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1.
The reaction of o-C6H4(AsMe2)2 with VCl4 in anhydrous CCl4 produces orange eight-coordinate [VCl4{o-C6H4(AsMe2)2}2], whilst in CH2Cl2 the product is the brown, six-coordinate [VCl4{o-C6H4(AsMe2)2}]. In dilute CH2Cl2 solution slow decomposition occurs to form the VIII complex [V2Cl6{o-C6H4(AsMe2)2}2]. Six-coordination is also found in [VCl4{MeC(CH2AsMe2)3}] and [VCl4{Et3As)2]. Hydrolysis of these complexes occurs readily to form vanadyl (VO2+) species, pure samples of which are obtained by reaction of [VOCl2(thf)2(H2O)] with the arsines to form green [VOCl2{o-C6H4(AsMe2)2}], [VOCl2{MeC(CH2AsMe2)3}(H2O)] and [VOCl2(Et3As)2]. Green [VOCl2(o-C6H4(PMe2)2}] is formed from [VOCl2(thf)2(H2O)] and the ligand. The [VOCl2{o-C6H4(PMe2)2}] decomposes in thf solution open to air to form the diphosphine dioxide complex [VO{o-C6H4(P(O)Me2)2}2(H2O)]Cl2, but in contrast, the products formed from similar treatment of [VCl4{o-C6H4(AsMe2)2}x] or [VOCl2{o-C6H4(AsMe2)2}] contain the novel arsenic(V) cation [o-C6H4(AsMe2Cl)(μ-O)(AsMe2)]+. X-ray crystal structures are reported for [V2Cl6{o-C6H4(AsMe2)2}2], [VO(H2O){o-C6H4(P(O)Me2)2}2]Cl2, [o-C6H4(AsMe2Cl)(μ-O)(AsMe2)]Cl·[VO(H2O)3Cl2] and powder neutron diffraction data for [VCl4{o-C6H4(AsMe2)2}2].  相似文献   

2.
Abstract

The reactions of hexachlorocyclotriphosphazene, N3P3Cl6 (1), with 2,2-dimethylpropane-1,3-diol (2), and bis(2-hydroxyethyl) ether (3) have been previously reported. Although both reactions gave the expected spiro, ansa, and bridged type products, open-chain and triply bridged derivatives from both systems and singly bridged derivatives from 2,2-dimethylpropane-1,3-diol (2) were not isolated, and doubly bridged compounds were only detected in trace amounts in both systems. However, in a subsequent reinvestigation in tetrahydrofuran (THF) solution, the reaction of 1 with the diols 2 and 3 gave the open chain compounds N3P3Cl5[O(CH2)2CMe2OH] (4) and N3P3Cl5[(OCH2CH2)2OH] (5), the singly bridged compound N3P3Cl5[(OCH2)2-CMe2]N3P3Cl5 (6), the doubly bridged compounds N3P3Cl4[(OCH2)2CMe2]2N3P3Cl4 (8) and N3P3Cl4[(OCH2CH2)2O]2N3P3Cl4 (9), and the triply bridged compounds N3P3Cl3[(OCH2)2-CMe2]3N3P3Cl3 (10) and N3P3Cl3[(OCH2CH2)2O]3N3P3Cl3 (11).

The doubly bridged derivatives were also isolated in better yields relative to earlier reports. The substituted cyclotriphosphazenes have been characterized by elemental analysis, mass spectrometry, as well as by 1H, 31P, and 13C NMR spectroscopy. It is found that with variation of the solvent there is a decrease in the product formed by intramolecular reactions (spiro and ansa derivatives) and a concomitant increase in the amount of products formed by intermolecular reactions (singly, doubly, and triply bridged derivatives) of cyclophosphazene.  相似文献   

