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1.
In ongoing attempts of directed synthesis of high-nuclearity Au-Pt carbonyl/phosphine clusters with [Ni6(CO)12]2- used as reducing agent and CO source, we have isolated and characterized two new closely related variable-stoichiometric trimetallic clusters, Pt3(Pt(1-x)Ni(x))(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1) and Pt2(Pt(2-y)Ni(y))(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2). Their M4Au2 cores may be envisioned as substitutional disordered butterfly-based M4Au2 frameworks (M = Pt/Ni) formed by connections of the two basal M(B) atoms with both (Au-Au)-linked Au(PPh3) moieties. Based upon low-temperature CCD X-ray diffraction studies of eight crystals obtained from different samples, ligation-induced site-specific Pt/Ni substitutional disorder (involving formal insertion of Ni in place of Pt) in a given crystal was found to occur only at the one OC-attached basal M(B) site in 1 or at both OC-attached basal M(B) sites in 2 corresponding to a crystal composite of the Pt3(Pt(1-x)Ni(x))Au2 core in 1 or of the Pt2(Pt(2-y)Ni(y))Au2 core in 2; the Ph3P-attached M(B) site (M(B) = Pt) in 1 and two wingtip M(w) sites (M(w) = Pt) in 1 and 2 were not substitutionally disordered. The resulting variable stoichiometry of the M4Au2 core in 1 may be viewed as a crystal composite of two superimposed individual stereoisomers, Pt4(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1a) and Pt3Ni(AuPPh3)2(mu2-CO)4(CO)(PPh3)3 (1b), in the averaged unit cell of a given crystal. Likewise, 2 represents the crystal-averaged composite of three individual stereoisomers, Pt4(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2a), Pt3Ni(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2b), and Pt2Ni2(AuPPh3)2(mu2-CO)4(CO)2(PPh3)2 (2c). Formal Ni substitution for Pt at only the basal M(B) site(s) in the four crystal composites each of 1 and 2 was found to vary widely from 17% to 79% Ni in 1 and from 21% to 95% Ni in 2. Nevertheless, reasonably close Pt/Ni occupancy factors were found within each of the four pairs of composite crystals selected from samples obtained from duplicate syntheses. Both 1 and 2 may be formally derived from the electronically equivalent classic butterfly Pt4(mu2-CO)5(PPh3)4 cluster by replacement of its bridging mu2-CO ligand spanning the basal M(B)-M(B) edge with two one-electron donating (Au-Au)-linked AuPPh3 moieties along with the substitution of a terminal CO in place of one or both M(B)-attached PPh3 ligands in 1 and 2, respectively; site-specific Pt/Ni substitutional disorder occurs only at the CO-attached M(B) sites. The variable-stoichiometric 1 and 2 re also electronically equivalent and geometrically related to the crystal-ordered butterfly-based Pt4(mu2-CO)4(PR3)4(mu3-HgX)2 clusters (R3 = Ph3, MePh2; X = CF3, Br, I).  相似文献   

