Structural and Physicochemical Characteristics of Tetrabutylammonium Tetrahalogenoferrates(III), [(C4H9)4N][FeBr4−nCln]

A series of tetrahalogenoferrates(III), [FeBr_4?nCl_n]^? (n=0‐4) stabilized with the tetrabutylammonium cation, of general formula [(C₄H₉)₄N][FeBr_4?nCl_n], has been synthesized. The crystal and molecular structure of [(C₄H₉)₄N][FeCl₄] was determined. The iron cation adopts slightly distorted tetrahedral coordination with two opposite angles smaller than tetrahedral one, two equal to tetrahedral and two larger than tetrahedral. The bond valences were computed. The total valence of iron atom is equal to 3.08. In the structure can be found only one hydrogen bond C(1)–H···Cl. Except mentioned there are no unusually intermolecular short contacts between ions existing in the structure. All [(C₄H₉)₄N][FeBr_4?nCl_n] (n=0‐4) compounds are isostructural in solid state. On the basis of conductometric measurements, relative stabilities of the anions have been estimated in methanol (MeOH), dimethyl sulfoxide (DMSO), acetone (AC), acetonitrile (AN) and dichloromethane (CH₂Cl₂) representing both polar (including amphiprotic and aprotic) as well as non‐polar solvents. Further, the dissociation constants of the compounds were calculated from the expanded Pitt's conductivity equation. The results of the conductometric measurements were supported by electronic spectra.     

Crystal Structure and Structural Transformation of [(CH3)3NH]2[CuZn(CN)5]

A newly synthesized coordination polymer, [(CH₃)₃NH]₂[CuZn(CN)₅], was investigated using ¹³C and ⁶³Cu solid‐state NMR techniques and single‐crystal X‐ray diffractometry. It consists of a three‐dimensional (3D) net composed of tetrahedral Cu^I and Zn^II ions and CN^– ligands bridging between the two metal ions. (CH₃)₃NH⁺ ions are trapped in the inner space of the 3D net. Three coordination sites of each metal ion are used for the formation of the 3D net and the remaining site is occupied by a unidentate CN^– ligand. The structure of the 3D net is chiral and categorized as srs in the notation of the Reticular Chemistry Structure Resource (RCSR). In water vapor or open air at room temperature under ambient pressure, a powder of [(CH₃)₃NH]₂[CuZn(CN)₅] showed a structural transformation to [(CH₃)₃NH][CuZn(CN)₄] · 1.5H₂O, which is a known compound with a diamond‐like 3D net of [CuZn(CN)₄]^– composed of tetrahedral Cu^I and Zn^II ions and bridging CN^– ligands. ⁶³Cu solid‐state NMR spectroscopy revealed that the Cu‐CN‐Zn orientation of the bridging CN^– ligands was conserved after the structural transformation.     

Structural and physico-chemical characteristics of tetraethylammonium tetrachloridoferrate(III)

The crystal structure of tetraethylammonium tetrachloridoferrate(III) was determined. The crystals are hexagonal, space group P6₃ mc, a = 8.198(1) Å, b = 8.198(1) Å, c = 13.183(3) Å, V = 767.3(2) Å³, Z = 2. The asymmetric unit of [(C₂H₅)₄N][FeCl₄] consists of half each of a tetraethylammonium cation and a tetrachloridoferrate(III) anion. Tetrachloridoferrate(III) ion adopts almost ideal tetrahedral geometry. Structural characterization of the compound is supplemented by the results of its magnetic susceptibility measurements and electron paramagnetic resonance (EPR) spectra. Magnetic measurements of a powdered [(C₂H₅)₄N][FeCl₄] sample gave a negative Weiss constant of ?1.57, which suggests antiferromagnetic coupling. The susceptibility curve of [(C₂H₅)₄N][FeCl₄] against temperature exhibits a maximum, indicating the presence of antiferromagnetic ordering with a Neel temperature of approximately 2.9 K.     

