Bismuth clusters

The polyhedra in Fig. 1 thus represent suitable shapes for cluster species with n skeletal atoms (each of which can furnish three AO s for use in skeletal bonding) and with (n + 1) skeletal bond pairs. Since it is the cluster symmetry that determines the number of bonding MO s, the same polyhedra can serve as the basis for the structures of a whole range of isoelectronic species, including neutral carboranes of formula C2B 2Hn, bismuth clusters, such as the trigonal-bipyramidal Bis " ",... 

Different bismuth clusters are apparently formed in reactions between bismuth and bismuth trichloride-aluminum trichloride mixtures, from which the salts (Big) " (AICl4 )3, and (Bi8) + (AICl4 )2 have been isolated 43). A trigonal-bipyramidal structure was predicted for Big (a closo 6 skeletal bond pair system cf. C2B3Hg), and a square anti-prismatic structure for Bi8 , as appropriate for an arachno 8-atom, 11 skeletal bond pair cluster. Similar polyhedral shapes appear likely for other clusters not only of bismuth but also of other heavy main group metals (the anion Pbg ", for example, is isoelectronic with Bi9 " ). 

Wade expanded the 1971 hypothesis to incorporate metal hydrocarbon 7T complexes, electron-rich aromatic ring systems, and aspects of transition metal cluster compounds [a parallel that had previously been noted by Corbett 19) for cationic bismuth clusters]. Rudolph and Pretzer chose to emphasize the redox nature of the closo, nido, and arachno interconversions within a given size framework, and based the attendant opening of the deltahedron after reduction (diagonally downward from left to right in Fig. 1) on first- and second-order Jahn-Teller distortions 115, 123). Rudolph and Pretzer have also successfully utilized the author s approach to predict the most stable configuration of SB9H9 (1-25) 115) and other thiaboranes. 

LMIG filled with bismuth (or gold) has been developed for SIMS (especially employed in ToF-SIMS) measurements. This primary ion source provides cluster beams of Bi with n = 1-7 which allow higher secondary ion yields compared to gallium or indium LMIGs ° and is well suited for special applications (biological imaging). Bismuth cluster ion beams have much better... 

Bismuth with a formal oxidation state of -3 is found in solid-state phases MsBi (M = alkali metal) and M)Bi2 (M = alkaline-earth metal). The compoundNasBi is metallic. Less reduced intermetallic phases with the alkali metals and alkaline-earth metals are also known. Examples inclnde MBi (M = Li, Na), MBi2 (M = K, Rb, Cs), and M Bk (M = Mg, Ca, Sr, Ba). The compounds M Bis (M = Ca, Sr, or Ba) superconduct at low temperatures. Some of these intermetallic phases have been extracted with amine solvents to yield anionic bismuth clusters in solntion (see Section 2.8.2). 

Some analogous rathenium- and osmium-bismuth clusters have been found. Examples include Bi2M3(CO)9 and H3BiM3(CO)9 (M = Ru, Os). The stmctures of the hydride compounds have both been determined and they are isostractural with the iron complexes as is Bi2Ru3(CO)9 withBi2Fe3(CO)9. The structure 0fBi2Os3(CO)9, on the other hand, has not been determined and its IR spectrum indicates that it probably has a different structure. A spirocyclic cluster [Ru2(CO)8(/X4-Bi)Ru3(CO)io(/x-Ft)] (39) has been reported. 

Na(crypt-222)]3[In4Bi5], all of which are prepared (mostly as solvates with 1,2-ethanediamine) in a similar way to reaction 14.52. The [PbySby], [GaBi3] and [InBi3] ions are tetrahedral in shape. The [In4Bi5] ion adopts a monocapped square-antiprism in which the Bi atoms occupy the unique capping site and the four open-face sites. These structures are consistent with Wade s rules (see Section 12.11) The syntheses of cationic bismuth clusters were described in Section 8.12. 

Symmetries given in Table 2 are idealized (and refer to the symmetry of the cluster without taking into account heteroatoms) and many of the clusters show distortions from these ideal symmetries. For example, the group 14 clusters Geg, Sng and Pbg have 2n + 4 cluster electrons and exist as the expected nido clusters with C4V monocapped square antiprismatic geometry. On the other hand, the bismuth cluster Big +, which also has a 2n + 4 electron count, instead exists in the closo Z>3h form with a tricapped trigonal prismatic structure. In fact, all these 9-atom clusters show some distortions from the idealised symmetry, and the energy differences between different geometries are small.The arachno clusters Sb4, Bi4 , Se4 + and Te4 + (square planar), and Sbg + and Big + (square antiprismatic) have... 

D. Touboul, F. Kollmer, et al. Improvement of biological time-of-flight-secondary ion mass spectrometry imaging with a bismuth cluster ion source, J. Am. Soc. Mass Spectrom. 16, 1608-1618 (2005). 

Currently, cluster primary ions [6-12] such as AUx (the gold cluster ion), Bix (the bismuth cluster ion), and Ceo [1,13,14], which produce larger fragment ions from proteins, are employed in the analysis of biomaterials... 

Magnusson, Y. F. P., SjovaU, P, Dangardt, F, Malmberg, P, Chen, Y. (2008). Lipid imaging of human skeletal muscle using TOF-SIMS with bismuth cluster ion as a primary ion source. Clin Physiol Funct Irmi0in , 28, 202-209. 

Nygren, H., Borner, K., Hagenhoff, B., Malmberg, P., Mansson, J. E. (2005). Localization of cholesterol, phosphochohne and galactosylceramide in rat cerebellar cortex with imaging TOF-SIMS equipped with a bismuth cluster ion source. Biochim Biophys Acta, 1737, 102-110. 

The syntheses of cationic bismuth clusters were described in Section 9.12. The [Bis] ion may also be obtained by oxidation of Bi using GaCls in benzene, or using AsFs. Although [Bis], [Big] and [Bi9] have been known for many years, no well-characterized example of a homopolyatomic antimony cation was reported until 2004. 

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