High Nuclearity Bimetallic Rhodium–Palladium Carbonyl Cluster Complexes. Synthesis and Characterization of Rh6(CO)16[Pd(PBu t 3)]3 and Rh6(CO)16[Pd(PBu t 3)]4

The reaction of Rh₄(CO)₁₂ with Pd(PBu ^t ₃)₂ yielded the high nuclearity bimetallic hexarhodium-tripalladium cluster complex Rh₆(CO)₁₆[Pd(PBu ^t ₃)]₃, 10, in 11% yield. Compound 10 was converted to the hexarhodium-tetrapalladium cluster Rh₆(CO)₁₆[Pd(PBu ^t ₃)]₄, 11, in 62% yield by reaction with an additional quantity of Pd(PBu ^t ₃)₂. Both compounds were characterized crystallographically. Structurally, both compounds consist of an octahedral cluster of six rhodium atoms with sixteen carbonyl ligands analogous to that of the known compound Rh₆(CO)₁₆. Compound 10 also contains three Pd(PBu ^t ₃) groups that bridge three Rh–Rh bonds along edges of the Rh₆ octahedron to give an overall D₃ symmetry to the Rh₆Pd₃ cluster. Compound 11 contains four edge bridging Pd(PBu ^t ₃) groups distributed across the Rh₆ octahedron to give an overall D_2d symmetry to the Rh₆Pd₄ cluster. Each Rh–Pd connection in both compounds contains a bridging carbonyl ligand that helps to stabilize the bond between the Pd(PBu ^t ₃) groups and the Rh atoms. Both compounds can be regarded as Pd(PBu ^t ₃) adducts of Rh₆(CO)₁₆.     

Synthesis, characterization, and electronic structures of a series of two-dimensional trimetallic cluster complexes, Ru3(CO)9(mu-SnPh2)3[Pt(PBu(t)3)]x, x = 0-3

The triruthenium-tritin cluster complex, Ru3(CO)9(mu-SnPh2)3, 13 was obtained from the reaction of Ru3(CO)12 with Ph3SnH. Compound 13 reacts with Pt(PBut3)2 to yield three new Pt(PBut3) adducts of 13 Ru3(CO)9(mu-SnPh2)3[Pt(PBut3)]x, 14-16 x = 1 - 3 formed by the addition of Pt(PBut3) groups to the Ru-Sn bonds. The new complexes form a novel series of trimetallic complexes having planar arrangements of the metal atoms. The UV-vis absorptions of the four complexes shift progressively to longer wavelengths as the number of platinum atoms is added to the cluster. The electronic structures of these complexes have been investigated in the ground and excited states by density functional theory and time-dependent density functional theory, and this has provided a detailed understanding of the metal-metal bonding and electronic transitions that are responsible for their UV-vis absorption properties. The predicted absorption maximum for the model structures for 13, 14, 15, and 16 at 465, 508, 556, and 585 nm differ only 4-18 nm from the experimental values of 474, 490, 552, and 576 nm. The shift of principal UV-vis absorption can be explained by a lowering of the HOMO-LUMO energy gap due to interactions of the platinum atoms with the HOMO and LUMO of the Ru3Sn3 core.     

Mechanism of protonation of [Pt(3)(mu-PBu(t)(2))3(H)(CO)2], yielding the hydride-bridged [Pt(3)(mu-PBu(t)(2))2(mu-H)(PBu(t)(2)H)(CO)2]OTf (Tf=CF(3)SO(2)), and the spectroscopic and theoretical characterization of a kinetic intermediate

