.85°). In cluster II, the Pd atoms form a planar six-membered cycle with Pd···Pd distances of 3.09–3.14 Å, the PdPdPd angles being 118.95°–120.80°. The Pd atoms are linked in pairs by two mercaptide bridges. The formation of clusters I and II in solution is proved by IR spectroscopy and calorimetry. Analogous clusters are formed in solution upon the reaction of palladium(II) diacetate with thiophenol.     

(18-Crown-6)sodium tribromide and (18-crown-6)potassium triiodide (with an admixture of bromodiiodide): Synthesis and crystal structure

Two crystalline host-guest complexes are synthesized and studied using X-ray diffraction analysis: (18-crown-6)sodium tribromide [Na(18-crown-6)]⁺ · Br ₃ ^? (I) and (18-crown-6)potassium tribromide (with an admixture of bromodiiodide) [K(18-crown-6)]⁺ · (Br_0.25I_2.75)^? (II). The structures of compound I (space group P2₁/_{n, a} = 8.957 Å, b = 8.288 Å, c = 14.054 Å, β = 104.80°, Z = 2) and compound II (space group Cc, a = 8.417 Å, b = 15.147 Å, c = 17.445 Å, β = 99.01°, Z = 4) are solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.098 (I) and 0.036 (II) for all 2311 (I) and 2678 (II) independent measured reflections on a CAD-4 automated diffractometer (λMoK _α). Similar crystalline complexes I and II exist as infinite chains of alternating complex cations and trihalide anions linked to each other through weak Na-Br or K-I coordination bonds. In [Na(18-crown-6)]⁺ and [K(18-crown-6)]⁺ complex cations, the Na⁺ or K⁺ cation (coordination number is eight) is located in the center of the cavity of the 18-crown-6 ligand and coordinated by the six O atoms and two terminal Br or I atoms of two trihalide anions lying on opposite sides of the rms plane of the crown ligand.     

Synthesis,crystal structure,and antibacterial activity of oxovanadium(V) complexes derived from <Emphasis Type="Italic">N</Emphasis>'-[1-(5-fluoro-2-hydroxyphenyl)methylidene]nicotinohydrazide and <Emphasis Type="Italic">N</Emphasis>'-(5-fluoro-2-hydroxybenzylidene)-2-hydroxynaphthylhydrazide

Two new oxovanadium(V) complexes, [VOL¹(OCH₃)(CH₃OH)] (I) and [VOL²(OCH₃)] (II), where L¹ and L² are the di-anionic form of N'-[1-(5-fluoro-2-hydroxyphenyl)methylidene]nicotinohydrazide and N'-(5-fluoro-2-hydroxybenzylidene)-2-hydroxynaphthylhydrazide, respectively, have been synthesized and characterized by elemental analysis, FT-IR spectra, and single crystal X-ray determination (CIF files CCDC nos. 891852 (I), 891853 (II)). The crystal of I is monoclinic: space group P2₁/c, a = 8.061(1), b = 15.293(2), c = 13.471(2) Å, ß = 92.595(2)°, V = 1658.8(4) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/n, a = 7.4454(9), b = 8.0833(9), c = 28.906(2) Å, ß = 92.644(2)°, V = 1737.8(3) ų, Z = 4. The V atom in I is in an octahedral coordination, and that in II is in a square-pyramidal coordination. The antibacterial activity of the compounds against various bacteria was assayed.     

