Metallation of aliphatic carbon atoms: II,syntheses and characterization of the cyclopalladated complexes of N,N-dimethylneopentylamine

N,N-Dimethylneopentylamine reacts with Pd(MeCO₂)₂ to give a novel trinuclear cyclopalladated complex [Me₂NCH₂CMe₂CH₂Pd(μ-MeCO₂)₂Pd(μ-MeCO₂)₂PdCH₂CMe₂CH₂NMe₂]?-0.5C₆H₆ (I). The reaction of I with PPh₃ affords both trans-[Pd(MeCO₂)₂(PPh₃)₂] (II) and [Pd(CH₂CMe₂CH₂NMe₂)(MeCO₂)(PPh₃)] (III). The reaction of III with LiCl yields a mononuclear cyclopalladated complex, [Pd(CH₂CMe₂CH₂NMe₂)Cl(PPh₃)] (IV).     

Acetylenic derivatives of metal carbonyls of the triad Fe,Ru, Os—XI Mass spectra of some binuclear complexes

The mass spectra of the following acetylenic derivatives of iron, ruthenium and osmium carbonyls are reported: the iron compounds Fe₂(CO)₆[C₂(C₆H₅)s₂]₂, Fe₂(CO)₆[C₂(CH₃)₂]₂ and Fe₂(CO)₆[C₂(C₂H₅)₂]₂, the ruthenium compounds Ru₂(CO)₆[C₂(C₆H₅)₂]₂, and Ru₂(CO)₆[C₂(CH₃)₂]₂ and the osmium compounds Os₂(CO)₆[C₂(C₆H₅)₂]₂, Os₂(CO)₆[C₂HC₆H₅]₂ and Os₂(CO)₆[C₂(CH₃)₂]₂. Iron compounds exhibit breakdown schemes where binuclear, mononuclear and hydrocarbon ions are present. On the other hand, ruthenium and osmium compounds fragment in a similar way and give rise to singly and doubly charged binuclear ions. Phenylic derivatives of ruthenium and osmium also give weak triply charged ions. The results are discussed in terms of relative strengths of the metal-metal and metal-carbon bonds.     

Synthesis of Inorganic Structural Isomers By Diffusion‐Constrained Self‐Assembly of Designed Precursors: A Novel Type of Isomerism

The structure of precursors is used to control the formation of six possible structural isomers that contain four structural units of PbSe and four structural units of NbSe₂: [(PbSe)_1.14]₄[NbSe₂]₄, [(PbSe)_1.14]₃[NbSe₂]₃[(PbSe)_1.14]₁[NbSe₂]₁, [(PbSe)_1.14]₃[NbSe₂]₂[(PbSe)_1.14]₁[NbSe₂]₂, [(PbSe)_1.14]₂[NbSe₂]₃[(PbSe)_1.14]₂[NbSe₂]₁, [(PbSe)_1.14]₂[NbSe₂]₂[(PbSe)_1.14]₁[NbSe₂]₁[(PbSe)_1.14]₁[NbSe₂]₁, [(PbSe)_1.14]₂[NbSe₂]₁[(PbSe)_1.14]₁[NbSe₂]₂[(PbSe)_1.14]₁[NbSe₂]₁. The electrical properties of these compounds vary with the nanoarchitecture. For each pair of constituents, over 20 000 new compounds, each with a specific nanoarchitecture, are possible with the number of structural units equal to 10 or less. This provides opportunities to systematically correlate structure with properties and hence optimize performance.     

