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1.
Electronic Structures of Organometallic Compounds of f Elements. 64 Does the Zwitterionic Nature of the Triphenylphosphine Oxide Ligand Manifest itself in its Spectrochemical Properties? The triphenylphosphine oxide mono adducts of the moiety tris(η5‐cyclopentadienyl)lanthanide(III) (Ln(Cp)3; Ln = Pr ( 1 ), La ( 2 )) were synthesized and structurally characterized. The Ln–O distances of these compounds are noticeably shorter than those of the corresponding THF adducts. A crystal field (CF) analysis of the optical spectra of 1 leads to a low absolute value of the quadratic CF parameter which is comparable with those of [Pr(Cp)3(L)]? adducts with anionic bases but not with [Pr(Cp)3(MeTHF)]. Reasons for the latter finding are presented.  相似文献   

2.
Electronic Structures of Highly Symmetrical Compounds of f Elements. 37 [1] Spectroscopic and Structural Characterization of Tris(2, 6‐di‐t‐butyl‐phenolato)lanthanide(III) (Ln(OAr′)3; Ln = Pr, Nd), and Parametric Analysis of the Crystal Field Splitting Pattern of Nd(OAr′)3 Pr(OAr′)3 and Nd(OAr′)3 crystallize (at approximately 150 K and 200 K, respectively) in the monoclinic space group P21 with four molecules in the unit cell. If one considers only the directly coordinating oxygen atoms, the effective crystal field is of C3v symmetry. The signals in the optical spectra of Pr(OAr′)3 are broad using either solutions or solids, even at ca. 80‐90 K, thus they are not suitable for interpretation purposes. Nd(OAr′)3, however, exhibits sharp absorption bands at room and low temperatures, which are assigned in analogy to the previously identified absorption transitions of Nd[N(SiMe3)2]3 based on optical polarization measurements. The thus derived crystal field splitting pattern is simulated by fitting the free parameters of a phenomenological Hamiltonian, achieving a reduced r.m.s. deviation of 26.4 cm—1 for 64 assignments. The parameters used allow the estimation of the ligand field strength associated with the (OAr′) ligand, the insertion of this ligand into empirical nephelauxetic and relativistic nephelauxetic series, and the setup of experimentally‐based non‐relativistic and relativistic molecular orbital schemes in the f range.  相似文献   

3.
Electronic Structures of Organometallic Complexes of f Elements. 68 Absorption and First Luminescence and Raman Spectroscopic Polarization Measurements of an Oriented Organometallic Single Crystal: Pr(C5Me4H)3 Optical polarization measurements of oriented single crystals of Pr(C5Me4H)3 ( 1 ) were performed at room temperature. In order to separate “cold” and “hot” f‐f‐transitions and νC–H combination vibrations, the absorption spectra of KBr pellets of compound 1 and La(C5Me4H)3 ( 2 ) were additionally recorded at ca. 77 K. To gather additional information about the wavefunctions of the crystal field (CF) states of complex 1 , a magnetic circular dichroism spectrum of 1 was recorded too. From the spectra obtained, a partial CF splitting pattern of 1 was derived, and simulated by fitting the free parameters of a phenomenological Hamiltonian, leading to a reduced r.m.s. deviation of 24.8 cm−1 for 24 assignments. On the basis of these phenomenological CF parameters, the global CF strength experienced by the Pr3+ central ion was estimated, and seems to be the largest one ever encountered in PrIII chemistry. The obtained Slater parameter F2 and the spin‐orbit coupling parameter ζ4f allow the insertion of compound 1 into empirical nephelauxetic and relativistic nephelauxetic series, respectively, of PrIII compounds. With its low F2 value, complex 1 is the most covalent PrIII compound (considering only f electrons) found to date. The experimentally‐based non‐relativistic molecular orbital scheme (in the f range) of complex 1 was determined and compared with the results of a previous Xα‐SW calculation on the ψ trigonal planar model compound Pr(η5‐C5H5)3. In the framework of the search for “polarized” luminescence transitions, polarized Raman spectra of 1 were recorded too, and compared to the corresponding FIR and IR spectra run by means of pellets.  相似文献   

