The chlorides Na3MCl6 (M  Eu?Lu,Y, Sc): Synthesis,crystal structures,and thermal behaviour

Single crystals of Na₃ErCl₆ were obtained via the metallothermic reduction of ErCl₃ with Na. The crystal structure is that of the mineral cryolite with a = 684.54(4), b = 725.18(4), c = 1012.39(6) pm, β = 90.768(5)°, Z = 2, space group P2₁/n. Two applicable synthetic routes to pure powder samples of the chlorides Na₃MCl₆ (M ? Eu? Lu, Y, Sc) are described. With M ? Dy? Lu, Y, Sc, these are isotypic with Na₃ErCl₆ while those with M ? Eu, Gd, Tb adopt a ?stuffed”? LiSbF₆-type structure. The dimorphism of Na₃GdCl₆ and dependence of the lattice constants and the molar volume upon temperature has been investigated: At 205°C, a first-order phase transition from the stuffed LiSbF₆-type Na₃GdCl₆-I to the cryolite-type Na₃GdCl₆-II occurs exhibiting a 3.71% negative molar volume discontinuity.     

Mass-analyzed threshold ionization and structural isomers of M(3)O(4) (M = Sc, Y, and La)

M(3)O(4) (M = Sc, Y, and La) were produced in a pulsed laser-vaporization molecular beam source and studied by mass-analyzed threshold ionization (MATI) spectroscopy and electronic structure calculations. Adiabatic ionization energies (AIEs) of the neutral clusters and vibrational frequencies of the cations were measured accurately for the first time from the MATI spectra. Five possible structural isomers of M(3)O(4) were considered in the calculations and spectral analysis. A cage-like structure in C(3v) point group was identified as the most stable one. The structure is formed by fusing three M(2)O(2) fragments together, each sharing two O-M bonds with others. The ground electronic state of the neutral clusters is (2)A(1) with the unpaired electron being largely a metal-based s character. Ionization of the (2)A(1) state yields a (1)A(1) ion state in a similar geometry to the neutral cluster. The AIEs of the clusters are 4.4556 (6), 4.0586(6), and 3.4750(6) eV for M = Sc, Y, and La, respectively. The observed vibrational modes of the cations include metal-oxygen stretching, metal triangle breathing, and oxygen-metal-oxygen rocking in the frequency range of 200-800 cm(-1).     

Photoelectron spectroscopy of anions at 118.2 nm: observation of high electron binding energies in superhalogens MCl4- (M=Sc, Y, La)

High energy photon is needed for photoelectron spectroscopy (PES) of anions with high electron binding energies, such as superhalogens and O-rich metal oxide clusters. The highest energy photon used for anion PES in the laboratory has been 157 nm (7.866 eV) from F2 eximer lasers. Here, we report an anion PES experiment using coherent vacuum ultraviolet radiation at 118.2 nm (10.488 eV) by tripling the third harmonic output (355 nm) of a Nd:YAG laser in a XeAr cell. Our study focuses on a set of superhalogen species, MCl(4) (-) (M=Sc, Y, La), which were expected to possess very high electron binding energies. While the 157 nm photon can only access the ground state detachment features for these species, more transitions to the excited states at binding energies higher than 8 eV are observed at 118.2 nm. The adiabatic detachment energies are shown to be, 6.84, 7.02, and 7.03 eV for ScCl(4) (-), YCl(4) (-), and LaCl(4) (-) eV, respectively, whereas their corresponding vertical detachment energies are measured to be 7.14, 7.31, and 7.38 eV.     

Reaction of 3-dimethylamino-(1,1 -dimethyl) propyl magnesium chloride with tin (IV) and tin (II) chlorides. Stabilization of a SnCl+ cation in the new tin cluster [Me2NCH2CH2C(Me2)SnCl]3 · SnCl2