Synthesis and crystal structures of cobalt(III) and zinc(II) complexes derived from 4-chloro-2-[(2-morpholin-4-ylethylimino)methyl]phenol with urease inhibitory activity

A new mononuclear cobalt(III) complex, [CoL₂(N₃)]₂ · CH₃OH (I), and a new mononuclear zinc(II) complex, [ZnLCl(CH₃OH)] (II) (HL = 4-chloro-2-[(2-morpholin-4-ylethylimino)methyl]phenol), were prepared and structurally characterized by elemental analyses, infrared spectroscopy, and single- crystal X-ray diffraction. The crystal of I is monoclinic: space group P2₁/c, a = 18.742(2) Å, b = 15.197(2) Å, c = 25.646(2) Å, β = 125.996(3)°, V = 5909.8(11) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/c, a = 7.257(1) Å, b = 24.707(2) Å, c = 9.637(1) Å, β = 101.557(2)°, V = 1692.9(3) ų, Z = 4. The Co atom in I is in an octahedral coordination, and the Zn atom in II is in a trigonal-bipyramidal coordination. The urease inhibitory test shows that complex I has strong urease inhibitory activity, while complex II has no activity.     

Binuclear bismuth halide complexes (<Emphasis Type="Italic">N</Emphasis>-Me(2,2'-BipyH))<Subscript>2</Subscript>[Bi<Subscript>2</Subscript>X<Subscript>10</Subscript>] (X = Cl,Br): Syntheses,crystal structures,and optical properties

Binuclear halide complexes (N-Me(2,2'-BipyH)₂[Bi₂X₁₀] (X = Cl (I), Br (II); 2,2'-Bipy = 2,2'-bipyridine) are synthesized by the reaction of solutions of [BiX₆]^3– and (N-Me(2,2'-BipyH)(NO₃)₂ in 2 M HX. The structure of [Bi₂X₁₀]^4– anions consists of octahedral fragments {BiX₆} linked by two μ₂-bridging halide ligands. The structures of the compounds are determined by X-ray diffraction analysis (CIF files CCDC 1455987 (I) and 1455988 (II)). The forbidden gap width E _g is determined for complex II from the diffuse reflectance spectrum.     

Three- and four-coordinated silver(I) ions in the coordination polymers [Ag(Me<Subscript>4</Subscript>Pyz)<Subscript>2</Subscript>]PF<Subscript>6</Subscript> and [Ag(2,3-Et<Subscript>2</Subscript>Pyz)<Subscript>2</Subscript>]PF<Subscript>6</Subscript>

The coordination polymers [AgPF₆(Me₄Pyz)₂] (I) and [AgPF₆(2,3-Et₂Pyz)₂] (II) were synthesized, and their structures were determined. Crystals of I are monoclinic, space group C2/c, a = 10.213(2) Å, b = 16.267(3) Å, c = 12.663(3) Å, β = 92.90(3)°, V = 2102.1(7) ų, ρ_calcd = 1.660 g/cm³, Z = 4. The structure of I is built of polymeric zigzag [Ag(C₈H₁₂N₂)] _∞ ⁺ chains and octahedral [PF₆] anions. The coordination polyhedron of the Ag⁺ ion is a flat triangle. Crystals of II are tetragonal, space group P \(\bar 4\)2(1)/c,a = b = 10.641(1) Å, c = 18.942(1) Å, V = 2144.6(2) ų, ρ_calcd = 1.627 g/cm³, Z = 4. In the structure of II, 2D cationic layers of fused square rings exist; the rings consist of four Ag⁺ cations linked by four bridging ligands of diethylpyrazine Et₂Pyz. The coordination polyhedron of the Ag⁺ ion is an irregular four-vertex polyhedron.     

Synthesis and structure of polycrystalline adducts of Co(II) azomethine complexes with redox-active 2,4,6,8-tetrakis-(<Emphasis Type="Italic">tert</Emphasis>-butyl)phenoxazin-1-one