4.
Electronic Structures of Highly Symmetrical Compounds of f Elements. 38 [1] Crystal, Molecular and Electronic Structure of Tris(hydrotris(1‐pyrazolyl)borato)samarium(III) Tris(hydrotris(1‐pyrazolyl)borato)samarium(III) (SmTp3) crystallizes in the space group P63/m (No. 176) with two molecules in the unit cell. The Sm3+ central ion is coordinated by nine N atoms in the shape of a tricapped trigonal prism, leading to an effective crystal field (CF) of D3h symmetry. The underlying CF splitting pattern was extracted from the absorption and luminescence spectra run at room and low temperatures, and simulated by fitting the free parameters of a phenomenological Hamiltonian achieving an r.m.s. deviation of 9.4 cm?1 for 58 assignments. The parameters used allow the estimation of the global ligand field strength experienced by the Sm3+ central ion, the insertion of SmTp3 into empirical nephelauxetic and relativistic nephelauxetic series, and the set‐up of experimentally based nonrelativistic and relativistic molecular orbital schemes in the f range.  相似文献   

5.
Synthesis of Dimethoxyethane and Tetrahydrofuran Complexes of Rare‐Earth Nitrates – Solid State Structure of Pr(NO3)3(thf)4 The solvated rare‐earth nitrates Ln(NO3)3(thf)n (Ln = Pr, n = 4 ( 1 ); Ln = Ho ( 2 ), Yb ( 3 ), n = 3 and Ln(NO3)3(dme)2; Ln = Pr ( 4 ), Ho ( 5 )) were obtained from Ln(NO3)3(H2O)x and HC(OCH3)3. Pale green thermally labile crystals of 1 were characterized by X‐ray crystallography. The praseodymium atoms in two independent monomeric molecules show capped trigonal prismatic and pentagonal bipyramidal coordination, respectively.  相似文献   

6.
Preparation and Crystal Structures of New Complex Clorides of Lanthanides containing 3, 5‐Dimethylpyridinium Cations: (3, 5‐Dimethylpyridinium)2[LnCl4(H2O)2]Cl (Ln = La, Pr) and (3, 5‐Dimethylpyridinium)3[TbCl6] Crystals of the complex chlorides (3, 5‐dimethylpyridinium)2[LaCl4(H2O)2]Cl ( 1 ), (3, 5‐dimethylpyridinium)2[PrCl4(H2O)2]Cl ( 2 ) and (3, 5‐dimethylpyridinium)3[TbCl6] ( 3 ) have been prepared by reaction of LnCl3 · x H2O (Ln = La, Pr, Tb; x = 6‐7) with 3, 5‐dimethylpyridiniumchloride in ethanol/butanol solution. The crystal structures have been determined from single crystal X‐ray diffraction data. The compounds 1 and 2 are isotypic with each other and crystallize in the triclinic space group P1¯ (Z = 2). The 3, 5‐dimethylpyridinium cations are linked by hydrogen bonds to the anionic part of the structure built up by isolated chloride ions and strings of edge coupled triangulated dodecahedra [LnCl4/2Cl2(H2O)2]. The organic units are arranged forming a “π‐stacking”. 3 cristallizes monoclinically in the space group P21/c (Z = 4). The structure contains octahedral building units [TbCl6]3—. These octahedra are interconnected by the organic cations via hydrogen bonds forming chains parallel to [0 0 1].  相似文献   

7.
Electronic Structures of Organometallic Complexes of f Elements. 67 First Parametric Analysis of the Absorption Spectrum of a Molecular Compound of CeIIIμ: Tris(η5‐tetramethylcyclopentadienyl)cerium(III) The absorption spectra (in the IR/NIR/Vis/UV range) of Ce(C5Me4H)3 ( 1 ) and La(C5Me4H)3 ( 2 ) were recorded at room and low temperatures. From the spectra obtained, two alternative closely related crystal field (CF) splitting patterns of 1 could be derived, and simulated by fitting the free parameters of a phenomenological Hamiltonian. The fact that the difference of the experimental energies of the barycenters of CF levels of the multiplets 2F7/2 and 2F5/2 is larger than in the gaseous free Ce3+ ion (“anti”‐relativistic nephelauxetic effect) could be explained by coupling effects of these multiplets via the CF, resulting in lower spin‐orbit coupling parameters than in the case of the gaseous free Ce3+ ion. The experimentally derived CF splitting pattern of 1 is compared with the predictions of previous non‐relativistic SW‐Xα and relativistic DV‐Xα calculations.  相似文献   

