首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A novel Pd(II) Benzo-15-crown-5 complex [Na(B15C5)]2[Pd(SCN)4] has been isolated and characterized by IR and X-ray diffraction analysis.The crystal structure belongs to monoclinic,space group P21/n with cell dimensions,a=1.0164(6),b=1.3743(3),c=1.4987(7) nm,b=95.248(6)o ,V=2.0847nm3,Z=2,F(000)=944,R=0.053,Rw=0.072.The compound consists of two [Na(B15C5)]+ complex cations and a [Pd(SCN)4]2- complex anion.Each sodium ion is coordinated by five crown ether oxygen atoms and one N atom from the SCN group of [Pd(SCN)4]2- to form stable neutral complex.  相似文献   

2.
用凝胶法合成了标题化合物[NH4(15-C-5)2][Cd2(SCN)5](15-C-5=C10H20O5)的晶体,并对其进行了红外光谱、元素分析等各项物理性质的测试,并经X射线单晶结构分析得到了配合物的全部晶体学数据:Mr=973.78,正交晶系,空间群Pnma,晶胞参数a=10.507(1)A,b=16.584(2)A,c=23.494(2)A,V=4093.8(3)A3,Z=4,Dc=2.580g/cm3,μ=13.31cm(-1),F(000)=1968,R=0.070,Rω=0.085。结构分析结果表明,配阳离子是由一个NH4+和两个15-C-5组成的,NH4+没有进入15-C-5空腔内,而是位于两个15-C-5之间,呈夹心结构;配阴离子是以[Cd2(SCN)5]为单元的阴离子长键,其中一组SCN-被四个Cd离子共享,其余两组SCN-被两个Cd离子共享,呈变形八面体构型。配阳离子[NH4(15-C5)2]+和配阴离子[Cd2(SCN)5]-间靠静电力结合成配合物晶体。  相似文献   

3.
苯并15-冠-5与Na_2[M(SCN)_4](M=Pd,Pt)配合物的合成与结构   总被引:2,自引:0,他引:2  
合成了苯并15-冠-5与Na_2[M(SCN)_4] (M = Pd, Pt)生成的配合物:[Na(B15- C-5)]_2[Pd(SCN)_4] (1), {[Na(B15-C-5)][Na(B15-C-5)(H_2O)]}[Pt(SCN)_4] (2)。1为单斜晶系,空间群P2_1/n,a = 1.0164(6) nm,b = 1.3743(3) nm,c = 1.4987(7) nm,β = 95.248(6)°,V = 2.0847 nm~3,Z = 2,D_(calcd) = 1. 47 g/cm~3,F(000) = 944,R = 0.053,wR = 0.072。2为三斜晶系,空间群P(1- bar),a = 1.1484(2) nm,b = 1.4210(3) nm,c = 1.5026(3) nm,α = 62.500 (3)°,β = 72.393(3)°,γ = 73.106(4)°,V = 2.0398(7) nm~3,Z = 2, D_(calcd) = 1.674 g/cm~3,F(000) = 1028,R_1 = 0.0327,wR_2 = 0.0885。1 由两个[Na(B15-C-5)]~+配阳离子和一个[Pd(SCN)_4]~(2-)配阴离子组成,两者通 过Na-N键形成中性配合物,[Na(B15-C-5)]~+A相对钯原子呈反式排列。2由[Na (B15-C-5)]~+和[Na(B15-C-5)(H_2O)]~+配阳离子和一个[Pt(SCN)_4]~(2-)配阴离 子组成,它们也通过Na-N键形成中性配合物,配阳离子相对铂原子呈顺式排列。2 的两个分子通过氢键形成二聚结构。  相似文献   

