Dimeric structures bismuth

The only example of a ketothiolate adopts a dimeric structure [Bi(PhCH S CH2C 0 Ph)3]2[CH2Cl2] in which one of the three S,0 chelate ligands effects a secondary interaction with a neighboring bismuth [Bi---S 3.494(5) and 3.551(5) A] to impose heptacoordination 62... 

The 8-N rule states that the number of bonds (or local coordination, x) equals 8 minus the number of the periodic group. This rule is illustrated in Fig. 1.2 where we see that for N — 7 the halogens take dimeric structure types with x = 1, for N = 6 the chalcogenides selenium and tellurium take helical chain structures with x = 2, for N = 5 the pnictides arsenic, antimony, and bismuth take a puckered layer structure with x = 3, and for N = 4 the semiconductors... 

The X-ray crystallographic study of compound 1 has shown that the bismuth center is described best as a distorted pentagonal bipyramidal. The Bi-S bond lengths are 2.581(4), 2.627(5) and 2.731(3) A, and the Bi-O bond lengths are 2.536(9), 2.575(11) and 2.650(9) A. In addition, there is some intermolecular interaction between the bismuth and sulfur atoms (3.494(5) and 3.551(5) A), which causes a dimeric structure in the solid state [92POL1219]. 

The X-ray structure analysis of compound 2 has shown that the bismuth center is surrounded by six sulfur atoms to form a trigonal antiprismatic geometry. All three dithiocarboxylate ligands are non-equivalent and the Bi-S bonds can be divided into two types short (2.617(2), 2.626(1) and 2.647(1) A) and long (2.963(2), 3.040(1) and 3.108(2) A). One of the sulfur atom coordinates weakly to the neighboring bismuth center (3.689 A) to form a dimeric structure in the solid state [87IC1453]. 

The structural chemistry of some metal dithiocarbamates, i.e. systematics, coordination modes, crystal packing, and supramolecular self-assembly patterns of nickel, zinc, cadmium, mercury,363 organotin,364 and tellurium,365 366 complexes has been thoroughly analyzed and discussed in detail. Supramolecular self-assembly frequently occurs in non-transition heavier soft metal dithiocarbamates. Thus, lead(II),367 bismuth(III)368 zinc,369 cadmium,370 and (organo)mercury371 dithiocarbamates are associated through M- S secondary bonds, to form either dimeric supermolecules or chain-like supramolecular arrays. The arsenic(III)372 and antimony(III)373 dithiocarbamates are... 

Monomeric arrangements are rare for alkoxide complexes of bismuth and require excess anionic ligands or bulky substituents. Otherwise the alkoxide ligands typically impose dimerization or multinuclear clustering, which are expressed in a variety of currently unusual structural arrangements (Table I). 

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... 

A variety of derivatives of bis-[Bi(tr)2X, X = Cl or N03], tris-(Bitr3), and tetra-([Bi(tr)4X][Na]) tropolonate complexes of bismuth (178, 179) have been prepared and spectroscopically characterized (176, 177, 180). Solid-state structures for examples of bis-(tropolonate) derivatives confirm the chelate interaction (171) and in the case of the nitrate derivative, reveal intermolecular alkoxide-bismuth [Bi-0 2.688 and 2.666 A] dimer contacts 52, which are slightly longer than the chelate bonds [Bi-0 2.130-2.323 A],... 

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