8.
Synthesis and Molecular Structure of [{Cp′(μ‐η1 : η5‐C5H3Me)Mo(μ‐AlRH)}2] (Cp′ = C5H4Me, R = iBu, Et) [Cp′2MoH2] reacts with HAlR2 to give [{Cp′(μ‐η1 : η5‐C5H3Me)Mo(μ‐AlRH)}2] (Cp′ = C5H4Me, R = iBu ( 1 ), Et ( 2 )). Crystal structure determinations were carried out on [Cp′2MoH2] and 1 . 1 exhibits a direct Mo–Al bond (2.636(2) Å).  相似文献   

9.
Reactions of Cp*NbCl4 and Cp*TaCl4 with Trimethylsilyl‐azide, Me3Si‐N3. Molecular Structures of the Bis(azido)‐Oxo‐Bridged Complexes [Cp*NbCl(N3)(μ‐N3)]2(μ‐O) and [Cp*TaCl2(μ‐N3)]2(μ‐O) (Cp* = Pentamethylcyclopentadienyl) The chloro ligands in Cp*TaCl4 (1c) can be stepwise substituted for azido ligands by reactions with trimethylsilyl azide, Me3Si‐N3 (A) , to generate the complete series of the bis(azido)‐bridged dimers [Cp*TaCl3‐n(N3)n(μ‐N3)]2 ( n = 0 (2c) , n = 1 (3c) , n = 2 (4c) and n = 3 (5c) ). If the solvent CH2Cl2 contains traces of water, an additional oxo bridge is incorporated to give [Cp*‐TaCl2(μ‐N3)]2(μ‐O) (6c) or [Cp*TaCl(N3)(μ‐N3)]2(μ‐O) (7c) , respectively. Both 6c and 7c are also formed in stoichiometric reactions from [Cp*TaCl2(μ‐OH)]2(μ‐O) (8c) and A . Analogous reactions of Cp*NbCl4 (1b) with A were used to prepare the azide‐rich dinuclear products [Cp*NbCl3‐n(N3)n(μ‐N3)]2 (n = 2 (4b) , and n = 3 (5b) ), and [Cp*NbCl(N3)(μ‐N3)]2(μ‐O) (7b) . The mononuclear complex Cp*Ta(N3)Me3 (10c) is obtained from Cp*Ta(Cl)Me3 and A . All azido complexes were characterised by their IR as well as their 1H and 13C NMR spectra; X‐ray crystal structure analyses are available for 6c and 7b .  相似文献   

10.
Syntheses and Crystal Structures of New Alkali Metal Rare‐Earth Tellurides of the Compositions KLnTe2 (Ln = La, Pr, Nd, Gd), RbLnTe2 (Ln = Ce, Nd) and CsLnTe2 (Ln = Nd) Of the compounds ALnQ2 (A = Na, K, Rb, Cs; Ln = rare earth‐metal; Q = S, Se, Te) the crystal structures of the new tellurides KLaTe2, KPrTe2, KNdTe2, KGdTe2, RbCeTe2, RbNdTe2, and CsNdTe2 were determined by single‐crystal X‐ray analyses. They all crystallize in the α‐NaFeO2 type with space group R3¯m and three formula units in the unit cell. The lattice parameters are: KLaTe2: a = 466.63(3) pm, c = 2441.1(3) pm; KPrTe2: a = 459.73(2) pm, c = 2439.8(1) pm; KNdTe2: a = 457.83(3) pm, c = 2443.9(2) pm; KGdTe2: a = 449.71(2) pm, c = 2443.3(1) pm; RbCeTe2: a = 465.18(2) pm, c = 2533.6(2) pm; RbNdTe2: a = 459.80(3) pm, c = 2536.5(2) pm, and CsNdTe2: a = 461.42(3) pm, c = 2553.9(3) pm. Characteristics of the α‐NaFeO2 structure type as an ordered substitutional variant of the rock‐salt (NaCl) type are layers of corner‐sharing [(A+/Ln3+)(Te2—)6] octahedra with a layerwise alternating occupation by the cations A+ and Ln3+.  相似文献   