4.
合成了苯并15-冠-5、二苯并18-冠-6与Na_2[Pt(SCN)_6]的配合物:[Na(B15- C-5)]_2[Pt(SCN)_6] (1),[Na(DB18-C-6)]_2[Pt(SCN)_6] (2),并通过元素分析 、红外光谱、单晶X射线衍射进行了表征。1为单斜晶系,空间群P2_1/c,a = 1. 0974(5) nm,b = 1.5187(7) nm,c = 1.3632(6) nm,β = 96.407(7)°,V = 2. 2568(18) nm~3,Z = 2,D_(calcd) = 1.746 g/cm~3,F(000) = 1184,R_1 = 0. 0357,wR_2 = 0.0868。 2为三斜晶系,空间群 P1-bar,a = 1.2500(3) nm,b = 1.2825(3) nm,c = 1.9342(4) nm,α = 106.82(3)°,β = 102.51(3)°,γ = 103.04(3)°,V = 2.7562 nm~3,Z = 2,D_(calcd) = 1.579 g/cm~3,F(000) = 1316,R_1 = 0.0364,wR_2 = 0.0771。配合物分别由两个[Na(B15-C-5)]~+, [Na(DB18-C-6)]~+配阳离子和一个[Pt(SCN)_6]~(2-)配阴离子组成。配阳离子和配 阴离子通过Na-N键形成二维网状结构。  相似文献   

5.
A differential pulse voltammetric study of complexes of Cd(II) and Pb(II) with crown ethers is reported. Measured log K(1) values for Cd(II) with 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane), 15-crown-5 (1,4,7,10,13-pentaoxacyclopentadecane), and 12-crown-4 (1,4,7,10-tetraoxacyclododecane) are respectively 2.53 (+/-0.06), 1.97 (+/-0.07), and 1.72 (+/-0.08) and for Pb(II) with 18-crown-6 is 4.17 (+/-0.03), all at 25 degrees C in 0.1 M LiNO(3). Cd(II) is smaller than is usually associated with strong bonding with crown ethers. The high log K(1) values for Cd(2+) with crown ethers found here are discussed in terms of distortion of Cd(II) by relativistic effects. The resulting plasticity of the coordination geometry of the Cd(II) ion allows it to meet the metal ion size requirements of all the crown ethers, allowing high log K(1) values to occur. Crystal structures for [Cd(bz-18-crown-6)(SCN)(2)] (1) (bz-18-crown-6 = benzo-1,4,7,10,13,16-hexaoxacyclooctadecane) and [K(18-crown-6)][Cd(SCN)(3)] (2) are reported. 1 was triclinic, space group P1, a = 8.5413(2), b = 10.0389(2), and c = 13.4644(2) A, alpha = 94.424(1), beta = 102.286(1), and gamma = 93.236(1) degrees, Z = 2, and final R = 0.023. 2 was orthorhombic, space group Cmc2(1), a = 14.7309(3), b = 15.1647(3), and c = 10.6154(2) A, Z = 4, and final R = 0.020. In 1, the Cd occupies the cavity of the bz-18-crown-6 with long average Cd-O bond lengths of 2.65 A and is N-bonded to the thiocyanates with short average Cd-N bonds of 2.12 A. In [Cd(bz-18-crown-6)(SCN)(2)], the linear coordination involving the Cd and the two N-bonded thiocyanate groups in 1 is discussed in terms of the role of relativistic effects in the tendency to linear coordination geometry in group 12 metal ions. In 2 Cd forms a polymeric structure involving thiocyanate bridges between Cd atoms and K(+) occupies the cavity of the crown ether. 2 highlights the fact that cadmium is almost never S-bonded to thiocyanate except in bridging thiocyanates.  相似文献   

6.
合成了苯并18-冠-6(B18C6)与M2[Pt(SCN)6](M=Na,K)的配合物:{[Na (B18C6)]6[Pt(SCN)6]}[Pt(SCN)6](SCN)2(1),[K(B18C6)]2[Pt(SCN)6]·4H2O(2). 通过元素分析、红外光谱、单晶X射线衍射进行了表征.1为单斜晶系、空间群R3^-, a=b=1.9933(3)nm,c=2.9760(6)nm,α=β=90°,γ=120°,V=10.240(3)nm^3,Z=3, Dcalcd=1.564g/cm^3,F(000)=4908,R1=0.0535,wR2=0.1030.2为三斜晶纱、空间群 P1^-,a=1.1692(3)nm,b=1.1853(4)nm,c=1.2381(5)nm,α=61.419(5)°,β=80.757 (8)°,γ=89.003(5)°,V=1.4836(9)nm^3,Z=1,Dcalcd=1.476g/cm^3,F(000)=666, R1=0.0696,wR2=0.1346.1由{[Na(B18C6)]6[Pt(SCN)6]}^4+配阳离子、[Pt(SCN)6] ^2-配阴离子和SCN^-阴离子组成。相邻{[Na(B18C6)]6[Pt(SCN)6]}^4+通过Na-O键 形成三维网状结构。[Pt(SCN)6]^2-和SCN^-仅起平衡电荷的作用.2由两个[K (B18C6)]^+配阳离子和一个[Pt(SCN)6]^2-配阴离子组成。相邻[K(B18C6)]2[Pt (SCN)6]离子对通过K-O键形成一维链状结构。  相似文献   