2.
This research constitutes an operational test to assess the influence of platinum-attached phosphine ligands in the formation process of "open-face" TlPt3 or "full" Pt3TlPt3 sandwich clusters. Accordingly, the reaction of TlPF6 with triphenylphosphine Pt4(mu2-CO)5(PPh3)4, under essentially identical boundary conditions originally used to prepare (90% yield) the triethylphosphine "full" Pt3TlPt3 sandwich, [(mu6-Tl)Pt6(mu2-CO)6(PEt3)6]+ (3) ([PF6]- salt), from Pt4(mu2-CO)5(PEt3)4 was carried out to see whether it would likewise afford the unknown triphenylphosphine Pt3TlPt3 sandwich analogue of or whether the change of phosphine ligands from sterically smaller, more basic PEt3 to PPh3 would cause the product to be the corresponding unknown triphenylphosphine "open-face" TlPt3 sandwich that would geometrically resemble the known bulky tricyclohexylphosphine [(mu3-Tl)Pt3(mu2-CO)3(PCy3)3]+ sandwich (2a). Both the structure and composition of the resulting "open-face" sandwich product, [(mu3-Tl)Pt3(mu2-CO)3(PPh3)3]+ (1a) ([PF6]- salt), were unequivocally established from a low-temperature CCD X-ray crystallographic determination. The calculated Pt/Tl atom ratio (3/1) of 75%/25% is in excellent agreement with that of 72(3)%/28(5)% obtained from energy-resolved measurements on a single crystal with a scanning electron microscope. Crystals (80% yield) of the orange-red were characterized by solid-state/solution IR and variable temperature 205Tl and 31P{1H} NMR spectra; the 31P{1H} spectra provide convincing evidence that is exhibiting dynamic behavior at room temperature in CDCl3 solution. The corresponding new "open-face" (mu3-AuPPh3)Pt3 sandwich, [(mu3-AuPPh3)Pt3(mu2-CO)3(PPh3)3]+ (1b) ([PF6]- salt), was quantitatively obtained from by reaction with AuPPh3Cl and spectroscopically characterized by IR and 31P{1H} NMR spectra. A comparative geometrical evaluation of the observed steric dispositions of the platinum-attached PR3 ligands in the "open-face" (mu3-Tl)Pt3 sandwiches of (with PPh3) and the known (with PCy3) and in the known "full" Pt3TlPt3 sandwich of (with PEt3) along with the considerably different observed steric dispositions of the PR(3) ligands in the known "open-face" (mu3-AuPCy3)Pt3 sandwich of (with PCy3) and in the known "full" Pt3AuPt3 sandwich of (with PPh(3)) has been performed. The results clearly indicate that, in contradistinction to the known triphenylphosphine Pt3AuPt3 sandwich of , PPh3 and bulkier PCy3 ligands of Pt3(mu2-CO)3(PR3)3 units are sterically too large to form "full" Pt3TlPt3 sandwiches. In other words, the nature of the thallium(I) sandwich-product in these reactions is sterically controlled by size effects of the phosphine ligands. Comparative examination of bridging carbonyl IR frequencies of and with those of closely related "open-face" and "full" sandwiches provides better insight concerning the relative electrophilic capacities of Tl+, Au+, and [AuPR3]+ components in forming sandwich adducts with Pt3(mu2-CO)3(PR3)3 nucleophiles.  相似文献   

3.
4.
New Research of Reaction Behaviour of Triorganylcyclotriphosphines. The Crystal Structures of [(PPh3)2Pt(PtBu)3], [(PPh3)2Pd(PtBu)2], [(CO)4Cr{(PiPr)3}2], [RhCl(PPh3)(PtBu)3], [(NiCO)62-CO)3{(PtBu)2}2], and [(CpFeCO)2(μ-CO)(μ-PHtBu)]+ · [FeCl3(thf)] By the reaction of triorganylcyclotriphosphines with transition metal complexes single- and polynuclear compounds are formed, in which the cyclophosphines are bonded in different ways to the metal, the ring either preserving structure or under going ring opening. Depending on the reaction conditions the following compounds can be characterized: [(PPh3)2Pt(PtBu)3] ( 1 ), [(PPh3)2Pd(PtBu)2] ( 2 ), [(CO)4Cr{(PiPr)3}2] ( 3 ), [RhCl(PPh3)(PtBu)3] ( 4 ), [(NiCO)62-CO)3{(PtBu)2}2] ( 5 ) and [(CpFeCO)2(μ-CO)(μ-PHtBu)]+ · [FeCl3(thf)] ( 6 ). The structures of 1 – 6 were obtained by X-ray single crystal structure analysis ( 1 : space group P21/n (No. 14), Z = 4, a = 1279.6(3) pm, b = 1733.1(4) pm, c = 2079.1(4) pm, β = 90.20(3)°; 2 : space group P21/c (No. 14), Z = 4, a = 1053.3(2) pm, b = 2085.2(4) pm, c = 1855.7(4) pm, β = 98.77(3)°; 3 : space group P 1 (No. 2), Z = 2, a = 1022.6(2) pm, b = 1026.4(2) pm, c = 1706.0(3) pm, α = 82.36(3)°, β = 86.10(3)°, γ = 64.40(3)°; 4 : space group P 1 (No. 2), Z = 2, a = 980.2(2) pm, b = 1309.5(3) pm, c = 1573.4(3) pm, α = 99.09(3)°, β = 99.46(3)°, γ= 111.87(3)°; 5 : space group P21/c (No. 14), Z = 4, a = 1804.0(5) pm, b = 2261.2(6) pm, c = 1830.1(7) pm, β = 96.99(3)°; 6 : space group P21/c (No. 14), Z = 4, a = 943.2(3) pm, b = 2510.6(7) pm, c = 1325.1(6) pm, β = 98.21(3)°).  相似文献   

