Four Phosphorus Atoms

Three groups of compounds comprise this class l-aza-2,3,4,5-tetraphos-phorines, l-aza-2,3,4,6-tetraphosphorine, and l-aza-2,3,5,6-tetraphosphorine. No references to any of these could be located. 

Schmidt-Dunker, W. Ploeger, G. Jakobi, and E. Schmadel, Ger. Offen. 

Schmid, and W. Haubold, Z. Anorg. Alig. Chem. 433, 229 (1977). 

Arbuzov, V. D. Cherepinskii-Malov, E. N. Dianova, A. 1. Gusev, and V. A. Shaparov, Dokl. Akad. Nuuk SSSR 243, 358 (1978). 

Edmundson, in Rodd s Chemistry of Carbon Compounds (S. Coffey, ed.), Vol. 4, Part K, p. 118. Elsevier, Amsterdam, 1979. 

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Quite a number of cyclic phosphonium salts have been prepared over the years. We have not generally included compounds here which contain fewer than three potential binding sites in a ring unless they are mentioned as by-products in another reaction. Horner, Kunz and Walach have utilized the well-known alkylation approach to prepare cyclic phosphonium salts containing four phosphorus atoms. The formation of the cyclic tetraphosphonium salts is shown below in Eq. (6.14). 

Note from Figure 21.7 (p. 566) that in both oxides, as in P4 itself, the four phosphorus atoms are at the corners of a tetrahedron. The P406 molecule can be visualized as derived from P4 by inserting an oxygen atom between each pair of phosphorus atoms. In P4O10, an extra oxygen atom is bonded to each phosphorus. 

Finally, some organocopper compounds undergo charge disproportionation under the influence of ligands that bind strongly to copper. Treatment of mesityl-copper with l,2-bis-(diphenylphosphino)ethane (DPPE), for example, results in the formation of bis(mesityl)copper anions and a copper cation to which four phosphorus atoms of two DPPE molecules are coordinated [75]. 

In addition, five heterodiphospholes (T-X) are known and are also dealt with in this chapter. Within the scope of this chapter are five-membered rings with three and four phosphorus atoms but no other heteroatoms. In these systems, full cyclic conjugation can only be attained if all phosphorus atoms are two-coordinate. The ring consequently must be negatively charged as in the 1,2,4- and 1,2,3-triphospholides (Y, Z) and in the tetraphospholides (iE). The pentaphospholide (0) is again beyond the definition but must not be excluded here. 

D. Metaphosphates with more than Four Phosphorus Atoms in the Anion. 23... 

It seemed probable, from the early results of chromatography, that the hydrolyzate from Graham s salt contains metaphosphates with more than four phosphorus atoms in the anion ring 350). A little later 186) the metaphosphate content of a freshly prepared solution of Graham s salt with a mean chain length n of 100-125 was given as ... 

Its molecular structure (Figure 37) consists of a centrosymmetric dimer with a bridging H2Al(OR)( U-OR)2Al(OR)H2 entity. The Ta atoms are approximately square pyramidal, with the four phosphorus atoms forming the basal plane (Ta lies 0.64 A out of it). The relatively short Ta—A1 distances are comparable to those found in other transition metal aluminum complexes (Ta—Al 2.79-3.13 A). The hydrogen atoms have not been located, but were evidenced by chemical and spectroscopic techniques (IR 1605, 1540 cm 1 HNMR 16.30p.p.m.). The Ta—(ju-H2)A1 unit is relatively stable, and (54) is inert to carbon monoxide or trimethylamine. It is a poor catalyst in the isomerization of 1-pentene. Formation of complexes analogous to (54) may explain the low yields often obtained from alkoxoaluminohy-drides and metal halides. 

White phosphorus consists of a molecule made up of four phosphorus atoms. It burns in pure oxygen to produce tetraphosphorus... 

Formulas are used to identify molecules of free elements. A molecule contains two or more nonmetallic atoms bonded together. Many free (uncombined) non-metallic elements exist as molecules, such as H2, N2, O2, F2, CI2, Br2, and I2, as well as P4 and Sg (Figure 5.1). The formula P4 indicates four phosphorus atoms bonded together. This formula does not represent a compound, because only one kind of atom is present. Elemental phosphorus in its lowest energy form occurs in such molecules. 

The DuPont ADN process involves hydrocyana-tion of butadiene (equations 5-8), catalyzed by air-and moisture-sensitive triarylphosphite-nickel(O) complexes [Ni(P(OAr)3)4]. The nickel is zero valent (see Oxidation Number) because it has its full complement of 10 electrons beyond the preceding inert gas (Ar) configuration, and the catalysts can actually be made directly from nickel metal and the phosphite ligands (see P-donor Ligands). The four phosphorus atoms each contribute an electron pair to give a total of 18 electrons, corresponding to the next inert gas (Kr), (see Effective Atomic Number Rule and Electronic Structure of Organometallic Compounds). 

The Al MASNMR spectrum of VPI-5 has also been reported earlier (7). The spectrum contains a major resonance near 37 ppm, a neighboring resonance at 28 ppm, and a small resonance below 0 ppm. The chemical shifts of these resonances are consistent with other hydrated aluminophosphate molecular sieves that contain tetrahedrally coordinated aluminum that are linked to four phosphorus atoms through bridging oxygen atoms (10,11). 

This formulation is confirmed by the fact that, on deamination, " it retains its tetranucleotide structure and pentabasicity, and hence contains no phosphoamide links. Bredereck and collaborators completely methylated thymonucleic acid, obtaining a product possessing seven A -methyl and three methoxyl groups to each four phosphorus atoms. On stepwise hydrolysis, this material gave 1,6-dimethyladenine, 1,6-di-methylcytosine, and 1-methylthymine. This confirms the previously-mentioned conclusion, that the sugar is attached to position 9 of the adenine and to position 3 of the pyrimidines. 

White phosphorus (P4) consists of four phosphorus atoms arranged at the corners of a tetrahedron. Draw the valence electrons on this structure to give a Lewis diagram that satisfies the octet rule. 

The chemical formula for a substance shows its chemical composition. This represents the elements present as well as the ratio in which the atoms of the elements occur. The formula for a single atom is the same as the symbol for the element. Thus, Na can represent a single sodium atom. It is unusual to find such isolated atoms in nature, with the exception of the noble gases (He, Ne, Ar, Kr, Xe, and Rn). A subscript following the symbol of an element indicates the number of atoms in a molecule. For instance, F2 indicates a molecule containing two fluorine atoms, and a molecule containing four phosphorus atoms. 

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