3.
Reaction of Tin Chlorides with Polysulfides. Crystal Structures of (PPh4)2[SnCl2(S6)2], (PPh4)2[Sn4Cl4S5(S3)O], and (PPh4)2[SnCl6] · S8 · 2CH3CN . The reaction of PPh4[SnCl3] with Na2S4 in acetonitrile in the presence of small amounts of water yields (PPh4)2[Sn4Cl4S5(S3)O] and minor amounts of (PPh4)2[SnCl2(S6)2], PPh4Cl · 2S8 and (PPh4)2[SnCl6]. SnCl4 is partially reduced by (PPh4)2Sx, PPh4[SnCl3] and (PPh4)2[SnCl6] · S8 · 2CH3CN being produced. According to the X-ray crystal structure determination the [Sn4Cl4S5(S3)O]2?-ion consists of an O atom that is coordinated by four Sn atoms which in turn are liked with one another by five single S atoms and one S3 group. In the [SnCl2(S6)2]2?-ion the Sn atom is octahedrally coordinated by two Cl atoms in trans arrangement and by two chelating S6 groups. Octahedral [SnCl6]2? ions and S8 molecules in the crown conformation are present in (PPh4)4[SnCl6] · S8 · 2CH3CN.  相似文献   

4.
Phosphoraneiminato Complexes of Vanadium. The Crystal Structure of [V3Cl6(NPMe3)5+]2[V4O4Cl8(NPMe3)22?] · 6 CH3CN Vanadiumtetrachloride reacts in CCl4 solution with Me3SiNPMe3 to form the donor acceptor complex [VCl4(Me3SiNPMe3)], which reacts with excess Me3SiNPMe3 in boiling acetonitrile to form the phosphoraneiminato complex [V3Cl6(NPMe3)5]+Cl?. Partial hydrolysis in acetonitrile solution leads to black single crystals of [V3Cl6(NPMe3)5+]2[V4O4Cl8(NPMe3)22?] · 6 CH3CN, which are characterized by a crystal structure determination. Space group P21/c, Z = 2, structure solution with 3 008 observed unique reflections, R = 0.090. Lattice dimensions at ?70°C: a = 1 379.0, b = 1 915.8, c = 2 278 pm, β = 102,79°. In the complex cation the three vanadium atoms form a trigonal bipyramid with two μ3-NPMe3 groups; the residual NPMe3? groups and the chlorine atoms are in terminal functions. In the anion [V4O4Cl8(NPMe3)2]2? the vanadium atoms are linked by μ2-O atoms to form a rectangle; in addition the two phosphoraneiminato ligands form μ2-N bridges.  相似文献   

5.
Reaction of phosphorus trichloride with tert-butanol and fluoroalcohols gave bis(fluoroalkyl) phosphites (RFO)2P(O)H in 42-89% yield, where RF=HCF2CH2, H(CF2)2CH2, H(CF2)4CH2, CF3CH2, C2F5CH2, C3F7CH2, (CF3)2CH, (FCH2)2CH, CF3(CH3)2C, (CF3)2CH3C, CF3CH2CH2, C4F9CH2CH2 and C6F13CH2CH2. Treatment of these with chlorine in dichloromethane gave the bis(fluoroalkyl) phosphorochloridates (RFO)2P(O)Cl in 49-96% yield. The chloridate (CF3CH2O)2P(O)Cl was isolated in much lower yield from the interaction of thionyl chloride with bis(trifluoroethyl) phosphite. Heating the latter in dichloromethane with potassium fluoride and a catalytic amount of trifluoroacetic acid gave the corresponding fluoridate (CF3CH2O)2P(O)F in 84% yield. Treatment of bis(trifluoroethyl) phosphite with bromine or iodine gave the bromidate (CF3CH2O)2P(O)Br and iodidate (CF3CH2O)2P(O)I in 51 and 46% yield, respectively. The iodidate is the first dialkyl phosphoroiodidate to have been isolated and characterised properly—its discovery lags behind the first isolation of a dialkyl phosphorochloridate by over 130 years. The fluoroalkyl phosphoryl compounds are generally more stable than known unfluorinated counterparts.  相似文献   

