Design, synthesis and characterization of a Pt-Gd metal-organic framework containing potentially catalytically active sites

The heterobimetallic metal-organic framework {[(BPDC)PtCl(2)](3)(Gd(H(2)O)(3))(2)}.5H(2)O (BPDC = 2,2'-bipyridine-5,5'-dicarboxylate) has been designed and synthesized by hydrothermal methods. The new coordination polymer contains subunits of (BPDC)PtCl(2) (1) where both N atoms of the BPDC ligand are attached to a square-planar Pt(II) center. The two remaining cis coordination sites at Pt(II) are occupied by chloride ions. The final structure (2) of the polymeric network is obtained when Gd(III) ions link together the (BPDC)PtCl(2) units, which are organized in sheets, into larger blocks. These blocks are stacked along the crystallographic [010] direction and are held together by a hydrogen bonding scheme that involves carboxylate oxygen atoms and water molecules in the coordination sphere of Gd. The coordination polymer 2 can be obtained in a single-step reaction or in a two-step synthesis where the corresponding Pt complex (1) was first synthesized followed by reacting 1 with Gd(NO(3))(3).6H(2)O. In situ high temperature powder X-ray diffraction shows that the crystalline coordination polymer transforms into an anhydrous modification at 100 degrees C. This modification is stable to 350 degrees C, at which temperature the structure starts to decompose. The coordination sphere around platinum in the polymer closely resembles organometallic Pt complexes that have been previously found to catalytically or stoichiometrically activate and functionalize hydrocarbon C-H bonds in homogeneous systems.     

A Sn(IV)-porphyrin-based metal-organic framework for the selective photo-oxygenation of phenol and sulfides

A functional tin(IV)-porphyrin derivative was used as a building block to construct a novel 3D porous metal-organic framework (MOF). The MOF is built up from tin(IV)-porphyrin struts linking up Zn atoms and formates joining Sn(IV) centers. The immobilization of the photoactive Sn-porphyrins in the channel walls lets the MOF present remarkable photocatalytic activities for the oxygenation of phenol and sulfides, resulting in excellent yields and remarkable selectivity in heterogeneous phases.     

混合配体构筑的Zn(Ⅱ)金属有机骨架化合物的合成、 结构与荧光性质

在水热条件下, 利用锌离子与2种有机配体合成出1个结构新颖的金属有机骨架化合物[Zn₂(BPDC)(IN)₂](H₂BPDC=4,4'-联苯二羧酸; HIN=异烟酸), 并通过单晶X射线衍射、 红外光谱、 热重分析和荧光光谱等对该化合物进行了表征. 结果表明, 该化合物结构中Zn离子与BPDC的羧基形成双核金属次级结构单元[Zn₂(—CO₂)₂(IN)₂], 相邻次级结构单元通过IN配离子连接形成[Zn₂(—CO₂)₂(IN)₂]_∞二维层面, 相邻的二维层通过BPDC相互连接形成具有三重互穿的简单格子拓扑结构. 该化合物表现出良好的荧光性质.     

Local structural characterization of Au/Pt bimetallic nanoparticles

In this study, we examined the amount-dependent change in morphology for a series of Au/Pt bimetallic nanoparticles synthesized using chemical reduction. The Au/Pt molar ratio was varied from 1/1 to 1/4 to synthesize Pt shell layers with different thicknesses. We have obtained that these bimetallic nanoparticles can form flower-like nanoparticles. Moreover, an extended X-ray absorption fine structure (EXAFS) analysis was used to demonstrate the structure of Au/Pt bimetallic nanoparticles. The EXAFS results confirmed the formation of a core–shell structure and inter-diffusion between Au and Pt atoms. The composition of the shell layer was found to be Pt-enriched Au/Pt alloy.     

