Preparation of Tetraaminophosphonium Salts by Ammonolysis of the Triamino(methylthio)‐phosphonium Ion

Unprecedented in chemistry, the acid-base pair H 8 PN 4 "7 PN 4~ enables structural comparison over a range of eight succes sive dissociation steps: According to the results of the X-ray struc ture analysis, 161 P(NH 2 ) 4 and I" ions form a CsCl-analogous arrangement in the solid. The P-N bond length (160.7(2) pm) ( Fig. 1) represents the shortest P-NH 2 bond distance reported to date. The valence sum for the phosphorus center (5.56), calculatThe characteristic building blocks in phosphorus(v) nitrides are PN 4 tetrahedra. Linkage of these structural elements through common corners allows access to a large number of condensa tion degrees. This is reminiscent of the varied structural chem istry of the silicates and phosphates.111 One of the extremes in the series of differently condensed phosphorus nitrides is the ionic compound Li 7 PN 4 , which comprises "isolated" PN] -ions. 121Due to its extremely high formal charge, no indications for the existence of this anion in solution have yet been found; there fore, Li 7 PN 4 is accessible only by solid-state reaction of the corresponding binary nitrides. Thus, the certainly high synthetic potential of isolated PN 4 groups in solution for the formation of well-defined Ρ-Ν solid compounds has remained unexplored.The salt Li 7 PN 4 is derived from the hypothetical acid H 7 PN 4 , which is suspected to be an unstable monophosphazene interme diate during ammonolysis of PC1 5 . 131 However, due to its high basicity and tendency to undergo condensation reactions it has not yet proven possible to isolate imidophosphoric acid triamide, H 7 PN 4 . With P(NH 2 ) 4 I (C) we report the first successful synthesis and structural proof of a tetraaminophosphonium salt, which can be regarded as a hydroiodide of H 7 PN 4 . The synthesis followed the modification of a procedure 141 that starts from phosphorothionic triamide (A).t51 Methylation of the sul phur atom in A with methyl iodide and careful subsequent am monolysis of Β readily yields the desired product C. As the last reaction step is a heterogeneous solid-liquid reaction, C is ob tained as a sparingly-soluble, fine-crystalline powder. The crys tal growth of tetraaminophosphonium iodide was severely ham pered by the fact that C is insoluble in most solvents and that, due to its reactivity, it easily undergoes hydrolysis and conden sation reactions. In the past methanol had been suggested as a solvent for C. However, according to our investigations pro longed exposure of C to methanol leads to the formation of tetramethylammonium iodide [Eq. (a)]. Sufficiently large single crystals of C were obtained by crystallization from dry acetonitrile employing a temperature gradient between 70 °C and room temperature. Obviously, tetraaminophosphonium iodide is sufficiently soluble at the higher temperature. ed from the four Ρ-Ν bonds according to O'Keeffe et al., (7] is indicative of significant polar bonding or multiple bonds between the phosphorus and nitrogen atoms. The electrostatic repulsion between the nitrogen atoms in PN 4 " (...

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“…

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mentioning

confidence: 99%

“…P(NH 2 ) 4 and I" ions form a CsCl-analogous arrangement in the solid. The P-N bond length (160.7(2) pm) ( Fig.…”

mentioning

confidence: 99%

Synthesis and Crystal Structure of the First Tetraaminophosphonium Salt P(NH₂)₄I

Schnick

Horstmann

Schmidpeter

1994

Angew. Chem. Int. Ed. Engl.

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“…We found out how to confine the reaction to substitution alone and thus obtain the tetraaminophosphonium chloride Cl ‫מ‬ [38,39]. [41,42]. Recently, Wolfgang Schnick, who is now also at this university, obtained P 3 N 5 in crystals suitable for structure analysis by thermolysis of the latter [43].…”

Section: Alfred Schmidpetermentioning

confidence: 96%

Molecules that we made: An essay on phosphorus chemistry

Schmidpeter¹

1999

Heteroatom Chem.

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Phosphorus–Nitrogen CompoundsBased in part on the article Phosphorus–Nitrogen Compounds by Robert H. Neilson which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Haiduc

2005

Encyclopedia of Inorganic Chemistry

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Phosphorus displays several oxidation states (+II, +III , +IV, and +V ) and coordination numbers (from one to six), and with nitrogen (also two‐, three‐, and four‐coordinate) can form a broad variety of compounds (purely inorganic or organo‐ N ‐ or ‐ P ‐substituted). In addition to mononuclear PN compounds, many short‐chain, polymeric, and cyclic compounds based on molecular skeletons formed by PN alternation are known. There are numerous classes of phosphorus–nitrogen compounds, and this article makes an attempt to introduce the most important ones in the limited space available by selecting what seem to be the most illustrative examples from a very rich chapter of chemistry.

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Preparation of Tetraaminophosphonium Salts by Ammonolysis of the Triamino(methylthio)‐phosphonium Ion

Cited by 11 publications

References 6 publications

Synthesis and Crystal Structure of the First Tetraaminophosphonium Salt P(NH₂)₄I

Synthesis and Crystal Structure of the First Tetraaminophosphonium Salt P(NH₂)₄I

Molecules that we made: An essay on phosphorus chemistry

Phosphorus–Nitrogen CompoundsBased in part on the article Phosphorus–Nitrogen Compounds by Robert H. Neilson which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

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Preparation of Tetraaminophosphonium Salts by Ammonolysis of the Triamino(methylthio)‐phosphonium Ion

Cited by 11 publications

References 6 publications

Synthesis and Crystal Structure of the First Tetraaminophosphonium Salt P(NH2)4I

Synthesis and Crystal Structure of the First Tetraaminophosphonium Salt P(NH2)4I

Molecules that we made: An essay on phosphorus chemistry

Phosphorus–Nitrogen CompoundsBased in part on the article Phosphorus–Nitrogen Compounds by Robert H. Neilson which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

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Synthesis and Crystal Structure of the First Tetraaminophosphonium Salt P(NH₂)₄I

Synthesis and Crystal Structure of the First Tetraaminophosphonium Salt P(NH₂)₄I