Bismuth cluster compounds

In all the cluster compounds discussed above there are sufficient electrons to form 2-centre 2-electron bonds between each pair of adjacent atoms. Such is not the case, however, for the cationic bismuth species now to be discussed and these must be considered as electron deficient . The unparalleled ability of Bi/BiCb to form numerous low oxidation-state compounds in the presence of suitable complex anions has already been mentioned (p. 564) and the cationic species shown in Table 13.12 have been unequivocally identified. 

X-ray studies confirm Bi2(ju,-OR)2 centrosymmetric dimers 4 in the solid state (24). Terminal alkoxides are generally bound more tightly than bridging units [terminal Bi-0 2.064(7) A bridging Bi-0 2.188(7) and 2.688(7) A], The bismuth oxide alkoxide cluster compounds [Bi6(p,3-07)(p,3-OC6F5) Bi(OC6F6)4 3(sol)2] [sol]2 (sol = thf or toluene) were also isolated as minor products (25). Both structures contain the unusual octahedral I Bi, (/x3-07 X/x3-OCeF.-) I" cores 5, which... 

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. 

Carbon functional groups, attachment to polysilanes, 3, 585 Carbon-heteroatom bond formation via antimony(III) compounds, 9, 428 via antimony(V) compounds, 9, 432 via bismuth(III) compounds characteristics, 9, 440 with copper catalysts, 9, 442 non-catalyzed reactions, 9, 443 with bismuth(V) compounds, 9, 450 with bismuthonium salts, 9, 449 with bismuth ylides, 9, 450 Carbon-heteroatom ligands in tetraosmium clusters, 6, 967 in tetraruthenium clusters, 6, 960... 

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). 

Several reviews have appeared describing metal-carbonyl complexes incorporating bismuth and the other heavy main group elements (see Cluster Compounds Inorganometallic... 

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. 

Application of this procedure to the post-transition metals forming clusters indicates that bare gallium, indium, and thallium vertices contribute one skeletal electron bare germanium, tin, and lead vertices contribute two skeletal electrons bare arsenic, antimony, and bismuth vertices contribute three skeletal electrons and bare selenium and tellurium vertices contribute four skeletal electrons in 2D and 3D aromatic clusters. Thus, Ge,Sn, and Pb vertices are isoelectronic withBH, Fe(CO)-, andC5H5Co vertices and As, Sb, and Bi vertices are isoelectronic with CH, Co(CO)v and C H Ni vertices in bare metal cluster compounds. 

A considerable number of cluster compounds of mercury, bismuth, the halogens and the chalcogens have now been prepared by the use of AsF 5 " and, to a lesser degree, SbFs and other oxidizing fluorides such as NbFs and TaFs. More recently, the use of catalysts to promote reactions in SO2 solutions has also been developed as an additional synthetic tool. ... 

The nature of the counterion in solid cluster compounds can have a major impact on cluster stability, even in compounds where the cluster-counterion contacts are found at van der Waals distances and the cluster-counterion interaction thus can be regarded as non-specific. For instance, BiiofHfClgjs and Bi5(MCl4)3 (M = Al, Qjjp9.2oo.248] jj contain bismuth in the formal oxidation state -1-0.6, but the former compound is made up of the sub-valent species Bi+ and Bi9, whereas the two... 

Bi2(SC6F5)6((i-X)] or [Bi3(SC6 F f/ii- Br)2]2 have been obtained by reaction of [Bi(SCf,F5L3] with halide anions.192 The reaction of BiBr3 with PhSeSiMe3 gives clusters, such as [Bi4(p-SePh)5(SePh)g] (20) or [Bi6(p-SePh)6 (SePh)10Br2].193 The use in medicine of bismuth compounds has lead to the... 

No Bi2Xi compound is known, but it has long been known that when metallic bismuth is dissolved in molten BiCl3 a black solid of approximate composition BiCl can be obtained. This solid is Bi24Cl28, and it has an elaborate constitution, consisting of four BiCll", one Bi2Clg, and two Bi + ions, the structures of which are depicted in Fig. 10-5. The electronic structure of the Bi + ion, a metal atom cluster, is best understood in terms of delocalized molecular orbitals. Other low-valent species present in various molten salt solutions are Bi+, Bi3+, Bi +, and Bi +. The last, in Bi8(AlCl4)2, has a square antiprismatic structure. 

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