Metallation studies of organofunctional trisiloxanes

Summary The organofunctional trisiloxanes Me₃SiOSiMe(R)OSiMe₃ [R=(CH₂)₂PPh₂, (CH₂)₃C₅H₄N, (CH₂)₃CN, (CH₂)₂Ph, (CH₂)₂SPh, CH=CH₂ and CH₂CH=CH₂] have been reacted with metal halide and-carbonyl moieties in order to determine the coordination preferences of materials being used as models for metallated longchain linear functionalised polysiloxanes. The products [Me₃SiOSiMe(R)OSiMe₃]₃ML_n [R=(CH₂)₂PPh₂, ML_n=RhCl],cis-[Me₃SiOSiMe(R)OSiMe₃]₂ML_n [R=(CH₂)₂PPh₂ or (CH₂)₃C₅H₄N, ML_n=Mo(CO)₄],trans-[Me₃SiOSiMe(R)OSiMe₃]₂ML_n[R=(CH₂)₂PPh₂, ML_n=NiCl₂, PdCl₂, PtCl₂ and [Rh(CO)Cl] and [Me₃SiOSiMe(R)OSiMe₃]ML_n [R=(CH₂)₂PPh₂, ML_n=Mo(CO)₃(2,2-bipyridine); R=(CH₂)₂Ph, ML_n=Mo(CO)₃; R=(CH₂)₃C₅H₄N, (CH₂)₃CN, or (CH₂)₂SPh, ML_n=Rh(CO)₂Cl; R=CH=CH₂ or CH₂CH=CH₂, ML_n=Fe(CO)₄] have been isolated and characterised spectroscopically in the course of these studies.     

Alkaline hydrolysis of diaryl ditellurides under phase transfer conditions; synthesis of alkyl aryl tellurides

The disproportionation reaction of diaryl ditellurides [(C₆H₅Te)₂, (p-CH₃C₆H₄Te)₂, (p-CH₃OC₆H₄Te)₂, (p-C₂H₅OC₄Te)₂, (2-naphthyl-Te)₂] with sodium hydroxide under phase transfer conditions at room temperature is described for the first time. The phase transfer catalyst used is 2HT-75, a trade name for a mixture of dialkyldimethylammonium chlorides. The intermediates aryl tellurolates react “in situ” with alkyl halides to give the corresponding alkyl aryl tellurides (ArTeR) in 52–72% yield. The following compounds were prepared: Ar  C₆H₅, R=CH₃(CH₂)₃CH₂, (CH₃)₂CHCH₂CH₂, (CH₃)₂CHCH₂, CH₃CHBrCH₂CH₂, CH₃(CH₂)₈CH₂, C₆H₅CH₂, ClCH₂, C₆H₅CH₂CH₂, CH₂CHCH₂, C₆H₅CHCHCH₂, C₆H₅SeCH₂, $\text{CH}{}_2\text{CH}{}_2\text{CH}{}_2\text{CHCHC}$H; Ar=p-CH₃C₆H₄, R = CH₃(CH₂)₂CH₂; Ar=p-CH₃OC₆H₄, R = CH₃(CH₂)₂CH₂; Ar = p-CH₂H₅OC₆H₄, R= CH₃(CH₂)₂CH₂; Ar = 2-naphthyl, R = CH₃(CH42)₂CH₂.     

Chalcogenolato-di-thiocarbamato-complexes of zinc: The X-ray single crystal structures of pyridine adducts

Novel mixed complexes 2,4,6-Me₃C₆H₂SZnS₂CNEt₂ (1), 2,4,6-Me₃C₆H₂SeZnSe₂CNEt₂ (2) and their pyridine adducts ([Zn(SC₆H₂Me₃-2,4,6)₂(C₅H₅N)₂] (3), [Zn(SeC₆H₂Me₃-2,4,6)₂(C₅H₅N)₂] (4) and (Et₂CNSe₂)₂Zn.NC₅H₅ (5) and (Et₂CNS₂)₂Zn.NC₅H₅ (6) have been synthesised and characterised. The X-ray single crystal structures of (4), (5) and (6) have been determined.     

Synthesis of cationic dialkylgold(III) complexes: nature of the facile reductive elimination of alkane