11.
The reaction of tris(bis(trimethylsilyl)amido)lanthanide(III) (Ln(btmsa)3) with two equiv. of cyclohexylisocyanide gives good yields of complexes of composition Ln(btmsa)3(CNC6H11)2 (Ln = Y( 1 ), La( 2 ), Ce( 3 ), Pr( 4 ), Nd( 5 ), Sm( 6 ), Eu( 7 ), Tb( 8 ), Dy( 9 ), Ho( 10 ), Tm( 11 ) and Yb( 12 )). Complex 5 crystallizes in the monoclinic space group C2/c with a = 25.689(8) Å, b = 12.165(2) Å, c = 17.895(15) Å, β = 122.47 (2)°, V = 4718.07 Å3, Z = 4 and R = 0.0342. The structure of compound 5 shows the five‐coordinate Nd3+ ion in a nearly exact trigonal bipyramidal environment with two CNC6H11 molecules in the axial and the three btmsa ligands in the equatorial positions. The linear dichroism spectrum of a single crystal of complex 5 was measured at room temperature, and the absorption spectrum of powdered material at low temperatures. From the spectra obtained a truncated crystal field (CF) splitting pattern is derived, and simulated by fitting the parameters of a phenomenological Hamiltonian. For 80 assignments a reduced r.m.s. deviation of 20.7 cm—1 is achieved. Making use of the calculated wavefunctions and eigenvalues the experimentally determined temperature dependence of μ2eff could be reproduced by adopting an orbital reduction factor k = 0.991, and on the basis of the CF parameters used the experimentally oriented non‐relativistic molecular orbital scheme of compound 5 is set up.  相似文献   

12.
Preparation and Crystal Structure of (4-Picolinium)[LnCl4(H2O)3] (Ln = La, Ce, Pr, Nd) The complex water containing chlorides (4-Picolinium)[LnCl4(H2O)3] (Ln = La, Ce, Pr, Nd) were prepared for the first time, and the crystal structures of (4-Picolinium)[LnCl4(H2O)3] (Ln = La, Pr) were determined on single crystals by X-ray methods. The isotypic compounds crystallize with triclinic symmetry, space group P1 , Z = 2. Surprisingly there exist the dimeric complex anions [Ln2Cl8(H2O)6]2? (Ln = La, Pr).  相似文献   

13.
Synthesis and Crystal Structures of Lanthanide Bromide Thiosilicates Ln3Br[SiS4]2 (Ln = La, Ce, Pr, Nd, Sm, Gd) Single crystals of the bromide—thiosilicates Ln3Br[SiS4]2 were prepared by reaction of lanthanide metal (Ln = La, Ce, Pr, Nd, Sm, Gd), sulfur, silicon and bromine in quartz glass tubes. The thiosilicates crystallize in the monoclinic spacegroup C2/c (Z = 4) isotypically to the iodide analogues Ln3I(SiS4)2 and the A—type chloride—oxosilicates Ln3Cl[SiO4]2 with the following lattice constants: La3Br[SiS4]2: a = 1583.3(4) pm, b = 783.0(1) pm, c = 1098.2(3) pm, β = 97.33(3)° Ce3Br[SiS4]2: a = 1570.4(3) pm, b = 776.5(2) pm, c = 1092.2(2) pm, β = 97.28(2)° Pr3Br[SiS4]2: a = 1562.6(3) pm, b = 770.1(2) pm, c = 1088.9(2) pm, β = 97.50(2)° Nd3Br[SiS4]2: a = 1561.4(4) pm, b = 766.0(1) pm, c = 1085.3(2) pm, β = 97.66(3)° Sm3Br[SiS4]2: a = 1555.4(3) pm, b = 758.5(2) pm, c = 1079.9(2) pm, β = 98.28(2)° Gd3Br[SiS4]2: a = 1556.5(3) pm, b = 750.8(1) pm, c = 1074.5(2) pm, β = 99.26(2)° In the crystal structures the bromide ions form chains along [001] with trigonal planar coordination by lanthanide cations, while the [SiS4]4‐—building units display isolated distorted tetrahedra.  相似文献   

