1,1,1-Tris(diphenylphosphinomethyl)ethane, also called Triphos, is an
organophosphorus compound
Organophosphorus chemistry is the scientific study of the synthesis and properties of organophosphorus compounds, which are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbo ...
with the formula CH
3C
2PPh2">H2PPh2sub>3. An air-sensitive white solid, it is a
tripodal ligand
Tripodal ligands are tridentate, tri- and tetradentate ligands. They are popular in research in the areas of coordination chemistry and homogeneous catalysis. Because the ligands are polydentate, they do not readily dissociate from the metal centre ...
("three-legged") of idealized C
3v symmetry. It was originally prepared by the reaction of
sodium diphenylphosphide and CH
3C(CH
2Cl)
3:
:3 Ph
2PNa + CH
3C(CH
2Cl)
3 → CH
3C
2PPh2">H2PPh2sub>3 + 3 NaCl
It forms complexes with many
transition metal
In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. The lanthanide and actinid ...
s, usually as a
tripodal ligand
Tripodal ligands are tridentate, tri- and tetradentate ligands. They are popular in research in the areas of coordination chemistry and homogeneous catalysis. Because the ligands are polydentate, they do not readily dissociate from the metal centre ...
. Such complexes are used to analyze mechanistic aspects of homogeneous catalysts. For example,
rhodium
Rhodium is a chemical element; it has symbol Rh and atomic number 45. It is a very rare, silvery-white, hard, corrosion-resistant transition metal. It is a noble metal and a member of the platinum group. It has only one naturally occurring isot ...
forms complexes with CH
3C
2PPh2">H2PPh2sub>3 like
2H4)">triphos)RhCl(C2H4) 2H4)">triphos)RhH(C2H4) and
2H5)(C2H4)">triphos)Rh(C2H5)(C2H4) provide model intermediates in the
catalytic
Catalysis () is the increase in reaction rate, rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst ...
cycle for hydrogenation of alkenes.
Triphos sometimes behaves as a
bidentate ligand
In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's ...
. Illustrative cases include ''fac''-
3Br(η2-triphos)">n(CO)3Br(η2-triphos)and
4(η2-triphos)">(CO)4(η2-triphos) where M is Cr, Mo, or W. Triphos serves as a tridentate-bridging ligand in an
icosahedral
In geometry, an icosahedron ( or ) is a polyhedron with 20 faces. The name comes . The plural can be either "icosahedra" () or "icosahedrons".
There are infinitely many non- similar shapes of icosahedra, some of them being more symmetrical tha ...
Au
13 cluster. The phosphine bridges three chlorogold(I) groups to form the tripod molecule of trichloro-1,1,1-(diphenylphosphinomethyl)ethanetrigold(I), CH
3C
2PPh2AuCl">H2PPh2AuClsub>3.
Related ligands
*
Tris(aminomethyl)ethane, a tripodal triamine (CH
3C(CH
2NH
2)
3)
*
Bis(diphenylphosphinoethyl)phenylphosphine (PhP(C
2H
4PPh
2)
2)
*Tris(2-diphenylphosphinoethyl)amine N
2CH2PPh2">H2CH2PPh2ref>
References
{{DEFAULTSORT:Tris(diphenylphosphinomethyl)ethane, 1,1,1-
Tertiary phosphines
Phenyl compounds
Chelating agents
Tridentate ligands