Air‐Stable,Well‐Soluble AI2[Nb6Cl18] Cluster Compounds (AI = Organic Cation): A New Route for Preparation,Single‐Crystal Structures,Properties, and ESI‐Mass Spectra

Five niobium cluster compounds of the A^I₂[Nb₆Cl₁₈] type (A^I = organic cation: [nPr₄N]⁺, [nBu₄N]⁺, [BMIm]⁺, [Ph₄P]⁺, and [PPN]⁺) are obtained through treatment of [Nb₆Cl₁₄(H₂O)₄] · 4H₂O with excess of thionyl chloride in the presence of an organic chloride, A^ICl. Single‐crystal structure studies show that the compounds consist of discrete cations and cluster [Nb₆Cl₁₈]^2– anions. The cluster unit of the hydrated cluster starting material is oxidized by two electrons. Powder diffraction studies and NMR spectroscopic measurements show all compounds to crystallize without co‐crystallized solvent molecules. They are air and water stable. The solubility in organic solvents changes to a great extent on changing the type of cation. The ESI‐MS spectra of [nPr₄N]₂[Nb₆Cl₁₈] and [Ph₄P]₂[Nb₆Cl₁₈] show the pseudomolecular peak of the anionic cluster as well as additional signals, which involve simultaneously chloride mass loss and reduction processes.     

A Systematic Investigation of Coinage Metal Carbonyl Complexes Stabilized by Fluorinated Alkoxy Aluminates

The reaction of Cu^I, Ag^I, and Au^I salts with carbon monoxide in the presence of weakly coordinating anions led to known and structurally unknown non‐classical coinage metal carbonyl complexes [M(CO)_n][A] (A=fluorinated alkoxy aluminates). The coinage metal carbonyl complexes [Cu(CO)_n(CH₂Cl₂)_m]⁺[A]^? (n=1, 3; m=4?n), [Au₂(CO)₂Cl]⁺[A]^?, [(OC)_nM(A)] (M=Cu: n=2; Ag: n=1, 2) as well as [(OC)₃Cu???ClAl(OR^F)₃] and [(OC)Au???ClAl(OR^F)₃] were analyzed with X‐ray diffraction and partially IR and Raman spectroscopy. In addition to these structures, crystallographic and spectroscopic evidence for the existence of the tetracarbonyl complex [Cu(CO)₄]⁺[Al(OR^F)₄]^? (R^F=C(CF₃)₃) is presented; its formation was analyzed with the help of theoretical investigations and Born–Fajans–Haber cycles. We discuss the limits of structure determinations by routine X‐ray diffraction methods with respect to the C? O bond lengths and apply the experimental CO stretching frequencies for the prediction of bond lengths within the carbonyl ligand based on a correlation with calculated data. Moreover, we provide a simple explanation for the reported, partly confusing and scattered CO stretching frequencies of [Cu^I(CO)_n] units.     

Stereochemistry of 2, 7-disubstituted and 1,2,7-trisubstituted 4-alkyldecahydro-4-quinolols

The configurations of the 2 and 4 centers in 1,2,7-trimethyl-, 2,7-dimethyl-, and 1,2-dimethyl-7-tert-butyl-4-alkyldecahydro-4-quinolols were assigned on the basis of a comparison of the^I[M-CH₃] +/^I _[M] ⁺ and I_[m] + peak intensity ratios (the [M-CH₃) + and [M-C₂H₅]⁺ ions are due to elimination of 2-CH₃ and 4-C₂H₅ groups, respectively) in the mass spectra of the stereoisomers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 809–811, June, 1976.     

Electron impact mass spectra of some salts of carboxylic acids with alkali (group Ia) metals

Thirteen of the salts of the alkali metals (Li, Na, K, Rb, Cs) with acetic, 2,2-dimethylpropionic, trifluoroacetic and heptafluorobutyric acid have been found to be sufficiently volatile to give mass spectra under normal electron impact conditions. The metal containing ions observed include (M=metal): [M]⁺, [MO]⁺, [MCO₂]⁺, [M₂]^+·, [M₂O]^+·, [M₂CO₂]^+· and the cluster ions [M_n (carboxylate)_n-1]⁺ for n = 2–8.     