The reactions of the functional Grignard reagent Me₂ NCH₂CH₂C(Me₂)MgCl (4) with tin tetrachloride, dimethyltin dichloride, and tin (II) chloride are described. From the reactions the compounds bis(3-dimethylamino-1,1-dimethylpropyl) tin dichloride, [Me₂NCH₂CH₂C(Me₂)]₂SnCl₂ (5) , dimethyl(3-dimethylamino-1,1-dimethylpropyl) chlorostannane, Me₂ClSnC(Me₂)CH₂CH₂NMe₂ (6) , 1,1,2,2-tetramethyl-1,2-bis(3-dimethylamino-1,1-dimethylpropyl) distannane,[Me₂SnC(Me₂)CH₂CH₂NMe₂]₂ (7) , 3-dimethylamino-(1,1-dimethyl)propyl tin (II) chloride, Me₂NCH₂CH₂C(Me₂)SnCl (8) , hexakis(3-dimethylamino-1,1-dimethylpropyl) cyclotristannane, {[Me₂NCH₂CH₂C(Me₂)]₂Sn}₃ (9a) , and the tin cluster [Me₂NCH₂CH₂C(Me₂)SnCl]₃ · SnCl₂ (10) have been isolated and characterized by means of multinuclear NMR and Mössbauer spectroscopy, and X-ray diffraction. 10 crystallizes in the trigonal space group P3₁ with the unit cell dimensions a 11.938, c 21.873 Å, V 2699.6 ų Z = 3. The structure was refined to a final R value of 0.064. 10 represents a tetranuclear cluster the skeleton of which is composed out of 4 Sn and a bridging Cl. Formally, the central tin atom is a SnCl⁺ cation stabilized by three stannylene units in a Ψ-trigonal bipyramidal environment. The tin-tin bond lengths are 288.2, 287.3 and 315.6 pm. The intramolecular Sn? N interactions amount to 242.8, 247.4 and 221.0 pm.     

Unexpected chemical and electrochemical properties of M3N@C80 (M = Sc, Y, Er)

The unexpected isomerization of N-ethyl [6,6]-pyrrolidino-Y3N@C80 to the [5,6] regioisomer is reported, as well as the synthesis, characterization, and electrochemical analysis of Er3N@C80 derivatives. A complete electrochemical study of the M3N@C80 species (M = Sc, Y, Er) and their derivatives is presented. We introduce electrochemistry as a new tool in the characterization of the [5,6] and [6,6] regioisomers of trimetallic nitride endohedral metallofullerenes.     

Schwingungsspektren und Kraftkonstanten der Elpasolithe Cs2KMF6 (M = Sc,Y, La,Gd, Yb)

Vibrational Spectra and Force Constants of the Elpasolites Cs₂KMF₆ (M = Sc, Y, La, Gd, Yb) The vibrational spectra of the elpasolites Cs₂KMF₆ (M = Sc, Y, La, Gd, Yb) have been recorded and assigned including the lattice vibrations. The vibrational frequencies thus obtained were used for the calculation of XVFF force constants. The values of the stretching force constants are discussed.     

Synthesis and characterization of tin(IV)/organotin(IV) complexes with 2-benzoylpyridine-N(4)-cyclohexylthiosemicarbazone [HBPCT]: X-ray crystal structure of [SnCl3(BPCT)]

Four new tin(IV)/organotin(IV) complexes, [SnCl₃(BPCT)] (2), [MeSnCl₂(BPCT)] (3), [Me₂SnCl(BPCT)] (4), and [Ph₂SnCl(BPCT)] (5), have been synthesized by the direct reaction of 2-benzoylpyridine-N(4)-cyclohexylthiosemicarbazone [HBPCT, (1)] and stannic chloride/organotin(IV) chloride(s) in absolute methanol under purified nitrogen. HBPCT and its tin(IV)/organotin(IV) complexes (2–5) were characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, and ¹H NMR spectral studies. In all the complexes, tin(IV) was coordinated via pyridine-N, azomethine-N, and thiolato-S from 1. The molecular structure of 2 has been determined by X-ray single-crystal diffraction analysis. Complex 2 is a monomer and the central tin(IV) is six-coordinate in a distorted octahedral geometry. The crystal system of 2 is monoclinic with space group P121/n1 and the unit cell dimensions are a?=?8.3564(3)?Å, b?=?23.1321(8)?Å, c?=?11.9984(4)?Å.     