Helical water chain mediated proton conductivity in homochiral metal-organic frameworks with unprecedented zeolitic unh-topology

Four new homochiral metal-organic framework (MOF) isomers, [Zn(l-L(Cl))(Cl)](H(2)O)(2) (1), [Zn(l-L(Br))(Br)](H(2)O)(2) (2), [Zn(d-L(Cl))(Cl)](H(2)O)(2) (3), and [Zn(d-L(Br))(Br)](H(2)O)(2) (4) [L = 3-methyl-2-(pyridin-4-ylmethylamino)butanoic acid], have been synthesized by using a derivative of L-/D-valine and Zn(CH(3)COO)(2)·2H(2)O. A three-periodic lattice with a parallel 1D helical channel was formed along the crystallographic c-axis. Molecular rearrangement results in an unprecedented zeolitic unh-topology in 1-4. In each case, two lattice water molecules (one H-bonded to halogen atoms) form a secondary helical continuous water chain inside the molecular helix. MOFs 1 and 2 shows different water adsorption properties and hence different water affinity. The arrangement of water molecules inside the channel was monitored by variable-temperature single-crystal X-ray diffraction, which indicated that MOF 1 has a higher water holding capacity than MOF 2. In MOF 1, water escapes at 80 °C, while in 2 the same happens at a much lower temperature (～40 °C). All the MOFs reported here shows reversible crystallization by readily reabsorbing moisture. In MOFs 1 and 2, the frameworks are stable after solvent removal, which is confirmed by a single-crystal to single-crystal transformation. MOFs 1 and 3 show high proton conductivity of 4.45 × 10(-5) and 4.42 × 10(-5) S cm(-1), respectively, while 2 and 4 shows zero proton conductivity. The above result is attributed to the fact that MOF 1 has a higher water holding capacity than MOF 2.     

The interaction of water with MOF-5 simulated by molecular dynamics

Force field parameters for use with metal-organic framework-5 (MOF-5 or IRMOF-1) are presented. Flexibility within the framework is included in this model, so that structural changes upon interaction with adsorbate molecules can be observed and quantified. The model was validated by comparing simulated lattice parameters of pure MOF-5 with X-ray diffraction results. For the first time, molecular dynamics simulations have been performed that show how water interacts with MOF-5. The framework is stable at water contents up to 2.3% by mass, but distortion in the lattice structure is already evident. At water contents of 3.9% and higher, the framework collapses because of the replacement of MOF O atoms by water O atoms in the Zn coordination shells. As a result, inorganic MOF O atoms are no longer coordinated by four Zn ions, and benzene dicarboxylate linkers are no longer tethered to Zn centers.     

Hydrido phosphanido bridged polynuclear complexes obtained by protonation of a phosphinito bridged Pt(I) complex with HBF4 and HF

