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.
The synthesis of the rhenacycles [Re(CO)3(PR3){Ph2P(Se)NP(Se)Ph22Se}], PR3 = PPh3 (1), PMePh2 (2), and PMe2Ph (3) by a straightforward high yield procedure is described. Attempts at the preparation of the spiro [Re(CO)2(Ph2PCH2CH2PPh22P){Ph2P(Se)NP(Se)Ph22Se}] resulted in the formation of complexes [Re2(CO)6{Ph2P(Se)NP(Se)Ph22Se}2(μ-Ph2PCH2CH2PPh2)] (4) and [Re(CO)3(Ph2PCH2CH2PPh22P){Ph2P(Se)NP(Se)Ph2Se}] (5). All new inorganic rhenacycles 1-5 were characterized in solution and in solid state. The X-ray diffraction analysis of [Re(CO)3PPh3{Ph2P(Se)NP(Se)Ph22Se}] showed that its MnSePNPSe ring conformation is sensitive to temperature.  相似文献   

2.
The halocarbonyls BrM(CO)5, M = Mn and Re, were reacted with the KN(SePPh2)2 salt in equimolar amounts; the reactions were thermally carried out and resulted in the generation of the hexacoordinated isostructural complexes [M(CO)4{Ph2P(Se)NP(Se)Ph2-Se,Se′}] with a twist MSePNPSe ring conformation. Complexes’ characterizations were achieved by IR, mass, NMR (1H, 13C, 31P, 77Se) spectroscopies, and by single-crystal X-ray diffraction.  相似文献   

3.
Reaction of ReBr(CO)5 with Li[Ph2P(O)NP(O)Ph2] afforded the cryptate Li[Re2(CO)6{μ-Ph2P(O)NP(O)Ph22O,O’}3]; whereas K[Ph2P(O)NP(O)Ph2] reacted with ReBr(CO)5 to give K[Re2(CO)6{μ-Ph2P(O)NP(O)Ph22O,O′}{Ph2P(O)NP(O)Ph22O,O′}2]. Other chalcogen ligands’ salts M[Ph2P(E)NP(E)Ph2], E = Se and S, M = K and Li gave dirhenium carbonyls with bromido and Ph2P(E)NP(E)Ph2, E = Se or S bridges upon reaction with ReBr(CO)5.  相似文献   

4.
The complexes [Rh(CO)(PPh3){Ph2PNP(O)Ph2-P,O}] (3), [Rh(CO)2{Ph2P(Se)NP(Se)Ph2-Se,Se′}] (5), and [Rh(CO)(PPh3){Ph2P(Se)NP(Se)Ph2-Se,Se′}] (6), were synthesised by stepwise reactions of CO and PPh3 with [Rh(cod){Ph2PNP(O)Ph2-P,O}] (2) and [Rh(cod){Ph2P(Se)NP(Se)Ph2-Se,Se′}] (4), respectively. The complexes 3, 5 and 6 have been studied by IR, as well as 1H and 31P NMR spectroscopy. The ν(CO) bands of complexes 3 and 6 appear at approximately 1960 cm−1, indicating high electron density at the RhI centre. The structure of complexes 3 and 6 has been determined by X-ray crystallography, and the 31P NMR chemical shifts have been resolved via low temperature NMR experiments. Both complexes exhibit square planar geometry around the metal centre, with the five-membered ring of complex 3 being almost planar, and the six-membered ring of complex 6 adopting a slightly distorted boat conformation. The C-O bond of the carbonyl ligand is relatively weak in both complexes, due to strong π-back donation from the electron rich RhI centre. The catalytic activity of the complexes 2, 3 and 6 in the hydroformylation of styrene has been investigated. Complexes 2 and 3 showed satisfactory catalytic properties, whereas complex 6 had effectively no catalytic activity.  相似文献   