5.
New platinum-mercury clusters, Pt4(HgX)2(μ-CO)4(PR3)4 (X=Cl, Br, I, CF3, or CCl3; R=Ph or Et), were synthesized. The molecular and crystal structure of the Pt4(HgBr)2(μ-CO)4(PPh3)4 cluster was established by X-ray structural analysis.  相似文献   

6.
7.
The cluster compounds [Pt3(μ-CO)3(PR3)3] act as Lewis bases towards the metal halides of Group XI, MX, Group XII, MX2, and Group XIII, MX3, to form cluster compounds of the composition [{MXn}{Pt3(μ-CO)3(PR3)3}]. The X-ray crystal structure, NMR and IR data are given for the compound [{ZnI}{Pt3(μ-CO)3(PPh(i-Pr)2)3}].  相似文献   

8.
The synthesis and structure of [{MgCl(thf)2}3(mu3-C3H5)2]2[Mg(C3H5)4], which contains both a cationic cluster Grignard and a tetraorganomagnesiate dianion, are reported.  相似文献   

9.
The new Pt-Au hydrido cluster compound [(H)Pt(AuPPh(3))(9)](NO(3))(2) (3) has been synthesized and characterized by NMR, FABMS, and single-crystal X-ray diffraction [triclinic, P&onemacr;, a = 17.0452(1) ?, b = 17.4045(2) ?, c = 55.2353(1) ?, alpha = 89.891(1) degrees, beta = 85.287(1) degrees, gamma = 75.173(1) degrees, V = 15784.0(2) ?(3), Z = 4 (two molecules in asymmetric unit), residual R = 0.089 for 45 929 observed reflections and 3367 variables, Mo Kalpha radiation]. The Pt(AuP)(9) core geometry is a distorted icosahedron with three vertices vacant. The Pt-Au, Au-Au, and Au-P distances are within the normal ranges observed in other Pt-Au clusters. This cluster is a catalyst for H(2)-D(2) equilibration in homogeneous solution phase and has been used in a general mechanistic study of this reaction catalyzed by Pt-Au clusters. We previously proposed that a key step in the mechanism for catalytic H(2)-D(2) equilibration is the dissociation of a PPh(3) ligand to give a cluster with an open Au site for bonding of H(2) or D(2). This was based on qualitative observations that PPh(3) inhibited the rate of HD production with [Pt(AuPPh(3))(8)](NO(3))(2) (1) as catalyst. In order to test this hypothesis, phosphine inhibition (on the rate of HD production) and phosphine ligand exchange kinetic experiments were carried out with [(H)(PPh(3))Pt(AuPPh(3))(7)](NO(3))(2) (2) and 3. In this paper we show that the rate constant for phosphine dissociation determined from the PPh(3) inhibition rate study of H(2)-D(2) equilibration with cluster 2 is nearly identical to the rate constant for dissociative phosphine ligand exchange. The slower rate for H(2)-D(2) equilibration observed with 3 compared with 2 (5.5 x 10(-3) vs 7.7 x 10(-2) turnover s(-1)) is explained by its smaller rate constant for phosphine dissociation (2.8 x 10(-5) vs 2.9 x 10(-4) s(-1)). The fact that clusters 2 and 3 show similar kinetic behaviors suggests that the PPh(3) dissociation step in the catalytic H(2)-D(2) equilibration is general for 18-electron hydrido Pt-AuPPh(3) clusters.  相似文献   