The six-coordinate cobalt complexes, C₅₇H_63.50N_4.50O₄Co (IIa), C₆₀H₆₉N₅O₄Co (IIb), C5₈H₆₇N₃O₈Co (IIc), C₅₆H₆₁N₅O₁₀Co (IId), C₅₆H₆₃N₃O₆Co (IIe), C₅₈H₆₆N₄O₆Co (IIf), and C₅₈H₆₃N₇O₈Co (IIg), adducts of high-spin tetrahedral Co(II) bis(salicylaldiminates) (C₂₉H_24.50N_3.50O₂Co (Ia), C₃₂H₃₀N₄O₂Co (Ib), C₃₀H₂₈N₂O₆Co (Ic), C₂₈H₂₂N₄O₈Co (Id), C₂₈H₂₄N₂O₄Co (Ie), C₃₀H₂₇N₃O₄Co (If), and C₃₀H₂₄N₆O₆Co (Ig)) and redox-active 2,4,6,8-tetrakis(tert-butyl)phenoxazin-1-one (L), were synthesized and studied for structure and magnetic properties. Complexes IIa–IIg have octahedral structure (CIF files CCDC nos. 1403920 (IIf), 1403922 (IIg)) and exist in the ground low-spin state (ls-Co^III-SQ), which arises upon intramolecular single-electron redox process in the ligand–metal system. The presence of substituents of different nature in the azomethine ligands of IIa–IIg does not induce any significant changes in their magnetic properties.     

Molecular and Crystal Structure of 1-(4-Fluorophenyl)-1,4-Dihydro-1<Emphasis Type="Italic">H</Emphasis>-Tetrazole-5-Thione and Its Complex with Cadmium(II)

The molecular and crystal structures of 1-(4-fluorophenyl)-1,4-dihydro-1H-tetrazole-5-thione (I) and its complex with cadmium(II) (II) are studied by single crystal XRD. Free ligand I is thione; it has a nonplanar structure (the torsion angle between the tetrazole and benzene rings is 54.99(7)°) and forms H-bonded centrosymmetric dimers via two N–H…S hydrogen bonds in the crystal. The dimers contain a central planar eight-membered {S=C–N–H…S=C–N–H…} ring. Complex II has a chain structure with the composition [(C₇H₄N₄FS)₂Cd]_n. The environment of the Cd(II) atom consists of two nitrogen atoms and two sulfur atoms from four ligands I and represents a distorted tetrahedron. When complex II forms, ligand I converts into the thiol form. Infinite 1D chains contain eight-membered {←S=C–N–Cd←S=C–N–Cd} rings in a chair conformation. The chains in the crystal are arranged in layers parallel to the (101) plane due to secondary intermolecular F…F and π–π-stacking interactions.     

Syntheses,Structures, and Magnetic Properties of Two Mn(II) Coordination Polymers Based on 4-Fluorocinnamic Acid and 1,10-Phenanthroline

Two Mn(II) coordination polymers, {[Mn₃ (Pfca)₆(Phen)₂] · 2DMF} _n (I) and [Mn(Pfca)₂(Phen)(H₂O)] _n (II) (HPfca = 4-fluorocinnamic acid, Phen = 1,10-phenanthroline), were synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and singlecrystal X-ray diffraction (CIF files CCDC nos. 967513 (I), 1542972 (II)). Complex I crystallizes in the triclinic crystal system, space group Pī with a = 11.0821(11), b = 12.2632(12), c = 15.0288(15) Å, α = 87.3760(10)°, β = 88.4610(10)°, γ = 81.2220(10)°, V = 2016.0(3) Å3, ρ_c = 1.369 g/cm³, M _r = 1662.25, Z = 1, F(000) = 853, μ = 0.543 mm^–1, the final R = 0.0592 and wR = 0.1681 for 15498 observed reflections with I > 2σ(I). Complex II is of monoclinic system, space group P2₁/c with a = 18.0539(19), b = 8.5806(9), c = 18.758(2) Å, β = 116.5700(10)°, V = 2599.0(5) ų, ρ_c = 1.491 g/cm³, M _r = 583.44, Z = 4, F(000) = 1196, μ = 0.567 mm^–1, the final R = 0.0337 and wR = 0.0853 for 18139 observed reflections with I > 2σ(I). Complex I features linear Mn(II)-trinuclear units, which form 1D chain structure through F···F weak interactions, and complex II is 1D polymeric Mn(II)-chains. Antiferromagnetic coupling interactions exist within Mn(II)- carboxylate trinuclear in I (J =–0.40 cm^–1) and Mn(II)-carboxylate chain in II (J =–0.45 cm^–1).     