The protonation of the phosphinito-bridged Pt(I) complex [(PHCy(2))Pt(μ-PCy(2)){κ(2)P,O-μ-P(O)Cy(2)}Pt(PHCy(2))](Pt-Pt) (1) by aqueous HBF(4) or hydrofluoric acid leads selectively to the hydrido-bridged solvento species syn-[(PHCy(2))(H(2)O)Pt(μ-PCy(2))(μ-H)Pt(PHCy(2)){κP-P(OH)Cy(2)}](Y)(2)(Pt-Pt) ([2-H(2)O]Y(2)) {Y = BF(4), F(HF)(n)} when an excess of acid was used. On standing in halogenated solvents, complex [2-H(2)O](BF(4))(2) undergoes a slow but complete isomerization to [(PHCy(2))(2)Pt(μ-PCy(2))(μ-H)Pt{κP-P(OH)Cy(2)}(H(2)O)](BF(4))(2)(Pt-Pt) ([4-H(2)O][BF(4)](2)) having the P(OH)Cy(2) ligand trans to the hydride. The water molecule coordinated to platinum in [2-H(2)O][BF(4)](2) is readily replaced by halides, nitriles, and triphenylphosphane, and the acetonitrile complex [2-CH(3)CN][BF(4)](2) was characterized by XRD analysis. Solvento species other than aqua complexes, such as [2-acetone-d(6)](2+) or [2-CD(2)Cl(2)](2+) were obtained in solution by the reaction of excess etherate HBF(4) with 1 in the relevant solvent. The complex [2-H(2)O](Y)(2) [Y = F(HF)(n)] spontaneously isomerizes into the terminal hydrido complexes [(PHCy(2))Pt(μ-PCy(2)){κ(2)P,O-μ-P(O)Cy(2)}Pt(H)(PHCy(2))](Y)(Pt-Pt) ([6](Y)). In the presence of HF, complex [6](Y) transforms into the bis-phosphanido-bridged Pt(II) dinuclear complex [(PHCy(2))(H)Pt(μ-PCy(2))(2)Pt{κP-P(OH)Cy(2)}](Y)(Pt-Pt) ([7](Y)). When the reaction of 1 with HF was carried out with diluted hydrofluoric acid by allowing the HF to slowly diffuse into the dichloromethane solution, the main product was the linear 60e tetranuclear complex [(PHCy(2)){κP-P(O)Cy(2)}Pt(1)(μ-PCy(2))(μ-H)Pt(2)(μ-PCy(2))](2)(Pt(1)-Pt(2)) (8). Insoluble compound 8 is readily protonated by HBF(4) in dichloromethane, forming the more soluble species [(PHCy(2)){κP-P(OH)Cy(2)}Pt(1)(μ-PCy(2))(μ-H)Pt(2)(μ-PCy(2))](2)(BF(4))(2)(Pt(1)-Pt(2)) {[9][BF(4)](2)}. XRD analysis of [9][BF(4)](2)·2CH(2)Cl(2) shows that [9](2+) is comprised of four coplanar Pt atoms held together by four phosphanido and two hydrido bridges. Both XRD and NMR analyses indicate alternate intermetal distances with peripheral Pt-Pt bonds and a longer central Pt···Pt separation. DFT calculations allow tracing of the mechanistic pathways for the protonation of 1 by HBF(4) and HF and evaluation of their energetic aspects. Our results indicate that in both cases the protonation occurs through an initial proton transfer from the acid to the phosphinito oxygen, which then shuttles the incoming proton to the Pt-Pt bond. The different evolution of the reaction with HF, leading also to [6](Y) or 8, has been explained in terms of the peculiar behavior of the F(HF)(n)(-) anions and their strong basicity for n = 0 or 1.     

MOF‐on‐MOF: Oriented Growth of Multiple Layered Thin Films of Metal–Organic Frameworks

The precise alignment of multiple layers of metal–organic framework (MOF) thin films, or MOF‐on‐MOF films, over macroscopic length scales is presented. The MOF‐on‐MOF films are fabricated by epitaxially matching the interface. The first MOF layer (Cu₂(BPDC)₂, BPDC=biphenyl‐4,4′‐dicarboxylate) is grown on an oriented Cu(OH)₂ film by a “one‐pot” approach. Aligned second (Cu₂(BDC)₂, BDC=benzene 1,4‐dicarboxylate, or Cu₂(BPYDC)₂, BPYDC=2,2′‐bipyridine‐5,5′‐dicarboxylate) MOF layers can be deposited using liquid‐phase epitaxy. The co‐orientation of the MOF films is confirmed by X‐ray diffraction. Importantly, our strategy allows for the synthesis of aligned MOF films, for example, Cu₂(BPYDC)₂, that cannot be grown on a Cu(OH)₂ surface. We show that aligned MOF films furnished with Ag nanoparticles show a unique anisotropic plasmon resonance. Our MOF‐on‐MOF approach expands the chemistry of heteroepitaxially oriented MOF films and provides a new toolbox for multifunctional porous coatings.     