Stereochemical applications of mass spectrometry. 3—Energy dependence of the fragmentation of stereoisomeric methylcyclohexanols

Breakdown graphs have been constructed from charge exchange data for the epimeric 2-methyl-, 3-methyl- and 4-methyl-cyclohexanols. Although the breakdown graphs for epimeric pairs are essentially identical above ～12 eV recombination energy, significant differences are observed for the epimeric 2-methyl- and 4-methyl-cyclohexanols at low internal energies. For the 2-methylcyclohexanols the ratio ([M? H₂O]^+·/[M]^+·)_cis/([M? H₂O]^+·/[M]^+·)_trans is 3.2 in the [C₆F₆]^+· charge exchange mass spectra. This is attributed to both energetic and conformational effects which favour the stereospecific cis-1,4-H₂O elimination for the cis epimer. The breakdown graph for trans-4-methylcyclohexanol shows a sharp peak in the abundance of the [M? H₂O]^+· ion at ～10 eV recombination energy which is absent from the breakdown graph for the cis epimer. This peak is attributed to the stereospecific cis-1,4-elimination of water from the molecular ion of the trans isomer; the reaction appears to have a low critical energy but a very unfavourable frequency factor, and alternative modes of water loss common to both epimers are observed at higher energies. As a result, in the [C₆F₆]^+· charge exchange mass spectra the ([M? H₂O]^+·/[M]^+·)_trans/([M? H₂O]^+·/[M]^+·)_cis ratio is ～24, compared to the value of 13 observed in the 70 eV EI mass spectra. No differences are observed in either the metastable ion abundances or the associated kinetic energy releases for epimeric molecules.     

Über quantitative Beziehungen Zwischen Fragmenten und Ihren Relativen Intensitäten im Massenspektrometer. III—Messung der Intensitätsverhältnisse aus der α-SWpaltung von Tertiären Alkjoholen und Äthern bei Niedriger Elektronenenergie

The ion intensity ratios from competing α-fissions of 30 tertiary aliphatic alcohols and 24 ethers of tertiary alcohols have been measured at 13 eV. The intensity ratios of ions [M ? alkyl1]+ and [M ? alkyl2]⁺ agree well with the reciprocal mass ratios of the respective ions in the case when the alkyl groups are not methyl (ion mass effect). The intensity ratios of [M ? alkyl]⁺ and [M ? methyl]⁺ are always too high, but intensity ratios of [M ? alkyl1]⁺ and [M ? alkyl2]⁺ may be derived indirectly from them, which also agree well with those values expected from the ion mass effect. By the indirect method it is shown, that for the 2,2-dialkyl-1,3-dioxolanes (ethylene ketals) the ion mass effect plays a dominant role too.     

Effect of collision gas pressure and collision energy on reactions between oxygen and the negative molecular ion of tetrachlorodibenzo-p-dioxins in the collision cell of a triple -quadrupole mass spectrometer

Low-energy reactive collisions between the negative molecular ion of a tetrachlorodibenzo-p-dioxin (TCDD) and oxygen inside the collision cell of a triple-stage quadrupole mass spectrometer produce a substitution ion [M ? Cl + O]^?, a phenoxide ion [C₆H_4-nO₂Cl_n]^?·, [M ? HCl]^?·, and Cl^? by which 1,2,3,4-, 1,2,3,6/1,2,3,7- and 2,3,7,8-TCDD isomers can be distinguished either directly or on the basis of intensity ratios. The collision conditions have an important effect on the relative abundances. Energy- and pressure-resolved curves show that the ions formed by a collisionally activated reaction (CAR) process, i.e. [M ? Cl + O]^? and [C₆H_4-n,O₂Cl_n]^?·, are favoured by a high pressure of oxygen (3-6 mTorr) (1 Torr = 133.3 Pa) and a low collision energy (0.1-7 eV), whereas the ions formed by a collisionally activated dissociation (CAD) process, i.e. [M ? HCl]^?· and Cl^?, are favoured by high pressure and high energy. By choosing a relatively low collision energy (5 eV) and high pressure (4 mTorr), the CAR and CAD ions can be clearly detected.     

