Crystal Structure of 4,7,13,16,21,24-Hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane Semihydrate Oxonium Tribromide

The crystal structure of 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo-[8.8.8]hexacosane semihydrate oxonium tribromide, [H₂(2.2.2-Crypt)·0.55H₂O]²⁺·H₃O⁺·3Br⁻ (I) was determined by XRD analysis. The triclinic structure of I (space group P , a = 10.026 Å, b = 11.292 Å, c = 13.115 Å, α = 78.37°, β = 72.11°, γ = 77.50°, Z = 2) was solved by direct methods; full-matrix least-squares refinement in an anisotropic approximation converged to R = 0.055 for all 4057 independent reflections collected (CAD-4 automatic diffractometer, λCuK _α).Original Russian Text Copyright © 2004 by A. N. Chekhlov__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1136–1141, November–December, 2004.     

Mixed Complex Salt [Cu4(SCN2H4)7(NO3)](NO3)(SO4) · 3.3H2O: Synthesis and X-Ray Diffraction Analysis

The complex salt [Cu₄(SCN₂H₄)₇(NO₃)](NO₃)(SO₄) · 3.3H₂O was synthesized via reaction of aqueous solutions of thiourea with copper nitrate at 80°C and studied using X-ray diffraction analysis. The conditions and reasons for the partial oxidation of thiourea to sulfate ions were established. The crystals are monoclinic: a = 12.6072(7) Å, b = 15.4265(8) Å, c = 22.108(1) Å, = 120.133(6)°, space group P2₁/c, Z = 4. The crystal structure consists of [Cu₄(SCN₂H₄)₇(NO₃)]³⁺ complex cations, SO₄ ^2–, and NO₃ ^– anions, and molecules of the water of crystallization. Three types of coordination of the Cu atom were distinguished in the structure: trigonal (Cu–S 2.213–2.279 Å), tetrahedral (Cu–S 2.315–2.459 Å), and trigonal–pyramidal (3+1) (Cu–S 2.26–2.288, Cu–O 2.68 Å). The NO₃ ligand was found to be orientationally disordered.     

Chloroaqua Complexes [M3S4(H2O)9?xClx](4?x)+ (M = Mo, W; x = 4, 6, 7) and Their Supramolecular Compounds with Cucur[8]uril

Compounds of trigonal cluster chloroaqua complexes with cucurbit[8]uril were synthesized by slowly evaporating HCl solutions of chalcogenides heterometallic cubane cluster complexes of molybdenum and tungsten with cucurbit[8]uril in air; the complexes were characterized by X-ray diffraction analysis: (H₃O)₈[Mo₃S₄(H₂O)_2.5Cl_6.5]₂Cl(PdCl₄)·(C₄₈H₄₈N₃₂O₁₆)· 29H₂O (a = 13.3183(17) Å, b = 13.7104(18) Å, c = 18.225(3) Å; α = 80.263(3)°, β = 77. 958(3)°, γ = 87.149(4)°, V = 3207.4(7) ų, space group P , Z = 1, ρ(calc) = 1.900 g/cm³), (H₃O)₄ [Mo₃S₄(H₂O)₃Cl₆]₂·(C₄₈H₄₈N₃₂O₁₆)₃·68H₂O (a = 21.413(6) Å, c = 49.832(10) Å; γ = 120°, V = 19788(8) ų, space group R , Z = 3, ρ(calc) = 1.695 g/cm³), (H₃O)₆ [Mo₃S₄(H₂O)₃Cl₆]₂Cl₂·(C₄₈H₄₈N₃₂O₁₆)·12H₂O (a = 15.881(2) Å, b = 17.191(2) Å, c = 23.276(4) Å; β = 98.865(15)°, V = 6278.7(15) ų, space group P2₁/c, Z = 2, ρ(calc) = 1.638 g/cm³), [W₃S₄(H₂O)₅Cl₄]₂·(C₄₈H₄₈N₃₂O₁₆)₃·35H₂O (a = 21.038(3) Å; α = 61.20(1)°, V = 6762.0(14) ų, space group R , Z = 1, ρ(calc) = 1.582 g/cm³). The [Mo₃S₄(H₂O)₃Cl₆]²⁻ anion complex was isolated as three geometrical isomers.Original Russian Text Copyright © 2004 by E. V. Chubarova, D. G. Samsonenko, H. G. Platas, F. M. Dolgushin, A. V. Gerasimenko, M. N. Sokolov, Z. A. Starikova, M. Yu. Antipin, and V. P. Fedin__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1049–1058, November–December, 2004.     