Metal-organic frameworks based on unprecedented trinuclear and pentanuclear metal-tetrazole clusters as secondary building units

Solvothermal reactions of manganese(II) chloride tetrahydrate with a bis-tetrazole ligand, 2,6-di(1H-tetrazol-5-yl)naphthalene (H(2)NDT), in N,N'-dimethylformamide (DMF)/MeOH mixed solvent at two slightly different temperatures, 75 and 100 °C, led to two different metal-organic frameworks (MOFs), [Mn(II)(3)O(HNDT)(2)(NDT)(DMF)(3)] (1) and [Mn(II)(5)O(2)(HNDT)(2)(NDT)(2)(DMF)(8)] (2), with different net topologies. Single-crystal X-ray diffraction studies reveal that 1 is constructed from an unprecedented trinuclear building block, [Mn(II)(3)O(CN(4))(6)], as a 6-connected trigonal prismatic secondary building unit (SBU) of topological D(3h) site symmetry, and that the ligand in the HNDT(-1)/NDT(2-) deprotonation states is a linker, where two tetrazole (CN(4)) groups of the ligand are connected via a rigid naphthyl group. The tetrazole groups in 1 adopt a 1,2-μ-bridging mode with the manganese(II) ions to form a μ(3)-oxo trinuclear SBU. The trigonalprismatic SBU in 1 is connected to six neighboring SBUs to form a three-dimensional MOF of acs net topology. 2 is constructed from an unprecedented pentanuclear building block, [Mn(II)(5)O(2)(CN(4))(8)], as an 8-connected tetragonal prismatic SBU of topological D(4h) site symmetry. The tetrazole groups in 2 adopt monodentate, 1,2-μ- and 2,3-μ-bridging bidentate and 1,2,3-μ-bridging tridentate binding modes with the manganese(II) centers to form a bis-μ(3)-oxo pentanuclear SBU of local C(2) site symmetry. The tetragonal prismatic SBU in 2 is connected to eight neighboring SBUs to form a 3-D MOF of bcu net topology.     

Solvatochromic behavior of a nanotubular metal-organic framework for sensing small molecules

A nanotubular metal-organic framework (MOF), {[(WS(4)Cu(4))I(2)(dptz)(3)]·DMF}(n) (dptz = 3,6-di(pyridin-4-yl)-1,2,4,5-tetrazine, DMF = N,N-dimethylformamide) for sensing small solvent molecules is presented. When accommodating different solvent molecules as guests, the resulting inclusion compounds exhibit different colors depending on the solvent guests, and more interestingly, the band gaps of these solvent-included complexes are in linear correlation with the polarity of the guest solvents. The solvent molecules can be sensed by the changes of UV-vis spectra of the corresponding inclusion compounds, showing a new way of signal transduction as a new kind of sensor. The sensing by such a MOF occurs within the channel-containing material rather than on the external surface.     

Crystal Structure,Fe3+ Luminescence Sensing and Color Tuning of 2D Lanthanide-metal-organic Frameworks Constructed from Tricarboxylic Acid Ligand

A new lanthanide metal-organic framework (MOF)[Eu(BTB)(phen)(DMF)]·DMF (1,DMF =N,N-dimethylformamide) was synthesized using H3BTB (1,3,5-tri(4-carboxyphenyl)ben...     

Pt3Ru6 clusters supported on gamma-Al2O3: synthesis from Pt3Ru6(CO)21(mu3-H)(mu-H)3, structural characterization, and catalysis of ethylene hydrogenation and n-butane hydrogenolysis

The supported clusters Pt-Ru/gamma-Al2O3 were prepared by adsorption of the bimetallic precursor Pt3Ru6(CO)21(mu3-H)(mu-H)3 from CH2Cl2 solution onto gamma-Al2O3 followed by decarbonylation in He at 300 degrees C. The resultant supported clusters were characterized by infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopies and as catalysts for ethylene hydrogenation and n-butane hydrogenolysis. After adsorption, the nu(CO) peaks characterizing the precursor shifted to lower wavenumbers, and some of the hydroxyl bands of the support disappeared or changed, indicating that the CO ligands of the precursor interacted with support hydroxyl groups. The EXAFS results show that the metal core of the precursor remained essentially unchanged upon adsorption, but there were distortions of the metal core indicated by changes in the metal-metal distances. After decarbonylation of the supported clusters, the EXAFS data indicated that Pt and Ru atoms interacted with support oxygen atoms and that about half of the Pt-Ru bonds were maintained, with the composition of the metal frame remaining almost unchanged. The decarbonylated supported bimetallic clusters reported here are the first having essentially the same metal core composition as that of a precursor metal carbonyl, and they appear to be the best-defined supported bimetallic clusters. The material was found to be an active catalyst for ethylene hydrogenation and n-butane hydrogenolysis under conditions mild enough to prevent substantial cluster disruption.     