Mass spectrometric investigation of stereosomeric 1,2-dimethyl-4-substituted decahydroquinol-4-ol N-oxides. Concerning the configuration of the asymmetric nitrogen atom

The main fragmentation pathways of the N-1, C-2 and C-4 stereoisomers of the 1,2-dimethyl-4-R-transdecahydroquinoline-4-ol N-oxides (R=C?CH, CH?CH₂ and C₂H₅) under electron impact are discussed. The correlation between the mass spectrometric chromatographic behaviour and the configuration of polar groups in the N-oxides examined is discussed. The mass spectra of the N-1 stereoisomers may be subdivided into two groups, depending only on the orientation of N→O group and not of the 4-OH group. The spectra of N-oxides with the axial N-oxide group reveal less intense ions and much more intense [M? CH₃]⁺, [M? O]⁺, [M? OH]⁺ and ions, whereas in the spectra of their equatorial epimers the abundance of the ions exceeds the intensities of the latter ions.     

The significance of field ionisation kinetics to ion structure: Isomerisation and decompostition of [C4H8]+· radical ions

The kinetics of formation of [C₃H₅]⁺[M ? CH₃]⁺, [C₃H₄]⁺·[M ? CH₄]⁺· and [C₂H₄]⁺·[M ? C₂H₄]⁺· from but-1-ene, cis- and trans-but-2-ene, 2-methylpropene, cyclobutane and methylcyclopropance following field ionisation have been determined as a function of time 20 (or 30) picoseconds to 1 nanosecond and at two points in the microsecond time-frame. The results are consistent with the supposition that at the shortest accessible times (20 to 30 picoseconds) the structure of the [C₄H₈]⁺· molecular ion qualitatively resembles that of its neutral precursor, but suggest that prior to decomposition within nanoseconds the various molecular ions (excepting cyclobutane where the processes are slower) attain a common structure or mixture of structures. Reaction pathways of the presumed known ion structures are delineated from the nature of decompostion at the shortest times.     

Die massenspektrometrische Fragmentierung von Neopentylpolyolestern. 1—Pentaerythrittetrafettsäureester

The fragmentation of the homologous fatty acid tetraesters of pentaerythritol (C-2 to C-14) upon electron impact was investigated. The main fragment ions are [M? RCOO]⁺ and [M? RCOOH]⁺, for which cyclic acetal structures are postulated. Subsequent fragmentation was elucidated by ‘direct analysis of daughter ion’ (DADI) measurements and high resolution measurements. Esters of branched fatty acids can be distinguished from esters of n-fatty acids by characteristic ions. Isomeric esters of n-fatty acids cannot be separated by gas chromatography but identification is also possible by mass spectrometry.     

MZn2HPO4PO4 (M=Na+, K+)的合成、表征和标准摩尔生成焓

采用低温固相法和水热法制备MZn2HPO4PO4 (M=Na+, K+) 并用XRD, FT-IR, TG and SEM对其进行表征,用等温量热计测定热化学性质。按照Hess’s定律,设计一新的热化学循环。结果表明,所合成的物质是等结构三斜晶系的目标产物,具有片层结构,分解温度分别为： 415 ℃和430 ℃。从测定的溶解焓和其他的标准热化学数据,计算出MZn2HPO4PO4 (M=Na+, K+) 的标准摩尔生成焓分别为：ΔfHm [NaZn2HPO4PO4, s]=-3042.38±0.31 kJ·mol-1; ΔfHm [KZn2HPO4PO4,s]=-3093.46 ±0.27 kJ·mol-1。     

Synthesis and structure of antimony complexes [Ph3AmP] 2 + [Sb2I8 · 2DMSO]2−, [Ph3PrP] 2 + [Sb2I8 · C4H8O2]2−, and [(HOCH2CH2)3NH] 4 + [Sb4I16]4−

The reaction of equimolar amounts of triphenylamyl- and triphenylpropylphosphonium iodides and triethanolammonium iodide with antimony iodide in dimethyl sulfoxide, dioxane, or acetone gave complexes [Ph₃AmP] ₂ ⁺ [Sb₂I₈ · 2DMSO]^2?, [Ph₃PrP] ₂ ⁺ [Sb₂I₈ · C₄H₈O₂]^2?, and [(HOCH₂CH₂)₃NH] ₄ ⁺ [Sb₄I₁₆]^4?, the structure of which was established by X-ray diffraction analysis. The cations of all complexes have slightly distorted tetrahedral structure, and the antimony atoms in the anions are hexacoordinated. The crystals of the complexes have intra- and intermolecular contacts, which form the structure.     