A series of gold(III) cations of the type cis-[CH₃)₂AuL₂]⁺ X^? where L  Ph₃, PMePh₂, PMe₂Ph, PMe₃, AsPh₃, AsPh₃, SbPh₃, $\text{1}\text{2}$H₂NCH₂CH₂NH₂, $\text{1}\text{2}$ Ph₂PCH₂CH₂-PPh₂, $\text{1}\text{2}$ Ph₂AsCH₂CH₂AsPh₂, and $\text{1}\text{2}$o-C₆H₄(AsMe₂)₂ and X  BF₄^?, PF₆^?, ClO₄^?, and F₃CSO₃^? has been prepared. In addition, the cis complexes [(CH₃)(CD₃)-Au(PPh₃)₂]F₃CSO₃, [(C₂H₅)₂Au(PPh₃)₂]F₃CSO and [(n-C₄H₉)₂Au(PPh₃)₂]F₃-CSO₃ have been synthesized. All have been characterized by PMR, Raman and infrared spectroscopy. These [R₂AuL₂]X compounds yield only ethane, butane, or octane via reductive elimination, and no disproportionation is observed. The alkane eliminations have been studied in CHCl₃, CH₃Cl₂, and CH₃COCH₃ solution as a function of temperature, concentration of the complex, and concentration of added ligand L. Elimination is fastest when L is bulky (PPh₃ > PMePh₂ > PMe₂Ph > PMe₃), decreases in the sequence SbPh₃ > AsPh₃ > PPh₃, is slow with chelating ligands, is inhibited by excess ligand, and there is small anion effect as X is varied. As R is varied, the rate of elimination decreases Bu ? Et > Me. An intramolecular dissociative mechanism is proposed which involves rapid elimination of alkane from an electron deficient dialkylgold(III) complex with nonequivalent gold—carbon bonds and produces the corresponding [AuL₂]X complex.     

The chemistry of chromyl fluoride III. Reactions with inorganic systems

Reactions of CrO₂F₂ with MF or MF₂ gave the corresponding M₂CrO₂F₄ and MCrO₂F₄ fluorochromates. With the Lewis Acids (SO₃, TaF₅, SbF₅) and (CF₃CO)₂O known and new chromyl compounds [CrO₂(CF₃COO)₂, CrO₂(SO₃F)₂, CrO₂FTaF₆, CrO₂FSbF₆, CrO₂FSb₂F₁₁] were produced. Chromyl fluoride and inorganic salts (CF₃COONa and NaNO₃) produced the following complexes - Na₂CrO₂F₂(CF₃COO)₂ and Na₂CrO₂F₂(NO₃)₂. Unusual solid products were obtained with CrO₂F₂ and NO, NO₂, SO₂.A new method of preparing CrO₂F₂ is also presented.     

Synthesis and thermal decomposition of potassium trioxalatoaluminate hydrate

The preparation of pure K₃Al(C₂O₄)₃·mH₂O (2<m<3) is described. Dependent on the mode of preparation, the following were found to be contaminants of the desired product: K₂C₂O₄·1H₂O; KHC₂O₄; KHC₂O₄·H₂C₂O₄·2H₂O; H₂C₂O₄·2H₂O; different forms of aluminium oxide hydrate; K₄Al₂(OH)₂(C₂O₄)₄· (2+x)H₂O (0.7<x<1.7) and K₂Al₂(H₂O)₂(C₂O₄)₄· 4H₂O.     

Thermogravimetric study of uranium phosphates

The thermal decomposition of UO₂NH₄PO₄ · 3H₂O and UO₂HPO₄ · 4H₂O was studied in the temperature range 25–1600?C. Both compounds gave U₂O₃P₂O₇ around 900?C after a two step dehydration and an orthophosphate-pyrophosphate transformation. UO₂NH₄PO₄ · 3H₂O did not form any pure intermediates, but (UO₂)₂P₂O₇ could be prepared from UO₂HPO₄ · 4H₂O. In air, U₂O₃P₂O₇ lost phosphorus above 1250?C. In argon, (UO)₂P₂O₇ was first formed between 1000 and 1290?C and this product only lost phosphorus at still higher temperatures. (UO)₂P₂O₇ was also obtained by reduction of (UO₂)₂P₂O₇ or U₂O₃P₂O₇ at 700?C in H₂ or with carbon black in argon above 1000?C. It oxidised in air above 250?C with the formation of U₂O₃P₂O₇.     

Reactions of osmium coordinated formaldehyde. Synthesis of complexes of selenoformaldehyde and telluroformaldehyde

Os(η²-CH₂O)(CO)₂(PPh₃)₂ reacts with CSe₂ to form a metallacycle O$\text{s(CH}{}_2\text{OC[Se}$]Se)(CO)₂(PPh₃)₂. This compound breaks down to Os(η²-CH₂Se)(CO)₂(PPh₃)₂ with probable loss of COSe. An alternative route to Os(η²-CH₂Se)(CO)₂(PPh₃)₂ and also Os(η²-CH₂Te)(CO)₂(PPh₃)₂ is through reaction of Os(CH₂I)I(CO)₂(PPh₃)₂ with SeH^? and TeH^?, respectively. HCl with Os(η²-CH₂E)(CO)₂(PPh₃)₂ (E = Se or Te) gives OsCl(EMe)(CO)₂(PPh₃)₂ while methyl iodide gives [Os(η²-CH₂EMe)(CO)₂ - (PPh₃)₂] I. BH₄^? reacts with these cations to cleave the CE bond and form Os(CH₃)(EMe)(CO)₂(PPh₃)₂.     

