Alkylation of [Pt2(μ-S)2(PPh3)4] with boronic acid derivatives

The reactivity of the metalloligand [Pt₂(μ-S)₂(PPh₃)₄] with the boron-functionalized alkylating agents BrCH₂(C₆H₄)B(OR)₂ (R = H or C(CH₃)₂) was investigated by electrospray ionization mass spectrometry (ESI-MS) in real time using pressurized sample infusion (PSI). The macroscopic reaction of [Pt₂(μ-S)₂(PPh₃)₄] with one mole equivalent of alkylating agents BrCH₂(C₆H₄)B{OC(CH₃)₂}₂ and BrCH₂(C₆H₄)B(OH)₂ gave the dinuclear monocationic μ-sulfide thiolate complexes [Pt₂(μ-S){μ-SCH₂(C₆H₄)B{OC(CH₃)₂}₂}(PPh₃)₄]⁺ and [Pt₂(μ-S){μ-S⁺CH₂(C₆H₄)B(OH)(O^?)}(PPh₃)₄]. The products were isolated as the [PF₆]^? salt and zwitterion, respectively, and fully characterized by ESI-MS, IR, ¹H and ³¹P NMR spectroscopy, and single-crystal X-ray structure determinations.     

A zwitterionic monoalkylated derivative of [Pt2(μ-S)2(PPh3)4] from 1,3-propanesultone

Reaction of dinuclear platinum(II) sulfido complex [Pt₂(μ-S)₂(PPh₃)₄] with 1,3-propanesultone gives the novel zwitterionic monoalkylated thiolate complex [Pt₂(μ-S){μ-S(CH₂)₃SO₃}·(PPh₃)₄], which was characterized by NMR spectroscopy, electrospray ionisation mass spectrometry, and a single crystal X-ray structure determination. Crystals are monoclinic, space group P2(1)/c with unit cell dimensions a = 16.8957(3) Å, b = 15.5031(3) Å, c = 28.0121(5) Å, β = 99.780(1)°, for Z = 4.     

Further investigations on the methylation chemistry of [Pt2(µ-S)2(PPh3)4]

The methylation product of the reaction between [Pt₂(µ-S)₂(PPh₃)₄] and MeI in diethyl ether has been reinvestigated using positive-ion electrospray mass spectrometry and found to be contaminated with the dimethylated iodide-containing complex [Pt₂(µ-SMe)₂(PPh₃)₃I]⁺, which is believed to be formed early in the reaction. New, facile routes to the monomethylated complex [Pt₂(µ-S)(µ-SMe)(PPh₃)₄]⁺ have been developed using mild methylating agents. Heating [Pt₂(µ-S)₂(PPh₃)₄] in neat dimethyl methylphosphonate results in rapid and selective conversion to [Pt₂(µ-S)(µ-SMe)(PPh₃)₄]⁺; methylation with Me₃S⁺OH^? in refluxing methanol also affords pure [Pt₂(µ-S)(µ-SMe)(PPh₃)₄]⁺, isolated as its hexafluorophosphate salt. The X-ray structure of the previously reported complex [Pt₂(µ-SMe)₂(PPh₃)₂I₂] has also been undertaken.     

Immobilization of [Pt2(μ-S)2(PPh3)4] on Polymeric Supports by Sulfide Alkylation and Phosphine Exchange Reactions

Abstract

The immobilization of the dinuclear platinum(II) sulfido complex [Pt₂(μ-S)₂ (PPh₃)₄] on solid supports has been investigated. Reaction with haloalkyl functionalized polymers [Merrifield's resin (chloromethylated polystyrene), chloropropyl silica, chloropropyl controlled pore glass, and bromopropyl polysiloxane] gives complexes immobilized through alkylation of one of the sulfide ligands, forming a μ-thiolate ligand acting as an anchor to the polymer support, akin to well-established reactions of [Pt₂(μ-S)₂(PPh₃)₄] with molecular alkylating agents. The model complex [Pt₂(μ-S)(μ-SCH₂SiMe₃)(PPh₃)₄]PF₆ was prepared as the first molecular silicon-containing derivative of [Pt₂(μ-S)₂(PPh₃)₄] and was fully characterized by NMR spectroscopy, electrospray ionization-mass spectrometry, and single-crystal X-ray diffraction. Immobilization of [Pt₂(μ-S)₂(PPh₃)₄] by phosphine exchange reactions was also achieved using commercial polystyrene-grafted triphenylphosphine or a new immobilized phosphine [derived by sequential functionalization of Merrifield's resin with a polyether amine and then Ph₂PCH₂OH].     