Reactivity of Ammonium Halides: Action of Ammonium Chloride and Bromide on Iron and Iron(III) Chloride and Bromide

Ammonium chloride and bromide, (NH₄)Cl and (NH₄)Br, act on elemental iron producing divalent iron in [Fe(NH₃)₂]Cl₂ and [Fe(NH₃)₂]Br₂, respectively, as single crystals at temperatures around 450 °C. Iron(III) chloride and bromide, FeCl₃ and FeBr₃, react with (NH₄)Cl and (NH₄)Br producing the erythrosiderites (NH₄)₂[Fe(NH₃)Cl₅] and (NH₄)₂[Fe(NH₃)Br₅], respectively, at fairly low temperatures (350 °C). At higher temperatures, 400 °C, iron(III) in (NH₄)₂[Fe(NH₃)Cl₅] is reduced to iron(II) forming (NH₄)FeCl₃ and, further, [Fe(NH₃)₂]Cl₂ in an ammonia atmosphere. The reaction (NH₄)Br + Fe (4:1) leads at 500 °C to the unexpected hitherto unknown [Fe(NH₃)₆]₃[Fe₈Br₁₄], a mixed‐valent Fe^II/Fe^I compound. Thermal analysis under ammonia and the conditions of DTA/TG and powder X‐ray diffractometry shows that, for example, FeCl₂ reacts with ammonia yielding in a strongly exothermic reaction [Fe(NH₃)₆]Cl₂ that at higher temperatures produces [Fe(NH₃)]Cl₂, FeCl₂ and, finally, Fe₃N.     

Zur Kenntnis der Sulfito-kobalt(III)-Ammine. III. Hydrogensulfitokobalt(III)-Ammine

Sulphito Cobalt(III) Ammines. III. Hydrogensulphito Cobalt(III) Ammines Concentrated acids react with [CoSO₃(NH₃)₅]⁺ salts hydrogen- sulphitopentaamminecobalt(III) complexes. [Co(HSO₃)(NH₃)₅]Cl₂, [Co(HSO₃)(NH₃)₅]Br₂ and [Co(HSO₃)(NH₃)₅](HSO₄)₂·H₂O have been isolated. These substances are yellow coloured in contrast to an earlier work which reported red colour. Furthermore, the hydrogensulphitoacidotetreaammine complexes [Co(HSO₃)Cl(NH₃)₄]Cl, [Co(HSO₃)Cl(NH₃)₄]ClO₄·H₂O, [Co(HSO₃)Br(NH₃)₄]Br and [Co(HSO₃) CN(NH₃)₄]Cl habe been prepared. [Co(HSO₃)Br(NH₃)₄]Br is losing spontaneously HBr forming [CoSO₃Br(NH₃)₄]. The neutral complex [Co(HSO₃)SO₃(NH₃)₄]·1/2H₂O has been obtained from cis- NH₄[Co(SO₃)₂(NH₃)₄] and HCl. The absorption spectra in the IR, visible and UV region are reported and discussed. The HSO₃ group is coordinated to Co through the S atom. The Co? S bond is weaker than in the sulphito complexes as concluded from the RAMAN spectrum. In the new complexes, the hydrogensulphito ligand causes a minor trans effect than the sulphito ligand.     

A mixed‐valence iron complex of the antitumour drug 6‐mercaptopurine: tris(6‐mercaptopurine)iron(II) tetrachloroferrate(III) chloride

Single crystals of the title complex, tris(1,6‐di­hydro‐9H‐purine‐6‐thione‐N⁷,S)­iron(II) tetra­chloro­ferrate(III) chloride, [Fe(C₅H₄N₄S)₃][FeCl₄]Cl, were grown on the surface of solid 6‐mercaptopurine monohydrate pellets in a solution of iron(III) chloride. The solution of the hexagonal structure required the application of twin refinement techniques. All the component ions lie on threefold rotation axes. The complex contains distorted octahedral [Fe(C₅H₄N₄S)₃]²⁺ cations with three N7/S6‐chelating neutral 6‐mercaptopurine ligands, tetrahedral [FeCl₄]^? anions with a mean Fe—Cl distance of 2.189 (1) Å, and free chloride ions.     

