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.     

Prediction of 195Pt NMR chemical shifts of dissolution products of H2[Pt(OH)6] in nitric acid solutions by DFT methods: how important are the counter‐ion effects?

¹⁹⁵Pt NMR chemical shifts of octahedral Pt(IV) complexes with general formula [Pt(NO₃)_n(OH)_{6 ? n}]^2?, [Pt(NO₃)_n(OH₂)_{6 ? n}]^{4 ? n} (n = 1–6), and [Pt(NO₃)_{6 ? n ? m}(OH)_m(OH₂)_n]^{?2 + n ? m} formed by dissolution of platinic acid, H₂[Pt(OH)₆], in aqueous nitric acid solutions are calculated employing density functional theory methods. Particularly, the gauge‐including atomic orbitals (GIAO)‐PBE0/segmented all‐electron relativistically contracted–zeroth‐order regular approximation (SARC–ZORA)(Pt) ∪ 6–31G(d,p)(E)/Polarizable Continuum Model computational protocol performs the best. Excellent second‐order polynomial plots of δ_calcd(¹⁹⁵Pt) versus δ_exptl(¹⁹⁵Pt) chemical shifts and δ_calcd(¹⁹⁵Pt) versus the natural atomic charge Q_Pt are obtained. Despite of neglecting relativistic and spin orbit effects the good agreement of the calculated δ ¹⁹⁵Pt chemical shifts with experimental values is probably because of the fact that the contribution of relativistic and spin orbit effects to computed σ^{iso 195}Pt magnetic shielding of Pt(IV) coordination compounds is effectively cancelled in the computed δ ¹⁹⁵Pt chemical shifts, because the relativistic corrections are expected to be similar in the complexes and the proper reference standard used. To probe the counter‐ion effects on the ¹⁹⁵Pt NMR chemical shifts of the anionic [Pt(NO₃)_n(OH)_{6 ? n}]^2? and cationic [Pt(NO₃)_n(OH₂)_{6 ? n}]^{4 ? n} (n = 0–3) complexes we calculated the ¹⁹⁵Pt NMR chemical shifts of the neutral (PyH)₂[Pt(NO₃)_n(OH)_{6 ? n}] (n = 1–6; PyH = pyridinium cation, C₅H₅NH⁺) and [Pt(NO₃)_n(H₂O)_{6 ? n}](NO₃)_{4 ? n} (n = 0–3) complexes. Counter‐anion effects are very important for the accurate prediction of the ¹⁹⁵Pt NMR chemical shifts of the cationic [Pt(NO₃)_n(OH₂)_{6 ? n}]^{4 ? n} complexes, while counter‐cation effects are less important for the anionic [Pt(NO₃)_n(OH)_{6 ? n}]^2? complexes. The simple computational protocol is easily implemented even by synthetic chemists in platinum coordination chemistry that dispose limited software availability, or locally existing routines and knowhow. Copyright © 2016 John Wiley & Sons, Ltd.     

HPLC Method for the Determination of the Purity of K[Pt(NH3)Cl3], a Precursor of the Platinum Complexes with Cytostatic Activity

K[Pt(NH₃)Cl₃], a valuable precursor for the preparation of platinum complexes with cytostatic activity, e.g. satraplatin, picoplatin, LA-12 and cycloplatam, is currently prepared from cis-[Pt(NH₃)₂Cl₂] or K₂[PtCl₄] and these are the usual impurities in the final product. A simple, selective and sensitive HPLC-UV analytical method for the determination of the purity of K[Pt(NH₃)Cl₃] and the quantification of the impurities has been developed and validated. The platinum complexes present in the final product were separated on a strong base ion exchange column by the gradient elution with detection at 213 nm. Intra-assay precisions for the platinum complexes respective to their ions ([PtCl₄]^2?, [Pt(NH₃)Cl₃]^? and cis-[Pt(NH₃)₂Cl₂]) were between 0.1 and 2.0% (relative standard deviation); intermediate precisions were between 1.4 and 2.0% and accuracies were between 98.6 and 101.4%. Limits of detection of [PtCl₄]^2?, [Pt(NH₃)Cl₃]^? and cis-[Pt(NH₃)₂Cl₂] were 6 µg · ml^?1, 13 mg · ml^?1 and 5 µg · ml^?1 respectively, limits of quantification of [PtCl₄]^2?, [Pt(NH₃)Cl₃]^? and cis-[Pt(NH₃)₂Cl₂] were 51 µg · ml^?1, 55 mg · ml^?1 and 20 µg · ml^?1 respectively.     