Synthesis and Structure of the Complex [Mo3(μ3-S)(μ2-S2)3(Et2NCS2)3 +Br-

Tri-₂-disulfido-₃-thiotris(diethyldithiocarbamato)-S,S'-triangle-trimolybdenum bromide [Mo₃(₃-S)(₂-S₂)₃(Et₂NCS₂)₃ ⁺Br^- was obtained and characterized.     

Cluster synthesis. 42. The synthesis and crystal and molecular structures of the sulfur-bridged platinum-ruthenium carbonyl cluster compounds PtRu3(CO)9 L(PPh3)(μ3-S)2 (L=CO,PPh3) and PtRu4(CO)12(PPh3)(μ4-S)2

Two new mixed metal cluster complexes PtRu₃(CO)₁₀(PPh₃)(₃-S)₂,3 14% yield and PtRu₃(CO)₉(PPh₃)₂(₃-S)₂,4 23% yield were obtained from the reaction of Ru₃(CO)₉(₃-S)₂,1 with Pt(PPh₃)₂(C₂H₄) at 0°C. The cluster of4 consists of a spiked triangle of four metal atoms with two triply bridging sulfido ligands. The reaction of Ru₄(CO)₁₁(₄-S)₂,2 with Pt(PPh₃)₂(C₂H₄) yielded the expanded mixed-metal cluster complex PtRu₄(CO)₁₂(PPh₃)(₄-S)₂,5 in 12% yield. The structure of the cluster5 can be described as a pentagonal bipyramid of five metal atoms and two sulfido ligands with one metal-metal bond missing. Compounds4 and5 were characterized by a single-crystal X-ray diffraction analyses.     

E/Z isomerism in monoalkylated derivatives of [Pt2(µ-S)2(PPh3)4] containing 2,4-dinitrophenylhydrazone substituents

Alkylation of [Pt₂(µ-S)₂(PPh₃)₄] with 2,4-dinitrophenylhydrazone-functionalized alkylating agents XC₆H₄C{=NNHC₆H₃(NO₂)₂}CH₂Br (X?=?H, Ph) gives monoalkylated cations [Pt₂(µ-S){µ-SCH₂C{=NNHC₆H₃(NO₂)₂}C₆H₄X}(PPh₃)₄]⁺. An X-ray diffraction study on [Pt₂(µ-S){µ-SCH₂C{=NNHC₆H₃(NO₂)₂}Ph}(PPh₃)₄]BPh₄ shows the crystal to be the Z isomer, with the phenyl ring and NHC₆H₃(NO₂)₂ groups mutually trans. ¹H- and ³¹P{¹H} NMR spectroscopic methods indicate a mixture of Z (major) and E (minor) isomers in solution, which slowly convert mainly to the E isomer. Reaction of [Pt₂(µ-S)₂(PPh₃)₄] with the dinitrophenylhydrazone of chloroacetone [ClCH₂C{=NNH(C₆H₃(NO₂)₂}Me] and NaBPh₄ gives [Pt₂(µ-S){µ-SCH₂C{=NNHC₆H₃(NO₂)₂}Me}(PPh₃)₄]BPh₄, which exists as a single (E) isomer.     

Platinum-silver clusters: synthesis and crystal structure of [Pt3Ag(μ-CO)3(PPh3)5]ClO4 · 2H2O

Reaction of [NBu₄]₂[Pt₁₂(CO)₂₄] with [Ag(PPh₃)₄]ClO₄ and PPh₃ leads to two isolable platinum-silver clusters; the title complex was characterised by single crystal X-ray diffraction. the Pt₃Ag core is tetrahedral; one Pt atom is seven-coordinated, the other two are six-coordinate.     