Crystal Structure of 4,7,13,16,21,24-Hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane Triaquachlorolithium Dichloride

The crystal adduct (1 :1) 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane triaquachlorolithium dichloride, [H₂(Crypt-222)]²⁺ · 2Cl^– · [LiCl(H₂O)₃] (I), was synthesized and studied using X-ray diffraction analysis. Structure I (space group R3, a = 7.922 Å, c = 37.207 Å, Z = 3) was solved by direct methods and anisotropically refined by the full-matrix least-squares method to R = 0.034 for 1363 independent reflections (CAD4 autodiffractometer, MoK ). Crystal I consists of disordered 2.2.2-cryptand dications, chloride anions, and tetrahedral [LiCl(H₂O)₃] complexes. All of them lie on threefold axes. There are tridentate ⁺N–H (···O)₃ hydrogen bonds in the [H₂(Crypt-222)]²⁺ dication. The crystal structure of adduct I contains a complex interionic hydrogen bonding system.     

Synthesis and Structure of [Co(NH<Subscript>3</Subscript>)<Subscript>6</Subscript>]<Subscript>2</Subscript>[W<Subscript>4</Subscript>Se<Subscript>4</Subscript>(CN)<Subscript>12</Subscript>]·8.5H<Subscript>2</Subscript>O

The compound [Co(NH₃)₆]₂[W₄Se₄(CN)₁₂]·8.5H₂O was obtained by evaporating an aqueous ammonia solution of K₆[W₄Se₄(CN)₁₂]·6H₂O and CoCl₂·6H₂O complexes. The starting Co(II) of CoCl₂·6H₂O transforms into [Co(NH₃)₆]³⁺ when exposed to air in a water-ammonia medium. Crystal data: triclinic crystal system, a = 10.7750(8) Å, b = 12.2843(9) Å, c = 19.6539(14) Å; α = 90.213(2)°, β = 99.910(2)°, γ = 114.737(1)°, V = 2319.1(3) ų, space group , Z = 2, D _x = 2.633 g/cm³.Original Russian Text Copyright © 2004 by I. V. Kalinina, Z. A. Starikova, F. M. Dolgushin, D. G. Samsonenko, and V. P. Fedin__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 905–908, September–October, 2004.     

Influence of the linking chain length on the recombination kinetics of covalently bonded triplet radical pairs and magnetic field effects

Nanosecond laser flash photolysis technique is used to study the formation and decay kinetics of covalently linked triplet radical pairs (RP) formed after photoinduced electron transfer in the series of 21 zinc porphyrin—chain—viologen (Pph—Sp_n—Vi²⁺) dyads, where the number of atoms (n) in the chain increases from 2 to 138. In poorly viscous polar solvents (acetone, CHCl₃—CH₃OH (1 : 1) mixture), the dependence of the rate constant of RP formation on n can be described by the equation k _e = k _e ⁰ n ^–a at k _e ⁰ = 2.95·10⁸ s^–1 anda = 0.8. In the zero magnetic field, the RP recombination rate constant (k _r(B = 0)) is significantly lower than k _e and ranges from 0.7·10⁶ to 8·10⁶ s^–1. The dependence of k _r(B = 0) on n is extreme. The dependence k _r(B = 0) reaches a maximum at n = 20. In the strong magnetic field (B = 0.21 T), the significant retardation of triplet RP recombination is observed. The chain length has an insignificant effect on k _r(B = 0.21 T), which ranges from 0.3·10⁶ to 0.9·10⁶ s^–1. The regularities found are discussed in terms of the interplay of molecular and spin dynamics.     

