Group 15 elements phosphorus

In 1985 McMahan and LeSar predicted that the triple bond in molecular nitrogen should be breakable under very high pressures and a solid should be formed which consists of trivalent (i.e. three-coordinate) nitrogen atoms (pressure-coordination rule). Such structures already exist at normal pressures for the other group 15 elements phosphorus, arsenic, antimony and bismuth. The transformation pressure for nitrogen should lie in a range between 500 and 940 kbar. An estimation... 

Main group elements Phosphorus, sulfur, caibon... 

Nitrogen is unusual in forming so many oxides. The acidity of the Group V oxides falls from phosphorus, whose oxides are acidic, through arsenic and antimony whose oxides are amphoteric, to the basic oxide ofbismuth. This change is in accordance with the change from the non-metallic element, phosphorus, to the essentially metallic element, bismuth. The +5 oxides are found, in each case, to be more acidic than the corresponding + 3 oxides. 

Supplementary Work, Vol 24 Perfluorohnloorganic Compounds of Mam Group Elements Part 3 Phosphorus, Arsenic, Antirnon and Bismuth Compounds Perfhiorohaloorganic Compounds of Main Group Elements Part 5 Compounds oj Nitrogen (Heteroc clrc Compounds)... 

H. Hoffmann and M. Becke-Goehring, Topics in Phosphorus Chemistry 8, 193-271 (1976) J. G. Riess in A. H. Cowley (ed.), Rings, Clusters and Polymers of the Main Group Elements, ACS Symposium Series No. 232, 17-47 (1983). 

Phosphorus, arsenic and antimony complexes of the main group elements. W. Levason and C. A. McAuliffe, Coord. Chem. Rev., 1976,19,173-185 (88). 

The in-V compounds combine the elements of Group HI (aluminum, gallium, indium) with those of Group V (phosphorus, arsenic, antimony, bismuth). As can be imagined, a wide variety of compounds can be produced which, in addition to the binary materials, also include ternary and even quaternary materials. 

Many of the properties of the group 15 element diheteroferrocences are very similar to ferrocenes and other metallocenes. It seems justified to regard the diheteroferrocenes as perturbed ferrocenes just as we regard the group 15 heterobenzenes as perturbed benzenes. Thus, it is very clear that the elements phosphorus, arsenic, antimony, and bismuth can take part in 7r-bonding in a manner similar to carbon. 

Two approaches have been used in the synthesis of these types of compounds. Small boron-phosphorus ring compounds can serve as building blocks, and addition and elimination reactions with other main group elements can then extend the cage structure (see Schemes 23 and 24, Section 12.12.6.4.5). Alternatively, an unsaturated carbenoid fragment can be added to the bicyclic fragment as illustrated in Scheme 31 <1998IC490>. 

Gonzales-Moraga, G. (1993). Cluster Chemistry. Springer-Verlag, New York. A comprehensive survey of the chemistry of clusters containing transition metals as well as cages composed of main-group elements such as phosphorus, sulfur, and carbon. 

The noticeable renaissance of main group chemistry is well reflected by the relatively large number of structures with main group elements determined by electron diffraction. Consider as examples the molecules with boron, silicon, phosphorus, or sulfur. 

In the latter case each 14-electron CpCo group completes its valence-shell by sharing electron pairs with one other CpCO group and with three phosphorus atoms, consistent with its diamagnetic character and with the observed geometry. It is likely that many more such mixed clusters, incorporating both transition metals and main group element, will be developed in the future. 

My purpose here is to Illustrate what can be accomplished with just one inorganic macromolecular system — in this case constructed from a backbone of phosphorus and nitrogen atoms. Almost certainly, other systems based on the Main Group elements can be developed to an equal or greater degree. I hope that the following comments will stimulate an increased interest in that direction. I will also attempt to illustrate the relationship between the fundamental chemistry and an approach to solving practical problems. 

Metalloporphyrins containing low valent main group elements show hyper-type UV-visible spectra and the corresponding higher valent complexes show normal spectra. Despite this, the phosphorus complexes [P(OEP)R2] show spectra with distinctly hyper character, with two extra Soret bands apparent. The extra Soret band in hyper complexes has been assigned to charge transfer from the low... 

An area of current development is the nomenclature of organometallic compounds. Organometallic compounds of Main Group elements can, to a first approximation, be considered to be derivatives of hydrides, and the methods of substitutive nomenclature can be applied. Even then, the accessibility of different oxidation states, as with phosphorus(iii) and phosphorus(v), introduces complications. Transition metal organometallic compounds are even more difficult to treat, and the development of a unified, self-consistent and accepted and applied nomenclature is not easy. Witness the different ways (k, t and italicised symbols) for denoting donor atoms in ligands. 

---