Pnictogens

We have developed several examples of fruitful areas in this chemistry that demonstrate feasibility. As one might expect, a list of compounds related to the pnictates proposed in Table 14.4 as the trivalent pnictogens and trielides should yield compounds of similar chemical composition. However, we can think of these systems in a slightly different manner. We can imagine a different formula from that in the previous equations ... 

The eclipsed conformations of 29, 48, and 32 bring the pairs of Sb and Bi atoms on opposing rings very close (3.58-3.69 A). These distances are significantly shorter than van der Waals radius separation (4.4 A for Sb Sb and 4.6 A for Bi Bi). Thus a direct secondary bonding between the pnictogen atoms seems likely. 

An intermolecular analog of this inter-ring pnictogen bonding is found in the thermochromic distibines and dibismuthines.45 For example, 2,2, 5,5 -tetramethylbistibole (87) crystallizes so that the Sb atoms are aligned in chains with close contacts between the Sb atoms of adjacent molecules. It seems more than coincidental that the intermolecular contacts in 87 occur at virtually the same distance as the intramolecular contacts in 29. See Figure 3. 

Thus the calculations indicate that the direct through-space bonding between the pnictogen atom p-orbitals controls the conformations of the heavier diheteroferrocenes. 

The heavier chalcogen and pnictogen analogues of many of these phosphine sulfides are also known (Table 1). 

Solid-state assemblies containing binary group 15/16 anions of the heavier pnictogens are also extremely well known, including the naturally occurring... 

Coordination Complexes of Bismuth(III) Involving Organic Ligands with Pnictogen or Chalcogen Donors Glen G. Briand and Neil Burford... 

COORDINATION COMPLEXES OF BISMUTH(III) INVOLVING ORGANIC LIGANDS WITH PNICTOGEN OR CHALCOGEN DONORS... 

Chart 1. Functional groups with chalcogen or pnictogen sites as donors to bismuth. 

Oxadative addition reactions of germylenes are a versatile method for the formation of germanium-pnictogen bonds.147-156 Reaction of germylenes with diazabutadienes yields [4+ 1]-cycloaddition products (Equation (115)),148... 

The metal to phosphorus (or arsenic) ratio varies between 1 1 (alkali metal phosphanides and arsanides) and 2 1 for bis(alkali metal) phosphanediides or arsanediides. In general, these compounds form pnictogen polyhedra with the faces being capped by monovalent metal atoms. For the alkaline-earth metal phosphorus cages, metal to phosphorus ratios between 1 2 for alkaline earth metal bis(phosphanides) and 1 1 for the phosphanediides of the divalent cations are possible. 

Tab. 3.6-3. Overview of cage compounds of the type [M Om(REH)x(RE)y] of the monovalent atoms M (alkali metals and copper) and the pnictogen atoms E (P, As).

New York Times Pull Document, http //www.sanacacio.net/118-saga/story.html (accessed November 2, 2005). Nit-Picking—/ say pnicogen, you say pnictogen. http //www.chm.bris.ac.uk/motm/ pinctogenZpnictogenh.htm (accessed June 8, 2005). 

In a marked contrast to the lighter pnictogen (P, As, Sb) elements, this class of bismuth ylides readily undergoes Corey-Chaycovsky-type epoxidations with aromatic, aliphatic, and ot,(3-unsaturated aldehydes to afford the corresponding... 

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