Crystal Structure and Thermal Behaviour of K2[CrF5·H2O]

K₂[CrF₅·H₂O] is monoclinic: a = 9.6835(3) Å, b = 7.7359(2) Å, c = 7.9564(3) Å, β = 95.94(1)°, Z = 4, space group C2/c (n^o 15). Its crystal structure was solved from its X‐ray powder pattern recorded on a powder diffractometer, using for the refinement the Rietveld method. It is built up from isolated octahedral [CrF₅·OH₂]^2? anions separated by potassium cations. The dehydration of K₂[CrF₅·H₂O] leads to anhydrous orthorhombic K₂CrF₅: a = 7.334(2) Å, b = 12.804(4) Å, c = 20.151(5) Å, Z = 16, space group Pbcn (n^o 60), isostructural with K₂FeF₅.     

Repeller-Induced dissociation of alkyl alcohols in thermospray mass spectrometry

Six alkyl alcohols were studied using thermospray mass Spectrometry. Whereas the dominant ion in the spectrum up to a repeller potential of 120 V was [M + NH₄]⁺, above that potential [M + H]⁺ and fragment ions appeared. The fragments observed were largely due to hydrogen release from alkyl ions ([C_nH_2n+1]⁺ – H2 → [C_nH_2n-1]⁺) and loss of water or some other stable molecule from the same species. The results are compared with those from ionization of the same alcohols under electron impact and photoionization conditions and with results obtained for methanol under thermospray conditions.     

Thermospray mass spectrometry of N-methylcarbamates

The thermospray mass spectrometry (TSP/MS) of five N-methylcarbamates is presented. This is the first time that ions other than [M + H]⁺ and [M + NH₄]⁺ have been reported using positive TSP/MS. Protonation of ROCONHCH₃ yields the [CH₃NH₂CO]^+· ion, with formation of the ion–molecule adduct [ROCONHCH₃ · CH₃NH₂CO]^+· through elimination of CO^+· from [CH₃NH₂CO]^+·, and the adduct [M + 75]^+·, [ROCONHCH₃ · OCONH₂CH₃]^+·, is also obtained.     

Die K4[Ag4O4] — Strukturfamilie

K₄[Ag₄0₄] Structure Type M₄[Ag₄O₄] (M ? Li? Cs) and M₄[Cu₄O₄] (M ? Li? Rb) have been prepared anew; as an example the crystal structure of K₄[Ag₄O₄] has been revised. Contrary to our first report [2, 3] it crystallizes in the space-group I4 m2 with the “ring” [Ag₄O₄]^4? which is not plane, however. Each two O^2? (trans-arrangement) are rather (0.02 Å) above and below the plane of the “ring”, respectively. The new parameters are given in the text. The distances, for example d(Ag⁺·O^2?) = 2.058 Å and the Madelung Part of Lattice Energy, MAPLE, are both in a very good agreement with the measurements and calculations, respectively, which have been done on other ternary oxides with silver.     

Syntheses and structural determinations of the nine-coordinate rare earth metal: Na4[DyIII(dtpa)(H2O)]2·16H2O,Na[DyIII(edta)(H2O)3]·3.25H2O and Na3[DyIII(nta)2(H2O)]·5.5H2O