7.
<正> The crystal and Molecular structure of [K(18-crown-6)](Bi(SCN)Cl3] has been deterained by X-ray diffraction Method. Its crystal is triclinic, space group Pl,with a = 9.233(4), b = 11.661(5), c=11.738(5)A,a= 81.82(4)° ,β=71.47(4)°,γ=75.55(4)°, and Z = 2. The final structural refine-ment converged with unweighted and weighted R factors of 0.051 and 0.047 for 2924 observed reflections. Results of the structure analysis indicate that the K+ ion enters the cavity of the 18-crown-6 to form the complex cation and one Bi(Ⅲ) atom, one SCN ligand and three Cl atoms fora the anion. Each Bi(Ⅲ) atoa is coordinated by four Cl atoas, of which two are shared with other Bi(Ⅲ) atom, one N atom and one S atoa from two SCN ligands respectively shared with a third Bi(Ⅲ) atoa, forming octahedral geometry.  相似文献   

8.
Four novel 2,3-naphtho-15-crown-5 (N15C5) and 2,3-naphtho-18-crown-6 (N18C6) complexes [Na(N15C5)]2[Pd(SCN)4] (1), [Na(N15C5)]2[Pt(SCN)4] (2), [K(N18C6)]2[Pd(SCN)4] (3) and [K(N18C6)]2[Pt(SCN)4] (4) were synthesized and characterized by elemental analysis, FT-IR spectra and single-crystal X-ray diffraction. The structure analyses reveal that both 1 and 2 are assembled into zigzag chains by the strong intermolecular pi-pi stacking interactions between adjacent 2,3-naphthylene groups of N15C5. The molecules of complexes 3 and 4 are linked into 1D chains by the bridging K-O(ether) interactions between the adjacent [K(N18C6)]+ units and the resulting chains are constructed into a novel 2D network by inter-chain pi-pi stacking interactions between the neighboring 2,3-naphthylene moieties of N18C6. According to the supramolecular self-assemblies of complexes 1-4, two types of stacking model of naphthylene groups are given and discussed.  相似文献   

9.
We report herein a novel coordination solid, [(DB24C8)Na][Cd(SCN)3] (6) (DB24C8 denotes dibenzo-24-crown-8), which exhibits a new type of [Cd(SCN)3-]infinity chain with two unusual stereochemical characteristics: (1) a mer-CdN3S3 coordination and (2) a linear Cd chain with a Cd...Cd...Cd angle of 180 degrees. In addition, the [(DB24C8)Na]+ monocation adopts a new structural type-a coiled structure-for the combination of crown ether DB24C8 and alkali metal Na+. The title compound crystallizes in a monoclinic unit cell of C2/c space group symmetry with lattice parameters a = 16.110(8) A, b = 20.380(5) A, c = 11.01(1) A, beta = 119.87(3) degrees, and Z = 4. The arrangement of the [Cd(SCN)3-](infinity) chains in the crystal lattice in the title compound is approximately hexagonal, creating triangular channels which are filled with [(DB24C8)Na]+ monocations. It was previously reasoned by us that the coiled [(DB24C8)Na]+ monocation, which lacks inversion or mirror symmetries, should enhance the tendency for the formation of the noncentrosymmetric space group of the title crystal, making it a potential second-order nonlinear optical crystal. Interestingly, however, the title compound crystallizes in a centrosymmetric space group (C2/c) and gives rise to no second harmonic generation (SHG). Previously known [Cd(SCN)3-](infinity) chains adopt fac-CdN3S3 coordination and a zigzag Cd chain configuration with a Cd...Cd...Cd angle of 165 degrees. The zigzag chains can align in either parallel or antiparallel fashion, resulting in efficient or no SHG effects, respectively. The linear Cd.Cd.Cd chain configuration observed in the title compound, on the other hand, makes it indistinguishable between parallel and antiparallel alignments. It is concluded that, to ensure the formation of noncentrosymmetric space groups, it is necessary to employ optically pure chiral cations as spacers and/or controllers. Furthermore, to enhance the nonlinear optical responses, [Cd(SCN)3-]infinity chains with fac-CdN3S3 coordination and parallel alignments of the zigzag Cd chains should be used.  相似文献   

