Hexaco-ordinate Phosphorus Compounds

Hexaco-ordinate Phosphorus Compounds - A series of heterocyclic phosphorates (133) with a P-C Bond in the ring have been prepared by the reaction of phosphonates 

Haenel, B. Ziemer, L. Riesel, P. Leibnitz and G. Ohms, Z, anorg. allg. Chem., 1988, 563,173. 

Krolevets, A.V.Adamov, A.G. Popov and I.V. Martynov, Bull. Acad. Sci. USSR (Engl.transi), 1988, 37, 2392. 

Tangour, C. Malavaud, M.T. Boisdon and J. Barrans, Phosphorus, Sulfur and Silicon, 1989, 45,189. 

The synthesis and remarkable resolution of a configurationally stable tris(tetra-chlorobenzene diolato) phosphate ion (105) has been achieved. The electron withdrawing effect of the twelve chlorine atoms in the three benzene rings apparently stabilises the molecule so that solutions of 105 at room temperature 

Finally, to end at what is essentially the beginning (at least of this chapter ) 

Cavell et al. have synthesised and characterised a series of neutral, hexaco-ordinate phosphorus compounds containing divalent, tridentate diphenol imine, azo and thio ligands. For example, the reaction of silylated Schiff base ligands e.g. 112) with PCI5 gave the neutral, hexacoordinate compound 113 by 

Kadyrov, I. Neda, T. Kaukorat, R. Sonnenburg, A. Fischer, P. G. Jones and 

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Hexaco-ordinated Phosphorus Compounds. - The reaction of PCt with alkylammonium fluorides in the presence of secondary amines gives PF5-amine adducts (132)60. The additional presence of alcohols or phenols leads to the formation of alkoxy- or aroxypenta-f luorophosphates, ROPF -. The PF -amine adducts may also be converted into ROPF - by treatment with alcohols or into ArNHPF -by treatment with primary arylamines. 

Several reports of the synthesis of hexaco-ordinate phosphorus compounds [e.. (81)] from tervalent phosphorus have appeared (see Chapter 2). P N.m.r. studies... 

Hexaco-ordinated Phosnhorus Compounds- The first examples of diazadiphosphetidines (128) with phosphonium and 6-coordinate phosphate centres without halogen atoms on phosphorus were formed from the reaction of... 

A number of important review articles have appeared in the area of pentaco-ordinate and hexaco-ordinate phosphorus chemistry. Robert Holmes has provided an extremely informative comparison of the hypervalency, stereochemistry and reactivity of silicon and phosphorus including the application of the latter to enzyme systems. The coordination chemistry of hydrophosphoranes including the formation of complexes from bicyclic-, tricyclic- and tetracyclic hydrophosphoranes has also been the subject of a comprehensive review with literature coverage to 1995. Numerous metal complexes are mentioned including Rh, Ru, Pd, Co, Fe, Mo, and W and the relevance to asymmetric catalysis is discussed. Neutral six-coordinate compounds of phosphorus, including mono-, di-, tri-, and tetracyclic examples, have also been reviewed. 

Introduction - It is gratifying to report that interest in hypervalent phosphorus chemistry has been maintained, especially with regard to structural studies and the synthetic utility of pentaco ordinate phosphorus compounds. A novel departure has appeared in the area of hexaco-ordinate phosphorus with the synthesis of further phosphorus derivatives of the porphyrin ring system containing hypervalent phosphorus coordinated by the tetrapyrrole unit. The chapter will take its usual format, however, and the details of this small nugget will therefore appear in the last section. 

Phosphines and Phosphonium Salts Pentaco-ordinated and Hexaco-ordinated Compounds Phosphine Oxide and Related Compounds Tervalent Phosphorus Acids Quinquevalent Phosphorus Acids Nucleotides and Nucleic Acids Ylides and Related Compounds Phosphazenes. 

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