Thio- und AmidothioDerivate der Diphosphor(IV)-säure

Thio and Amidothio Derivatives of Diphosphorus(IV) Acid Oxothiodiphosphates(IV) with anions [P₂O_nS_6?n]^4? (n = 1–5) are formed by steps wise substitution of thio by oxo ligands in hexathiodiphosphate(4–). Oxidative ammonolysis of thianion leads to amidothio derivatives, [P₂(NH₂)S₅]^3? and [P₂(NH₂)₂S₄]^2?.     

Kinetic characterization of the interactions of trans-dichloro-platinum(IV) anticancer prodrugs and a model compound with thiosulfate

Sodium thiosulfate has been utilized as a rescuing agent for relief of the toxic effects of cisplatin and carboplatin. In this work, we characterized the kinetics of reactions of the trans-dichloro-platinum(IV) complexes cis-[Pt(NH₃)₂Cl₄], ormaplatin [Pt(dach)Cl₄] and trans-[PtCl₂(CN)₄]^2? (anticancer prodrugs and a model compound) with thiosulfate at biologically important pH. An overall second-order rate law was established for the reduction of trans-[PtCl₂(CN)₄]^2? by thiosulfate, and varying the pH from 4.45 to 7.90 had virtually no influence on the reaction rate. In the reactions of thiosulfate with cis-[Pt(NH₃)₂Cl₄] and with [Pt(dach)Cl₄], the kinetic traces displayed a fast reduction step followed by a slow substitution involving the intermediate Pt(II) complexes. The reduction step also followed second-order kinetics. Reductions of cis-[Pt(NH₃)₂Cl₄] and [Pt(dach)Cl₄] by thiosulfate proceeded with similar rates, presumably due to their similar configurations, whereas the reduction of trans-[PtCl₂(CN)₄]^2? was about 1,000 times faster. A common reduction mechanism is suggested, and the transition state for the rate-determining step has been delineated. The activation parameters are consistent with transfer of Cl⁺ from the platinum(IV) center to the attacking thiosulfate in the rate-determining step.     

Theoretical study of the electronic spectra of bi‐ and tri‐heteronuclear platinum complexes

The electronic structure and the spectroscopic properties of [Pt(NH₃)₄][Au(CN)₂]₂, [Pt(NH₃)₄][Ag(CN)₂]₂, [Pt(CNCH₃)₄][Pt(CN)₄], and [Pt(CNCH₃)₄][Pd(CN)₄] were studied at the HF, MP2, B3LYP, and PBE levels. In all the complexes, it was found that the nature of the intermetal interactions is consistent with the presence of a high‐ionic contribution (90%) and a dispersion‐type interaction (10%). The absorption spectra of these complexes were calculated by the single‐excitation time‐dependent (TD) method at the HF, B3LYP, and PBE levels. The [Pt(NH₃)₄][M(CN)₂]₂ (M ? Au, Ag) complexes showed a ¹(dσ* → pσ) transition associated with a metal–metal charge transfer. On the other hand, the [Pt(CNCH₃)₄][M(CN)₄] (M ? Pt, Pd) complexes showed a ¹(dσ* → π*) transition associated with a metal‐to‐metal and ligand charge transfer. The values obtained theoretically are in agreement with the experimental range. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008     

The solid state reaction between hexaamminechromium(III) complexes and L-α-alanine