10.
0 IntroductionThe rapid development in the area of polymericmetalorganic frameworks (MOFs) continues to producevarious structures with interesting compositions andtopologies[1 ̄5] , along with potential applications asfunctional solid materials for molecular selection, ionexchange, and catalysis[6 ̄10]. By the careful selectionand design of organic ligands, such as linear isothio-cyanate-based building blocks, a wide variety of solid-state supramolecular architectures have been con-structed[1…  相似文献   

11.
Halogeno-Nitrosyl Complexes of Molybdenum and Tungsten. Crystal Structures of [Na2(15-Crown-5)2(CH3CN)][MoCl4(NO)2] and [Na(15-Crown-5)]2[MoF4Cl(NO)] MoCl2(NO)2 and WCl2(NO)2, respectively, react with excess sodium fluoride in acetonitrile at room temperature and in the presence of 15-crown-5 to give crystalline mixtures, which consist of the title compounds, respectively of [Na(15-crown-5)]2[WCl4(NO)2] and [Na(15-crown-5)]2[WF4Cl(NO)], and which can be separated by selection. The complexes are characterized by their i.r. spectra, the molybdenum compounds additionally by crystal structure determinations. [Na2(15-crown-5)2(CH3CN)][MoCl4(NO)2]: Space group P21, Z = 2, 5415 independent unique reflexions, R = 0.039. Lattice dimensions at ?10°C: a = 984.3, b = 1231.1, c = 1483.0 pm, β = 105.67°. The compound consists of cations [Ne(l5-crown-5)(CH3CN)]+, in which the sodium ion is surrounded by the five O-atoms of the crown ether and by the N-atom of the acetonitrile molecule, as well as of anions, which form an ion pair {Na(15-crown-5)[MoCl4(NO)2]}?. In the in pairs the sodium ion is coordinated by the five oxygen atoms of the crown ether and by two chlorine atoms of the [MoCI4(NO)2]2? unit. The nitrosyl ligands take the cis-position a t the molybdenum atom which is in a distorted octahedrally fashion. [Na(15-crown-5)]2[MoF4Cl(NO)]. Space group C2/c, Z = 4, 1933 independent unique reflexions, R = 0.078. Lattice dimensions at ?7O°C: D : 1.585.8, b = 1171.5, c = 1771.5 pm, β = 114.91°. The compound forms an ion triple, in which the sodium ions are linked to five oxygen atoms each of the crown ether molecules, and to two F-atoms of the [MoF4Cl(NO)]2? unit. The F-atom which is arranged in trans-position to the nitrosyl ligand coordinates with both sodium ions; thus an unusual T-shaped arrangement results for this F-atom. The sole terminal F-Atom and the Cl-atom are disordered in two positions.  相似文献   

12.
用凝胶法生长了标题配合物[NH_4(B15C5)_2][Cd(SCN)_3]的晶体,并对其进行了红外光谱,元素分析等各项物理性质的测试。经X射线单晶结构分析得到了配合物的全部晶体学数据:M_r=841.31,正交晶系,空间群P2_12_12_1,晶胞常数a=10.970(3),b=21.834(3),c=15.563(4),V=3727(3),Z=4,D_x=1.50g/cm ̄3,F(000)=1736,μ=7.09cm ̄(-1),R=0.070,R_w=0.063。结构分析结果表明,配阳离子[NH_4(B15C5)_2] ̄+和配阴离子[Cd(SCN)_3] ̄-间靠静电力结合成配合物。  相似文献   