5.
New Cu(I) and Ag(I) complexes were prepared by reaction of [M(NCCH3)4][X] (M = Cu or Ag; X = BF4 or PF6) with the bidentate chalcogenide ligands Ph2P(E)NHP(E)Ph2 (E = S, S2dppa; E = Se, Se2dppa), and dpspf (1,1′-bis(diphenylselenophosphoryl)ferrocene). Copper and silver behaved differently. While three molecules of either S2dppa and Se2dppa bind to a distorted tetrahedral Cu4 cluster, with deprotonation of the ligand, 1:2 complexes of the neutral ligands are formed with Ag(I), with a tetrahedral coordination of the metal. The [Cu4{Ph2P(Se)NP(Se)Ph2}3]+ clusters assemble as dimers, held together by weak Se?Se distances interactions. Another dimer was observed for the [Ag(dpspf)]+ cation, with two short Ag?Se distances. DFT and MP2 calculations indicated the presence of attracting interactions, reflected in positive Mayer indices (MI). The electrochemistry study of this species showed that both oxidation and reduction took place at silver.  相似文献   

6.
Mononuclear complexes of the type, M(CO)4[Se2P(OR)2] (M = Mn, R = iPr, 1a; Et, 1b; M = Re, R = iPr, 3a; Et, 3b) can be prepared from either [-Se(Se)P(OiPr)2]2 (A) or [Se{-Se(Se)P(OEt)2}2] (B) with M(CO)5Br. O,O′-dialkyl diselenophosphate ([(RO)2PSe2]-, abbreviated as dsep) ligands generated from A and B act as a chelating ligand in these complexes. Upon refluxing in acetonitrile, these mononuclear complexes yield dinuclear complexes with a general formula of [M2(CO)6{Se2P(OR)2}2] (M = Mn, R = iPr, 2a; Et, 2b; M = Re, R = iPr, 4a; Et, 4b). Dsep ligands display a triconnective, bimetallic bonding mode in the dinuclear compounds and this kind of connective pattern has never been identified in any phosphor-1,1-diselenoato metal complexes. Compounds 2b, 3b, and 4 are structurally characterized. Compounds 2b and 3b display weak, secondary Se?Se interactions in their lattices.  相似文献   

7.
The iron trithiocarbonato complex CpFe(CO)2S-SCS2Ph) (1a) and its selenodithiocarbonato analogue CpFe(CO)2Se-SeCS2Ph) (1b) were generated by room temperature reactions of (μ-Ex)[CpFe(CO)2]2 (E = S; x = 2, 3. E = Se; x = 1) with PhSC(S)Cl. These compounds can be converted into the complexes CpFe(CO)(κ2S,E-ECS2Ph) [E = S (2a), Se (2b)], in which the trithiocarbonato or the selenodithiocarbonato ligand is bonded to the iron in a chelate form, under photolytic conditions. The composition and structure of all products have been verified by elemental analyses, IR and 1H NMR spectroscopies. The crystal structures for compounds 1a, 1b, and 2b show a three-legged piano-stool configuration at Fe in each complex. The spectroscopic and structural data in this work are commensurate with the electronic factor of the S- and Se-donor ligands.  相似文献   

8.
Aryl M(κ1-Ar)(CO)nP5−n [M = Mn, Re; Ar = C6H5, 4-CH3C6H4; n = 2, 3; P = P(OEt)3, PPh(OEt)2, PPh2OEt] and Re(κ1-C6H5)(CO)3[Ph2PO(CH2)3OPPh2] complexes were prepared by allowing hydrides MH(CO)nP5−n to react first with triflic acid and then with the appropriate aryl lithium (LiAr) compounds. The complexes were characterized spectroscopically (IR and 1H, 31P, 13C NMR) and by the X-ray crystal structure determination of Re(κ1-C6H5)(CO)3[Ph2PO(CH2)3OPPh2] derivative. Protonation reaction of the aryl complexes with HBF4 · Et2O lead to free hydrocarbons Ar-H and the unsaturated [M(CO)nP5−n]+ cations, separated as solids in the case of [Re(CO)3P2]BF4 derivatives.  相似文献   

