Open-Shell Organometallics as a Bridge between Werner-Type and Low-Valent Organometallic Complexes. The Effect of the Spin State on the Stability, Reactivity, and Structure.

The geometrical structure of small nickel clusters is probed via molecular adsorption of nitrogen on their surfaces. Nitrogen uptake patterns can be rationalized with the proposed structures if it is assumed that N2 binds to every exposed nickel atom, that the binding energies decrease with increasing metal—metal coordination, and that atoms that are four or less coordinate can bind two nitrogen molecules. In some cases nitrogen adsorption causes a change in cluster structure, usually to one that can accommodate more nitrogen molecules. Cluster structures are proposed for all clusters (bare and nitrogenated) in the 3–15‐atom size range except Ni4 and Ni11. The nitrogen uptake for Ni4 is consistent with virtually any structure, and the data for Ni11 could not be interpreted in terms of a specific structure. In general, nickel cluster structures are different from those found for rare gas clusters as well as those derived from bulk packing. A comparison of the experimental results with existing theoretical ...

The structure of small nickel clusters. I. Ni3–Ni15

http://alpha.chem.umb.edu/chemistry/ch611/documents/18erule.pdf

Understanding the eighteen-electron rule

Unter Phosphor-, Arsen-, Antimon- und Bismutliganden verstand man bis vor kurzem fast ausschlieslich Verbindungen wie R3E, R2E(CH2)nER2 und RC[(CH2)nER2]3 (E = P,As,Sb,Bi), deren freies Elektronenpaar am E-Atom als 2e-Donor fungiert. Das Forschungsinteresse gilt aber zunehmend den substituentenfreien En-Liganden (n = 1-6), die bevorzugt aus EX3(X = F,Cl,Br,Ph), E(SiMe3)3, (RAs)n, P4S3, As4S4, grauem Arsen und vor allem P4 und As4 erhaltlich sind und die in Gegenwart bestimmter Ubergangsmetallkomplexfragmente koordinativ stabilisiert werden konnen. In Zwei- und Dreikernkomplexen mit P1-, As1- und Sb1-Liganden treten M-E-Mehrfachbindungsanteile auf. E-Atome konnen aber auch teilweise oder vollstandig in Hohlraumen der unterschiedlichsten Metallcluster eingeschlossen sein. Besonders haufig entstehen Metallatetrahedrane mit bis zu drei E-Atomen. Die mit Abstand groste Koordinationsvielfalt weisen neben den E1 - die E4-Liganden auf, denen man sowohl in Form intakter Tetraeder als auch als Bestandteile von Ketten, Polycyclen, Wurfeln und eines trigonalen Prismas begegnet. Die zu den carbocyclischen (CH)n-π-Systemen isoelektronischen Phosphor- und Arsenanaloga cyclo-En eignen sich als Liganden fur Sandwich- (n = 3,4,5) und Tripeldeckerkomplexe (n = 3,5,6). Nicht zuletzt sind diese Verbindungen aufgrund ihrer Reaktivitat und der Parallelen zur Organischen Chemie und Festkorperchemie bei Chemikern verschiedener Disziplinen auf reges Interesse gestosen.

Komplexe mit substituentenfreien acyclischen und cyclischen Phosphor‐, Arsen‐, Antimon‐ und Bismutliganden

Metal chalcogenide cluster chemistry

Electron counting in clusters: A view of the concepts

This paper describes the synthesis of trinuclear metal complexes containing benzene in a new face-capping bonding mode, (μ 3 :η 2 :η 2 :η 2 -C 6 H 6 ), that accurately models the coordination geometry of benzene chemisorbed non surface of a close-packed metal lattice. [Os 3 (CO) 9 (μ 3 :η 2 :η 2 :η 2 -C 6 H 6 )]

A face-capping bonding mode for benzene in triosmium carbonyl cluster complexes

Preparation, molecular structure and solution properties of 1-[1,1'-bis(diphenylphosphino)ferrocene]palladatetraborane

Synthesis, molecular and electronic structure of Os3(CO)10(μ2-η3-C3H5)(AuPEt3): a triosmium cluster exhibiting an allyl ligand with a novel mode of coordination

The reaction of the ‘butterfly’ cluster [Ru4H2(C)(CO)12] with PhCCPh, in hexane, gives [Ru4H(CO)12(CCPhCHPh)] in which direct coupling between the alkyne and the carbide occurs, and X-ray analysis of this product indicates that the organic fragment co-ordinates to the metal framework in a manner reminiscent of an allyl group.

Steven M. Owen

Papers

Electron counting in clusters: A view of the concepts

A face-capping bonding mode for benzene in triosmium carbonyl cluster complexes

Preparation, molecular structure and solution properties of 1-[1,1'-bis(diphenylphosphino)ferrocene]palladatetraborane

Synthesis, molecular and electronic structure of Os3(CO)10(μ2-η3-C3H5)(AuPEt3): a triosmium cluster exhibiting an allyl ligand with a novel mode of coordination

Direct evidence for alkyne coupling to the interstitial carbon in [Ru4H2(C)(CO)12]; crystal and molecular structure of [Ru4H(CO)12(CCPhCHPh)]