10.
Li Z  Loh ZH  Mok KF  Hor TS 《Inorganic chemistry》2000,39(23):5299-5305
Three heterometallic Au-Pt complexes [Pt2(PPh3)4(mu-S)(mu 3-S)Au(PPh3)][PF6] (2), [Pt2(PPh3)4(mu 3-S)2Au2(mu-dppm)]-[PF6]2 (3), and [Pt2(PPh3)4(mu 3-S)2Au2(mu-dppf)][PF6]2 (4) have been synthesized from Pt2(PPh3)4(mu-S)2 (1) [dppm = Ph2PCH2PPh2; dppf = (C5H4PPh2)2Fe] and characterized by single-crystal X-ray crystallography. In 2, the Au(I) atom is anchored on only one of the sulfur centers. In 3 and 4, both sulfur atoms are aurated, showing the ability of 1 to support an overhead bridge structure, viz. [Au2(P-P)], with or without the presence of Au-Au bond. The change of dppf to dppm facilitates such active interactions. Two stereoisomers of complex 3 (3a,b) have been obtained and characterized by single-crystal X-ray crystallography. NLDFT calculations on 2 show that the linear coordination mode is stabilized with respect to the trigonal planar mode by 14.0 kJ/mol. All complexes (2-4) are fluxional in solution with different mechanisms. In 2, the [Au(PPh3)] fragment switches rapidly between the two sulfur sites. Our hybrid MM-NLDFT calculations found a transition state in which the Au(I) bears an irregular trigonal planar geometry (delta G++ = 19.9 kJ/mol), as well as an intermediate in which Au(I) adopts a regular trigonal planar geometry. Complexes 3a,b are roughly diastereoisomeric and related by sigma (mirror plane) conversion. This symmetry operation can be broken down to two mutually dependent fluxional processes: (i) rapid flipping of the dppm methylene group across the molecular plane defined by the overhead bridge; (ii) rocking motion of the two Au atoms across the S...S axis of the (Pt2S2) core. Modeling of the former by molecular mechanics yields a steric barrier of 29.0 kJ/mol, close to that obtained from variable-temperature 31P(1Hz) NMR study (33.7 kJ/mol). In 4, the twisting of the ferrocenyl moiety across the S...S axis is in concert with a rocking motion of the two gold atoms. The movement of dppf is sterically most demanding, and hence, 4 is the only complex that shows a static structure at lower temperatures. Pertinent crystallographic data: (2) space group P1, a = 15.0340(5) A, b = 15.5009(5) A, c = 21.9604(7) A, alpha = 74.805(1) degrees, beta = 85.733(1) degrees, gamma = 78.553(1) degrees, R = 0.0500; (3a) space group Pna2(1), a = 32.0538(4) A, b = 16.0822(3) A, c = 18.9388(3) A, R = 0.0347; (3b) space group Pna2(1), a = 31.950(2) A, b = 16.0157(8) A, c = 18.8460(9) A, R = 0.0478; (4) space group P2(1)/c, a = 13.8668(2) A, b = 51.7754(4) A, c = 15.9660(2) A, beta = 113.786(1) degrees, R = 0.0649.  相似文献   