The solid reaction between [Cr(NH₃)₆]X₃(X^? = Cl, I, SCN and NO₃) and L-α-alanine was studied under continuous rise in temperature and isothermal heating. Under continuous rise in temperature, the main products were [Cr(NCS)₃-(NH₃)₃] (X^? = NCS) and [Cr(L-ala)₃] (X^? = NO₃), when [Cr(NH₃)₆]Cl₃ and [Cr(NH₃)₆]I₃ as starting complexes were used; in both cases only the decomposition proceeds. Under isothermal heating at 150°C the main products were [CrCl(NH₃)₅]-Cl₂ (X^? = Cl), [Cr(NH₃)₆]I₂ (X^? = I), [Cr(NCS)₃(NH₃)₃] (X^? = SCN) and [Cr(L-ala)₃] (X^? = NO₃). In those matrix reactions, the ease of anion coordination was: SCN^? > Cl^? > I^? > alanine. For the synthesis of tris(alaninato)chromium(III) complex the most desirable starting complex was [Cr(NH₃)₆](NO₃)₃.The solid state reaction between [Cr(en)₃]X₃ type complexes and NH₄X (X^? = F, Cl, Br, I and SCN), KX (X^? = Cl, Br and I), and NaSCN have been reported by Wendlandt and Stembridge¹. They reported that the reaction product in most cases, was cis-[Cr(en)₂Y₂]X, where Y and X are the same or different anions, depending upon the matrix material employed and the thermal matrix method appears to be a useful new route for the synthesis of bis(ethylendiamine(chromium(III) complexes.In the previous paper², the solid state reaction between [Cr(NH₃)₆](NO₃)₃ and L-amino acids has been utilized in the preparation of tris(amino acidato)chromium(III) complexes. The preparation of [Cr(L-ala)₃] by the solid state reaction between [Cr(NH₃)₆](NO₃)₃ and L-alanine have been reported. No studies on the effect of the counter-ion have been reported.In this paper, various hexaamminechromium(III) complexes, [Cr(NH₃)₆]X₃ (X^? = Cl, I, SCN and NO₃), were heated with L-α-alanine under continuous rise in temperature and under isothermal heating at 150°C for studies on the ease of anion coordination. It will seen that the anion which replaces the ammonia in the hexaamminechromium(III) complex comes from either the alanine or counter-ion.     

Outer-sphere electron-transfer reactions with the participation of platinum(IV) haloammines

The kinetics of some outer-sphere electron-transfer reactions with the participation of the complexes [Pt(NH₃)_nX_6–n]² (n=6–0, X=Cl^–, Br^–) and dipyridyl complexes of Os(II), Ru(II), Ir(III), and Cr(II) have been investigated by means of luminescence-quenching measurements and flash photolysis. Estimates of the values of the Pt(IV)/Pt(III) one-electron potential and the change in the free energy of activation of electron self-exchange processes of the type Pt(IV) Pt(III) have been obtained on the basis of an analysis of the dependence of the rate constant on the change in the free energy accompanying the electrontransfer process.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 4, pp. 455–462, July–August, 1990.     

[Yb(NH3)8][Yb(Pyr)6] – Elektrid‐induzierte Synthese und Kristallisation aus flüssigem Ammoniak

[Yb(NH₃)₈][Yb(Pyr)₆]: Electride Induced Synthesis and Crystallization from Liquid Ammonia Single crystalline yellow [Yb(NH₃)₈][Yb(Pyr)₆] (Pyr^? = pyrrolate anion, C₄H₄N^?) was obtained by the reaction of ytterbium metal with pyrrole (C₄H₄NH) in liquid ammonia at ?35 °C. Significant excess of ammonia together with avoiding a pyrrole excess prevents formation of the molecular compound [Yb(Pyr)₃(PyrH)₂(NH₃)₂]. [Yb(NH₃)₈][Yb(Pyr)₆] consists of two homoleptic ionic units and rapidly decomposes if removed from the ammonia atmosphere, viz. it shows an ammonia vapour pressure >1 bar.     