Thermogravimetric and differential scanning calorimetric investigations of manganese–glycine interactions

Thermogravimetric (t.g.) and differential scanning calorimetric (d.s.c.) data have been used to study metal–amino acid interactions in adducts of general formula MnCl₂ · ngly (gly = glycine, n = 0.7, 2.0, 4.0 and 5.0). All the prepared adducts exhibit only a one step mass loss associated with the release of glycine molecules, except for the 0.7gly adduct, which exhibits two glycine mass loss steps. From d.s.c. data, the enthalpy values associated with the glycine mass loss can be calculated: MnCl₂ · 0.7gly = 409 and 399 kJ mol^–1, MnCl₂ · 2.0gly = 216 kJ mol^–1, MnCl₂ · 4.0gly = 326 kJ mol^–1 and MnCl₂ · 5.0gly = 423 kJ mol^–1, respectively. The enthalpy associated with the ligand loss, plotted as function of the number of ligands for the n = 2.0, 4.0 and 5.0 adducts, gave a linear correlation, fitting the equation: H (ligand loss)/kJ mol^–1 = 67 × (number of ligands, n) + 76. A similar result was achieved when the enthalpy associated with the ligand loss was plotted as a function of the _a(COO^–) bands associated with the coordination through the carboxylate group, 1571, 1575 and 1577 cm^–1, respectively, for the n = 2.0, 4.0 and 5.0 adducts, giving the equation H (ligand loss) /kJ mol^–1 = 33.5 × _a(COO^–) /cm^–1 – 52418.5. This simple equation provides evidence for the enthalpy associated with the ligand loss being very closely related to the electronic density associated with the metal–amino acid bonds.     

Facile generation of platinum(IV) compounds with mixed labile moieties. Hydrogen peroxide oxidation of platinum(II) to platinum(IV) compounds

Hydrogen peroxide oxidation of platinum(II) compounds containing labile groups such as Cl, OH, and alkene moieties has been carried out and the products characterized. The reactions of [Pt^II (X)₂ (N–N)] (X = Cl, OH, X₂ = isopropylidenemalorate (ipm); N–N 2,2-dimethyl-1,3-propanediamine [(dmpda), N-isopropyl-1,3-propanediamine (ippda)] with hydrogen peroxide in an appropriate solvent at room temperature affords [Pt^IV (OH)(Y)(X)₂(N–N)] (Y = OH, OCH₃). The crystal structures of [Pt^IV(OH)(OCH₃)(Cl)₂(dmpda)]·2H₂O (P-1 bar, a = 6.339(2) Å , b = 9.861(1) Å, c = 11.561(1) Å, a = 92.078(9)°, β = 104.78(1)°, γ=100.54(1)°, V = 684.3(2) ų, Z = 2R = 0.0503) and [Pt^IV(OH)₂(ipm)(ippda)]·3H₂O (C 2/c, a = 27.275(6) Å, b=6.954(2) Å, c = 22.331(4) Å, β = 118.30(2)°, V = 3729(2) ų, Z = 8, R = 0.0345) have been solved and refined. The local geometry around the platinum(IV) atom approximates to a typical octahedral arrangement with two added groups (OH and OCH₃; OH and OH) in a transposition. The platinum(IV) compounds with potential labile moieties may be important intermediate species for further reactions.     

Molecular state of hydrochloric acid in its tributyl phosphate extracts

Using IR spectroscopy we have shown that at digerent equilibrium concentrations of HCl in aqueous phases, its tributyl phosphate @acts contain: 1) at C_Hcl ^a < 2.3 M, micelle-like associates H₅O₂ ⁺(H₂O)_n–2(TBP)_mCl^–·(H₂0·TBP)₂ (n 26 and m 13), the structure of micelles is discussed 2) at 2.3 M < C_HCl ^a < 5.6 M, dimer associates [H₅O₂ ⁺(H₂O)₂Cl^–(H₂O·TBP)₂]₂; 3) at 5.6 M < C_HCl ^a < 8.5 M, H-bonded molecular fragments H₅O₂ ⁺(TBP)_2/3Cl^–(A); and 4) at C_HCl ^a > 8.5 M, considerable amounts of the H₃O⁺ tisolvate start to form in molecular fragments H₃O⁺(TBP)_1/3Cl ^–(B) H-bonded with the nearest neighbors. At C_Hcl ^a > 5.6 M, almost no free TBP molecules occur in the extracts and a structured liquid forms from the A fragments; and at C_Hcl ^a > 8.5 M, from the B fragments.Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturmoi Khimii, Vol. 34, No. 5, pp. 72–79, September–October, 1993.Translated by K. Shaposhnikova     

Coordination compounds of nickel with trithiocyanuric acid. Part IV. Structure of [Ni(pmdien)(ttcH)] (pmdien = N,N,N′,N′,N′′-pentamethyldiethylenetriamine,ttcH3 = trithiocyanuric acid)