Hydrothermal Syntheses, Crystal Structure and Thermal Behavior of [(CH_3)_2NH_2]_2[B_5O_6(OH)_4]_2·[HCON(CH_3)_2] and [NH_3CH_2CH_2NH_3]_2·[B_(14)O_(20)(OH)_6]

Two novel organic base templated nonmetal borates [(CH₃)₂NH₂]₂[B₅O₆(OH)₄]₂·[HCON(CH₃)₂] ( ? ) and [NH₃CH₂CH₂NH₃]₂[B₁₄O₂₀(OH)₆] ( II ) have been synthesized under hydrothermal conditions, and characterized by elemental analyses, FT‐IR spectroscopy, X‐ray diffraction, and TG‐DTA. Their crystal structures were determined from single crystal X‐ray diffraction. The crystal structure of compound I is characterized by forming a 3D supramolecular structure with large channels along axes b and c through O? H···O hydrogen‐bonding among the [B₅O₆(OH)₄]^? anions. The crystal structure of compound II is characterized by forming a 3D supramolecular structure with large channels along axis a and direction [111] through O? H···O hydrogen‐bonding among the [B₁₄O₂₀(OH)₆]^4? anions. The templating organic amine cations in I and II are both obtained through in situ hydrothermal reactions, and are both located in the channels of the 3D supramolecular structure, respectively. Their thermal behavior has been also investigated.     

New crystal forms of tris(2-aminoethanolato-O,N)cobalt(III): Structures and properties

Crystal forms of cobalt(III) tris(2-aminoethanolate) hydrates, i.e., red cubic crystals of the composition fac-[Co(NH₂CH₂CH₂O)₃] · 5.44H₂O (fac-I · 5.44H₂O) and blue prismatic crystals of the composition mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) were studied by the ⁵⁹Co, ¹³C NMR and X-ray diffraction methods. It was found that mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) is a new pseudopolymorphic modification of fac-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (fac-I · 3H₂O), while fac-I · 3H₂O represents a new polymorphic modification of the complex mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) described previously. The comparative analysis of the spectra revealed dynamic equilibrium between these geometric isomers; the fac-isomer is stable in aqueous solutions.     

Darstellung und Strukturaufklärung von Ammonium‐tetraamminlithium‐amidotrithiophosphat‐Ammoniak(1/1) (NH4) [Li(NH3)4] [P(NH2)S3] · NH3

Synthesis and Crystal Structure of Ammonium Tetraamminelithium Amidotrithiophosphate‐Ammonia(1/1)(NH₄)[Li(NH₃)₄][P(NH₂)S₃]·NH₃ Colourless crystals of (NH₄)[Li(NH₃)₄][P(NH₂)S₃]·NH₃ were prepared by the reduction of P₄S₁₀ with a solution of lithium in liquid ammonia. The X‐ray structure determination shows them to contain the pseudo‐tetrahedral amidotrithiophosphate anion [P(NH₂)S₃]²⁻ (point group C_S), which is the hitherto unknown final member of a series of previously characterized amidothiophosphates. The ammonium ion and the ammonia molecule of solvation form an diamminehydrogen(1+)‐ion N₂H₇⁺ with a short, nearly linear hydrogen bond of 2.864(3) Å.     

Homoleptic Octahedral Methylamine Complexes of Manganese(II): Solvothermal Syntheses and Crystal Structures of [Mn(NH2CH3)6]Cl2 and the Pentaselenide [Mn(NH2CH3)6]Se5