The reaction of the Pt(I)Pt(I)Pt(II) triangulo cluster Pt(3)(micro-PBu(t)()(2))(3)(H)(CO)(2) (1) with TfOH (Tf = CF(3)SO(2)) affords the hydride-bridged cationic derivative [Pt(3)(mu-PBu(t)()(2))(2)(mu-H)(PBu(t)()(2)H)(CO)(2)]OTf (2). With TfOD the reaction gives selectively [Pt(3)(mu-PBu(t)(2))(2)(mu-D)(PBu(t)(2)H)(CO)(2)]OTf (2-D(1)), implying that the proton is transferred to a metal center while a P-H bond is formed by the reductive coupling of one of the bridging phosphides and the terminal hydride ligand of the reagent. The reaction proceeds through the formation of a thermally unstable kinetic intermediate which was characterized at low temperatures, and was suggested to be the CO-hydrogen-bonded (or protonated) [Pt(3)(mu-PBu(t)(2))(3)(H)(CO)(2)].HOTf (3). An ab initio theoretical study predicts a hydrogen-bonded complex or a proton-transfer tight ion pair as a possible candidate for the structure of the kinetic intermediate.     

Synthesis of PtRu5(CO)14(PBu(t)3)(mu-H)2(mu6-C) and its reactions with Pt(PBut3)2, HGePh3, and HSnPh3

Reaction of PtRu5(CO)15(PBut3)(C), 3, with hydrogen at 97 degrees C yielded the new dihydride-containing cluster compound PtRu5(CO)14(PBut3)(mu-H)2(mu6-C), 5. Compound 5 was characterized crystallographically and was shown to contain an octahedral cluster consisting of one platinum and five ruthenium atoms with a carbido ligand in the center. Two hydrido ligands bridge two oppositely positioned PtRu bonds. Compound 5 reacts with Pt(PBut3)2 to yield Pt2Ru5(CO)14(PBut3)2(mu-H)2(mu6-C), 6, a Pt(PBut3) adduct of 5, by adding a Pt(PBut3) group as a bridge across one of the Ru-Ru bonds in the square base of the Ru5 portion of the cluster. Compound 6 is dynamically active on the NMR time scale by a mechanism that appears to involve a shifting of the Pt(PBut3) group from one Ru-Ru bond to another. Two new complexes, PtRu5(CO)13(PBut3)(mu-H)3(GePh3)(mu5-C), 7, and PtRu5(CO)13(PBut3)(mu-H)2(mu-GePh2)(mu6-C), 8, were obtained from the reaction of 5 with HGePh3. The cluster of 7 has an open structure in which the Pt(PBut3) group bridges an edge of the square base of the square pyramidal Ru5 cluster. Compound 7 also has three bridging hydrido ligands and one terminal GePh3 ligand. When heated to 97 degrees C, 7 is slowly converted to 8 by cleavage of a phenyl group from the GePh3 ligand and elimination of benzene by its combination with one of the hydrido ligands. The PtRu5 metal cluster of 8 has a closed octahedral shape with a GePh2 ligand bridging one of the Ru-Ru bonds. Two tin-containing compounds, PtRu5(CO)13(PBut3)(mu-H)3(SnPh3)(mu5-C), 9, and PtRu5(CO)13(PBut3)(mu-H)2(mu-SnPh2)(mu6-C), 10, which are analogous to 7 and 8 were obtained from the reaction of 5 with HSnPh3.     

Crystal structures of [MEn2][Pt(NO2)4] (M = Cu,Pd)

By single crystal X-ray diffraction the structures of [CuEn₂][Pt(NO₂)₄] and [PdEn₂][Pt(NO₂)₄] are determined. In the structures, the main structural moieties are identified. It is shown that the structure of [PdEn₂][Pt(NO₂)₄] can be considered as quasi-one-dimensional: in the _Y axis direction, the stacks of alternating complex cations and anions locate.     