Ni^II mixed-ligand complexes of compositions [Ni(pmdien)(ttcH)] (1), [Ni(baphen)₂(ttcH)] · 4H₂O (2), [Ni-(dpa)(ttcH)(H₂O)] (3), [Ni(cyclam)(ttcH)] · 2H₂O (4), [Ni(hexaa)](ttcH) (5) and [Ni(hexab)(ttcH)] · 2H₂O (6), (baphen = 4,7-diphenyl-1,10-phenanthroline, dpa = 2,2-dipyridylamine, cyclam = 1,4,8,11-tetraazacyclotetradecane, hexaa = 1,3,6,9,11,14-hexaazatricyclo[12.2.1.1^6,9]-octadecane, hexab = 1,8-dimethyl-1,3,6,8,10,13-hexaazacyclotetradecane) have been prepared and characterized by means of i.r., u.v.–vis. spectroscopies and magnetochemical measurements. The redox properties of the complexes were studied by cyclic voltammetry. The crystal and molecular structure of [Ni(pmdien)(ttcH)] was determined. The nickel atom is penta-coordinated by three N atoms of pmdien, and by S and N atoms of trithiocyanurate(2–) anion.     

Structural studies on 3-acetyl-1,5-diaryl and 3-cyano-1,5-diaryl formazan chelates with cerium(III), thorium(IV) and uranium(VI)

Summary Solid complexes of 3-acetyl-1,5-diaryl and 3-cyano-1,5-diaryl formazans were prepared and characterized by elemental analysis, IR, NMR, TGA and DTA analyses. Based on these studies, the suggested general formula for the complexes is [M(HL) _m (OH^–) _n or (NO ₃ ^– or Cl^–) _x ·(H₂O) _y or (C₂H₅OH orDMSO) _z , where HL=formazanM=Ce³⁺, Th⁴⁺, and UO ₂ ²⁺ ,m=1–2,n=0–3,x=0–3,y=0–4 andz=0–3. The metal ions are expected to have coordination numbers 6–8.

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Strukturuntersuchungen an 3-Acetyl-1,5-diaryl- und 3-Cyan-1,5-diaryl-formazan-Chelaten mit Cer(III), Thorium(IV) und Uran(VI)

Zusammenfassung Die hergestellten Chelate wurden mittels Elementaranalyse, IR, NMR, TGA und DTA charakterisiert. Darauf basierend wird die generelle Formel [M(HL) _m (OH^–) _n bzw. (NO ₃ ^– oder Cl^–) _x ·(H₂O) _y oder (C₂H₅OH bzw.DMSO) _z ] vorgeschlagen, wobei HL=Formazan,M=Ce³⁺, Th⁴⁺ oder UO ₂ ²⁺ ,m=1–2,n=0–3,x=0–3,y=0–4 undz=0–3. Die Metallionen haben Koordinationszahlen von 6–8.

     

Crystal Structure of Hexafluosilicates of Protonated Thiosemicarbazide and 2,5-Diamino-1,3,4-thiadiazole Produced in the Reaction of Thiosemicarbazide with Fluosilicic Acid

The structure of the crystal complex (L¹H)₂(L²H)(SiF₆)_1.5(L¹is thiosemicarbazide, L²is 2,5-diamino-1,3,4-thiadiazole) was studied by X-ray diffraction analysis. The complex was prepared by reacting an aqueous solution of L¹with 45% fluosilicic acid. The crystals are monoclinic: a= 16.080(3) Å, b= 5.4860(8) Å, c= 20.079(4) Å, = 91.46(1)°, Z= 4, space group P2/n, R= 0.0427. The components of the ionic structure of the complex are L¹H⁺and L²H⁺cations and SiF^2– ₆anions combined by a system of H bonds of the NH···S and NH···F types, the -nitrogen atom of the hydrazine fragment and the endocyclic nitrogen atom of the heterocycle being the protonation centers in L¹H⁺and L²H⁺, respectively. The bond lengths in the SiF^2– ₆anions range within 1.621(6)–1.691(2) Å.     

A physicochemical study of Schiff base metal complexes derived from α-benzylmonoxime

Summary Metal complexes of general formula [M(DDE)·nH₂O]· nH₂O and [M(DDB)·nH₂O] [where M = Co^II, Ni^II, Cu^II, Pd^II and UO ₂ ²⁺ ; n = 0–4; DDE and DDB are the anion of bis(1,2-diphenyl-1-hydroxyimino-2-ethylidine)-1,2-diaminoethane and bis(l,2-diphenyl-l-hydroxy-imino-2-ethylidine)-1,4-diaminobenzene, respectively] were prepared and characterized by i.r. electromagnetic and n.m.r. spectroscopy and magnetic measurements.     