6.
Reaction of [M(NH3)6]Cl3 (M = Co, Rh, Ir) and [Ir(NH3)5(OH2)]Cl3 with (NH4)2C2O4 · H2O in aqueous solution resulted in the isolation of [M(NH3)6]2(C2O4)3 · 4 H2O and [Ir(NH3)5(OH2)]2(C2O4)3 · 4 H2O, respectively. The complexes have been characterized by X‐ray crystallography, IR and UV/VIS spectroscopy. The isomorphous compounds crystallize in the orthorhombic space group Pnnm (No. 58). Four molecules of crystal water are involved in an extended three‐dimensional hydrogen bonding network. The librational modes of the lattice water around 600 cm–1 allow the characterization of [Ir(NH3)6]2(C2O4)3 · 4 H2O and [Ir(NH3)5(OH2)]2(C2O4)3 · 4 H2O, respectively, by IR spectroscopy. The band around 600 cm–1 shows a significant frequency shift in the IR spectra of the hexaammine and aquapentaammine complex of iridium(III) and, by that, a distinction is possible.  相似文献   

7.
Summary The paper presents data on the solubility of La, Ce, Pr, Nd sulfates in the polycomponent system La2(SO4)3·8H2O-Ce2(SO4)3·8H2O-Pr2(SO4)3·8H2O-Nd2(SO4)3· 8H2O-H2SO4-H2O (at 25°C and 64°C) as well as in the same polycomponent system but in the presence of CaSO4·2H2O. The solubility of the sulfates — ocathydrates of Pr at 25°C and 64°C and of La and Ce at 64°C in tricomponent systemLn 2(SO4)3·8H2O-H2SO4-H2O are also reported.
Löslichkeit einiger Lanthanidsulfate in Mehrkomponenten-Systemen mit H2SO4
Zusammenfassung Die Arbeit präsentiert Daten für die Löslichkeit von La-, Ce-, Pr- und Nd-Sulfaten in den Vielkomponenten-Systemen La2(SO4)3·8H2O-Ce2(SO4)3·8H2O-Pr2(SO4)3·8H2O-Nd2(SO4)3· 8H2O-H2SO4-H2O (bei 25°C und 64°C) sowie in den gleichen Systemen, jedoch in Anwesenheit von CaSO4·2H2O. Über die Löslichkeit von Sulfatoctahydraten von Pr bei 25°C und 64°C und von La und Ce bei 64°C in den Dreikomponenten-SystemenLn 2(SO4)3·8H2O-H2SO4-H2O wird auch berichtet.
  相似文献   

8.
Eu3+-doped Ca2SnO4 (solid solutions of Ca2−xEu2xSn1−xO4, 0?x?0.3) and Eu3+ and Y3+-codoped Ca2SnO4 (Ca1.8Y0.2Eu0.2Sn0.8O4) were prepared by solid-state reaction at 1400 °C in air. Rietveld analysis of the X-ray powder diffraction patterns revealed that Eu3+ replaced Ca2+ and Sn4+ in Eu3+-doped Ca2SnO4, and that Eu3+ replaced Ca2+ and Y3+ replaced Sn4+ in Ca1.8Y0.2Eu0.2Sn0.8O4. Red luminescence at 616 nm due to the electric dipole transition 5Do→7F2 was observed in the photoluminescence (PL) spectra of Ca2−xEu2xSn1−xO4 and Ca1.8Y0.2Eu0.2Sn0.8O4 at room temperature. The maximum PL intensity in the solid solutions of Ca2−xEu2xSn1−xO4 was obtained for x=0.1. The PL intensity of Ca1.8Y0.2Eu0.2Sn0.8O4 was 1.26 times greater than that of Ca2−xEu2xSn1−xO4 with x=0.1.  相似文献   

9.
Abstract

The reaction of [MoCl(GeCl3)(CO)3(NCMe)2] with an equimolar quantity of L?L {L?L = 2,2′-bipy, 1,10-phen, Ph2P(CH2)nPPh2 (n = 1 or 2)} in CH2Cl2 at room temperature gave either [MoCl(GeCl3)(CO)3(L?L)] (L?L = 2,2′-bipy or 1,10-phen) (1 and 2) or [MoCl(GeCl3)(CO)2 (NCMe)(L?L)]{L?L = Ph2P(CH2)nPPh2 (n = 1 or 2) (3 or 4), respectively. Equimolar quantities of [MoCl(GeCl3)(CO)2(NCMe){Ph2P(CH2)PPh2}] (3) and L?L {L?L = 2,2′-bipy or Ph2P(CH)2PPh2} react in CH2Cl2 at room temperature to afford the cationic complexes [Mo(GeCl3)(CO)2{Ph2P(CH2) PPh2}(L?L)]Cl (5 and 6) in good yield. The cationic nature of 6 was established by chloride exchange by reacting Na[BPh4] with 6 in acetonitrile to give the tetraphenylborate complex [Mo(GeCl3)(CO)2{Ph2P(CH2)PPh2}2][BPh4] (7). Reaction of equimolar quantities of [MoCl(GeCl3) (CO)3(NCMe)2] and PhP(CH2CH2PPh2)2 in CH2Cl2 at room temperature afforded the dicarbonyl complex [MoCl(GeCl3)(CO)2{PhP(CH2CH2PPh2)2}] (8) in good yield.  相似文献   