11.
de Silva N  Dahl LF 《Inorganic chemistry》2005,44(26):9604-9606
The preparation and molecular structure of the initial nanosized platinum-gold carbonyl cluster, Pt(13)[Au(2)(PPh(3))(2)](2)(CO)(10)(PPh(3))(4) (1), are described. A comparative analysis reveals its pseudo-D(2)(h) geometry, consisting of a centered Pt(13) icosahedron encapsulated by two centrosymmetrically related bidentate [Ph(3)PAu-AuPPh(3)]-capped ligands along with 4 PR(3) and 10 CO ligands, to be remarkably similar to that of the previously reported Pt(17)(mu(2)-CO)(4)(CO)(8)(PEt(3))(8) (2). Reformulation of 2 as Pt(13)[(PtPEt(3))(2)(mu(2)-CO)](2)(CO)(10)(PEt(3))(4) emphasizes the steric/electronic resemblance of the bulky-sized bidentate [Ph(3)PAu-AuPPh(3)] and [(PtPEt(3))(2)(mu(2)-CO)] capping ligands in 1 and 2, respectively, as well as their identical electron counts of 162 cluster valence electrons for a centered Pt(13) icosahedron. We hypothesize that analogous steric effects of their ligand polyhedra in 1 and 2 play a crucial role along with electronic effects in the formation and stabilization of these two nanosized clusters that contain an otherwise unknown centered icosahedron of platinum atoms.  相似文献   

12.
A novel complex Cu(PPh3)2(acac) 1 (PPh3 = triphenylphosphine, acac = acetylacetone) was obtained by a solution reaction and structurally characterized by X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 13.7361(8), b = 12.8204(7), c = 19.7638(13) , β = 95.946(2)°, C41H37CuO2P2, Mr = 687.19, V = 3461.7(4) 3, Z = 4, Dc = 1.319 g/cm3, S = 1.067, μ(MoKα) = 0.758 mm–1, F(000) = 1432, R = 0.0403 and wR = 0.0990. Complex 1 is characterized by an isolated structure. X-ray structure analysis of 1 shows that acac behaves as a chelating ligand and PPh3 coordinates as a monodentate ligand to the Cu(I) atoms. Photoluminescent investigation reveals that the title complex displays a strong green-light emission.  相似文献   

13.
14.
15.
We report about the first X-ray structure analyses of the CS2 and CO2 adducts with carbodiphosphorane C(PPh3)2 and the synthesis and X-ray structure analysis of group 6 carbonyl complexes with compound S2CC(PPh3)2 as a ligand [(CO)4MS2CC(PPh3)2] (M = Cr, Mo, W). The nature of the carbon-carbon bonding in X2CC(PPh3)2 and in the model compounds X2CC(PH3)2 and the metal-ligand bonding in [(CO)4MoS2CC(PH3)2] have been analyzed with charge and energy decomposition methods using DFT calculations. Carbodiphosphoranes C(PR3)2 are double electron pair donors having sigma- and pi-carbon lone-pair orbitals as the two highest occupied MOs.  相似文献   

16.
The hydroxo complex cis-[L2Pt(mu-OH)]2(NO3)2 (L = PMe2Ph), in various solvents, reacts with 1-methylcytosine (1-MeCy) to give as the final product the cyclic species cis-[L2Pt{1-MeCy(-H),N 3N 4}]3(NO3)3 (1) in high or quantitative yield. X-ray analysis of 1 evidences a trinuclear species with the NH(2)-deprotonated nucleobases bridging symmetrically the metal centers through the N3 and N4 donors. A multinuclear NMR study of the reaction in DMSO-d6 reveals the initial formation of the dinuclear species cis-[L2Pt{1-MeCy(-H),N 3N 4}]2(2+) (2), which quantitatively converts into 1 following a first-order kinetic law (at 50 degrees C, t(1/2) = 5 h). In chlorinated solvents, the deprotonation of the nucleobase affords as the major product (60-70%) the linkage isomer of 1, cis-[L2Pt{1-MeCy(-H)}]3(3+) (3), in which three cytosinate ligands bridge unsymmetrically three cis-L2Pt(2+) units. In solution, 3 slowly converts quantitatively into the thermodynamically more stable isomer 1. No polynuclear adducts were obtained with the hydroxo complex stabilized by PPh3. cis-[(PPh3)2Pt(mu-OH)]2(NO3)2 reacts with 1-MeCy, in DMSO or CH2Cl2, to give the mononuclear species cis-[(PPh3)2Pt{1-MeCy(-H)}(1-MeCy)](NO3) (4) containing one neutral and one NH2-deprotonated 1-MeCy molecule, coordinated to the same metal center at the N3 and N4 sites, respectively. X-ray analysis and NMR studies show an intramolecular H bond between the N4 amino group and the uncoordinated N3 atom of the two nucleobases.  相似文献   