Piperazine Functionalization of C70 for Incorporation into Supramolecular Assemblies

The photochemical reaction of piperazine with C₇₀ produces a mono‐adduct (N(CH₂CH₂)₂NC₇₀) in high yield (67 %) along with three bis‐adducts. These piperazine adducts can combine with various Lewis acids to form crystalline supramolecular aggregates suitable for X‐ray diffraction. The structure of the mono‐adduct was determined from examination of the adduct I₂N(CH₂CH₂)₂NI₂C₇₀ that was formed by reaction of N(CH₂CH₂)₂NC₇₀ with I₂. Crystals of polymeric {Rh₂(O₂CCF₃)₄N(CH₂CH₂)₂NC₇₀}_n?nC₆H₆ that formed from reaction of the mono‐adduct with Rh₂(O₂CCF₃)₄ contain a sinusoidal strand of alternating molecules of N(CH₂CH₂)₂NC₇₀ and Rh₂(O₂CCF₃)₄ connected through Rh?N bonds. Silver nitrate reacts with N(CH₂CH₂)₂NC₇₀ to form black crystals of {(Ag(NO₃))₄(N(CH₂CH₂)₂NC₇₀)₄}_n?7nCH₂Cl₂ that contain parallel, nearly linear chains of alternating (N(CH₂CH₂)₂NC₇₀ molecules and silver ions. Four of these {Ag(NO₃)N(CH₂CH₂)₂NC₇₀}_n chains adopt a structure that resembles a columnar micelle with the ionic silver nitrate portion in the center and the nearly non‐polar C₇₀ cages encircling that core. Of the three bis‐adducts, one was definitively identified through crystallization in the presence of I₂ as ¹²{N(CH₂CH₂)₂N}₂C₇₀ with addends on opposite poles of the C₇₀ cage and a structure with C_2v symmetry. In ¹²{I₂N(CH₂CH₂)₂N}₂C₇₀, individual ¹²{I₂N(CH₂CH₂)₂N}₂C₇₀ units are further connected by secondary I2???N2 interactions to form chains that occur in layers within the crystal. Halogen bond formation between a Lewis base such as a tertiary amine and I₂ is suggested as a method to produce ordered crystals with complex supramolecular structures from substances that are otherwise difficult to crystallize.     

Organotin and tin(IV) derivatives of dimethyldithioarsinic acid

Organotin derivatives of dimethyldithioarsinic (dithocacodylic) acid have been obtained from the appropriate organotin chloride and the sodium salt of the latter. Tin(IV) chloride and NaS₂AsMe₂ · 2 H₂O yielded only two products, namely Cl₂Sn(S₂AsMe₂)₂ and Sn (S₂AsMe₂)₄, regardless of the reagent ratio. Spectroscopic characterization of the compounds (infrared and¹H NMR) provides structural information suggesting that the dimethyldithioarsinato group behaves as monodentate (or anisobidentate) ligand in Me₂Sn(S₂AsMe₂)₂, Bu₂Sn-(S₂AsMe₂)₂ and Cy₃Sn(S₂AsMe₂), as bidentate in Ph₂Sn(S₂AsMe₂)₂, Ph₃Sn(S₂AsMe₂) and Cl₂As(S₂AsMe₂)₂, whereas Sn(S₂AsMe₂)₄ contains both mono- and bidentate ligands, presumably in a six-coordinate structure.     