Zur Kenntnis der Zustandsdiagramme SECl3/MCl2 (SE = La,Sm, Gd,Yb; M = Sr,Ba)

On Phase Diagrams of Rare Earth Trichlorides/MCl₂ (Rare Earth = La, Sm, Gd, yb; M = Sr, Ba) The systems LaCl₃(SmCl₃, GdCl₃, YbCl₃)? SrCl₂(BaCl₂) were determined by difference thermal analysis. The phase diagrams contain compounds of the formula BaLnCl₅, M₂LnCl₇, Ba₃LnCl₉ and probably Sr₄LnCl₁₁, which decompose peritectoidally resp. peritectically. Sr₂SmCl₇ and Sr₂GdCl₇ are isotypic, and as indicated by the very similar reflection patterns of the Guinier photographs related to the structure of the compound Sm₃Cl₇. The phase diagrams are comparable to the systems LnCl₃? LnCl₂ with similar radii quotients of the cations. The enthalpies of mixing of the systems LaCl₃(GdCl₃, YbCl₃)? SrCl₂ were measured calorimetrically. The values are exothermic, the minima were found at approximately 65 mol-% SrCl₂.     

Homoleptic tetrahydrometalate anions MH(4)(-) (M = Sc,Y, La). Matrix infrared spectra and DFT calculations

Laser-ablated Sc, Y, and La atoms react with molecular hydrogen upon condensation in excess argon, neon, and deuterium to produce the metal dihydride molecules and dihydrogen complexes MH(2) and (H(2))MH(2). The homoleptic tetrahydrometalate anions ScH(4)(-), YH(4)(-), and LaH(4)(-) are formed by electron capture and identified by isotopic substitution (D(2), HD, and H(2) + D(2) mixtures). Doping with CCl(4) to serve as an electron trap virtually eliminates the anion bands, and further supports the anion identifications. The observed vibrational frequencies are in agreement with the results of density functional theory calculations, which predict electron affinities in the 2.8-2.4 eV range for the (H(2))ScH(2), (H(2))YH(2), and (H(2))LaH(2) complexes, and indicate high stability for the MH(4)(-) (M = Sc, La, Y) anions and suggest the promise of synthesis on a larger scale for use as reducing agents.     

Luminescence of Sb3+ in rare earth orthoborates LnBO3 (Ln = Sc,Y, La,Gd, Lu)

The luminescence of several Sb³⁺-activated rare earth orthoborates (LnBO₃Sb³⁺; Ln = Sc, Y, La, Gd, Lu) are reported. In all compositions the Stokes shift of the Sb³⁺ luminescence is rather large, resulting in rather low quenching temperatures (200 K or lower). The Stokes shift appears to be dependent on the coordination number and on the radius of the host lattice cation. This is explained from the assumed tendency of the Sb³⁺ ion to occupy an off-center position which becomes more apparent when the space available for the Sb³⁺ ion increases. The present results are compared with those on LnBO₃Bi³⁺. It appears that the Stokes shift of the Bi³⁺ luminescence is more sensitive to the host lattice and is smaller than the Stokes shift of the Sb³⁺ luminescence. This is explained by the large radius of the Bi³⁺ ion compared to the Sb³⁺ ion. In GdBO₃Sb³⁺ thermally activated energy transfer is observed from Gd³⁺ to Sb³⁺.     

Luminescence of iron(III): In zircon-structured phosphates MPQ4 (M = Sc,Lu, Y)

Luminescence and decay time measurements are presented for Fe³⁺ -doped ScPO₄, LuPO₄ and YPO₄. The Fe³⁺ ion gives a red luminescence. A consistent interpretation of the luminescence data is possible by assuming that the Fe³⁺ ion in ScPO₄ is surrounded by four oxygen ions within a relatively weak crystal field and in LuPO₄ and YPO₄ by eight oxygen ions within a relatively strong crystal field.     

Synthesis and characterization of imidocubanes with exocube Ge(IV) and Sn(IV) substituents: [M(mu3-NGeMe3)]4 (M = Sn, Ge, Pb); [Sn(mu3-NSnMe3)]4

The heteroleptic lithium amide, [(Me3Sn)(Me3Ge)NLi.(Et2O)]2 (2), reacts with MCl(2) (M = Sn, Ge, Pb) to yield the corresponding cubane complexes [M(mu3-NGeMe3)]4 [M = Sn (3), Ge (4), Pb (5)]. In an analogous reaction with SnCl2, the lithium stannylamide, [(Me3Sn)2NLi.(Et2O)]2 (1), produces the mixed-valent Sn congener [Sn(mu3-NSnMe3)]4 (6). All imidocubanes contain both di- and tetravalent group 14 metals that are bridged by N. These structures are comprised of M4N4 (M = Sn, Pb, Ge) cores that possess varying distortion from perfect cube geometry. The Pb derivative (5) exhibits enhanced volatility and vapor-phase integrity.     

