Metal-metal stretching frequencies in metal-cluster complexes. Approximate force constant calculations for some small metal clusters

1980 ◽  
Vol 19 (9) ◽  
pp. 2825-2829 ◽  
Author(s):  
Ian A. Oxton
Keyword(s):  
Force Constant ◽  
Metal Clusters ◽  
Metal Cluster ◽  
Cluster Complexes ◽  
Metal Metal

Delocalized bonding in tetrahedral organo-transition metal clusters: an EHMO study of metal vertex rotations in Co2Fe(CO)9S, CpMoCo2(CO)8CR, and in Cp2Mo2(CO)4(RC≡CR)

1996 ◽  
Vol 74 (6) ◽  
pp. 1021-1031 ◽  
Author(s):  
Krisztina L. Malisza ◽  
Lijuan Li ◽  
Michael J. McGlinchey
Keyword(s):  
Transition Metal ◽  
Key Words ◽  
Molecular Orbital ◽  
Metal Clusters ◽  
Metal Cluster ◽  
Molecular Orbital Calculations ◽  
Transition Metal Clusters ◽  
X Ray ◽  
Metal Bonding ◽  
Metal Metal

Molecular orbital calculations at the extended Hückel level are used to rationalize the barriers to vertex rotation in the tetrahedral metal cluster complexes FeCo2(CO)9S, 2, and (C5H5)MoCo2(CO)8CH, 3. It is shown that, in accord with experimental observations on 2, rotation of an Fe(CO)3 fragment through 60° brings about a weakening of the metal–metal bonding interactions within the FeCo2 triangle. In the MoCo2 cluster, 3, rotation of the CpMo(CO)2 fragment about an axis joining the molybdenum to a central point within the tetrahedron gives rise to three minima in which the cyclopentadienyl ring is oriented proximal or distal relative to the capping carbynyl moiety, or in the plane of the three metals. The rotation trajectory of the CpMo(CO)2 vertices in Cp2Mo2(CO)4(HC≡CH), 4, has been elucidated by means of a Bürgi–Dunitz analysis of the X-ray crystal structures of a series of related clusters in which the CpMo(CO)2 units exhibit a range of orientations. The calculations suggest that the barriers to vertex rotations in 4 are primarily of steric rather than electronic origin. Key words: metal clusters, vertex rotations, EHMO calculations.

Infrared spectroscopy of unsupported metal cluster complexes using multiple photon dissociation

1986 ◽  
Vol 85 (2) ◽  
pp. 1198-1199 ◽  
Author(s):  
M. R. Zakin ◽  
R. O. Brickman ◽  
D. M. Cox ◽  
K. C. Reichmann ◽  
D. J. Trevor ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Metal Cluster ◽  
Cluster Complexes

The chemistry of stabilized clusters

1982 ◽  
Vol 308 (1501) ◽  
pp. 27-34 ◽  
Keyword(s):  
Electron Donor ◽  
Organic Molecules ◽  
Metal Cluster ◽  
Organic Substrates ◽  
Insertion Reactions ◽  
Donor Ligand ◽  
Small Organic Molecules ◽  
Wide Range ◽  
Metal Metal ◽  
High Yields

Studies of the chemistry of metal cluster complexes and, in particular, their reactions with small organic molecules, have been confined to relatively few systems. Among the reasons for this are: (i) not many clusters are easily synthesized in high yields; (ii) their reactions often give a multitude of products that are difficult to separate and characterize; (iii) the conditions required to bring about reactions often lead to fragmentation of the cluster into lower nuclearity (often mononuclear) species. One cluster whose chemistry has been extensively studied is [Os 3 H 2 (CO) 10 ]. This can be synthesized in high yields from [Os 3 (CO) 12 ] + H 2 (Knox et al. 1975) and reacts readily under mild conditions with a wide range of electron-donor molecules by virtue of its coordinative unsaturation (Shapley et al. 1975; Deeming & Hasso 1976; Adams & Golembeski 1979). Formally, one may consider that a metal—metal double bond is present, which is reduced to a single bond on coordination of an additional two-electron donor ligand such as an organophosphine. The presence of metal—hydrogen bonds in this cluster and the cluster’s ability to coordinate organic substrates enable it to undergo a wide variety of insertion reactions, leading to products that may be regarded as intermediates in the reduction of organic molecules by clusters (Deeming & Hasso 1975; Keister & Shapley 1975).

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