Pt nanoparticles@photoactive metal-organic frameworks: efficient hydrogen evolution via synergistic photoexcitation and electron injection

Pt nanoparticles of 2-3 nm and 5-6 nm in diameter were loaded into stable, porous, and phosphorescent metal-organic frameworks (MOFs 1 and 2) built from [Ir(ppy)(2)(bpy)](+)-derived dicarboxylate ligands (L(1) and L(2)) and Zr(6)(μ(3)-O)(4)(μ(3)-OH)(4)(carboxylate)(12) secondary building units, via MOF-mediated photoreduction of K(2)PtCl(4). The resulting Pt@MOF assemblies serve as effective photocatalysts for hydrogen evolution by synergistic photoexcitation of the MOF frameworks and electron injection into the Pt nanoparticles. Pt@2 gave a turnover number of 7000, approximately five times the value afforded by the homogeneous control, and could be readily recycled and reused.     

Synthesis of a New Two-dimensional Cd（Ⅱ） Coordination Compound by Benzotriazole-5-carboxylate Acid and 1,10-Phenanthroline and Its Crystal Structure and Characterization

A mixed-ligand metal-organic complex [Cd（C7H3N3O2）（C12H8N2）]n was synthesized by cadmium（Ⅱ） nitrate, 1,10-phenanthroline（phen） and benzotriazole-5-carboxylate acid（H2btca）. Single crystal X-ray analysis indicates that complex 1 has a two-dimensional layer structure and crystallizes in an orthorhombic space group（Pbca）, with cell parameters, a=1.7422（6） nm, b=0.9264（3） nm, c=2.0729（7） nm, α=90°, β=90°,γ=90°, V=3.346（2） nm^3, Z=8. Each central Cd（Ⅱ） is six-coordinated by four N atoms, two of which are from 1,10-phenanthroline, and the other two from two different triazole nitrogen atoms and two O atoms from benzotriazole-5-carboxylate, forming a distorted octahedral geometry. Adjacent Cd（Ⅱ） centers are bridged by benzotriazole-5-carboxylate molecules to form a one-dimensional chain, which is further connected by the nitrogen atoms of btca^2- to form an extended two-dimensional wave-like layer, with OFF（offset face-to-face） stacking interactions between phen ligands in adjacent layers, which are helpful to forming the three-dimensional supramolecular structure.     

Microporous 3D aluminum MOF doped into chitosan‐based mixed matrix membranes for ethanol/water separation

An aluminum metal–organic framework (Al‐MOF), [Al(OH)(BPDC)] (DUT‐5; BPDC = Biphenyl‐4,4′‐dicarboxylate), was synthesized using solvothermal reactions. The high surface area and micropores (approximately 1.2 nm) of DUT‐5 were characterized using N₂ gas sorption measurements. The thermal stability of DUT‐5 and its phase purity were also investigated. The different amounts of DUT‐5 (0.1, 0.15, and 0.2 wt%) were successfully incorporated into the chitosan (CS) polymer to prepare a mixed matrix membrane (MMM) for the pervaporation of water/ethanol at 25°C. In particular, when 0.15 wt% of DUT‐5 was loaded, the DUT‐5@CS MMMs displayed excellent permeability and selectivity in ethanol/water separation. The results indicated that compared with pristine chitosan membranes, the flux of DUT‐5@CS membranes with 0.15 wt% loading significantly increased from 315 to 378 (g/m² h^?1) and the separation factor from 347 to 3,429. These promising results of the microporous Al‐MOF doped into chitosan MMMs reveal its good application potential for the bio‐ethanol separation processes.     