Reactions of Beryllium Halides in Liquid Ammonia: The Tetraammineberyllium Cation [Be(NH3)4]2+, its Hydrolysis Products,and the Action of Be2+ as a Fluoride‐Ion Acceptor

The first structural characterization of the text‐book tetraammineberyllium(II) cation [Be(NH₃)₄]²⁺, obtained in the compounds [Be(NH₃)₄]₂Cl₄ ? 17NH₃ and [Be(NH₃)₄]Cl₂, is reported. Through NMR spectroscopic and quantum chemical studies, its hydrolysis products in liquid ammonia were identified. These are the dinuclear [Be₂(μ‐OH)(NH₃)₆]³⁺ and the cyclic [Be₂(μ‐OH)₂(NH₃)₄]²⁺ and [Be₃(μ‐OH)₃(NH₃)₆]³⁺ cations. The latter species was isolated as the compound [Be₃(μ‐OH)₃(NH₃)₆]Cl₃ ? 7NH₃. NMR analysis of solutions of BeF₂ in liquid ammonia showed that the [BeF₂(NH₃)₂] molecule was the only dissolved species. It acts as a strong fluoride‐ion acceptor and forms the [BeF₃(NH₃)]^? anion in the compound [N₂H₇][BeF₃(NH₃)]. The compounds presented herein were characterized by single‐crystal X‐ray structure analysis, ⁹Be, ¹⁷O, and ¹⁹F NMR, IR, and Raman spectroscopy, deuteration studies, and quantum chemical calculations. The extension of beryllium chemistry to the ammine system shows similarities but also decisive differences to the aquo system.     

Thermal studies of some biologically active oxovanadium(IV) complexes containing 8-hydroxyquinolinate and hydroxamate ligands

The thermal decomposition behaviours of oxovanadium(IV)hydroxamate complexes of composition [VO(Q)_2?n(HL^1,2)_n]: [VO(C₉H₆ON)(C₆H₄(OH)(CO)NHO)] (I), [VO(C₆H₄(OH)(CO)NHO)₂] (II), [VO(C₉H₆ON)(C₆H₄(OH)(5-Cl)(CO)NHO)] (III), and [VO(C₆H₄(OH)(5-Cl)(CO)NHO)₂] (IV) (where Q?=?C₉H₆NO^? 8-hydroxyquinolinate ion; HL¹?=?[C₆H₄(OH)CONHO]^? salicylhydroxamate ion; HL²?=?[C₆H₃(OH)(5-Cl)CONHO]^? 5-chlorosalicylhydroxamate ion; n?=?1 and 2), which are synthesised by the reactions of [VO(Q)₂] with predetermined molar ratios of potassium salicylhydroxamate and potassium 5-chlorosalicylhydroxamate in THF?+?MeOH solvent medium, have been studied by TG and DTA techniques. Thermograms indicate that complexes (I) and (III) undergo single-step decomposition, while complexes (II) and (IV) decompose in two steps to yield VO(HL^1,2) as the likely intermediate and VO₂ as the ultimate product of decomposition. The formation of VO₂ has been authenticated by IR and XRD studies. From the initial decomposition temperatures, the order of thermal stabilities for the complexes has been inferred as III?>?I > II?>?IV.     

Oxidative addition reactions of [Pt(CN)4]2−; A 13C and 195Pt NMR study

¹³C and ¹⁹⁵Pt NMR measurements show that complexes of the type trans-[Pt(CN)₄X₂]^2? are formed on addition of X₂ (X = Br, Cl, I) to M₂[Pt(CN)₄] (M = K or NBu₄) in aqueous and chloroform solution respectively. Addition of ICN to K₂[Pt(CN)₄] (60% ¹³CN^?) in aqueous solution results in the formation of potassium pentacyanoiodoplatinate(IV) with complete¹³CN^?/¹²CN^?scrambling. The reaction of equi-molar amounts of trans-[PtX₂(CN)₄]^2? (X = Br and Cl), which was previously claimed to result in complete transformation into trans-[PtBrCl(CN)₄]^2?, is instead shown to result in an approximately statistical redistribution of halogens. A progressive shift of δ_Pt to high field is observed on successive replacement of ¹²CN^? by ¹³CN^? in [Pt(CN)₄]^2?.     

