Trimethylolpropane phosphite
Trimethylolpropane phosphite, C2H5C(CH2O)3P, is a phosphite ester used as a ligand in organometallic chemistry. Trimethylolpropane phosphite is sometimes abbreviated to EtCage. It is a white solid that is soluble in organic solvents. It is also highly toxic.[1]
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Names | |||
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IUPAC name
4-Ethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane | |||
Other names
EtCage; Ethyl bicyclic phosphite; Trishydroxymethylpropane bicyclic phosphite | |||
Identifiers | |||
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ECHA InfoCard | 100.011.385 | ||
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CompTox Dashboard (EPA) |
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Properties | |||
C6H11O3P | |||
Molar mass | 162.125 g·mol−1 | ||
Appearance | white waxy solid | ||
Melting point | 56 °C (133 °F; 329 K) | ||
organic solvents | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
Infobox references | |||
Preparation and reactions
It is prepared by reaction of trimethylolpropane with phosphorus trichloride or by transesterification with trimethylphosphite:[2]
- P(OMe)3 + EtC(CH2OH)3 → 3 MeOH + EtC(CH2O)3P
The first member of this series was derived from trimethylolethane,[3] but these derivatives are often poorly soluble. For this reason, the ethyl derivative has received more attention.[4]
Reactions
The compound forms an isolable ozonide, which degrades above 0 °C to release singlet O2.[1]
Coordination chemistry
Several EtCage complexes are known, since the ligand is highly basic (for a phosphite) and has a small ligand cone angle (101°). Illustrative complexes include [(EtCage)2Mo(CO)4], [Ir4(CO)11(EtCage)] and (CpMe5)RuCl(EtCage)2, shown below.
Safety
Trimethylolpropane phosphite is very toxic and is a convulsant. LD50 is 1.1 mg per kg bodyweight (mice, i.p.).[5][6]
References
- Ende, Christopher; Parker, Kathlyn (2014). "4-Ethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane". e-EROS Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rn01781.CS1 maint: uses authors parameter (link)
- Verkade, J. G. "Spectroscopic studies of metal-phosphorus bonding in coordination complexes" Coordination Chemistry Reviews 1972, vol. 9, 1-106. doi:10.1016/S0010-8545(00)80224-6
- Verkade, J. G.; Reynolds, L. T. "The synthesis of a novel ester of phosphorus and of arsenic" Journal of Organic Chemistry (1960), 25, 663-5. doi:10.1021/jo01074a622
- Huttemann, T. J., Jr.; Foxman, B. M.; Sperati, C. R.; Verkade, J. G. "Transition metal complexes of a constrained phosphite ester. IV. Compounds of cobalt(I), cobalt(III), nickel(II), and nickel(0)" Inorganic Chemistry (1965), 4(7), 950-3. doi:10.1021/ic50029a005
- Ralf Stöhr et al. Chemische Kampfstoffe und Schutz vor chemischen Kampfstoffen 2. Aufl. Militärverlag der DDR, 1985 (german)
- Milbrath, Dean S.; Engel, Judith L.; Verkade, John G.; Casida, John E. (1979). "Structure-toxicity relationships of 1-substituted-4-alkyl-2,6,7-trioxabicyclo[2.2.2.]octanes". Toxicology and Applied Pharmacology. 47: 287–93. doi:10.1016/0041-008X(79)90323-5. PMID 452023.CS1 maint: uses authors parameter (link)