Reaction of [Fe2(CO)8(mu-CF2)] with AsMe3 and other Lewis bases: syntheses, crystal structures of [Fe(CO)6(AsMe3)2(mu-CF2)] and [Fe(CO)5(AsMe3)3(mu-CF2)], and theoretical considerations

The difluorcarbene complex [Fe2(CO)8(mu-CF2)] (2) reacts with AsMe3 under CO substitution to give the mu-CF2 containing complexes [Fe2(CO)6(AsMe3)2(mu-CF2)] (4) and [Fe2(CO)5(AsMe3)3(mu-CF2)] (5) which have an [Fe2(CO)9]-like structure as shown by X-ray analyses. In the solid state, 4 forms two isomers, 4a and 4b, in a 3 to 1 ratio, which differ in the position of the mu-CF(2) ligand; 4a has a local C(2) axis and 4b has C1 symmetry. The Fe-Fe distances in 4 and 5 are 2.47 A and are the shortest ones found in [Fe2(CO)9]-like compounds. Efforts were also undertaken to replace one or more CO groups in 2 by other ligands, such as N (bpy, phen, pzy, etc.) or P donors (dppe, dppm). With dppm, only the CF(2) free complex, [Fe2(CO)4(mu-Ph2PCH2PPh2)2(mu-CO)] (6), could be detected and characterized by X-ray analysis. Most of the reactions resulted in the formation of red-brown materials which were insoluble in the usual solvents and which could not be characterized. The use of CH2Cl2 during the attempts to crystallize a product from the reaction of 2 and phen gave [Fe(phen)3]Cl2 (7) in low yields. For 4 and 5, the electronic structures were analyzed using the atoms in molecules (AIM) theory. No electron density was found between the two iron atoms, and the short contacts can be interpreted in terms of a pi-interaction.     

Substitution of [M(bpyMe)Cl3] and [M(bpyMe-H)Cl2] (M = Pd or Pt; bpyMe =N-methyl-2,2′-bipyridylium ion) withN-heterocycles

Summary The complex Pt(bpyMe)Cl₃ (bpyMe = N-methyl-2,2-bipyridylium cation) reacts with pyridine(py) to give cis-[Pt(bpy-Me) (py)Cl₂]⁺, which on heating cyclometallates with loss of py to give Pt(bpyMe-H)Cl₂; some Pt(py)₂Cl₂ is also formed. Pt(bpyMe)Cl₃ reacts with 2,2-bipyridyl (bpy) to yield a mixture of [Pt(bpyMe-H)(bpy)]²⁺ and [Pt(bpy)₂]²⁺. The analogous reactions with Pd(bpyMe)Cl₃ proceed under very mild conditions to afford PdL₂Cl₂ (L₂ = 2py, bpy).     

Synthesis of big palladium clusters. Preparation of Pd23(CO)20(PEt3)8

Selective methods for the synthesis of the cluster Pd₂₃(CO)₂₀L₈, L=PEt₃, have been suggested. The compound has been prepared by two routes: by the reaction of Pd₁₀(CO)₁₂L₆ with Me₃NO in the presence of HOAc with removal of CO from the gas phase, and by the reaction of Pd₁₀(CO)₁₂L₆ with Pd(OAc)₂ and CO followed by oxidation by Me₃NO in an inert atmosphere.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1299–1300, July, 1993.     

Cyanide-bridged [Fe8M6] clusters displaying single-molecule magnetism (M=Ni) and electron-transfer-coupled spin transitions (M=Co)

Cyanide‐bridged metal complexes of [Fe₈M₆(μ‐CN)₁₄(CN)₁₀ (tp)₈(HL)₁₀(CH₃CN)₂][PF₆]₄?n CH₃CN?m H₂O (HL=3‐(2‐pyridyl)‐5‐[4‐(diphenylamino)phenyl]‐1H‐pyrazole), tp^?=hydrotris(pyrazolylborate), 1 : M=Ni with n=11 and m=7, and 2 : M=Co with n=14 and m=5) were prepared. Complexes 1 and 2 are isomorphous, and crystallized in the monoclinic space group P2₁/n. They have tetradecanuclear cores composed of eight low‐spin (LS) Fe^III and six high‐spin (HS) M^II ions (M=Ni and Co), all of which are bridged by cyanide ions, to form a crown‐like core structure. Magnetic susceptibility measurements revealed that intramolecular ferro‐ and antiferromagnetic interactions are operative in 1 and in a fresh sample of 2 , respectively. Ac magnetic susceptibility measurements of 1 showed frequency‐dependent in‐ and out‐of‐phase signals, characteristic of single‐molecule magnetism (SMM), while desolvated samples of 2 showed thermal‐ and photoinduced intramolecular electron‐transfer‐coupled spin transition (ETCST) between the [(LS‐Fe^II)₃(LS‐Fe^III)₅(HS‐Co^II)₃(LS‐Co^III)₃] and the [(LS‐Fe^III)₈(HS‐Co^II)₆] states.     