Synthesis of the five-coordinate organoplatinum cation [PtMe(pp3)]+ (pp3 =P(CH2CH2PPh2)3) by oxidative addition of methyl iodide to [Pt2(μ-pp3)2]

The complex [Pt₂(μ-pp₃)₂] (pp₃ = P(CH₂CH₂PPh₂)₃), produced by treatment of [PtH(pp₃)]⁺ with sodium amalgam, has been shown to react with methyl iodide to give [PtMe(pp₃)]⁺. The new complexes have been characterized by ¹H, ³¹P and ¹⁹⁵Pt NMR spectroscopy.     

Synthesis and characterisation of novel selenium-containing clusters; crystal structures of [Ru4(μ4-Se)2(CO)8(μ-CO)3] and [Ru3(μ3-Se)2(CO)7(Ph2P(CH2)3PPh2)]

The compound [Ru₄(μ-Se)₂(CO)₈(μ3-CO)₃] (1), has been obtained in good yield by vacuum pyrolysis of [RU₃(CO)₁₂] with [Ph₂Se₂] at 185°C. Reaction of 1 with 1,3-bis(diphenylphosphino)propane at room temperature affords the novel cluster [RU₃(μ₃-Se)₂(CO)₇(Ph₂P(CH₂)₃PPh₂)] (2). The structures of 1 and 2 have been determined by an X-ray diffraction study.     

Synthesis and Structure of the Copper(Ⅰ) Complex [Cu(PPh3)2(BH4)]

Mononuclear copper( Ⅰ ) complex [Cu(PPh3)2(BH4)] has been synthesized by ligand replacement reaction in methanol and characterized by elemental analyses, molecular weight determination, IR spectra and X-ray single crystal analysis,its conductivity has also been measured. The crystal is monoclinic, space group C2/c, a =24.776(4), b=9.173(7), c=15.564(2)A; β=116.10(1)°, V=3176.73 A3, Z =4, F(000)=1256, μ(MoKα)=8.11 cm-1, Dc=1. 26 g/cm3, M=602.79, R=0. 039, Rw= 0. 050. The results show that PPh3 coordinates as monodentate ligand to the Cu ( Ⅰ ) atoms, and BH4 behaves as a bidentate ligand in the prepared complex.The central copper atom belongs to tetrahedron coordination geometry.     

Nickel-Ruthenium Mixed-Metal Carbonyl Clusters Syntheses and Solid State Structures of the Two Tetrahedral Clusters [PPh4][NiRu3(μ3 H)(CO)9(μ-CO)3] and [NEt4]2[NiRu3(CO)8(μ-CO)4]

Redox condensation of [Ru₃H(CO)₁₁]- with Ni(CO)₄, in tetrahydrofuran solution, under a nitrogen atmosphere, yields the tetranuclear anion [NiRu_H(CO)₁₁)-. Subsequent deprotonation with Bu'OK in acetonitrile solution leads to the formation of the related dianion. Both anions have been characterized by spectroscopic techniques, elemental analysis and single crystal X-ray diffraction. [PPh₄][NiRu₃H(CO)₁₂] crystallizes in the triclinic space group PI with unit cell dimensionsof a = 11.842(2) Å,b = 12.335(3) Å, c = 13.3080) Å,a = 91.89(2)°, = 93.35(1)°,y = 96.41(2)°, Z = 2, V= 1926.9(7) Å'. The NiRu₃, metal core of the molecule defines a distorted tetrahedron with nine terminal and three edge bridging carbonyl groups. The hydrido ligand was located by difference Fourier techniques and was found to bridge the NiRu₂ basal triangle at a distance of 0.88(6) A from this plane. Selected average distances and angles are: Ru-Ru = 2.839 Å, Ru-Ni = 2.640 Å, Ru-C, = 1.910 A,Ru-C _b = 2.084 Å, Ni-C _b = 2.022 Å, Ru-H = 1.77 Å, C-0, = 1.135 Å, C-O _b = 1.159 Å, M-C-O, = 176.3°,M-C--O _b = 139.3°;other distances are: Ni-C₁ = l.758(7) Å, Ni-H= 1.85(7) Å. [NEt₄]₂[NiRu₃(CO)₁₂] crystallizes in the orthorhombic space group Pnma (no. 62) with unit cell dimensions ofa=20.247(5) Å,b = 15.038(4)Å,c = 12.079(3) Å, Z=4, V=3678(2) A'. The molecule contains a tetrahedral NiRu₃ core with eight terminal and four edge bridging carbon monoxide groups which bridge the three Ni-Ru and one Ru-Ru bond. Average distances and angles are: Ru -Ru =2.3050A Ru-Ni 2.648 Å, Ru-C _t = 1.878 Å, Ru-C _b 2.045 Å, Ni-C _b = 2.055 Å, C-O _t = 1.145 Å, C-01,=1.157 Å, M-C-O,= 176.9°, M-C-O _b = 138.6°; other distance is: Ni-C _t = 1.754(10) Å,t = terminal,b = bridging.     