Isotype Strukturen einiger Hexaamminmetall(II)-halogenide von 3d-Metallen: [V(NH3)6]I2, [Cr(NH3)6]I2, [Mn(NH3)6]Cl2, [Fe(NH3)6]Cl2, [Fe(NH3)6]Br2, [Co(NH3)6]Br2 und [Ni(NH3)6]Cl2

The Structures of some Hexaammine Metal(II) Halides of 3 d Metals: [V(NH₃)₆]I₂, [Cr(NH₃)₆]I₂, [Mn(NH₃)₆]Cl₂, [Fe(NH₃)₆]Cl₂, [Fe(NH₃)₆]Br₂, [Co(NH₃)₆]Br₂ and [Ni(NH₃)₆]Cl₂ Crystals of yellow [V(NH₃)₆]I₂ and green [Cr(NH₃)₆]I₂ were obtained by the reaction of VI₂ and CrI₂ with liquid ammonia at room temperature. Colourless crystals of [Mn(NH₃)₆]Cl₂ were obtained from Mn and NH₄Cl in supercritical ammonia. Colourless transparent crystals of [Fe(NH₃)₆]Cl₂ and [Fe(NH₃)₆]Br₂ were obtained by the reaction of FeCl₂ and FeBr₂ with supercritical ammonia at 400°C. Under the same conditions orange crystals of [Co(NH₃)₆]Br₂ were obtained from [Co₂(NH₂)₃(NH₃)₆]Br₃. Purple crystals of [Ni(NH₃)₆]Cl₂ were obtained by the reaction of NiCl₂ · 6H₂O and NH₄Cl with aqueous NH₃ solution. The structures of the isotypic compounds (Fm3 m, Z = 4) were determined from single crystal diffractometer data (see “Inhaltsübersicht”). All compounds crystallize in the K₂[PtCl₆] structure type. In these compounds the metal ions have high-spin configuration. The orientation of the dynamically disordered hydrogen atoms of the ammonia ligands is discussed.     

THE SYNTHESIS OF TRISELENOCARBONATE COMPLEXES OF PLATINUM

The addition of dichloromethane solutions of carbon diselenide to liquid ammonia containing suspensions of platinum bis-phosphine dichlorides [PtCl₂(PR_X)_n] (n = 2, (PR_X) = PMe₃, PMe₂Ph, PMePh₂, and PPh₃, n = 1, (PR_X) = dppm, dppe, dppp, dppf) gives, after evaporation of the ammonia and extraction of the reaction residues with dichloromethane, the appropriate platinum bis-phosphine triselenocarbonate complexes in reasonable yields (40–60%).     

Synthesis of cross linked platinum metal containing polyyne polymers

Reaction of Pt(PⁿBu₃)₂Cl₂ (1) or Pt(AsⁿBu₃₂Cl₂ (2) with stoichiometric amounts of 1,3,5-triethynylbenzene, [1,3,5-(H? C?C? )₃C₆H₃] (3)yields monomeric, [1,3,5-Cl(PⁿBu₃)₂(Pt? C? C? )₃C₆H₃] (4), [1,3,5-(C1)(AsⁿBu₃)₂Pt? C? C? ₃C₆H₃] (5) or polymeric, {1,3,5-[(PⁿBu₃)₂Pt? C?C? ]₃C₆H₃? )ⁿ (6), {1,3,5-[(AsⁿBu₃)₂Pt? C? C? ]₃C₆H₃? }ⁿ (7) complexes. Treatment of (1) with (3) and 2,5-diethynyl-p-xylene,H? C? C? C₆H₂(CH₃)₂? C? C? H (8) in varying molar ratios yields a series of high molecular weight cross linked platinum metal containing polyyne copolymers.     