Zn(Ⅱ),Cd(Ⅱ)与混合配体构筑三维贯穿金属有机配位聚合物的合成、结构与荧光性能

在中温混合溶剂热条件下, 分别用锌离子和镉离子与二羧酸和二吡啶基配体反应合成出2个新颖的金属有机配位聚合物[Zn(BPDC)(BPE)·(DMF)₂](JUC-91)和[Cd(BPDC)(BPE)·(DMF)₂](JUC-92)[BP-DC:4,4'-联苯二羧酸,BPE:反式1,2-二(4-吡啶基)乙烯,DMF:N,N'-二甲基甲酰胺], 并通过X射线单晶衍射、 元素分析、 热重分析、 粉末X射线衍射、 拓扑结构分析和荧光光谱对化合物的结构、 组成和性质进行了表征. X射线单晶衍射结果表明, 化合物JUC-91和JUC-92均具有三维开放骨架结构, 其中, JUC-91具有五重贯穿的金刚石拓扑结构, JUC-92具有双重贯穿的简单立方格子结构.     

Synthetic control to achieve lanthanide(III)/pyrimidine-4,6-dicarboxylate compounds by preventing oxalate formation: structural, magnetic, and luminescent properties

Control over the synthetic conditions in many metal/diazinedicarboxylato systems is crucial to prevent oxalate formation, since dicarboxylato ligands easily undergo degradation in the presence of metal salts. We report here an efficient route to obtain oxalato-free compounds for the lanthanide/pyrimidine-4,6-dicarboxylato (pmdc) system on the basis of the reaction temperature and nonacidic pH or oxygen free atmosphere. Two different crystal architectures have been obtained: {[Ln(μ-pmdc)(1.5)(H(2)O)(3)]·xH(2)O}(n) (1-Ln) and {[Ln(2)(μ(4)-pmdc)(2)(μ-pmdc)(H(2)O)(2)]·H(2)O}(n) (2-Ln) with Ln(III) = La-Yb, except Pm. Both crystal structures are built from distorted two-dimensional honeycomb networks based on the recurrent double chelating mode established by the pmdc. In compounds 1-Ln, the tricapped trigonal prismatic coordination environment of the lanthanides is completed by three water molecules, precluding a further increase in the dimensionality. Crystallization water molecules are arranged in the interlamellar space, giving rise to highly flexible supramolecular clusters that are responsible for the modulation found in compound 1-Gd. Two of the coordinated water molecules are replaced by nonchelating carboxylate oxygen atoms of pmdc ligands in compounds 2-Ln, joining the metal-organic layers together and thus providing a compact three-dimensional network. The crystal structure of the compounds is governed by the competition between two opposing factors: the ionic size and the reaction temperature. The lanthanide contraction rejects the sterically hindered coordination geometries whereas high-temperature entropy driven desolvation pathway favors the release of solvent molecules leading to more compact frameworks. The characteristic luminescence of the Nd, Eu, and Tb centers is improved when moving from 1-Ln to 2-Ln compounds as a consequence of the decrease of the O-H oscillators. The magnetic properties of the compounds are dominated by the spin-orbit coupling and the ligand field perturbation, the exchange coupling being almost negligible.     