9.
The syntheses and characterisation of the Co(III) complexes [(L)Co(O2CO)]ClO4 (L = a tripodal tetraamine ligand = baep, abap, uns-penp, dppa, trpn) are reported. Geometric isomers are possible for all but the trpn complex, owing to the non-equivalence of the three arms on the tripodal ligand, and both NMR and X-ray crystallography are used to identify the single isomer formed. X-ray crystal structures of the complexes [(L)Co(O2CO)]ClO4 · xH2O (L = baep, x = 0.5; L = abap, x = 0; L = uns-penp, x = 1; L = dppa, x = 0; L = trpn, x = 1) are reported; little variation is observed in the geometry of the carbonate chelate ring while significant lengthening of bonds and expansion of angles involving the cobalt ion occurs as the number of six-membered chelate rings in the complex cations increases. 59Co NMR chemical shift data for the complexes show the expected linear relationship between λmax, the wavelength of the lowest energy dd transition, and γ, the magnetogyric ratio of the 59Co nucleus. An excellent correlation between Δ, the d orbital splitting parameter, and δ(59Co) also exists for these complexes. Rate data for the acid hydrolysis of [(L)Co(O2CO)]+ (L = uns-penp, dppa) in 1.0 M HClO4 differ by two orders of magnitude, and this is attributed to the differing steric accessibility of the endo O atoms in each complex. DFT calculations on the complexes reproduce the isomeric preferences, UV–Vis and 59Co NMR spectroscopic data well, provided that solvent effects are included.  相似文献   

10.
The series of complexes [XRu(CO)(L-L)(L′)2][PF6] (X = H, TFA, Cl; L-L = 2,2′-bipyridyl, 1,10-phenanthroline, 5-amino-1,10-phenanthroline and 4,4′-dicarboxylic-2,2′-bipyridyl; L′2 = 2PPh3, Ph2PC2H4PPh2, Ph2PCHCHPPh2) have been synthesized from the starting complex K[Ru(CO)3(TFA)3] (TFA = CF3CO2) by first reacting with the phosphine ligand, followed by reaction with the L-L and anion exchange with NaPF6. In the case of L-L = phenanthroline and L′2 = 2PPh3, the neutral complex Ru(Ph3P)(CO)(1,10-phenanthroline)(TFA)2 is also obtained and its solid state structure is reported. Solid state structures are also reported for the cationic complexes where L-L = phenanthroline, L2 = 2PPh3 and X = Cl and for L-L = 2,2′-bipyridyl, L2 = 2PPh3 and X = H. All the complexes were characterized in solution by a combination of 1H and 31P NMR, IR, mass spectrometry and elemental analyses. The purpose of the project was to synthesize a series of complexes that exhibit a range of excited-state lifetimes and that have large Stokes shifts, high quantum yields and high intrinsic polarizations associated with their metal-to-ligand charge-transfer (MLCT) emissions. To a large degree these goals have been realized in that excited-state lifetimes in the range of 100 ns to over 1 μs are observed. The lifetimes are sensitive to both solvent and the presence of oxygen. The measured quantum yields and intrinsic anisotropies are higher than for previously reported Ru(II) complexes. Interestingly, the neutral complex with one phosphine ligand shows no MLCT emission. Under the conditions of synthesis some of the initially formed complexes with X = TFA are converted to the corresponding hydrides or in the presence of chlorinated solvents to the corresponding chlorides, testifying to the lability of the TFA Ligand. The compounds show multiple reduction potentials which are chemically and electrochemically reversible in a few cases as examined by cyclic voltammetry. The relationships between the observed photophysical properties of the complexes and the nature of the ligands on the Ru(II) is discussed.  相似文献   

11.
Several (azido)iridium(III) complexes having a pentamethylcyclopentadienyl (Cp∗) group, [Cp∗Ir(N3)2(Ph2Ppy-κP)] (1: Ph2Ppy = 2-diphenylphosphinopyridine), [Cp∗Ir(N3)(Ph2Ppy-κP,κN)]CF3SO3 (2), [Cp∗Ir(N3)(dmpm)]PF6 (3: dmpm = bis(dimethylphosphino)methane), [Cp∗Ir(N3)(Ph2Pqn)]PF6··CH3OH (4··CH3OH: Ph2Pqn = 8-diphenylphosphinoquinoline), and [Cp∗Ir(N3)(pybim)] (5: Hpybim = 2-(2-pyridyl)benzimidazole) have been prepared and their crystal structures have been analyzed by X-ray diffraction. In complex 1, the Ph2Ppy ligand is only coordinated via the P atom (-κP), while in 2 it acts as a bidentate ligand through the P and N atoms (-κP,κN) to form a four-membered chelate ring. Comparing the structural parameters of the chelate ring in 2 with those of a similar five-membered chelate ring formed by Ph2Pqn in 4, it became apparent that the angular distortion in the Ph2Ppy-κP,κN ring was remarkable, although the Ir–P and Ir–N bonds in the Ph2Ppy-κP,κN ring were not elongated very much from the corresponding bonds in the Ph2Pqn-κP,κN ring. In the pybim complex 5, the five-membered chelate ring was coplanar with the pyridine and benzimidazolyl rings. With the related (azido)iridium(III) complexes analyzed previously, comparison of the structural parameters of the Ir–N3 moiety in [Cp∗IrIII(N3)(L–L′)]+/0 complexes reveals an anomalous feature of the 2,2′-bipyridyl (bpy) complex, [Cp∗Ir(N3)(bpy)]PF6.  相似文献   