Three complexes, Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and Na₃[Dy^III (nta)₂(H₂O)]?·?5.5H₂O, have been synthesized in aqueous solution and characterized by FT–IR, elemental analyses, TG–DTA and single-crystal X-ray diffraction. Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O crystallizes in the monoclinic system with P2₁/n space group, a?=?18.158(10)?Å, b?=?14.968(9)?Å, c?=?20.769(12)?Å, β?=?108.552(9)°, V?=?5351(5)?ų, Z?=?4, M?=?1517.87?g?mol^?1, D _c?=?1.879?g?cm^?3, μ?=?2.914?mm^?1, F(000)?=?3032, and its structure is refined to R ₁(F)?=?0.0500 for 9384 observed reflections [I?>?2σ(I)]. Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O crystallizes in the orthorhombic system with Fdd2 space group, a?=?19.338(7)?Å, b?=?35.378(13)?Å, c?=?12.137(5)?Å, β?=?90°, V?=?8303(5)?ų, Z?=?16, M?=?586.31?g?mol^?1, D _c?=?1.876?g?cm^?3, μ?=?3.690?mm^?1, F(000)?=?4632, and its structure is refined to R ₁(F)?=?0.0307 for 4027 observed reflections [I?>?2σ(I)]. Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O crystallizes in the orthorhombic system with Pccn space group, a?=?15.964(12)?Å, b?=?19.665(15)?Å, c?=?14.552(11)?Å, β?=?90°, V?=?4568(6)?ų, Z?=?8, M?=?724.81?g?mol^?1, D _c?=?2.102?g?cm^?3, μ?=?3.422?mm^?1, F(000)?=?2848, and its structure is refined to R ₁(F)?=?0.0449 for 4033 observed reflections [I?>?2?σ(I)]. The coordination polyhedra are tricapped trigonal prism for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O and Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O, but monocapped square antiprism for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O. The crystal structures of these three complexes are completely different from one another. The three-dimensional geometries of three polymers are 3-D layer-shaped structure for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, 1-D zigzag type structure for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and a 2-D parallelogram for Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O. According to thermal analyses, the collapsing temperatures are 356°C for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, 371°C for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and 387°C for Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O, which indicates that their crystal structures are very stable.     

Anomalies in the molecular ion region in the electron impact mass spectra of α- and β-hydroxyesters

In the electron impact mass spectra of some alkyl α- and β-hydroxyesters (introduced using the gas chromatography/mass spectrometry (GC/MS) technique), the absence of the molecular ion M^+· and the presence of the [M + 1]⁺ ion instead is observed. This phenomenon is especially characteristic of C₃? C₆ glycolates and diethyl malate, and is due to chemical auto-ionization—ion-molecule reactions in the high concentration gradient at the top of the GC peak. The existence of the [M ? 2]^+·, [M ?1]⁺ and M^+· ions in the mass spectra of other β- and α-hydroxyesters is discussed.     

Electron-impact studies—LI: Hydrogen randomization in the stilbene molecular ion

Hydrozen randomization precedes the formation of M^+· ? H· and M^+· ? CH₃· species from the stilbene molecular ion at 15 eV. The carbon atom involved in the M^+· ? CH₃· elimination originates randomly from the whole molecule. The [M ? 15] ion (m/e 165) in the spectra of stilbene and 9,10-dihydrophenanthrene is produced from a common ion.     

Bismuth compounds [Ph3BuP]+I?, [Ph3BuP] 2+ [Bi2I8 · 2Me2C=O]2?, and [Ph3BuP] 2+ [Bi2I8 · 2Me2S=O]2?: Syntheses and crystal structures

The complexes [Ph₃BuP]₂⁺[Bi₂I₈ · 2Me₂C=O]²⁻ (II) and [Ph₃BuP]₂⁺[Bi₂I₈ · 2Me₂S=O]²⁻ (III) are synthesized by the reactions of triphenyl(n-butyl)phosphonium iodide (I) with bismuth iodide in acetone and dimethyl sulfoxide. In the cations of complexes I–III, the P atoms have a distorted tetrahedral coordination (CPC angles 106.3(2)°–112.0(3)°). The butyl group in cation I is disordered over two positions. In the binuclear centrosymmetric anions of structures II and III, the octahedrally coordinated bismuth atoms are linked in pairs by two bridging (br) iodine atoms (Bi-I_br 3.1508(7) and 3.2824(8) ? in compound II, 3.1961(3) and 3.3108(3) ? in complex III), which are coplanar to four terminal (t) iodine atoms (Bi-I_t 2.9260(7) and 2.9953(6) ? in complex II, 2.9206(3) and 2.9786(3) ? in complex III). The two remaining positions at the bismuth atom are occupied by the iodine atom (Bi-I_t 2.8531(7) ? in complex II, 2.8984(3) ? in complex III) and O atom of the organic molecule (Bi-O 2.747(6) ? in complex II, 2.507(3) ? in complex III). Original Russian Text ? V.V. Sharutin, I.V. Egorova, N.N. Klepikov, E.A. Boyarkina, O.K. Sharutina, 2009, published in Koordinatsionnaya Khimiya, 2009, Vol. 35, No. 3, pp. 188–192.