Syntheses,Structures, Fluorescence and Magnetism of Six Lanthanide Metal-organic Frameworks Based on Silicon-centered Tetrahedral Ligand

Multifunctional lanthanide metal-organic frameworks(MOFs), M(H₄TCPS)(H₂O)_1.5[M=Tb(JUC-95a), Er(JUC-95b), Dy(JUC-95c), Tm(JUC-95d), Y(JUC-95e) and Pr(JUC-95f); H₄TCPS=tetrakis(4-carboxyphenyl)silane] were synthesized via the reaction of the lanthanide metal ions(Ln₃?) with a rigid silicon-centered tetrahedral carbo- xylate ligand H₄TCPS via a hydrothermal synthesis method. X-Ray diffraction(XRD) analyses reveal that they are extremely similar in structure and crystallized in a monoclinic system with space group C2/c. Two eight-coordinated metal centers and four tetrahedral H₄TCPS groups constructed a paddle-wheel building block. The paddle-wheel buil- ding blocks assembled with each other via one oxygen bridge from a water molecule to lead to a 1D infinite inorganic rod-shaped chain, -Y-O-C-O-Y-, along the [001] direction. These 1D inorganic rod-shaped chains linked with the phenyl groups of the tetrahedral H₄TCPS ligand to form a 3D framework. In addition, the luminescent and magnetic properties of these compounds show that they could be potential antiferromagnetic and fluorescent materials.     

亚铁金属有机层的合成、结构及其超快仿生催化性能

六水合四氟硼酸亚铁、三水合四氰基铂酸钾和4-甲基吡啶-N-氧化物在水和乙醇中自组装形成了一种新的二维金属有机框架(Fe-MOF).单晶结构分析表明,Fe-MOF结晶于单斜空间群P21/c.在Fe-MOF中,每个[Pt(CN)4]2-通过氰基桥联4个Fe原子,而每个Fe原子与4个[Pt(CN)4]2-的 N相连形成二维(...     

Reductive elimination/oxidative addition of carbon-hydrogen bonds at Pt(IV)/Pt(II) centers: mechanistic studies of the solution thermolyses of Tp(Me2)Pt(CH3)2H

Reductive elimination of methane occurs upon solution thermolysis of kappa(3)-Tp(Me)2Pt(IV)(CH(3))(2)H (1, Tp(Me)2 = hydridotris(3,5-dimethylpyrazolyl)borate). The platinum product of this reaction is determined by the solvent. C-D bond activation occurs after methane elimination in benzene-d(6), to yield kappa(3)-Tp(Me)2Pt(IV)(CH(3))(C(6)D(5))D (2-d(6)), which undergoes a second reductive elimination/oxidative addition reaction to yield isotopically labeled methane and kappa(3)-Tp(Me)2Pt(IV)(C(6)D(5))(2)D (3-d(11)). In contrast, kappa(2)-Tp(Me)2Pt(II)(CH(3))(NCCD(3)) (4) was obtained in the presence of acetonitrile-d(3), after elimination of methane from 1. Reductive elimination of methane from these Pt(IV) complexes follows first-order kinetics, and the observed reaction rates are nearly independent of solvent. Virtually identical activation parameters (DeltaH(++)(obs) = 35.0 +/- 1.1 kcal/mol, DeltaS(++)(obs) = 13 +/- 3 eu) were measured for the reductive elimination of methane from 1 in both benzene-d(6) and toluene-d(8). A lower energy process (DeltaH(++)(scr) = 26 +/- 1 kcal/mol, DeltaS(++)(scr) = 1 +/- 4 eu) scrambles hydrogen atoms of 1 between the methyl and hydride positions, as confirmed by monitoring the equilibration of kappa(3)-Tp(Me)()2Pt(IV)(CH(3))(2)D (1-d(1)()) with its scrambled isotopomer, kappa(3)-Tp(Me)2Pt(IV)(CH(3))(CH(2)D)H (1-d(1'). The sigma-methane complex kappa(2)-Tp(Me)2Pt(II)(CH(3))(CH(4)) is proposed as a common intermediate in both the scrambling and reductive elimination processes. Kinetic results are consistent with rate-determining dissociative loss of methane from this intermediate to produce the coordinatively unsaturated intermediate [Tp(Me)2Pt(II)(CH(3))], which reacts rapidly with solvent. The difference in activation enthalpies for the H/D scrambling and C-H reductive elimination provides a lower limit for the binding enthalpy of methane to [Tp(Me)2Pt(II)(CH(3))] of 9 +/- 2 kcal/mol.