17.
Pt(2)(mu-Se)(2)(PPh(3))(4) reacts with PtCl(2)(cod) to give (Pt(2)(mu(3)-Se)(2)(PPh(3))(4)[Pt(cod)])(2+) and an unexpected cod-rich product that arises from metal scrambling, viz. (Pt(mu(3)-Se)(2)(PPh(3))(2)[Pt(cod)](2))(2+). The formation of these species was detected and followed by electrospray mass spectrometry (ESMS) and subsequently verified by batch synthesis and crystallographic characterization. Other metal-scrambled aggregate products were successfully detected.  相似文献   

18.
19.
Thermolyses of [(PMe2Ph)2PdB8H12] and [(PMe2Ph)2PtB8H12] respectively yield eighteen-vertex [(PMe2Ph)2Pd2B16H20(PMe2Ph)2] and [(PMe2Ph)3Pt2B16H18(PMe2Ph)], which exhibit structure models for probable successive precursive intermediates for the more condensed macropolyhedral metallaboranes [(PMe2Ph)4Pt3B14H16], [(PMe2Ph)2Pt2B12H16] and [(PMe2Ph)2Pt2B16H15(C6H4Me)(PMe2Ph)] that have previously been reported as products from [(PMe2Ph)2PdB8H12] thermolyses.  相似文献   

20.
The reactions of the hydroxo complexes [M(2)R(4)(mu-OH)(2)](2)(-) (M = Pd, R = C(6)F(5), C(6)Cl(5); M = Pt, R = C(6)F(5)), [[PdR(PPh(3))(mu-OH)](2)] (R = C(6)F(5), C(6)Cl(5)), and [[Pt(C(6)F(5))(2)](2)(mu-OH)(mu-pz)](2-) (pz = pyrazolate) with H(2)S yield the corresponding hydrosulfido complexes [M(2)(C(6)F(5))(4)(mu-SH)(2)](2-), [[PdR(PPh(3))(mu-SH)](2)], and [[Pt(C(6)F(5))(2)](2)(mu-SH)(mu-pz)](2-), respectively. The monomeric hydrosulfido complexes [M(C(6)F(5))(2)(SH)(PPh(3))](-) (M = Pd, Pt) have been prepared by reactions of the corresponding binuclear hydrosulfido complexes [M(2)(C(6)F(5))(4)(mu-SH)(2)](2-) with PPh(3) in the molar ratio 1:2, and they can be used as metalloligands toward Ag(PPh(3))(+) to form the heterodinuclear complex [(C(6)F(5))(2)(PPh(3))[S(H)AgPPh(3)]], and toward Au(PPh(3))(+) yielding the heterotrinuclear complexes [M(C(6)F(5))(2)(PPh(3))[S(AuPPh(3))(2)]]. The crystal structures of [NBu(4)](2)[[Pt(C(6)F(5))(2)(mu-SH)](2)], [Pt(C(6)F(5))(2)(PPh(3))[S(H)AgPPh(3)]], and [Pt(C(6)F(5))(2)(PPh(3))[S(AuPPh(3))(2)]] have been established by X-ray diffraction and show no short metal-metal interactions between the metallic centers.  相似文献   

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