10.
Cyclic Polyselenidoarsenates(III) and Polyselenidoantimonates(III): PPh4[Se5AsSe], PPh4[AsSe6–xS x ], (PPh4)2[As2Se6] · 2 CH3CN, and (PPh4)2[Se6SbSe]2 In acetonitrile, AsCl3 and sodiumphenolate formed Cl2AsOPh which then was reacted with PPh4Se5 and finally with Na2Se to yield PPh4[Se5AsSe]. With Na2S instead of Na2Se, PPh4[AsSe6–xSx] was obtained; the sulfur contents increased with increasing reaction temperature and time (x = 0.21 to 1.09). With PPh4Se2 instead of PPh4Se5, (PPh4)2[1,4-As2Se6] · 2 CH3CN and PPh4[Se5AsSe] were the products. With SbCl3 instead of AsCl3, (PPh4)2[Se6SbSe]2 formed. PPh4[Se5AsSe] can also be produced from As2Se3, PPh4Br, Na2Se and selenium in acetonitrile. The crystal structure of PPh4[SeAsSe5] is isotypic with PPh4[S5AsS] (X-ray structure analysis with 2414 observed reflexions, R = 0.038). The Se5AsSe– ion consists of a six-membered AsSe5 ring in chair conformation, and the As atom has an additional terminal Se atom. The compounds PPh4[AsSe6–xSx] have the same crystal structures, with sulfur atoms taking all selenium positions at random, but with a preference for the terminal position. The anion in (PPh4)2[As2Se6] · 2 CH3CN also has a six-membered ring structure in chair conformation, with two arsenic atoms in positions 1 and 4. The centrosymmetric anion in (PPh4)2[Se6SbSe]2 consists of a central Sb2Se2 ring, and a Se6 ligand is bonded in a chelating manner to each Sb atom (X-ray structure analysis with 2669 observed reflexions, R = 0.099). 77Se-NMR spectra are reported.  相似文献   

11.
(NEt4)2[WIVO(S2C2(CN)2)2] (1), isolated by reaction of Na2 WO4, Na2S2C2(CN)2 (Na2mnt) in acidified (pH5.5) aqueous medium in the presence of excess of sodium dithionite and NEt4Br, reduces CO2/HCO 3 − (pH 7.5) to yield HCOO− and (NEt4)2[WVIO2(S2C2(CN)2)2] (2) mimicking tungsten-formate dehydrogenase (W-FDH) activity. (1) reacts with Na2MoO4 in acidic medium to produce [MoIvO(S2C2(CN)2)2]2− implicating the displacement of tungsten by molybdenum from the cofactor complex in W-FDH.  相似文献   