13.
[Na(15-crown-5)][ReFCl3(NO)(CH3CN)] Synthesis, IR Spectrum, and Crystal Structure The title compound has been prepared by the reaction of [ReCl3(NO)2(CH3CN)] with the equivalent amount of sodium fluoride in the presence of 15-crown-5 in boiling acetonitrile, forming blue crystals. They were characterized by IR spectroscopy and by an X-ray structure determination. Space group P21/n, Z = 4,2117 observed independent reflections, R = 0.037, wR = 0.029. Lattice dimensions at 20°C: a = 834.0(2), b = 1600.0(3), c = 1670.0(3) pm; β = 104.19(3)°. The compound forms an ion pair via one Na F contact of 234.4 pm and one Na Cl contact of 293.4 pm; the nitrosyl ligand ist in trans-position to the F atom of the anion [ReFCl3(NO)(CH3CN)].  相似文献   

14.
The reaction of an alkali metal aluminohydride MAlH4 (M = Li, Na) with N,N'-bis-(tert-butyl)sulfamide or N,N'-bis-(benzyl)sulfamide in THF produces the complex ions (Al[SO2(NR)2]2)- (R = tBu, Bn). The X-ray structures of [Li(THF)2(Al[SO2(NtBu)2]2)] infinity (1), [Na(15-crown-5)][Al(SO2(NtBu)2)2], (2) and ([Na(15-crown-5)][O2S(mu-NBn)2Al(mu-NBnSO2NBn)])2 (3.3THF) are reported. The two diazasulfate ligands [SO2(NtBu)2]2- are N,N' chelated to Al3+ in both 1 and 2. In the lithium derivative 1 the spirocyclic (Al[SO2(NtBu)2]2)- anions are bridged by the bis-solvated cations Li(THF)2+ to give a polymeric strand. In the sodium salt 2 the complex anion is O,O' chelated to Na+, which is further encapsulated by a 15-crown-5 ligand to give a monomeric ion-pair complex. By contrast, the benzyl derivative 3 forms a dimer in which the terminal [SO2(NBn)2]2- ligands are (N,N'),(O,O') bis-chelated to Al3+ and Na+, respectively, and the bridging ligands adopt a novel N,O-chelate, N'-monodentate bonding mode. The central core of 3 consists of two four-membered AlOSN rings bridged by two NtBu groups. Crystal data: 1, orthorhombic, Pna2(1), a = 20.159(5) degrees, b = 10.354(3) degrees, c = 15.833(4) degrees, alpha = beta = gamma = 90 degrees, V = 3304.7(15) A3, Z = 4; 2, monoclinic, P2(1)/n, a = 16.031(2) A, b = 9.907(2) A, c = 23.963(4) A, beta = 103.326(2) degrees, Z = 4; 3, triclinic, P1, a = 12.7237(11) A, b = 14.0108(13) A, c = 16.2050(14) A, alpha = 110.351(2) degrees, beta = 111.538(2) degrees, gamma = 97.350(2) degrees, Z = 1.  相似文献   

15.
A new one-dimensional polymeric complex [Cd(SCN)2(H2O)]L (L = N,N?-bis(furan- 2-ylmethylene)hydrazine) has been synthesized and characterized by IR, UV spectra, TG-DTA technique and single-crystal X-ray diffraction analysis. It crystallizes in triclinic, pace group P1 with a = 5.9268(8), b = 10.8678(15), c = 13.3671(19) , α = 109.295(2), β = 95.092(2), γ = 97.8580(10)°, V = 796.70(19) 3, Z = 2, C12H10CdN4O3S2, Mr = 434.76, μ = 1.648 mm–1, Dc = 1.812 g/cm3, F(000) = 428, R = 0.0308 and wR = 0.0769. The crystal structure reveals that the structure of [Cd(SCN)2(H2O)]n features di-μ-1,3-thiocyante bridges and 1D chains. The octahedrally coordinated Cd atom is surrounded by one oxygen atom from water molecule, three S atoms and two Natoms from five di-μ-1,3 thiocyanato bridges. The Cd atoms are connected by two di-μ-1,3 thiocyanato bridges with the Cd(1)…Cd(1A) separation of 4.239(1)  and Cd(1)…Cd(1B) of 5.852(1). In addition, the one-dimensional straight chain structure is further connected by multiform intermolecular N-H…O hydrogen bonds and π…π interactions to form a three-dimensional supramolecular structure.  相似文献   