Synthesis and reactions of some sulfur ylide complexes of palladium

The iodo-bridged sulfur ylide complex [Pd(μ-I)((CH₂)₂(SO)(CH₃))]₂ (1) when treated with dithiolates, acetylacetone and various Lewis bases gave [Pd((CH₂)₂(SO)(CH₃))(S ∼ S)] (S ∼ S = S₂CN(C₂H₅)₂, S₂COC₂H₅ and S₂P(OC₂H₅)₂), [Pd((CH₂)₂(SO)(CH₃))(acac)] (acac = acetylacetonate) and [PdI((CH₂)₂(SO)(CH₃))(base)]a (base = PPh₃, (P(OMe)₃, P(OPh)₃ and C₅H₅N). In the presence of a phase transfer catalyst (PTC). The reactions rates and yields were greatly increased. Reaction of several related sulfur ylide complexes with I₂, HI or aqueous NaOH gave 1. The single crystal structure of [Pd((CH₂)₂(SO)(CH₃))₂] was determined (orthorhombic, Pbcn, a 13.379(2), b 8.081(1), c 9.048(2) Å, V 978.2 ų, Z = 4). The compound has a rather long PdCH₂ bond (2.096(1) Å, mean).     

Formation of supramolecular complexes in reactions of adduct formation of zinc diethyldithiocarbamate with morpholine. Molecular structures and thermal properties

A supramolecular compound of the general formula [Zn{NH(CH₂)₄O} {S₂CN(C₂H₅)₂}₂]₄ · NH(CH₂)₄O · C₂H₄{N(CH₂)₄O}₂ (I) was obtained and examined by X-ray diffraction analysis and thermography. According to X-ray diffraction data, the crystal lattice of compound I shows an unusual alternation of two independent centrosymmetric supramolecular complexes [Zn{NH(CH₂)₄O} {S₂CN(C₂H₅)₂}₂]₂ · C₂H₄{N(CH₂)₄O}₂ (Ia) and [Zn{NH(CH₂)₄O} {S₂CN(C₂H₅)₂}₂]₂ · NH(CH₂)₄O (Ib). Either complex includes two molecules of an adduct of bis(diethyldithiocarbamato)zinc with morpholine and outer-sphere molecules of 1,2-dimorpholinoethane or morpholine. Adduct molecules are structurally nonequivalent in pairs and linked with solvate molecules by hydrogen bonds. The calculated geometries of the zinc polyhedra are intermediate between trigonal bipyramid and tetragonal pyramid. Thermal decomposition of supramolecular compound I proceeds through desorption of the outer-sphere and coordinated organic molecules; in the final step, defragmentation of the dithiocarbamate part gives zinc sulfide.     

Electrochemical fluorination of chlorine-containing amines

The electrochemical fluorination of chlorine-containing alkylamines has been studied. It was found that, in general, the carbon-chlorine bond in the alkylamines is retained during electrochemical fluorination is anhydrous hydrogen fluoride, yielding chlorine-containing polyfluoroalkylamines. Perfluoroalkylamines and fluorocarbons were also produced.By the use of this method, several new chloropolyfluoroamines such as (CF₃)₂NCF₂CClF₂, (C₂F₅)₂NCF₂CClF₂, (CF₃)(C₂F₅)NCF₂CClF₂, (CClF₂CF₂)₂NCF₃, (CClF₂CF₂)₂NC₂F₅, (C₂F₅)(CClF₂CF₂)NF, (CClF₂CF₂)₂NF, (CF₃)₂NCF₂CF₂CClF₂, $\text{CF}{}_2\text{(CF}{}_2\text{)}{}_3\text{N}$CF₂CClF₂, and $\text{CF}{}_2\text{CF}{}_2\text{OC}{}_2\text{F}{}_4\text{N}$CF₂CClF₂ have been isolated and characterized.     

Mass spectra of organometallic compounds—VII; Organonitrogen derivatives of metal carbonyls