SnO2负载Au和M-Au(M=Pt,Pd)催化剂及其低温催化氧化CO性能

以SnO₂为载体, 采用沉积沉淀法(DP)、共沉淀法(CP)和浸渍法(IM)制备了金负载Au/SnO₂催化剂, 同时采用沉积沉淀法制备了M-Au/SnO₂(M=Pd, Pt)双金属负载催化剂. 通过X射线衍射(XRD)、BET比表面积测定、透射电镜(TEM)和X射线光电子能谱(XPS)等技术对样品进行表征, 并测定其对CO的催化活性. 结果表明: 与CP法和IM 法相比, DP法制备的Au/SnO₂-DP 催化剂, Au 颗粒(<5 nm)较小, 分布均匀; Au/SnO₂-DP 中的Au 是以金属态Au0存在, 而Au/SnO₂-CP 和Au/SnO₂-IM 中, 金以Au⁰和Au³⁺的混合价态存在, 在Au/SnO₂-DP和M-Au/SnO₂中的Au、Pt、Pd和SnO₂之间存在相互作用; Au/SnO₂-DP 催化性能明显优于Au/SnO₂-CP 和Au/SnO₂-IM. Au与Pt 和Pd的双金属复合催化剂催化活性明显提高. 不同方法制备Au/SnO₂催化活性的差别主要是由于Au颗粒大小和Au氧化态的不同而产生. 而M-Au/SnO₂活性提高, 可能是由于Au与Pt 和Pd之间的相互作用.     

一维链状冠醚配合物[k(18-C-6)]~2[M(NO~2)~4](H~2O)(M=Pd,Pt) 的合成与结构

研究了18-C-6分别与k~2[Pd(NO~2~4],k~2[Pt(NO~2)~4])的反应,并通过元素分析、红外光谱、单晶X射线衍射对生成的配合物[k(18-C-6)]~2[Pd(NO~2)~4](H~2O)~0.5(1)和[k(18-C-6)]~2,k~2[Pt(NO~2)~4])(H~2O)(2)进行了表征,两个配合匀匀为单斜晶系,空间P2~1/c.1的晶体学数据：α=1,7104(3),c=1,5763(3)nm,β=93.49(3)°,V=3.9987(14)nm^3,Z=4,D~c=1.507g/cm^3,F(000)=1880,R~1=0.0681,~wR~2=0.1004。2的晶体学数据：a=1.1312(3)nm,b=1.4227(2)nm,c=1.2266(3)nm,β93.141(10)°,V=1.9711(8)nm^3,Z=4,D~c=1.614g/cm^3,F(000)=936,R~1=0.0265,~wR~2=0.0721。在固态,配合物1具有[(18-c-6)]~2[Pd(NO~2)~4](H~2O)(1a)和[(18---c-6)]~2[Pd·(NO~2)~4](1b)两个分子,两者比例这1：1前者相邻的两个分子通过水分是的氧原子相连接形成一维链状结构,后者形面假一维链状结构,在配合物2中相邻的两个分子通过品分子中的氧原子相连接形成一维链状结构。     

Synthesis and characterisation of nu3-octahedral [Ni36Pd8(CO)48]6- and [Ni35Pt9(CO)48]6- clusters displaying unexpected surface segregation of Pt atoms and molecular and/or crystal substitutional Ni/Pd and Ni/Pt disorder