12.
Reactivity of the ruthenium complexes [Ru(κ3-tptz)(PPh3)Cl2] (1) and [Ru(κ3-tpy)(PPh3)Cl2] (2) [tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine; tpy = 2,2′:6′,2″-terpyridine] with several α-amino acids [glycine (gly); leucine (leu); isoleucine (isoleu); valine (val); tyrosine (tyr); proline (pro) and phenylalanine (phe)] have been investigated. Cationic complexes with the general formulations [Ru(κ3-L)(κ2-L″)(PPh3)]+ (L = tptz or tpy; L″ = gly, leu, isoleu, val, tyr, pro, and phe] have been isolated as tetrafluoroborate salts. The resulting complexes have been thoroughly characterized by analytical, spectral and electrochemical studies. Molecular structures of the representative complexes [Ru(κ3-tptz)(val)(PPh3)]BF4 (6), [Ru(κ3-tpy)(leu)(PPh3)]BF4 (10) and [Ru(κ3-tpy)(tyr)(PPh3)]BF4 (13) have been determined crystallographically. The complexes [Ru(κ3-tptz)(leu)(PPh3)]BF4 (4), [Ru(κ3-tptz)(val)(PPh3)]BF4 (6), [Ru(κ3-tpy)(leu)(PPh3)]BF4 (10) [Ru(κ3-tpy)(tyr)(PPh3)] BF4·3H2O (13) exhibited DNA binding behavior and acted as mild Topo II inhibitors (10-40%). The complexes also inhibited heme polymerase activity of the malarial parasite Plasmodium yoelii lysate.  相似文献   

13.
The phosphite complexes cis-[PtMe2L(SMe2)] in which L = P(OiPr)3, 1a, or L = P(OPh)3, 1b, were synthesized by the reaction of cis,cis-[Me2Pt(μ-SMe2)2PtMe2] with 2 equiv. of L. If 4 equiv. of L was used the bis-phosphite complexes cis-[PtMe2L2] in which L = P(OiPr)3, 2a, or L = P(OPh)3, 2b, were obtained. The reaction of cis-[Pt(p-MeC6H4)2(SMe2)2] with 2 equiv. of L gave the aryl bis-phosphite complexes cis-[Pt(p-MeC6H4)2L2] in which L = P(OiPr)3, 2a′, or L = P(OPh)3, 2b′. Use of 1 equiv. of L in the latter reaction gave the bis-phosphite complex along with the starting complex in a 1:1 ratio.The complexes failed to react with MeI. The reaction of cis,cis-[Me2Pt(μ-SMe2)2PtMe2] with 2 equiv. of the phosphine PPh3 gave cis-[PtMe2(PPh3)2] and cis-[PtMe2(PPh3)(SMe2)] along with unreacted starting material. Reaction of cis-[PtMe2L(SMe2)], 1a and 1b with the bidentate phosphine ligand bis(diphenylphosphino)methane, dppm = Ph2PCH2PPh2, gave [PtMe2(dppm)], 8, along with cis-[PtMe2L2], 2. The reaction of cis-[PtMe2L(SMe2)] with 1/2 equiv. of the bidentate N-donor ligand NN = 4,4′-bipyridine yielded the binuclear complexes [PtMe2L(μ-NN)PtMe2L] in which L = P(OiPr)3, 3a, or L = P(OPh)3, 3b.The complexes were fully characterized using multinuclear NMR (1H, 13C, 31P, and 195Pt) spectroscopy.  相似文献   