14.
The rate constants for the addition of the OP·(OPri)2, Me3C·, and Me(CH2)3 ·CH2 radicals to the methano[60]fullerenes C60CX1X2 (X1 = X2 = CO2Et; X1 = CO2Me, X2 = OP(OMe)2; X1 = X2 = OP(OEt)2) were determined by ESR spectroscopy. Methanofullerenes are more reactive toward these radicals than C60 fullerene.  相似文献   

15.
Electronic Structures of Highly Symmetrical Compounds of f Elements. 36 [1] Parametric Analysis of the Optical Spectra of an Oriented Tris(hydrotris(1‐pyrazolyl)borato)praseodymium(III) Single Crystal The absorption and luminescence spectra of polycrystalline tris(hydrotris(1‐pyrazolyl)borato)‐praseodymium(III) (PrTp3) were measured at room temperature as well as at low temperatures. At room temperature the “polarized” luminescence spectra of a small oriented PrTp3 single crystal could also be recorded. On the basis of these spectroscopic findings the underlying crystal field splitting pattern could be derived, and simulated by fitting the free parameters of a phenomenological Hamiltonian, achieving a reduced r.m.s. deviation of 17.3 cm—1 for 37 assignments. On the basis of the parameters used, the global ligand field strength experienced by the Pr3+ central ion as well as the individual ligand field strength associated with one Tp ligand are determined, nephelauxetic and relativistic nephelauxetic effects are estimated, and the experimentally orientiented nonrelativistic and relativistic molecular orbital schemes in the f range are set up.  相似文献   

16.
Multifaceted Coordination Chemistry of Vanadium(V): Substitution, Rearrangement Reactions, and Condensation Reactions of Oxovanadium(V) Complexes of the Tripodal Oxygen Ligand LOMe? = [η5‐(C5H5)Co{P(OMe)2(O)}3]? The octahedral oxovanadium(V) complex [V(O)F2LOMe] of the tripodal oxygen ligand LOMe? = [η5‐(C5H5)Co{P(OMe)2(O)}3]? reacts with alcohols and phenol with substitution of one fluoride ligand to form alkoxo complexes [V(O)F(OR)LOMe], R = Me, Et, i‐Prop, Ph. In the presence of water, however, both fluoride ions are substituted and a complex with the composition VO2LOMe can be isolated. The crystal structure shows that the oxo‐bridged trimer [{V(O)(LOMe)O}3] was synthesized. In the presence of BF3 the fluoride ligand in the alkoxo‐complex [V(O)F(OEt)LOMe] can be exchanged for pyridine to yield [V(O)(OEt)pyLOMe]BF4. Analogous attempts to exchange the fluoride ligand for tetrahydrofuran and acetonitrile induces a rearrangement reaction that leads to the vanadium complex [V(O)(LOMe)2]BF4. The crystal structure of this compound has been determined. Its 1H and 31P‐NMR spectra show that it is a highly fluxional vanadium complex at ambient temperature in solution. The two tripodal ligands LOMe? coordinate the vanadium centre as bidentate or tridentate ligands. The exchange bidentate/tridentate becomes slow on the NMR time scale below about 200 K.  相似文献   

17.
Syntheses and Crystal Structures of [Cu4(As4Ph4)2(PRR′2)4], [Cu14(AsPh)6(SCN)2(PEt2Ph)8], [Cu14(AsPh)6Cl2(PRR′2)8], [Cu12(AsPh)6(PPh3)6], [Cu10(AsPh)4Cl2(PMe3)8], [Cu12(AsSiMe3)6(PRR′2)6], and [Cu8(AsSiMe3)4(PtBu3)4] (R, R′ = Organic Groups) Through the reaction of CuSCN with AsPh(SiMe3)2 in the presence of tertiary phosphines the compounds [Cu4(As4Ph4)2(PRR′2)4] ( 1 – 3 ) ( 1 : R = R′ = nPr, 2 : R = R′ = Et; 3 : R = Me, R′ = nPr) and [Cu14(AsPh)6(SCN)2(PEt2Ph)8] ( 4 ) can be synthesised. Using CuCl instead of CuSCN results to the cluster complexes [Cu14(AsPh)6Cl2(PRR′2)8] ( 5–6 ) ( 5 : R = R′ = Et; 6 : R = Me, R′ = nPr), [Cu12(AsPh)6(PPh3)6] ( 7 ) and [Cu10(AsPh)4Cl2(PMe3)8] ( 8 ). Through reactions of CuOAc with As(SiMe3)3 in the presence of tertiary phosphines the compounds [Cu12(AsSiMe3)6(PRR′2)6] ( 9 – 11 ) ( 9 : R = R′ = Et; 10 : R = Ph, R′ = Et; 11 : R = Et, R′ = Ph) and [Cu8(AsSiMe3)4(PtBu3)4] ( 12 ) can be obtained. In each case the products were characterised by single‐crystal‐X‐ray‐structure‐analyses. As the main structure element 1 – 3 each have two As4Ph42–‐chains as ligands. In contrast 4 – 12 contain discrete AsR2–ligands.  相似文献   