12.
The synthesis and structural characterization of the first coordination compounds of bis(diphosphacyclobutadiene) cobaltate anions [M(P2C2R2)2]? is described. Reactions of the new potassium salts [K(thf)3{Co(η4‐P2C2tPent2)2}] ( 1 ) and [K(thf)4{Co(η4‐P2C2Ad2)2}] ( 2 ) with [AuCl(tht)] (tht=tetrahydrothiophene), [AuCl(PPh3)] and Ag[SbF6] afforded the complexes [Au{Co(P2C2tPent2)2}(PMe3)2] ( 3 ), [Au{Co(P2C2Ad2)2}]x ( 4 ), [Ag{Co(P2C2Ad2)2}]x ( 5 ), [Au(PMe3)4][Au{Co(P2C2Ad2)2}2] ( 6 ), [K([18]crown‐6)(thf)2][Au{Co(P2C2Ad2)2}2] ( 7 ), and [K([18]crown‐6)(thf)2][M{Co(P2C2Ad2)2}2] ( 8 : M=Au 9 : M=Ag) in moderate yields. The molecular structures of 2 and 3 , and 6 – 9 were elucidated by X‐ray crystallography. Complexes 4 – 9 were thoroughly characterized by 31P and 13C solid state NMR spectroscopy. The complexes [Au{Co(P2C2Ad2)2}]x ( 4 ) and [Ag{Co(P2C2Ad2)2}]x ( 5 ) exist as coordination polymers in the solid state. The linking mode between the monomeric units in the polymers is deduced. The soluble complexes 1 – 3 , 6 , and 7 were studied by multinuclear 1H‐, 31P{1H}‐, and 13C{1H} NMR spectroscopy in solution. Variable temperature NMR measurements of 3 and 6 in deuterated THF reveal the formation of equilibria between the ionic species [Au(PMe3)4]+, [Au(PMe3)2]+, [Co(P2C2R2)2]?, and [Au{Co(P2C2R2)2}2]? (R=tPent and Ad).  相似文献   

13.
Polynuclear Pd(II) and Ni(II) complexes of macrocyclic polyamine 3,6,9,16,19,22‐hexaazatricyclo[22.2.2.211,14]‐triaconta 11,13,24,26(l),27,29‐hexaene (L) in solution were investigated by electrospray ionization mass spectrometry (ESIMS). For methanol solution of complexes M2LX4 (M = Pd(II) and Ni(II), X= Cl and I), two main clusters of peaks were observed which can be assigned to [M2LX3]+ and [M2LX2]2+. When Pd2LCl4 was treated with 2 or 4 mol of AgNO3, it gave rise formation of Pd2LCl2 (NO3)2 · H2O and [Pd2L(H2O)m(NO3)n](4‐n)+, respectively. ESMS spectra show that the dissociation of the former in the ionization process gave peaks of [Pd2LCl2]2+ and [(Pd2LCl2)NO3]+, while dissociation of the later gave the peaks of [Pd2L(CH3CO2)2]2+ and [Pd2L(CH3CO2)2](NO3) + in the presence of acetic acid. Similar species were observed for Pd2LI4 when treated with 4 mol of AgNO3. When [Pd2L · (H2O)m(NO3)n](4‐n)+ reacted with 2 mol of oxalate anions at 40°C, [Pd4L2(C2O4)2(NO3)2]2+ and [Pd4L2(C2O4)2 (NO3)]3+ were detected. This implies the formation of square‐planar molecular box Pd4L2(C2O4)2(NO3)4 in which C2O4? may act as bridging ligands as confirmed by crystal structure analysis. The dissociation form and the stability of complex cations in gaseous state are also discussed. This work provides an excellent example of the usefulness of ESIMS in the identification of metal complexes in solution.  相似文献   

14.
The reactions of the fluoride-ion donor, XeF6, with the fluoride-ion acceptors, M′OF4 (M′=Cr, Mo, W), yield [XeF5]+ and [Xe2F11]+ salts of [M′OF5]− and [M2O2F9]− (M=Mo, W). Xenon hexafluoride and MOF4 react in anhydrous hydrogen fluoride (aHF) to give equilibrium mixtures of [Xe2F11]+, [XeF5]+, [(HF)nF]−, [MOF5]−, and [M2O2F9]− from which the title salts were crystallized. The [XeF5][CrOF5] and [Xe2F11][CrOF5] salts could not be formed from mixtures of CrOF4 and XeF6 in aHF at low temperature (LT) owing to the low fluoride-ion affinity of CrOF4, but yielded [XeF5][HF2]⋅CrOF4 instead. In contrast, MoOF4 and WOF4 are sufficiently Lewis acidic to abstract F− ion from [(HF)nF]− in aHF to give the [MOF5]− and [M2O2F9]− salts of [XeF5]+ and [Xe2F11]+. To circumvent [(HF)nF]− formation, [Xe2F11][CrOF5] was synthesized at LT in CF2ClCF2Cl solvent. The salts were characterized by LT Raman spectroscopy and LT single-crystal X-ray diffraction, which provided the first X-ray crystal structure of the [CrOF5]− anion and high-precision geometric parameters for [MOF5]− and [M2O2F9]−. Hydrolysis of [Xe2F11][WOF5] by water contaminant in HF solvent yielded [XeF5][WOF5]⋅XeOF4. Quantum-chemical calculations were carried out for M′OF4, [M′OF5]−, [M′2O2F9]−, {[Xe2F11][CrOF5]}2, [Xe2F11][MOF5], and {[XeF5][M2O2F9]}2 to obtain their gas-phase geometries and vibrational frequencies to aid in their vibrational mode assignments and to assess chemical bonding.  相似文献   