14.
Diamagnetic ruthenium(II) complexes of the type [Ru(L)(CO)(B)(EPh3)] [where E = As, B = AsPh3; E = P, B = PPh3, py (or) pip and L = dibasic tridentate ligands dehydroacetic acid semicarbazone (abbreviated as dhasc) or dehydroacetic acid phenyl thiosemicarbazone (abbreviated as dhaptsc)] were synthesized from the reaction of [RuHCl(CO)(B)(EPh3)2] (where E = As, B = AsPh3; E = P, B = PPh3, py (or) pip) with different tridentate chelating ligands derived from dehydroacetic acid with semicarbazide or phenylthiosemicarbazide. All the complexes have been characterized by elemental analysis, FT-IR, UV–Vis and 1H NMR spectral methods. The coordination mode of the ligands and the geometry of the complexes were confirmed by single crystal X-ray crystallography of one of the complexes [Ru(dhaptsc)(CO)(PPh3)2] (5). All the complexes are redox active and are monitored by cyclic voltammetric technique. Further, the catalytic efficiency of one of the ruthenium complexes (5) was determined in the case of oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of N-methylmorpholine-N-oxide.  相似文献   

15.
Treating the complexes [Rh(TFA)(PPh3)2], [Rh(HFA)(PPh3)2], and [Rh(TFA)(Cod)] (TFA - trifluoroacetylacetonate, HFA - hexafluoroacetylacetonate, Cod - 1,5 cyclooctadiene) with an excess of NaBPh4 in acetonitrile yields the rhodium(I) complexes with coordinated [BPh4] anion, [Rh(PPh3)2(π-PhBPh3)] · 2MeCN (I) and [Rh(Cod)(π-PhBPh3)] (II). The reactions present a new example of β-diketonate ligand replacement. The 1H, 31P, and 11B NMR spectra of I and II are discussed. [Rh(PPh3)2(π-PhBPh3)] has been characterized by single crystal X-ray analysis.  相似文献   

16.
The chiral ligand S-(Ph2P)2N(CHMePh) reacts with Ni(CO)4 in benzene solution to yield the mononuclear complex [Ni(CO)22-(PPh2)2N(CHMePh)}] (1). The reactions of the chiral ligand with the solvated complexes [(η5-C5Me5)MCl(solvent)2]BF4 (M = Rh, Ir) or with the binuclear complex [{(η6-C6Me6)RuCl}2(μ-Cl)] in the presence of a chloride scavenger, give cationic complexes of the type [(ηn-ring)MCl{κ2-(PPh2)2N(CHMePh)}]BF4n-ring = η5-C5Me5; M = Rh (2), Ir (3). η6-C6Me6; M = Ru (4)]. The 31P NMR spectra of compounds 2-4 show two signals corresponding of two phosphorus nuclei with different chemical environments. The related complex [(η5-C5H5)Fe(CO){κ2-(PPh2)2N(CHMePh)}]BF4 (5) was prepared by reaction of the ligand with the complex [(η5-C5H5)Fe(CO)2I] in toluene following by a metathesis with AgBF4. This compound exhibits only one signal in the 31P NMR spectra at room temperature, which splits into two signals at low temperature (213 K). The crystal structures of complexes 2, 3 and 5 have been determined by X-ray diffraction studies. All complexes show the presence of an intramolecular π-stacking interaction. The separation between least-squares planes defined by the two intramolecularly stacked phenyl rings are in the range 3.318-3.649 Å.  相似文献   

17.
A series of germylene and stannylene (Me2NCH2CH2O)2E (E = Ge, 1; E = Sn, 2) complexes of group 6 metals and iron carbonyls L·M(CO)n (M = Cr, Mo, W, n = 5 (3-8), n = 4 (9, 10); M = Fe, n = 4 (11, 12)) were prepared. These complexes were characterized by 1H, 13C NMR, FTIR and elemental analysis. Ligand properties of 1 and 2 were compared to PPh3 and dmiy (N,N′-dimethylimidazolin-2-ylidene) using theoretical calculations (PBE/TZ2P) and FTIR. Ligand dissociation energies increase in the order Ph3P < 21 < dmiy, while donor strength rise in the order PPh< dmiy < 2 < 1.  相似文献   