18.
Ln3UO6Cl3 (Ln=La, Pr, Nd) — The First Oxochlorouranates of the Rare Earths . The new compounds Ln3UO6Cl3 (Ln=La, Pr, Nd) were prepared by heating stoichiometric amounts of LnOCl/Ln2O3/U3O8 (7 : 1 : 1) (Ln=La, Nd) and PrOCl/Pr6O11/U3O8 (12 : 1 : 2) in silica ampoules (5 d, 1000°C, Ln=La; 9 d 800°C, Ln=Pr, Nd) in the presence of an excess of chlorine [p(Cl2, 25°C)=1 atm]. Single crystals were obtained by chemical transport reactions using chlorine [p(Cl2, 25°C)=1 atm] as transport agent [T2=1000°C→T1=900°C (Ln=La); T2=840°C→T1=780°C (Ln=Pr, Nd)]. Crystals of Ln3UO6Cl3 (Ln=La, Pr, Nd) were investigated by X-ray diffraction methods and La3UO6Cl3 additionally by high resolution electron microscopy. The compounds Ln3UO6Cl3 crystallize in the hexagonal spacegroup P63/m (No. 176) with Z=2 formula units per unit cell. Isotypical structure refinements resulted in R=3.04% respectively Rw=1.91% (Ln=La), R=4.72% respectively Rw=3.80% (Ln=Pr) and R=3.99% respectively Rw=2.49% (Ln=Nd). Uranium is coordinated with six oxygen atoms forming a trigonal prism. Lanthanide ions are 10-coordinated (6 oxygen atoms, 4 chlorine atoms).  相似文献   

19.
Low‐Temperature Oxidation in Liquid Ammonia: [Eu2(Ind)4(NH3)6], the First Indolate of a Rare Earth Element Intensively yellow to orange coloured, transparent crystals of [Eu2(Ind)4(NH3)6] were obtained by low‐temperature oxidation of europium metal with indole (C8H6NH) in liquid ammonia at —50 °C and subsequent melting of the reaction mixture in excess indole at 120 °C. [Eu2(Ind)4(NH3)6] has a dimeric structure and contains divalent Eu. The coordination sphere around the europium atoms consists of five N atoms of two cisoid indolate anions and three NH3 molecules as well as an η5‐coordinating π‐system of another indolate ligand, bridging to the next Eu atom with an sp2‐orbital.  相似文献   

20.
Syntheses of Oxovanadium(V) Halide Complexes Stabilized with Tripodal Oxygen Ligands LR = [η5‐(C5H5)Co{PR2(O)}3], R = OMe, OEt The sodium salts of the tripodal oxygen ligands LR = [η5‐(C5H5)Co{PR2(O)}3] (R = OMe, OEt) react with the oxovanadium halides V(O)F3 and V(O)Cl3 to yield deep red compounds of the type [V(O)X2LR]. Halide exchange reactions with [V(O)Cl2LOMe] und [V(O)F2LOMe] aiming at the preparation of the analogous bromide complex [V(O)Br2LOMe] led to the isomer [VO(LOMe)2][V(O)Br4]. The crystal structure of [V(O)Cl2LOMe] has been determined by single crystal x‐ray diffraction. The compound crystallizes in the monoclinic space group P21/n with a = 9.6332(8), b = 15.0312(11) and c = 15.3742(12)Å, β = 100.181(8)°. The coordination around vanadium is distorted octahedral.  相似文献   

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