Heteronuclear Metal Clusters Research Articles

Elemental laser secondary-neutral-mass spectroscopy signal enhancement in layer interfaces: New evidence for cluster contribution in nonresonant laser multiphoton postionization.

We report evidence of a significant signal enhancement caused by fragmentation of heteronuclear metal clusters during interface analysis using laser secondary-neutral-mass spectroscopy (LSNMS). Measurements have been performed in Ti-Pt-Ti thin film interfaces and pure Ti. The LSNMS signal of atomic Ti shows a pronounced peak in the interfaces. A comparison of the velocity distributions of Ti atoms in the Ti-Pt interface and in the pure Ti layer clearly shows that clusters, in particular TiPt clusters, are responsible for the interface peak

Heteronuclear diatomic metal cluster ions in the gas phase: theoretical treatment of magnesium-iron cation (MgFe+) and study of its reactions with hydrocarbons

The unique reactivity of MgFe + is described. This cluster reacts with linear alkenes (C 2 -C 6 ) by displacement of magnesium to form an Fe + -olefin product. In contrast, MgFe + reacts with alcohols by displacement of the iron to form a Mg + -alcohol product. This is the first example of a changeover in the relative metal-ligand bond energies with both metals in a dimer being selectively displaced. MgFe + also reacts with cyclic alkenes. For example, it dehydrogenates cyclohexene to form MgFe + -benzene, which reacts further to displace the magnesium and form benzene-Fe + -cyclohexene. MgFe + is unreactive with small alkanes (C 2 -C 4 ) but reacts with larger alkanes (C 5 -C 7 ) to form a MgFe + -alkene product. An uppere limit of 34±5 kcal/mol for D°(Mg + -Fe) has been established by use of ion-molecule reactions

Full spin-orbit configuration interaction calculations on electronic states of LiBe

Ab initio calculations are reported for the simplest heteronuclear metal cluster, LiBe. Full spin-orbit configuration interaction calculations in the context of relativistic effective core potentials lead to accurate potential energy curves for low-lying states. Results are compared with recent experimental observations and with all electron multi-reference configuration interaction calculations.

ChemInform Abstract: Condensation and Degradation Products from the Thermolysis Reactions of the Bridged Diphenylphosphido Derivatives (Ru3(μ2‐PPh2)(μ2‐H)(CO)9), (Ru3(μ2‐PPh2)2(μ2‐H)2(CO)8), (Ru3(μ2‐PPh2)3(μ2‐H)(CO)7) and (Ru3(μ2‐PPh2)3(μ2‐H)(CO)6(PPh2H)).

AbstractAs part of a program aimed at exploring the potential of the diphenylphosphido and phenylphosphinidene ligands for stabilizing homo‐ and heteronuclear metal clusters of unusual geometry and stereochemistry, the thermolysis of the title compounds is examined with the object of developing high yield syntheses of higher nuclearity Ru clusters containing bridging diphenylphosphido and/or capping phenylphosphinidene groups.

Novel Anionic Aryl Complexes of RhIII: [Rh(C6F5)5]2⊖ and [Rh(C6F5)4(CO)2]⊖

The RhIII complexes 2 and 3 are very stable, both in the solid state as well as in solution. The square‐pyramidal complex 2 is formed on reaction of 1 with LiC6F5, and can be carbonylated with CO to the octahedral complex 3, which is also accessible by reaction of the Rh1 complex [RhCl(CO)2]2 with LiC6F5 + BrC6F5. 2 and 3 should be suitable starting compounds for the synthesis of homo‐ and heteronuclear metal clusters. equation image

Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 83. Molybdenum and tungsten complexes containing the alkylidyne group C{η6-C6H4(OMe-2)Cr(CO)3}

The alkylidyne-metal complexes [CrM{µ-σ:η6-CC6H4(OMe-2)}(O2CCF3)(CO)5L2][M = Mo or W, L2= tmen (Me2NCH2CH2NMe2) or bipy (2,2′-bipyridine)] and [CrM{µ-σ:η6-CC6H4(OMe-2)}(CO)5L]{M = Mo, L =η-C5H5 or HB(pz)3[hydrotris(pyrazol-1-yl)borate]; M = W, L =η-C5H5} have been prepared. In these species the alkylidyne ligand attached to Mo or W is η6-co-ordinated to a Cr(CO)3 group. Several reactions of the complexes [CrM{µ-σ:η6-CC6H4(OMe-2)}(CO)5(η-C5H5)] with low-valent metal compounds have been studied. These have led to the isolation of various heteronuclear metal cluster compounds with bonds between molybdenum or tungsten and platinum, nickel, cobalt, and rhodium. The n.m.r. data for the new products are reported and discussed in relation to the structures proposed.

Structural similarities and differences among mixed-metal clusters containing a single M(PPh 3) (M = Cu, Ag or Au) fragment

The heteronuclear metal clusters [H 3MRu 4(CO) 12(PPh 3)] and [MFe 3(μ-COMe)(CO) 10(PPh 3)] (M = Cu, Ag or Au) have been prepared; the gold-tetraruthenium cluster has a different metal core geometry to that adopted by the copper and silver analogues, whereas all three iron-Group IB mixed-metal clusters have the same geometry.

Laser vaporization of alloys: Laser induced fluorescence of heteronuclear metal clusters

We demonstrate in this manuscript that the laser vaporization–laser induced fluorescence technique can be a very useful tool in studies of heteronuclear metal molecules. We examine here the products of vaporization of copper with the group III A elements Ga and In. The electronic transitions of CuGa and CuIn diatomics are reported and discussed, as well as some new observations of the Cu2 spectra and dynamics. It is also shown that the metals are initially vaporized in an atomic form and that the molecular species are formed collisionally in the gas phase.

Novel routes to heteronuclear metal clusters containing rhodium

Logical methods for preparing small metal clusters with heteronuclear metal-metal bonds can be devised by appreciating the isolobal relationships that exist between certain metal ligand combinations and organic fragments. Thus the group W(CO) 2 (r|-C 5 H 5 ) has frontier orbitals of similar pattern to those of CH, while those of Rh(CO) (r|-C 5 Me 5 ) and CH 2 are also similar. This paper shows how such ideas have been employed to generate compounds with bonds between rhodium and other metals.

Molecular orbital analysis of the bonding in low nuclearity gold and platinum tertiary phosphine complexes and the development of isolobal analogies for the M(PR 3) fragment

The stoichiometries and geometries of gold and platinum tertiary phosphine cluster compounds of the type M n (PR 3) n x+ ( n = 3–6) have been analysed using extended Hückel molecular orbital calculations. The isolobal nature of the M(PH 3) fragment depends critically on the nature of the metal atom M, and may be used to provide a basis for predicting a wide spectrum of homo- and hetero-nuclear metal cluster compounds.

Polynuclear tungsten-iron, -ruthenium and -osmium carbonyl complexes: crystal structures of [FeW2(µ3-C2R2)(CO)6(η-C5H5)2], [OsW2(µ3-C2R2)(CO)7-(η-C5H5)2](two isomers), and [Os3W(µ3-CR)(CO)11(η-C5H5)](R = C6H4Me-4)

Reactions of polynuclear carbonyl complexes of iron, ruthenium, or osmium with [WCR(CO)2(η-C5H5)](R = C6H4Me-4) afford several heteronuclear metal cluster compounds, and the structures of [FeW2(µ3-C2R2)(CO)6(η-C5H5)2], [Os3W(µ3-CR)(CO)11(η-C5H5)], and [OsW2(µ3-C2R2)(CO)7(η-C5H5)](two isomers) have been established by X-ray diffraction.