15.
The acid–base reaction between Y(CH2SiMe3)3(thf)2 and the pyridyl‐functionalized cyclopentadienyl (Cp) ligand C5Me4H? C5H4N (1 equiv) at 0 °C afforded a mixture of two products: (η5:κ‐C5Me4? C5H4N)Y(CH2SiMe3)2(thf) ( 1 a ) and (η5:κ‐C5Me4? C5H4N)2YCH2SiMe3 ( 1 b ), in a 5:2 ratio. Addition of the same ligand (2 equiv) to Y(CH2SiMe3)3(thf)2, however, generated 1 b together with the novel complex 1 c , the first well defined yttrium mono(alkyl) complex (η5:κ‐C5Me4? C5H4N)[C5HMe3(η3‐CH2)‐C5H4N‐κ]Y(CH2SiMe3) containing a rare κ/η3‐allylic coordination mode in which the C? H bond activation occurs unexpectedly with the allylic methyl group rather than conventionally on Cp ring. If the central metal was changed to lutetium, the equimolar reaction between Lu(CH2SiMe3)3(thf)2 and C5Me4H? C5H4N exclusively afforded the bis(alkyl) product (η5:κ‐C5Me4? C5H4N)Lu(CH2SiMe3)2(thf) ( 2 a ). Similarly, the reaction between the ligand (2 equiv) and Lu(CH2SiMe3)3(thf)2 gave the mono(alkyl) complex (η5:κ‐C5Me4? C5H4N)2LuCH2SiMe3 ( 2 b ), in which no ligand redistribution was observed. Strikingly, treatment of Sc(CH2SiMe3)3(thf)2 with C5Me4H? C5H4N in either 1:1 or 1:2 ratio at 0 °C generated the first cyclopentadienide‐based scandium zwitterionic “tuck‐over” complex 3 , (η5:κ‐C5Me4? C5H4N)Sc(thf)[μ‐η5:η1:κ‐C5Me3(CH2)‐C5H4N]Sc(CH2SiMe3)3. In the zwitterion, the dianionic ligand [C5Me3(CH2)‐C5H4N]2? binds both to Sc13+ and to Sc23+, in η5 and η1/κ modes. In addition, the reaction chemistry, the molecular structures, and the mechanism are also discussed in detail.  相似文献   

16.
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 C2v 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.  相似文献   

17.
A cobalt-poor or iron rich bicomponent mixture of Co0.9Fe2.1O4/Fe2O3 and Co0.8Fe2.2O4/Fe2O3 anode materials have been successfully prepared using simple, cost-effective, and scalable urea-assisted auto-combustion synthesis. The threshold limit of lower cobalt stoichiometry in CoFe2O4 that leads to impressive electrochemical performance was identified. The electrochemical performance shows that the Co0.9Fe2.1O4/Fe2O3 electrode exhibits high capacity and rate capability in comparison to a Co0.8Fe2.2O4/Fe2O3 electrode, and the obtained data is comparable with that reported for cobalt-rich CoFe2O4. The better rate performance of the Co0.9Fe2.1O4/Fe2O3 electrode is ascribed to its unique stoichiometry, which intimately prefers the combination of Fe2O3 with Co1−xFe2+xO4 and the high electrical conductivity. Further, the high reversible capacity in Co0.9Fe2.1O4/Fe2O3 and Co0.8Fe2.2O4/Fe2O3 electrodes is most likely attributed to the synergistic electrochemical activity of both the nanostructured materials (Co1−xFe2+xO4 and Fe2O3), reaching beyond the well-established mechanisms of charge storage in these two phases.  相似文献   