[Mn(NH₂CH₃)₆]Cl₂ ( 1 ) and [Mn(NH₂CH₃)₆]Se₅ ( 2 ) were prepared by solvothermal reactions in liquid methylamine from MnCl₂ at 150 °C for 1 and from a mixture of MnCl₂, Rb₂Se and selenium at 120 °C for 2 . Both 1 and 2 were obtained in high yields as colorless and dark‐red crystals and represent the first homoleptic methylamine complexes with coordination number six. Compound 1 crystallizes rhombohedral (R$\bar{3}$ , Z = 3) and is built of only slightly distorted octahedral [Mn(NH₂CH₃)₆]²⁺ cations and Cl^– anions. Compound 2 crystallizes orthorhombic (Pnna, Z = 4) and is built of octahedral [Mn(NH₂CH₃)₆]²⁺ cations showing a strong angular distortion and of Se₅^2– anions in the form of chains in transoid conformation. DFT calculations reveal an almost undistorted ground state structure for [Mn(NH₂CH₃)₆]²⁺ with N–Mn–N angular distortions of 1° from orthogonality, close to the structure found for the complex in 1 . The calculated energy necessary for a distortion as found in the structure of 2 is rather low and amounts to 26 kJmol^–1 which is in the range typical for hydrogen bonds. The N–Mn–N angular distortions of the complex cation in 2 , observed in the range of 10°, is caused by cation‐anion interactions in the crystal structure by N–H ···· Se hydrogen bonds.     

Crystal Structure,Thermal and Electric Behaviour of [(CH3)2NH2]3[As2Cl9] and [(CH3)2NH2][AsOCl2]

Single crystals of the organic‐inorganic arsenate(III): [(CH₃)₂NH₂]₃[As₂Cl₉] and [(CH₃)₂NH₂][AsOCl₂] have been grown from aqueous hydrochloric acid solution. The crystals [(CH₃)₂NH₂]₃[As₂Cl₉] have been investigated by X‐ray diffraction (at 253 K), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dilatometric and dielectric methods. They undergo two structural phase transitions of first order at 228/235 and 298/307 K (on cooling/heating), respectively, which are classified as an "order‐disorder" type. The trigonal [(CH₃)₂NH₂]₃[As₂Cl₉] structure (at 253 K, intermediate phase (II)) refined in the space group R3c, consists of isolated [As₂Cl₉]^3‐ bioctahedral units and dimethylammonium cations hydrogen bonded to the bridging Cl atoms of the anions. The crystals of [(CH₃)₂NH₂][AsOCl₂] at 100 K are orthorhombic, space group Cmca. The structure contains one‐dimensional chains formed by strong distorted [AsO₂Cl₄] octahedra. The dimethylammonium cations reveal distinct disorder.     

IR spectra and thermal decomposition/dehydration of double complex salts of lanthanum(III) sulphate complex anions with several cobalt(III) ammine complex cations

Double complex salts of lanthanum(III) sulphate complex anions with several cobalt(III) ammine complex cations, [Co(NH₃)₆][La(SO₄)₃]·H₂O (1), (NH₄)₃[Co(NH₃)₅ H₂O]-[La(SO₄)₃]₂·2H₂O (2), and (NH₄)₃[Co(NH₃)₄(H₂O)₂][La(SO₄)₃]₂·2H₂O (3), were prepared by the addition of hexaamminecobalt(III), pentaammineaquacobalt(III), and cis- tetra-amminediaquacobalt(III) complexes to the solution containing lanthanum(III) ion and excess ammonium sulphate. The IR spectra of sulphate groups of these double complex salts were much more complicated than those of the almost free sulphate groups such as (NH₄)₂SO₄ and [Co(NH₃)₆]₂(SO₄)₃·5H₂O. Furthermore, values of activation energy in the dehydration process of 1, 2 and 3 were estimated using modified Doyle's and Wiedemann's method. They were 95.6 ± 4.3, 157.1 ± 15.5 and 163.2 ± 20.8 kJ mol^?1, respectively. Here, one molecule water is released per molecule of 1, 2 and 3.     

