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]
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]
^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 (2): 287–93.
doi:
10.1016/0041-008X(79)90323-5.
PMID452023.