Trimethylolpropane phosphite
 
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| Names | |||
|---|---|---|---|
|  IUPAC name
 4-Ethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane  | |||
|  Other names
 EtCage; Ethyl bicyclic phosphite; Trishydroxymethylpropane bicyclic phosphite  | |||
| Identifiers | |||
|  824-11-3  | |||
| 3D model (Jmol) | Interactive image | ||
| ChemSpider |  12655  | ||
| ECHA InfoCard | 100.011.385 | ||
| EC Number | 212-523-3 | ||
| PubChem | 13210 | ||
 
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| Properties | |||
| C6H11O3P | |||
| Molar mass | 162.12 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).  | |||
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| Infobox references | |||
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.
Ligand in coordination chemistry
It is prepared by reaction of trimethylolpropane with phosphorus trichloride or by transesterification with trimethylphosphite:[1]
- P(OMe)3 + EtC(CH2OH)3 → 3 MeOH + EtC(CH2O)3P
 
The first member of this series was derived from trimethylolethane,[2] but these derivatives are often poorly soluble. For this reason, the ethyl derivative has received more attention.[3]
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.
 
 RuCl(EtCage)2-from-xtal-1996-3D-balls.png)
References
- ↑ 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
 