Kristallstruktur und Schwingungsspektrum von (H2NPPh3)2[SnCl6]·2CH3CN

Crystal Structure and Vibrational Spectrum of (H₂NPPh₃)₂[SnCl₆]·2CH₃CN Single crystals of (H₂NPPh₃)₂[SnCl₆]·2CH₃CN ( 1 ) were obtained by oxidative addition of tin(II) chloride with N‐chloro‐triphenylphosphanimine in acetonitrile in the presence of water. 1 is characterized by IR and Raman spectroscopy as well as by a single crystal structure determination: Space group , Z = 2, lattice dimensions at 193 K: a = 1029.6(1), b = 1441.0(2), c = 1446.1(2) pm, α = 90.91(1)°, β = 92.21(1)°, γ = 92.98(1)°, R₁ = 0.0332. 1 forms an ionic structure with two different site positions of the [SnCl₆]^2? ions. One of them is surrounded by four N‐hydrogen atoms of four (H₂NPPh₃)⁺ ions, four CH₃CN molecules form N–H···N≡C–CH₃ contacts with the other four N‐hydrogen atoms of the cations. Thus, 1 can be written as [(H₂NPPh₃)₄(CH₃CN)₄(SnCl₆)]²⁺[SnCl₆]^2?.     

Functionalised Tris(pyrazolyl)methane Ligands and Re(CO)3 Complexes Thereof

The synthesis of new tripodal nitrogen ligands derived from tris(pyrazolyl)methane (Tpm^R, R = H, tBu, Ph in 3‐position) is described. After deprotonation of the parent tris(pyrazolyl)methane Tpm^R, the carbanion reacts readily with ethylene oxide to yield the 3,3,3‐tris(3′‐substituted pyrazolyl)propanol ligands[(3‐Rpz)₃CCH₂CH₂OH, R = H, tBu, Ph, 1a – c ]. These ligands can be easily derivatised at the alcohol function. Microwave‐assisted reactions of these ligands and [Re(CO)₅Br] yields the complex [( 1a )Re(CO)₃]Br ( 4 ) in the case of ligand 1a , whereas in the case of the substituted ligands 1b and 1c degradation was observed. The degradation products are identified as [(Hpz^R)₂Re(CO)₃Br] [R = tBu ( 7b ), Ph ( 7c )]. These complexes were also prepared directly from [Re(CO)₅Br] and the corresponding pyrazoles by microwave‐assisted synthesis. The Re(CO)₃ complexes 4 and [( 1a )Re(CO)₃]OTf ( 5 ) are water‐soluble. The structures of 5· H₂O and [{(pz)₃CCH₂CH₃}Re(CO)₃]OTf · 1.5H₂O · ¹/₂CH₃CN ( 6· 1.5H₂O · ¹/₂CH₃CN) as well as the structure of 7b have been elucidated by X‐ray crystallography.     

Crystal Structures and Hydrogen Bonding of Two Complexes containing the [Ammine‐chlorido‐ethylenediamine‐bis(pyridine)cobalt(III)]2+ Cation

The crystal structures of two classical cobalt(III) complexes comprising the [CoCl(NH₃)(en)(py)₂]²⁺ cation were determined by single‐crystal X‐ray diffraction. Both complexes, dark red [CoCl(NH₃)(en)(py)₂]Cl₂ · H₂O ( 1 ) and purple [CoCl(NH₃)‐(en)(py)₂][HgCl₄] · 1.125H₂O ( 2 ), crystallize in the triclinic space group P1 . In both compounds, the Co atom exhibits a typical octahedral coordination and the configuration index of the complex is OC‐6‐43. In the case of the chloride ( 1 ), the asymmetric unit comprises one formula unit, whereas there are two formula units in the case of the tetrachloridomercurate ( 2 ). Complex cations, anions, and crystal water molecules are interconnected by various N–H ··· N, N–H ··· Cl, N–H ··· O, O–H ··· Cl, and O–H ··· O bridge bonds. As a result, compound 1 features a two‐dimensional layer structure and compound 2 exists as a three‐dimensional network.     