Synthesis,crystal structures,and antimicrobial activity of copper(II) and zinc(II) complexes derived from 2-bromo-4-chloro-6-[(2-morpholin-4-ylethylimino)methyl]phenol

An end-to-end azido-bridged dinuclear copper(II) complex [Cu₂L₂(μ_1,3-N₃)](NO₃) (I) and a mononuclear zinc(II) complex [ZnCl₂(HL)] ? CH₃OH (II), where L is 2-brom-4-chloro-6-[(2-morpholin- 4-ylethylimino)methyl]phenolate, have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination (CIF files CCDC nos. 1415217 (I), 1415218 for (II)). The crystal of I is monoclinic: space group C2/c, a = 28.684(2), b = 7.1787(5), c = 18.292(1) Å, β = 117.887(3)°, V = 3329.1(4) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/c, a = 10.8207(9), b = 12.3398(7), c = 14.9477(7) Å, β = 93.473(3)°, V = 1992.2(2) ų, Z = 4. The Schiff base ligand in I coordinates to the Cu atom through the phenolate O, imine N, and morpholine N atoms, while the Schiff base ligand in II coordinates to the Zn atom through the phenolate O and imine N atoms, with the morpholine N atom protonated. The effect of these complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans was studied.     

New catecholate complexes of triphenylantimony(V) based on 6-iminomethyl-3,5-di-<Emphasis Type="Italic">tert</Emphasis>-butylpyrocatechols N-functionalized by the aniline or phenol group

The following new triphenylantimony(V) catecholate complexes bearing the protonated imine group are synthesized from the new sterically hindered 3,5-di-tert-butylpyrocatechols (6-(CH=N-o-(C₆H₄–NH₂))-3,5-Cat)H₂ (H₂L¹) and (6-(CH=N-o-(C₆H₄–OH))-3,5-Cat)H₂ (H₂L²) containing in position 6 the iminomethyl group bonded to the aniline or phenol substituent: (6-(CH=NH⁺-o-(C₆H₄–NH₂))-3,5-Cat)SbPh₃X (X = Br (I), OMe (III)) and (6-(CH=NH⁺-o-(C₆H₄–OH))-3,5-Cat)SbPh₃X (X = Br (II), OMe (IV)). The molecular structure of complex III · CH ₃ OH in the crystalline state is determined by X-ray diffraction analysis (CIF file CCDC no. 1554694). The electrochemical properties of complexes III and IV are studied by cyclic voltammetry.     

Crystal structures of polyphosphates MCs<Subscript>5</Subscript>(PO<Subscript>3</Subscript>)<Subscript>8</Subscript> (M = Pr,Eu, and Gd)

Crystals of double polyphosphates EuCs₅(PO₃)₈ (I) and GdCs₅(PO₃)₈ (II) have been studied by X-ray diffraction. The isostructural crystals of I and II are monoclinic, space group C2. Only unit cell parameters have been determined for the crystals of double Pr and Cs polyphosphate (III). This crystal is isostructural with earlier studied La₃Cs₁₅P₂₄O₇₂ · 6H₂O (IV). The crystals of compounds III and IV are triclinic, space group P1, Z = 1; a = 11.987(2) and 12.178(5) Å, b = 14.754(8) and 14.740(8) Å, c = 14.692(8) and 14.847(9) Å, α = 60.15(4)° and 60.87(5)°, β = 67.04(4)° and 66.35(4)°, γ = 78.76(3)° and 77.54(4)°, respectively. In compounds I and II, the polyphosphate anions exist as infinite chains. The M^IIIO₈ polyhedra are isolated from each other but share edges and faces with the CsO _n polyhedra.