Antimycobacterial activity of mixed-ligand copper quinolone complexes

New mixed-ligand Cu^II, complexes: [Cu(cf)(phen)Cl)](BF₄) · 4H₂O (3), [Cu(cf)(bipy)(Cl)](BF₄) · 2H₂O (4) and [Cu(cf)(dafone)(Cl)](BF₄) · 2H₂O (5) (cf = ciprofloxacin, phen = 1,10-phenanthroline, bipy = 2,2-bipyridine and dafone = 4,5-diazafluoren-9-one) have been isolated and characterized by elemental analyses, i.r., u.v.–vis. spectra, magnetic susceptibility and cyclic voltammetry. Complex (4) crystallizes in the monoclinic space group P2₁/n with a = 13.8919(13) Å, b = 14.5718(13) Å, c = 14.0725(13) Å, = 95.150(2)°, V=2837.2(5) ų. All complexes possess square-pyramidal geometry. The antimycobacterial activity of ciprofloxacin and complexes (3–5) has been evaluated against Mycobacterium smegmatis, which shows clear enhancement in the antitubercular activity upon copper complexation with N—N donors.     

Quantum chemical modeling of the photode-composition of the water dimer in chlorophyll complexes of magnesium and manganese

On the basis of quantum-chemical calculations in the MPNDO/3 approximation, a reaction has been proposed for the photodecomposition of water in complexes M·Chl_a...(H₂O)₂M·Chl_a+O₂+4H⁺+4e^– (M=Mg, Mn), which suggests an interpretation of the primary event of photosynthesis. Calculations of the photosynthetic evolution of oxygen according to the Joliot-Kok model in complexes M·Chl_a...(H₂O)₂ are in good agreement with the experimental data of the thermoluninescence of chlorophyll photosystem II.Kiev Polytechnic Institute. Translated from Zhurnal Strukturnoi Khimii, Vol. 34, No. 2, pp. 33–38, March–April, 1993.     

Synthesis and Structure of the Supramolecular Adduct Formed by the [Mo3S4(H2O)7Cl22+ Cluster Complex with Cucurbituril: {[Mo3S4(H2O)7Cl2](C36H36N24O12)} Cl2·10H2O

Slow crystallization of an HCl solution containing cucurbituril (C₃₆H₃₆N₂₄O₁₂) and a triangular molybdenum cluster aqua complex [Mo₃S₄(aq)]⁴⁺ yielded a supramolecular adduct of { [Mo₃S₄(H₂O)₇Cl₂]×(C₃₆H₃₆N₂₄O₁₂₎Cl₂·10H₂O composition. The molecular and crystal structure of the adduct were established by single crystal X-ray diffraction. Monoclinic crystal system, space group P2₁/c, a = 21.4762(2) Å, b = 14.6853(1) Å, c = 24.6480(3) Å; β = 112.8366(5)°, V _cell = 7164.26(12) ų, Z = 4, ρ_calc = 1.725 g/cm³.Original Russian Text Copyright © 2004 by E. V. Chubarova, D. G. Samsonenko, J. H. Platas, M. N. Sokolov, and V. P. Fedin__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 950–954, September–October, 2004.     

Crystal structure and spectra of the Ni(II) complex of pyridine-2,6-dithio-carbomethylamide

The crystal structure of the paramagnetic bis(pyridine-2,6-dithiocarbomethylamide) nickel(II) nitrate (NiPDTA) is described: C₁₈H₂₂N₆S₄·(NO₃)₂·(H₂O)_1,5, monoclinic, C2/c,Z=4,a=14.705 (3) Å,b=23.254 (8) Å,c=8.383 (3) A, =98.18 (2)°,d _x=1.55 gcm^–3,d _m=1.53 gcm^–3. The structure was solved withPatterson and differenceFourier techniques and refined to a residual ofR=0.053. The nickel is surrounded by a square bipyramidal coordination of four thioamide sulfur atoms and two pyridine nitrogen atoms. Vibrational and electronic band positions for this compound are discussed.