The positive-ion mass spectra of the following organonitrogen derivatives of metal carbonyls are discussed: (i) The compounds NC₅H₄CH₂Fe(CO)₂C₅H₅, NC₅H₄CH₂COMo(CO)₂C₅H₅, NC₅H₄CH₂W(CO)₃C₅H₅, NC₅H₄CH₂COMn(CO)₄, C₅H₁₀NCH₂CH₂Fe(CO)₂C₅H₅, (CH₃)₂NCH₂CH₂COFeCOC₅H₅ and (CH₃)₂NCH₂CH₂COMn(CO)₄ obtained from metal carbonyl anions and haloalkylamines, (ii) The isocyanate derivative C₅H₅Mo(CO)₃CH₂NCO; (iii) The arylazomolybdenum derivatives RN₂Mo(CO)₂C₅H₅ (R ? phenyl, p-tolyl, or p-anisyl); (iv) The compound (C₆H₅N)₂COFe₂(CO)₆ obtained from Fe₃(CO)₁₂ and phenyl isocyanate; (v) The N,N,N′,N′-tetramethylethylenediamine complex (CH₃)₂NCH₂CH₂N(CH₃)₂W(CO)₄. Further examples of eliminations of hydrogen, CO, and C₂H₂ fragments were noted. In addition evidence for the following more unusual processes was obtained: (i) Elimination of HCN fragments from the ions [NC₅H₄CH₂MC₅H₅]⁺ to give the ions [(C₅H₅)₂M]⁺ (M ? Fe, Mo and W); (ii) Conversion of C₅H₅Mo(CO)₃CH₂NCO to C₅H₅Mo(CO)₂CH₂NCO within the mass spectrometer; (iii) Elimination of N₂ from [RN₂MoC₅H₅]⁺ to give [RMoC₅H₅]⁺; (iv) Novel eliminations of HNCO, FeNCO, and C₆H₅NC fragments in the mass spectrum of (C₆H₅N)₂COFe₂(CO)₆; (v) Facile dehydrogenation of the N,N,N′,-N′-tetramethylethylenediamine ligand in the complex (CH₃)₂NCH₂CH₂N(CH₃)₂W(CO)₄.     

Chemistry of organosilicon compounds: CIV. Syntheses of novel organoelement heterocycles containing titanium and silicon

Four new dicyclopentadienyltitanium(IV) metallocycles, Cp₂TiCH₂XCH₂ (X = SiMe₂OSiMe₂, SiMe₂CH₂SiMe₂, SiMe₂SiMe₂, and SiMe₂SiMe₂SiMe₂) are prepared and characterized.     

Preparation of nanocrystalline BiFeO3 and kinetics of thermal process of precursor

The Bi₂Fe₂(C₂O₄)₅·5H₂O was synthesized by solid-state reaction at low heat using Bi(NO₃)₃·5H₂O, FeSO₄·7H₂O, and Na₂C₂O₄ as raw materials. The nanocrystalline BiFeO₃ was obtained by calcining Bi₂Fe₂(C₂O₄)₅·5H₂O at 600 °C in air. The precursor and its calcined products were characterized by thermogravimetry and differential scanning calorimetry, FT-IR, X-ray powder diffraction, and vibrating sample magnetometer. The data showed that highly crystallized BiFeO₃ with hexagonal structure [space group R3c(161)] was obtained when the precursor was calcined at 600 °C in air for 1.5 h. The thermal process of the precursor in air experienced five steps which involved, at first, the dehydration of an adsorption water molecule, then dehydration of four crystal water molecules, decomposition of FeC₂O₄ into Fe₂O₃, decomposition of Bi₂(C₂O₄)₃ into Bi₂O₃, and at last, reaction of Bi₂O₃ and Fe₂O₃ into hexagonal BiFeO₃. Based on Starink equation, the values of the activation energies associated with the thermal process of Bi₂Fe₂(C₂O₄)₅·5H₂O were determined. Besides, the most probable mechanism functions and thermodynamic functions (ΔS ^≠, ΔH ^≠, and ΔG ^≠) of thermal processes of Bi₂Fe₂(C₂O₄)₅·5H₂O were also determined.     

A study of the selenites of cerium

The solubilities of the systems CeO₂-SeO₂-H₂O and Ce₂O₃-SeO₂-H₂O were studied at 100°C. The field of crystallization of Ce(SeO₃)₂ was established in the system CeO₂-SeO₂-H₂O, and fields of crystallization of Ce₂(SeO₃)₃ and Ce₂(SeO₃)₃H₂SeO₃ were established in the system Ce₂O₃-SeO₂-H₂O. The compound obtained were identified by means of chemical, X-ray and derivatograph analysis. The mechanism of thermal dissociation of Ce(SeO₃)₂, Ce₂(SeO₃)₃ and Ce₂(SeO₃)₃·H₂SeO₃ was studied. This revised version was published online in August 2006 with corrections to the Cover Date.