18.
Fe(CO)4X2 complexes [X = I (1), Br(1′)] react with phosphine ligands L (L = PMe3, PEt3, PMe2Ph, PMePh2, PPh3) via a two-step mechanism: in the first step fac-Fe(CO)3LX2 complexes are formed; in the second step two parallel pathways, a and b, are observed; in pathway a, reductive elimination with formation of equimolar amounts of Fe(CO)3L2 (5) and phosphonium salts [LX]+X is observed; in pathway b, disubstituted dihalide complexes cis,trans,cis-Fe(CO)2L2X2 are formed. The relative weights of pathways a and b depend on the basicity, steric hindrance and concentration of ligand L, on the nature of the halogen and on temperature. A radical mechanism which accounts for most of the experimental results is proposed.  相似文献   

19.
The salts [S(NMe2)3][MF6] (M = Nb, 2a; M = Ta, 2b) and [S(NMe2)3][M2F11] (M = Nb, 2c; M = Ta, 2d) have been prepared by reacting MF5 (M = Nb, 1a; M = Ta, 1b) with [S(NMe2)3][SiMe3F2] (TASF reagent) in the appropriate molar ratio. The solid state structure of 2b has been ascertained by X-ray diffraction. The 1:1 molar ratio reactions of 1a with a variety of organic compounds (L) give the neutral adducts NbF5L [L = Me2CO, 3a; L = MeCHO, 3b; L = Ph2CO, 3c; L = tetrahydrofuran (thf), 3d; L = MeOH, 3e; L = EtOH, 3f; L = HOCH2CH2OMe, 3g; L = Ph3PO, 3h; L = NCMe, 3i] in good yields. The complexes MF5L [M = Nb, L = HCONMe2, 3j; M = Nb, L = (NMe2)2CO, 3k; M = Ta, L = (NMe2)2CO, 3l; M = Nb, L = OC(Me)CHCMe2, 3m] have been detected in solution in admixture with other unidentified products, upon 2:1 molar reaction of 1 with the appropriate reagent L. The ionic complexes [NbF4(tht)2][NbF6], 4a, and [NbF4(tht)2][Nb2F11], 4b, have been obtained by combination of tetrahydrothiophene (tht) and 1a, in 1:1 and 2:3 molar ratios, respectively. The treatment of 1 with a two-fold excess of L leads to the species [MF4L4][MF6] [M = Nb, L = HCONMe2, 5a; M = Ta, L = HCONMe2, 5b; M = Nb, L = thf, 5c; M = Ta, L = thf, 5d; M = Nb, L = OEt2, 5e]. The new complexes have been fully characterised by NMR spectroscopy. Moreover, the revised 19F NMR features of the known compounds MF5L [M = Ta, L = Me2CO, 3n; M = Ta, L = Ph2CO, 3o; M = Ta, L = MePhCO, 3p; M = Ta, L = thf, 3q; M = Nb, L = CH3CO2H, 3r; M = Nb, L = CH2ClCO2H, 3s; M = Ta, L = CH2ClCO2H, 3t], TaF4(acac), TaF4(Me-acac) and [TaF(Me-acac)3][TaF6] (Me-acac = methylacetylacetonato anion) are reported.  相似文献   

20.
Photoirradiation of a toluene solution of [ReH(CO)3(L)] [S. Bolaño, J. Bravo, R. Carballo, S. García-Fontán, U. Abram, E.M. Vázquez-López, Polyhedron 18 (1999) 1431-1436] [L = 1,2-bis(diphenylphosphinoxy)ethane] in the presence of PPhn(OR)3−n (n = 0, 1; R = Me, Et) leads to the replacement of a CO ligand by the corresponding monodentate phosphite or phosphonite ligand to give new hydride compounds of formula [ReH(CO)2(L)(L′)] [L′ = P(OMe)3 (1); P(OEt)3 (2); PPh(OMe)2 (3); PPh(OEt)2 (4)]. Protonation of compounds 1-4 in CD2Cl2, with HBF4.OMe2 or with HOOCCF3 at 193 K in a NMR tube, gave the corresponding dihydrogen complexes. When the temperature was increased from 193 to 293 K, the η2-H2 ligand was replaced by OMe2 or OOCCF3 groups (depending on the acid employed) to give new stable complexes and the loss of H2 gas.  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