Studies pertaining to the mechanism of “Pt(PCy3)“ addition. The reaction of MPt(μ-H)(μ-PnPr2)Pt(CO)(PCy3) with Pt(C2H4)2(PCy3)

The reaction of Pt(C₂H₄)₂(PCy₃) with (OC)₄M(μ-H)(μ-PⁿPr₂)Pt(CO)(PCy₃, (1: M  Cr, Mo, W) occurs in a highly specific, kinetically controlled manner to give MPt₂(μ²_MPt-CO)(η²_PtPt-H)(μ²_MPt-PⁿPr₂)(CO)₄ (PCy₃)₂ (5), as the first formed trimer. The trimer 5 (M  Mo, W) isomerizes to give MPt₂(μ²_PtPt-CO) ((μ²_MPtH)(μ²_MPt-PⁿPr₂)(CO)₄)PCy₃)₂ (6) which in turn isomerizes to MPt₂μ²_MPtCO)(μ²_MPt (μ²_PtPt-PⁿPr₂)(CO)₄(PCy₃)₂ (7, as the final isolable product. These results provide a detailed insight into the mechanism of “Pt(PCy₃) addition”, a cluster assembly process.     

(μ3-S)Fe2CoCu(PPh3)2(CO)8催化苯乙烯环丙烷化反应研究

以异核金属原子簇合物为催化剂的配位催化反应, 已在均相催化反应中得到应用. 簇合物中不同金属间的协同作用使其在催化领域展现出广阔的应用前景[1]. 然而,催化反应中簇合物是否以完整的骨架起催化作用,一直是人们关注的焦点. 在金属原子簇作催化剂前体的均相催化反应中,迄今只在少数的例子中有确凿的证据表明原子簇整体分子起催化作用[2]. 一般认为,在配位饱和的金属簇合物的催化反应中,簇合物稳定性越好,催化活性越差;而活性好的催化剂前体,簇合物骨架常解体.     

Properties of a New 58-Electron Butterfly [Pt4(μ2-dpam)3(μ2-CO)3(η1-dpam)]2+ Cluster

A new organometallic cluster [Pt₄(₂-dpam)₃(₂-CO)₃(¹-dpam)] X₂ (X=CF₃CO ₂ ^- ; 4a) was prepared from a reaction between Pt(dpam)(CF₃CO₂)₂ and CO in a methanol (water mixture). The PF ₆ ^- salt 4b is obtained from an anion exchange with NH₄PF₆ in methanol. Dark red crystals suitable for X-ray crystallography (X=PF ₆ ^- ) revealed the commonly encountered butterfly structure for a 58-electron Pt cluster (angle between the two Pt₃ planes =95.36(8)°, nonbonding Pt...Pt distance =3.094(1) Å). The structure consists of two edge sharing Pt₃ triangles, a small one 'Pt₃(₂-dpam) ₃ ²⁺ and a larger one Pt₃(₂-CO)₃(L)₃ where L=As group. The Extended Huckel Molecular Orbital calculations (EHMO) have been rationalized from interactions of two L and PtL ₂ ²⁺ fragments onto the planar triangular Pt₃(₂-CO)₃L₃ cluster (L = AsH₃). The compound is luminescent at 77 K with a structureless band located at 690 nm (_e=3.2 ±0.2s). Finally, the ¹H NMR spectra are interpreted, particularly with respect to fluxionality and presence of two isomers. X-ray data for 4b: orthorhombic, C c2a, a=26.320(9), b=27.613(6), c=28.891(4) Å, V=20998(9) ų, Z=4, D(calc.)=1.925 Mg/m³.