The synthesis and structure, as well as the chemical and electrochemical characterisation of two new nu(3)-octahedral bimetallic clusters with the general [Ni(44-x)M(x)(CO)(48)](6-) (M = Pd, x = 8; M = Pt, x = 9) formula is reported. The [Ni(35)Pt(9)(CO)(48)](6-) cluster was obtained in reasonable yields (56 % based on Pt) by reaction of [Ni(6)(CO)(12)](2-) with 1.1 equivalents of Pt(II) complexes, in ethyl acetate or THF as the solvent. The [Ni(36)Pd(8)(CO)(48)](6-) cluster was obtained from the related reaction with Pd(II) salts in THF, and was isolated only in low yields (5-10 % based on Pd), mainly because of insufficient differential solubility of its salts. The unit cell of the [NBu(4)](6)[Ni(35)Pt(9)(CO)(48)] salt contains a substitutionally Ni-Pt disordered [Ni(24)(Ni(14-x)Pt(x))Pt(6)(CO)(48)](6-) (x = 3) hexaanion. A combination of crystal and molecular disorder is necessary to explain the disordering observed for the Ni/Pt sites. The unit cell of the corresponding [Ni(36)Pd(8)(CO)(48)](6-) salt contains two independent [Ni(30)(Ni(8-x)Pd(x))Pd(6)(CO)(48)](6-) (x = 2) hexaanions. The two display similar substitutional Ni-Pd disorder, which probably arises only from crystal disorder. The structure of [Ni(36)Pd(8)(CO)(48)](6-) establishes the first similarity between the chemistry of Ni-Pd and Ni-Pt carbonyl clusters. A comparison of the chemical and electrochemical properties of [Ni(35)Pt(9)(CO)(48)](6-) with those of the related [Ni(38)Pt(6)(CO)(48)](6-) cluster shows that surface colouring of the latter with Pt atoms decreases redox as well as protonation propensity of the cluster. In contrast, substitution of all internal Pt and two surface Ni with Pd atoms preserves the protonation behaviour and is only detrimental with respect to its redox aptitude. A qualitative rationalisation of the different surface-site selectivity of Pt and Pd, based on distinctive interplays of M--M and M--CO bond energies, is suggested.     

Synthesis and properties of palladium diselenolenes: X-ray crystal structures of [Pd[SeC(R(1))=C(R(2))Se](PBu(3))(2)] [R(1), R(2) = (CH(2))(n), n = 4, 5, 6

The reaction between [Pd(2)(dba)(3)] (dba = dibenzylideneacetone), tributylphosphine, and a bis(cycloalkeno)-1,4-diselenin leads to either a mononuclear diselenolene [Pd[SeC(R(1))=C(R(2))Se](PBu(3))(2)] or a dinuclear diselenolene [Pd(2)[SeC(R(1))=C(R(2))Se](2)(PBu(3))(2)] [R(1), R(2) = (CH(2))(n), n = 4, 5, 6] depending on the stoichiometry employed. Treatment of the dinuclear diselenolenes with 1,2-bis(diphenylphosphino)ethane (dppe) provides a high-yielding route to the mononuclear species [Pd[SeC(R(1))=C(R(2))Se](dppe)]. All new compounds have been characterized by standard spectroscopic and analytical techniques, in particular by multinuclear NMR spectroscopy; the structure of each of the mononuclear tributylphosphine complexes has been determined by X-ray crystallography. Computational studies show that the observed asymmetry of the diselenolenes in the solid state is a result primarily of intramolecular repulsive interactions between the ligands.     

