Anion clusters

Leopold D G, Ho J and Lineberger W C 1987 Photoelectron spectroscopy of mass-selected metal cluster anions. I. Cuji, n = 1 -10 J. Chem. Phys. 86 1715... 

Gantefor G, Meiwes-Broer K H and Lutz H O 1988 Photodetachment spectroscopy of cold aluminum cluster anions Phys. Rev. A 37 2716... 

Iseda M, Nishio T, Han S Y, Yoshida H, Terasaki A and Kondow T 1997 Electronic structure of vanadium cluster anions as studied by photoeieotron spectroscopy J. Chem. Phys. 106 2182... 

The reaction between a trinuclear metal carbonyl cluster and trimetbyl amine borane has been investigated (41) and here the cluster anion functions as a Lewis base toward the boron atom, forming a B—O covalent bond (see Carbonyls). Molecular orbital calculations, supported by stmctural characterization, show that coordination of the amine borane causes small changes in the trinuclear framework. 

In the families of heptanuclear clusters, two geometries are found the capped octahedron that is typical for 98-valence electrons, and the vertex-sharing open tetrahedral (butterfly) stmctures typical for 106-valence electrons. An example of the former is Osy(CO)22 (51) an example of the latter is [H2AuOsg(CO)2Q] (52). In the AuOs cluster anion, the gold atom is at the vertex-sharing position. 

There are many related compounds, including rhodium carbonyl cluster anions, which are present in the solutions cataly2ing ethylene glycol formation and which may be the catalyticaHy active species or in equiUbrium with them (38). 

Figure 4.8 Slruclures of selecled lilhium compounds having coordinalion numbers ranging from 2 lo 6. (a) The unique slructurc of (b) The cluster anion iLi (N = CPh2)6 O PiNMe2)3 ] showing four...

Figure 13.25 (a) Structure of the anion As7 , isoelectronic with As4Se3 (p. 581). The sequence of As-As distances (base>cap>side) is typical for such cluster anions but this alters to the sequence base >side>cap for neutral species such as As7(SiMe3)3 shown in (b). 

Reaction of P4Sc4 with soluble polyselenides afforded the first isolated P/Se anion, the yellow P2Seg (17) which further reacts with Fe(CO)s to generate the novel brown cluster anion [Fe2(CO)4(PSc5)2] (18).Numerous other examples are known indeed, the whole field is still rapidly developing and many new types of compound are being synthesized and characterized each year. 

Fig. 27. In vanadium borate 106 the macrocyclic borate ring (left) is sandwiched by two smaller (VO)60i2 rings (right) of triangular form via six axial B-( 3-0)-V bonds to form a cage-like cluster anion...

Vanadium borophosphates 107-109 that contain cluster anions with different ring sizes can be synthesized by hydrothermal reactions of vanadium(III) oxide, boric acid and an appropriate phosphate salt [145,146]. The ring size of the cluster anion with the composition [(VO)2BP20iol 4-6 is determined by the size of the cation that is, however, included only in the interior of the cages with n = 5 and 6 (Fig. 28). 

Fig 28. Vanadium borophosphates with the composition [(VO)2BP20io] n form cage-like cluster anions, which may be empty (107, n = 4) or centered by a cation (109, n = 6). For clarity only half of the vanadium and phosphorus atoms of the cluster anions are shown... 

Furche, F., Ahlrichs, R., Weis, P., Jacob, C., Gilb, S., Bierweiler, T. and Kappes, M.M. (2002) The structures of small gold cluster anions as determined by a combination of ion mobility measurements and density functional calculations. Journal of Chemical Physics, 117, 6982-6990. 

Wallace, W.T., Wyrwas, R.B., Whetten, R.L., Mitric, R. and Bonadc-Kouteck, V. (2003) Oxygen adsorption on hydrated gold cluster anions experiment and theory. Journal of the American Chemical Society, 125, 8408-8414. 

It has been reported that Cgo and its derivatives form optically transparent microscopic clusters in mixed solvents [25, 26]. Photoinduced electron-transfer and photoelectrochemical reactions using the C o clusters have been extensively reported because of the interesting properties of C o clusters [25,26]. The M F Es on the decay of the radical pair between a Cgo cluster anion and a pyrene cation have been observed in a micellar system [63]. However, the MFEs on the photoinduced electron-transfer reactions using the Cgo cluster in mixed solvents have not yet been studied. 

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