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Kristallstruktur und Spektren des Pyridin-2,6-dithiocarbomethylamid Nickel(II)-Komplexes

Zusammenfassung Die Kristallstruktur des paramagnetischen bis(Pyridin-2,6-dithiocarbomethylamid) Nickel(II)-nitrats (NiPDTA) wurde bestimmt. C₁₈H₂₂N₆S₄Ni·(NO₃)₂·(H₂O)_1,5, monoklin, C2/c,Z=4,a=14,705 (3) Å,b=23,254 (8) Å,c=8,383 (3) A, =98,18 (2)°,d _x=1,55gcm^–3,d _m=1,53gcm^–3. Das Phasenproblem wurde mittelsPatterson-und Differenz-Fourier-Synthese bestimmt und die Struktur bis zu einem kristallographischenR-Faktor vonR=0.053 verfeinert. Das Nickel-Atom ist von vier Thioamid-Schwefelatomen und zwei Pyridin-Stickstoffatomen in quadratisch-bipyramidaler Anordnung umgeben. Schwingungsspektren und Anregungsspektren des Komplexes werden diskutiert.

     

Kinetics of the anation reaction of pentaamineaquacobalt(III) by phosphorous acid/hydrogenphosphite

Summary The kinetics of the anation reaction of [Co(NH₃)₅H₂O]³⁺ by H₃PO₃/H₂PO ₃ ^– , to give [CoH₂PO₃(NH₃)₅]²⁺, have been studied at 60, 70 and 80°C, in the acidity range [H⁺](M)=1.5 · 10^–1 –2.0 · 10^–3. Only H₂PO₃ is found to be reactive. The rate data is consistent with an I_d mechanism. The mean value of outer sphere association of [Co(NH₃)H₂O]³⁺ with H₂PO ₃ ^– is 1.5 M^–1. Values of the interchange constants are: 10⁴4k_i(s^–1)= 0.29, 1.47, 5.13, at 60, 70 and 80 °C respectively (H= 1.4 · 10²KJmol^–1, S=8.3 · 10 JK^–1 mol^–1). The first acidity constant of H₃PO₃ at I=1.0 has also been determined: 10²K_a(M)=4.8, 5.2 and 5.5, at 25, 40 and 50 °C respectively.     

Channel inclusion of potassium and tetrachloroplatinate ions in a complex formed between 1,3-diamino-2-propanone and K2PtCl4 in an acidic medium

The crystalline complex dipotassium 1,3-diammonio-2-propanone tetrachloroplatinate trihydrate, formulated as K₂[(NH₃CH₂C)₂O][PtCl₄]₂ · 3H₂O, has been prepared while synthesizing complexes analogous tocis-dichlorodiamine Pt(II). Its structure is orthorhombic, space groupPnma,M _r = 896.1,F(000) = 1640,a = 8.428(4),b = 20.360(10),c = 12.141(7)A,V = 2083.3ų,Z = 4,D _x = 2.860 g cm^–3, (MoK _x) = 196 cm^–1, finalR = 0.083 for 1379 unique reflections. The structure consists of a very extended hydrogen bonded network which involves half of the PtCl₄ ^2– ions, the organic molecules and the water molecules of hydration, leaving large oval channels which accommodate potassium cations and tetrachloroplatinate anions. Within the channel the potassium and tetrachloroplatinate ions pack in columns extending along the a axis. The dense packing is rather reminiscent of that found in the neat salt where each potassium ion is surrounded by six chlorine atoms which describe a polyhedron of a distorted trigonal prism with K⁺ —C1 distances ranging between 3.163–3.187 Å. There is some indirect evidence for the formation of 1,3-diammonio-2-propanone dications which counterbalance the charges of half of the PtCl₄ ^2– ions by protonation of each of the amino nitrogens. The carbonyl oxygens, however, are involved only in a very weak O-C-O interactions along thea axis.     

Two new copper(II) complexes containing the benzene-1,3,5-tricarboxylic acid anion and 1,4,7-triazacyclononane

Two new copper(II) complexes, [Cu(tacn)(H₂BTC)₂]·2H₂O (1) and [Cu(tacn)(H₂BTC)(H₂O)](H₂BTC)·5H₂O (2), where H₂BTC^– = the benzene-1,3,5-tricarboxylic acid anion and tacn =1,4,7-triazacyclononane, have been synthesized and their structures determined. Copper(II) ions of both (1) and (2) are five-coordinate with three nitrogen atoms of tacn and two oxygen atoms of either H₂BTC^– or H₂O. Hydrogen bonds in these two complexes result in them being differently packed in the crystal cell.