16.
<正> The title compound was prepared from the reaction of diaza-18-crown-6 and sodium chloroacetate in aqueous solution and crystallized from ethanol solution by standing for a long time. The complex [Na(C16H28N2O8)·Na(H2O)5]2Cl-·2H2O+·H2O (Mr = 655. 45) crystalizes in triclinic system,space group P1 with a = 9. 623(2),b = 10. 902(3),c=15. 867(3) A ;α= 104. 63(2),β= 105. 42(2),γ=99. 88(2)°,V = 1502. 3A3,Dc=1. 09gcm-3,Z = 2,F(000) = 516,final R=0. 075 for 3218 observed reflections. The donor atoms O(4) ,O(7) ,O(13) ,O(16) ,N(1) and N(10) from the crown ether as well as the oxygen atoms O(21) and O(26) from two car boxy lato anions are coordinated cooperatively to the Na(1)+ ion to form crown ether solvated cation in a tetragonal prismatic geometry. The O(22) of one carboxylato anion, which does not coordinate the Na(1) + ion,interacts with the Na(2)+ion together with the oxygen atoms of five water molecules to form a hydrated cation having a deformed octahedral configuration.  相似文献   

17.
In contrast to the neutral macrocycle [UN*(2)(N,C)] (1) [N* = N(SiMe(3))(3); N,C = CH(2)SiMe(2)N(SiMe(3))] which was quite inert toward I(2), the anionic bismetallacycle [NaUN*(N,C)(2)] (2) was readily transformed into the enlarged monometallacycle [UN*(N,N)I] (4) [N,N = (Me(3)Si)NSiMe(2)CH(2)CH(2)SiMe(2)N(SiMe(3))] resulting from C-C coupling of the two CH(2) groups, and [NaUN*(N,O)(2)] (3) [N,O = OC(═CH(2))SiMe(2)N(SiMe(3))], which is devoid of any U-C bond, was oxidized into the U(V) bismetallacycle [Na{UN*(N,O)(2)}(2)(μ-I)] (5). Sodium amalgam reduction of 4 gave the U(III) compound [UN*(N,N)] (6). Addition of MN(3) or MCN to the (N,C), (N,N), and (N,O) metallacycles 1, 4, and 5 led to the formation of the anionic azide or cyanide derivatives M[UN*(2)(N,C)(N(3))] [M = Na, 7a or Na(15-crown-5), 7b], M[UN*(2)(N,C)(CN)] [M = NEt(4), 8a or Na(15-crown-5), 8b or K(18-crown-6), 8c], M[UN*(N,N)(N(3))(2)] [M = Na, 9a or Na(THF)(4), 9b], [NEt(4)][UN*(N,N)(CN)(2)] (10), M[UN*(N,O)(2)(N(3))] [M = Na, 11a or Na(15-crown-5), 11b], M[UN*(N,O)(2)(CN)] [M = NEt(4), 12a or Na(15-crown-5), 12b]. In the presence of excess iodine in THF, the cyanide 12a was converted back into the iodide 5, while the azide 11a was transformed into the neutral U(V) complex [U(N{SiMe(3)}SiMe(2)C{CHI}O)(2)I(THF)] (13). The X-ray crystal structures of 4, 7b, 8a-c, 9b, 10, 12b, and 13 were determined.  相似文献   

18.
CrystalStructureof[La(NO_3)_3(12-crown-4)-(H_2O)](12-crown-4)MaoJiang-Gao;JinZhong-Sheng;YuFeng-Lan(LaboratoryofRareEarthChemi?..  相似文献   

19.
1 INTRODUCTION Coordination polymers have attracted the atten- tion of chemists, physicists, and materials scientists owing to their fascinating structures and potential functional applications in the last decade[1~4]. The bridging ligands play a central role in constructing functional coordination polymers, and weak nonco- valent interactions like hydrogen bonding or π-π stacking plays an important role in molecular self- assembly[5~7]. As a multidentate and rigid ligand with multi-pr…  相似文献   

20.
1 INTRODUCTION For a long time much research interest has been focused on coordination polymeric compounds[1] be- cause they may afford new materials with useful properties, such as catalytic activity, micro-porosity, electrical conductivity, non-linear optical activity, magnetic coupling behavior and so on[2]. Thiocya- nate anion, pyridine N-oxide and its derivatives be- long to very useful bridge ligands and many com- plexes[3~5] with one of them as bridge ligand exhibit special propert…  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号