18.
closo-Undecaborates were synthesized by the deprotonation of B11H13(SMe2) with LitBu in thp or K[BHEt3] in thf, [Li(thp)3]2[B11H11] and K2[B11H11] being obtained in 83 and 93% yield, respectively. K2[B11H11] can be transformed into A2[B11H11] with the corresponding ammonium chlorides in aqueous solution (A = [NMe3Ph], [NBzlEt3], [N(PPh3)2]). The crystal structure analysis of [Li(thp)3]2[B11H11] (space group P21/c) reveals a rather distorted octadecahedron for the [B11H11]2– anion, whereas the corresponding octadecahedron in [NBzlEt3]2[B11H11] (space group P212121) exhibits a structure close to C2v symmetry, expected for the free anion. The protonation of [B11H11]2– at low temperature gives [B11H12]–, whose structure could be elucidated by NMR methods; it is formed, apparently, by the opening of the B1–B4 edge of [B11H11]2– in the course of its known degenerate skeletal rearrangement, followed by the protonation of the B2–B4 edge. The reaction of [B11H12]– with a second molecule of the acid HX (X = CF3COO) gives nido-[B11H13X]–. The addition of BH3 to [B11H11]2– yields closo-[B12H12]2– under loss of H2. Two [B11H11]2– units are fused by the aid of FeCl3, with the known anion [B22H22]2– as the product, whose 11B-NMR signals could completely be assigned on the basis of Cs symmetry. The compound [NBzlEt3][N(PPh3)2][B22H22] crystallizes in the space group Pna21.  相似文献   

19.
Trimerization of Dicyanamide Ions C2N3– in the Solid – Syntheses, Crystal Structures, and Properties of NaCs2(C2N3)3 und Na3C6N9 · 3 H2O The Tricyanomelaminate Na3C6N9 · 3 H2O is obtained by heating NaC2N3 to 500 °C and subsequent crystallization from water. According to the single-crystal structure determination (Na3C6N9 · 3 H2O: P62c; a = 1023.53(8), c = 650.85(15) pm, Z = 2, R1 = 0.0276, wR2 = 0.0710) in the solid cyclic C6N93– ions occur. Partial ion exchange and crystallization from water yields anhydrous NaCs2(C2N3)3. The X-ray structure determination (NaCs2(C2N3)3: P63/m, a = 700.01(4), c = 1449.29(7) pm, Z = 2, R1 = 0.0173, wR2 = 0.0432) reveals C2N3– ions in the solid. Calorimetric investigations and detailed IR spectroscopy of NaC2N3, Na3C6N9, Na3C6N9 · 3 H2O, as well as NaCs2(C2N3)3 reveal in combination with the structure analyses that NaC2N3 transforms to Na3C6N9 above 380 °C by trimerization of the C2N3– ions in the solid. Above 180 °C the hydrate Na3C6N9 · 3 H2O reversibly dehydrates.  相似文献   

20.
Molybdenum(VI) and tungsten(VI) dioxodiazide, MO2(N3)2 (M=Mo, W), were prepared through fluoride–azide exchange reactions between MO2F2 and Me3SiN3 in SO2 solution. In acetonitrile solution, the fluoride–azide exchange resulted in the isolation of the adducts MO2(N3)2⋅2 CH3CN. The subsequent reaction of MO2(N3)2 with 2,2′‐bipyridine (bipy) gave the bipyridine adducts (bipy)MO2(N3)2. The hydrolysis of (bipy)MoO2(N3)2 resulted in the formation and isolation of [(bipy)MoO2N3]2O. The tetraazido anions [MO2(N3)4]2− were obtained by the reaction of MO2(N3)2 with two equivalents of ionic azide. Most molybdenum(VI) and tungsten(VI) dioxoazides were fully characterized by their vibrational spectra, impact, friction, and thermal sensitivity data and, in the case of (bipy)MoO2(N3)2, (bipy)WO2(N3)2, [PPh4]2[MoO2(N3)4], [PPh4]2[WO2(N3)4], and [(bipy)MoO2N3]2O by their X‐ray crystal structures.  相似文献   

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