Synthesis and structure of the organometallic MFe2(mu3-S)2 clusters (M = Mo or Fe)

New organometallic clusters with the MFe2(mu3-S)2 core (M = Mo or Fe) have been synthesized from inorganic [MoFe3S4] or [Fe4S4] clusters under high pressure CO. The reaction of (Cl4-cat)2Mo2Fe6S8(PR3)6[R = Et, (n)Pr] with high pressure CO produced the crystalline [MoFe2S2]4+ clusters, (Cl4-cat)Mo(O)Fe2S2(CO)(n)(PR3)6-n[n= 4, Et =I, (n)Pr =II; n = 5, Et =III] after flash column chromatography. The similar [MoFe2S2]4+ cluster, (Cl4-cat)2MoFe2S2(CO)2(depe)(2)(IV), also has been achieved by the reactions of (Cl4-cat)MoFe3S3(CO)6(PEt3)2 with depe by reductive decoupling of the cluster. For the [Fe3(mu3-S)2]4+ cluster, [Fe4S4(PcHex3)4](BPh4) was reacted with high pressure CO to produce a new Fe3S2(CO)7(PcHex)(2)(V) compound. These reactions generalized the preparation of organometallic compounds from inorganic clusters. All the compounds have been characterized by single crystal X-ray crystallography. A possible reaction pathway for the synthesis of the MFe2(mu3-S) clusters (M = Mo or Fe) has also been suggested.     

Nucleophilic attack on cluster-bound acetylide ligands derived from the iron ketenylidene, [Fe3(CO)9(CCO)]2−

Reaction of the iron ketenylidene (PPN)₂[Fe₃(CO)₉CCO] [PPN =bis (triphenylphosphine)nitrogen(+1)] with trifluoroacetic anhydride forms a highly electrophilic acetylide cluster (PPN)[Fe₃(CO)₉CCOC(O)CF₃] (lc), analogous to the known compounds (PPN)[Fe₃(CO)₉CCOR] [R=Et, (Ia); Ac, (Ib)] prepared from the reaction of ethyl triflate and acetyl chloride on the ketenylidene. Reaction of phosphines and (Ib, c) yield phosphonium acetylides [Fe₃(CO)₉CCPR₃] [(II),R=Ph], with loss of (PPN)[CH₃CO₂] or (PPN)[CF₃CO₂]. Additionally, (Ic) and triphenylarsine react to give an analogous arsonium acetylide [Fe₃(CO)₉CCAsPh₃] (III). No reaction occurs when an excess of arsine is added to (Ib). The reaction of (Ib, c) with anionic nucleophiles is reported, including reaction of Na[CpFe(CO)₂] and (Ib) to afford an unusual metallated acetylide cluster (PPN) [Fe₃(CO)₉CCFe(CO)₂Cp] (IV). Clusters (II), (III), and (IV) are spectroscopically characterized and a single crystal x-ray structure determination of (IV) is reported. (PPN)[Fe₃(CO)₉CCFe(CO)₂Cp] (IV) crystallizes in the monoclinic space group P2₁/n;a=17.793(2) Å;b=16.108(3) Å;c=18.157(3) Å;=107.62(1)⁰;V=4959(3) ų;Z=4. Refinement of 469 variables on 5981 observed [I>3(I)] reflections converged toR=3.5% andRw=4.7%.     

One- or two-dimensional 2,3-naphtho crown ether complexes [Na(N15C5)]2[M(SCN)4] and [K(N18C6)]2[M(SCN)4] (M = Pd, Pt) constructed by pi-pi stacking interactions

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.     

Carbonyl complexes of platinum(0): synthesis and structure of [(Cy3P)2Pt(CO)] and [(Cy3P)2Pt(CO)2

The platinum(0) monocarbonyl complex, [(Cy(3)P)(2)Pt(CO)], was synthesized by reaction of [(Cy(3)P)(2)Pt] with [(η(5)-C(5)Me(5))Ir(CO)(2)] and subsequent irradiation. X-ray structure analysis was performed and represents the first structural evidence of a platinum(0) monocarbonyl complex bearing two free phosphine ligands. Its corresponding dicarbonyl complex [(Cy(3)P)(2)Pt(CO)(2)] was synthesized by treatment of [(Cy(3)P)(2)Pt] with CO at -40 °C and confirmed by X-ray structure analysis.