Darstellung und Charakterisierung von [Pt(mal)2]2− und von trans-[Pt(mal)2X2]2− (X = Cl,Br, I,SCN)

Preparation and Characterization of [Pt(mal)₂]^2? and trans-[Pt(mal)₂X₂]^2? (X = Cl, Br, I, SCN) By twofold treatment of K₂[PtCl₄] with potassium hydrogen malonate in a queous solution the yellow K₂[Pt(mal)₂] · H₂O is obtained. After extraction with tetrabutylammonium ions into dichloromethane by oxidative addition at ?90°C the Pt^IV complexes [Pt(mal)₂X₂]^2?, X = Cl, Br, I, SCN, are formed. The SCN ligands are coordinated to Pt via S. The IR and Raman spectra are discussed and assigned.     

Posters

Abstract.

The reaction of thionyl chloride with liquid ammonia produces the thionyl imide anion, NSO^? Addition of metal chloride bis-phosphine complexes such as [PtCl₂(PMe₃)₂] the resulting NH₃(I) solution has been shown to produce compounds of the type [Pt(NSO)₂(PMe₃)₂].^[1] Here, we describe the synthesis of Hg(NSO)₂ in liquid ammonia, using HgCl₂ as the starting material.     

Pt(II) ASSISTED DEOXYGENATION OF COORDINATED SULFOXIDES BY HYDROCHLORIC- OR HYDROBROMIC ACID

Abstract

The interaction of the complexes (Et₄ N)[Pt(R₂ SO)X₃] (R = Me, Et, CH₂ Ph, X [dbnd] C1; R [dbnd] Me, X [dbnd] Br) and cis-[Pt(Me₂ SO)₂ Cl₂] with concentrated HX (X [dbnd] Cl. Br) results in the reduction of the coordinated sulfoxides and oxidation of Pt(II) to Pt(IV). As a result [Pt(R₂ S)X₅ and [Pt(R₂S)₂ X₄] are formed. Ligands R₂ S can be removed from the complexes and isolated in a free state.     

Synthesis and characterization of Ru(III), Rh(III), Pt(IV) and Ir(III) thiosemicarbazone complexes

Ru(III), Rh(III), Pt(IV) and Ir(III) complexes of 2-furfural thiosemicarbazone as ligand have been synthesised. These complexes have the composition [M(ligand)₂X₂]X (M = Ru(III) Rh(III) and Ir(III) X = Cl and Br) and [Pt(ligand)₂ X₂] X₂ (X = Cl, Br and 1/2SO₄). The deprotonated ligand forms the complexes of the formulae M(ligand-H)₃ and Pt(ligand-H)₃Cl. All these complexes have been characterized by elemental analysis, magnetic measurements, electronic and infrared spectral studies. All the complexes are six-coordinate octahedral.     

Die Ammonolyse von (NH4)2GeF6. Darstellung und Struktur von NH4[Ge(NH3)F5]

Ammonolysis Reaction of (NH₄)₂GeF₆. Synthesis and Structure of NH₄[Ge(NH₃)F₅] (NH₄)₂GeF₆ reacts with ammonia to yield NH₄[Ge(NH₃)F₅] at 280°C. The reaction path was elucidated by in situ time and temperature resolved X-ray powder diffraction. NH₄[Ge(NH₃)F₅] crystallizes isostructurally to NH₄[Si(NH₃)F₅] in the tetragonal space group P4/n (No. 85) with lattice constants a = 619.41(1) pm and c = 724.70(1) pm. The germanium atom is coordinated by five fluorine atoms and the nitrogen atom of the ammonia molecule. The ammonium cation is located on the Wyckoff position (2 a) in P4/n. The crystal structure is stabilized by extensive hydrogen bonding.