Conformational Rigidity in Complexes [MCl(tBu2PH)3] (M = Rh,Ir)

Reactions of [{M(μ‐Cl)(coe)₂}₂] (M = Rh, Ir; coe = cis‐cyclooctene) with the secondary phosphane tBu₂PH under various molar ratios were investigated. Probably, for kinetic reasons, the reaction behavior of the rhodium species differed from that of the iridium analogue in some instances. During these studies complexes [MCl(tBu₂PH)₃] [M = Rh ( 1 ), Ir ( 2 )] were isolated, and solution variable‐temperature ³¹P{¹H} NMR studies revealed that these complexes show a conformational rigidity on the NMR time scale. Spectra recorded in the temperature range from 173 to 373 K indicated in each case only one rotamer containing three chemically nonequivalent phosphanes due to the restricted rotation of these ligands about the M–P bonds and the tert‐butyl substituents around the P–C(tBu) bonds, respectively. Compound 1 showed in solution already at room temperature in several solvents a dissociation of a phosphane ligand affording the known complex [{Rh(μ‐Cl)(tBu₂PH)₂}₂] beside the free phosphane. In contrast to these findings, the iridium analogue 2 remained completely unchanged under similar conditions and exhibited, therefore, some kinetic inertness. For a better understanding of the NMR spectroscopic investigations, the molecular structure of 1 in the solid state was confirmed by X‐ray crystallography.     

Electronic Structure and Redox Properties of Metal Nitride Endohedral Fullerenes M3N@C2n (M=Sc,Y, La,and Gd; 2n=80, 84, 88, 92, 96)

An extensive study of the redox properties of metal nitride endohedral fullerenes (MNEFs) based on DFT computational calculations has been performed. The electronic structure of the singly oxidized and reduced MNEFs has been thoroughly analyzed and the first anodic and cathodic potentials, as well as the electrochemical gaps, have been predicted for a large number of M₃N@C_2n systems (M=Sc, Y, La, and Gd; 2n=80, 84, 88, 92, and 96). In particular, calculations that include thermal and entropic effects correctly predict the different anodic behavior of the two isomers (I_h and D_5h) of Sc₃N@C₈₀, which is the basis for their electrochemical separation. Important differences were found in the electronic structure of reduced M₃N@C₈₀ when M=Sc or when M is a more electropositive metal, such as Y or Gd. Moreover, the changes in the electrochemical gaps within the Gd₃N@C_2n series (2n=80, 84, and 88) have been rationalized and the use of Y‐based computational models to study the Gd‐based systems has been justified. The redox properties of the largest MNEFs characterized so far, La₃N@C_2n (2n=92 and 96), were also correctly predicted. Finally, the quality of these predictions and their usefulness in distinguishing the carbon cages for MNEFs with unknown structures is discussed.     

Remarkable metal-rich ternary chalcogenides Sc14M3Te8 (M = Ru,Os)

In this novel motif, scandium atoms define infinite parallel chains of alternate trans-face-sharing cubes and pairs of square antiprisms in which each polyhedron is also centered by an M atom (M = Ru, Os). These chains are further linked into a three-dimensional structure by Sc(Te2Te4/2) octahedra. Physical property measurements show Sc14Ru3Te8 to be metallic and Pauli-paramagnetic, consistent with the results of extended Hückel band structure calculations. Matrix effects are evident in the dimensions within the chains. The major interactions are Sc-M and Sc-Te.     

Cation deficient layered Ruddlesden-Popper-related oxysulfides La2LnMS2O5 (Ln=La, Y; M=Nb, Ta)

The structures of the new oxysulfide Ruddlesden-Popper phases La2LnMS2O5 (Ln=La, Y; M=Nb, Ta) are reported together with an iodide-containing variant: La3-xNb1+xS2O5I2x (0相似文献   

Li(thf)3cyclo-(P4tBu4CH)]--synthesis, molecular structure and dynamic behaviour

[Li(thf)3cyclo-(P4tBu4CH)] (2-Li), containing the first tetraphosphacyclopentanide anion cyclo-(P4tBu4CH)- (2), was prepared, and its dynamic behaviour in solution analysed by variable-temperature 31P NMR spectroscopy.     