Iridium (III) and rhodium (III) triazoles by 1,3-dipolar cycloadditons to a coordinated azide in iridium (III) and rhodium (III) compounds

The reaction of [(η⁵-C₅Me₅)M(μCl)Cl]₂ with the ligand (L^∩L) in the presence of sodium methoxide yielded compounds of general formula [(η⁵-C₅Me₅)M(L^∩L)Cl] (1–10) (where M = Ir or Rh and L^∩L = N^∩O or O^∩O chelate ligands). Azido complexes of formulation [(η⁵-C₅Me₅)M(L^∩L)N₃] (11–20) have been prepared by the reaction of [(η⁵-C₅Me₅)M(μN₃)(X)]₂ (X = Cl or N₃) with the corresponding ligands or by the direct reaction of [(η⁵-C₅Me₅)M(L^∩L)Cl] with NaN₃. These azido complexes [(η⁵-C₅Me₅)M(L^∩L)N₃] undergo 1,3-dipolar cycloaddition reaction with substituted alkynes in CH₂Cl₂ and for the first time in ethanol at room temperature to yield iridium (III) and rhodium (III) triazoles (21–28). The compounds were characterized on the basis of spectroscopic data, and the molecular structures of 2 and 26 have been established by single crystal X-ray diffraction.     

Controlled Aggregation of Multiple Guanidinium Ions through a Hydrogen‐Bonded Network Assembly with Deprotonated Forms of Kemp’s Triacid

A series of five complexes that incorporate the guanidinium ion and various deprotonated forms of Kemp’s triacid (H₃KTA) have been synthesized and characterized by single‐crystal X‐ray analysis. The complex [C(NH₂)₃⁺] ? [H₂KTA^?] ( 1 ) exhibits a sinusoidal layer structure with a centrosymmetric pseudo‐rosette motif composed of two ion pairs. The fully deprotonated Kemp’s triacid moiety in 3 [C(NH₂)₃⁺] ? [KTA^3?] ( 2 ) forms a record number of eighteen acceptor hydrogen bonds, thus leading to a closely knit three‐dimensional network. The KTA^3? anion adopts an uncommon twist conformation in [(CH₃)₄N⁺] ? 2 [C(NH₂)₃⁺] ? [KTA^3?] ? 2 H₂O ( 3 ). The crystal structure of [(nC₃H₇)₄N⁺] ? 2 [C(NH₂)₃⁺] ? [KTA^3?] ( 4 ) features a tetrahedral aggregate of four guanidinium ions stabilized by an outer shell that comprises six equatorial carboxylate groups that belong to separate [KTA^3?] anions. In 3 [(C₂H₅)₄N⁺] ? 20 [C(NH₂)₃⁺] ? 11 [HKTA^2?] ? [H₂KTA^?] ? 17 H₂O ( 5 ), an even larger centrosymmetric inner core composed of eight guanidinium ions and six bridging water molecules is enclosed by a crust composed of eighteen axial carboxyl/carboxylate groups from six HKTA^2? anions.     

2,6‐Bis(azaindole)pyridine: reactivity with iron(III) and copper(II) salts

1‐[6‐(1H‐Pyrrolo[2,3‐b]pyridin‐1‐yl)pyridin‐2‐yl]‐1H‐pyrrolo[2,3‐b]pyridin‐7‐ium tetrachloridoferrate(III), (C₁₉H₁₄N₅)[FeCl₄], (II), and [2,6‐bis(1H‐pyrrolo[2,3‐b]pyridin‐1‐yl‐κN⁷)pyridine‐κN]bis(nitrato‐κO)copper(II), [Cu(NO₃)₂(C₁₉H₁₃N₅)], (III), were prepared by self‐assembly from FeCl₃·6H₂O or Cu(NO₃)₂·3H₂O and 2,6‐bis(1H‐pyrrolo[2,3‐b]pyridin‐1‐yl)pyridine [commonly called 2,6‐bis(azaindole)pyridine, bap], C₁₉H₁₃N₅, (I). Compound (I) crystallizes with Z′ = 2 in the P space group, with both independent molecules adopting a trans–trans conformation. Compound (II) is a salt complex with weak C—H...Cl interactions giving rise to a zigzag network with π‐stacking down the a axis. Complex (III) lies across a twofold rotation axis in the C2/c space group. The Cu^II center in (III) has an N₃O₂ trigonal–bipyramidal environment. The nitrate ligand coordinates in a monodentate fashion, while the bap ligand adopts a twisted tridentate binding mode. C—H...O interactions give rise to a ribbon motif.