The crystal and molecular structure of cyclopentadienyltin(II) chloride. The bonding of the cyclopentadienyl group in tin(II) compounds

The crystal and molecular structure of cyclopentadienyltin(II) chloride has been determined from three-dimensional X-ray data. The crystals are orthorhombic, space group Pc2₁n. The unit cell, of dimensions a = 5.711(5), b = 6.225(5), c = 17.24(2) Å, contains four molecules. The structure has been refined by full matrix least squares techniques to a final R value of 0.083 for 717 independent reflections. In the crystal unsymmetrical tin-chlorine bridges are present between the units of C₅H₅SnCl.It is suggested that in cyclopentadienyltin(II) compounds the cyclopentadienyl group occupies more than one coordination site as a result of the donation of π electron density from the cyclopentadienyl ring into an empty acceptor orbital of the tin atom having π symmetry.     

Metal Nitride Cluster Fullerene M3N@C80 (M=Y,Sc) Based Dyads: Synthesis,and Electrochemical,Theoretical and Photophysical Studies

The first pyrrolidine and cyclopropane derivatives of the trimetallic nitride templated (TNT) endohedral metallofullerenes I_h‐Sc₃N@C₈₀ and I_h‐Y₃N@C₈₀ connected to an electron‐donor unit (i.e., tetrathiafulvalene, phthalocyanine or ferrocene) were successfully prepared by 1,3‐dipolar cycloaddition reactions of azomethine ylides and Bingel–Hirsch‐type reactions. Electrochemical studies confirmed the formation of the [6,6] regioisomers for the Y₃N@C₈₀‐based dyads and the [5,6] regioisomers in the case of Sc₃N@C₈₀‐based dyads. Similar to other TNT endohedral metallofullerene systems previously synthesized, irreversible reductive behavior was observed for the [6,6]‐Y₃N@C₈₀‐based dyads, whereas the [5,6]‐Sc₃N@C₈₀‐based dyads exhibited reversible reductive electrochemistry. Density functional calculations were also carried out on these dyads confirming the importance of these structures as electron transfer model systems. Furthermore, photophysical investigations on a ferrocenyl–Sc₃N@C₈₀‐fulleropyrrolidine dyad demonstrated the existence of a photoinduced electron‐transfer process that yields a radical ion pair with a lifetime three times longer than that obtained for the analogous C₆₀ dyad.     

The crystal and molecular structure of trimethyltin(IV) chloride, a chlorine-bridged, linear polymer

The crystal and molecular structure of trimethyltin(IV) chloride has been determined by the heavy-atom technique, and refined to a final R value of 0.041 for 1375 independent reflections (2θ < 53°; Mo-K_a radiation I > 2σ(I)) recorded at 138 ± 2 K on a Nonius CAD-4 counter diffractometer. The crystals are monoclinic with space group I2/c; a 12.541(8), b 9.618(11), c 11.015(11) Å, β 92.62(7)°, Z = 8, D_calcd 1.994 g cm⁻³. The needle crystals are composed of polymeric chains of chlorine atoms bridging non-planar trimethyltin(IV) units at unequal (2.430(2) and 3.269(2) Å) distances. The zig-zag chains are bent at chlorine (angle Sn---Cl Sn 150.30(9)°), but nearly linear at tin (angle Cl---Sn Cl 176.85(6)°) to describe a distorted trigonal bipyramidal geometry at tin with the trimethyltin groups eclipsed. The interchain d(Sn Cl) distances are greater than 4.1 Å. The angles carbon—tin—carbon (mean 117.1(3)°) are larger than tetrahedral, while the angles carbon—tin—chlorine (mean 99.9(2) Å) are smaller, in accord with isovalent hybridization principles, but more severely distorted than in the gas-phase, monomeric structure. The tin—chlorine distance of 2.430(2) Å is also longer than in the gas phase monomer, and the intermolecular contact of 3.269 Å is shorter than in other organotin chloride bridged systems (sum of Van der Waals radii 3.85 Å).