Xantphos 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 ...

derived from the

heterocycle A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, proper ...

xanthene Xanthene (9''H''-xanthene, 10''H''-9-oxaanthracene) is the organic compound with the formula CH2 6H4sub>2O. It is a yellow solid that is soluble in common organic solvents. Xanthene itself is an obscure compound, but many of its derivatives are u ...

. It is used as a bidentate

diphosphine Diphosphane, or diphosphine, is an inorganic compound with the chemical formula . This colourless liquid is one of several binary phosphorus hydrides. It is the impurity that typically causes samples of phosphine to ignite in air. Properties, ...

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 el ...

and is noteworthy for having a particularly wide

bite angle In coordination chemistry, the bite angle is the angle on a central atom between two bonds to a bidentate ligand. This ligand–metal–ligand geometric parameter is used to classify chelation, chelating ligands, including those in organometallic ...

(108°). Such ligands are useful in the

hydroformylation In organic chemistry, hydroformylation, also known as oxo synthesis or oxo process, is an industrial process for the production of aldehydes () from alkenes (). This chemical reaction entails the net addition of a formyl group () and a hydrogen ...

alkene In organic chemistry, an alkene, or olefin, is a hydrocarbon containing a carbon–carbon double bond. The double bond may be internal or at the terminal position. Terminal alkenes are also known as Alpha-olefin, α-olefins. The Internationa ...

s. Illustrative of its wide bite angle, it forms both cis and trans adducts of

platinum(II) chloride Platinum(II) chloride describes the inorganic compounds with the formula Pt Cl2. They are precursor used in the preparation of other platinum compounds. Platinum(II) chloride exists in two crystalline forms ( polymorphs), but the main properties ...

. In the latter context, xantphos is classified as a

trans-spanning ligand Trans-spanning ligands are bidentate ligands that can span opposite sites of a complex with square-planar geometry. A wide variety of ligands that chelate in the cis fashion already exist, but very few can link opposite vertices on a coordination po ...

. A related bidentate ligand with a greater bite angle is

spanphos SPANphos is an organophosphorus compound used as a ligand in organometallic chemistry, organometallic and coordination chemistry. The compound is a rare example of a trans-spanning ligand and rigidly links mutually trans coordination sites. By vir ...

. The ligand is prepared by double directed lithiation of 9,9-dimethylxanthene with

sec-butyllithium ''sec''-Butyllithium is an organometallic compound with the Chemical formula, formula CH3CHLiCH2CH3, abbreviated ''sec''-BuLi or ''s''-BuLi. This Chiral (chemistry), chiral organolithium reagent is used as a source of ''sec''-butyl carbanion in o ...

followed by treatment with

chlorodiphenylphosphine Chlorodiphenylphosphine is an organophosphorus compound with the formula (C6H5)2PCl, abbreviated Ph2PCl. It is a colourless oily liquid with a pungent odor that is often described as being garlic-like and detectable even in the ppb range. It is ...

.{{cite journal , author = Mirko Kranenburg, Yuri E. M. van der Burgt, Paul C. J. Kamer, Piet W. N. M. van Leeuwen, Kees Goubitz, and Jan Fraanje , title = New Diphosphine Ligands Based on Heterocyclic Aromatics Inducing Very High Regioselectivity in Rhodium-Catalyzed Hydroformylation: Effect of the Bite Angle , year = 1995 , journal =

Organometallics ''Organometallics'' is a biweekly journal published by the American Chemical Society. Its area of focus is organometallic and organometalloid chemistry. This peer-reviewed journal has an impact factor of 3.837 as reported by the 2021 Journal Citat ...

, volume = 14 , issue = 6, pages = 3081–3089 , doi = 10.1021/om00006a057, s2cid = 53053952 , url = https://pure.uva.nl/ws/files/2969936/882_9954y.pdf

References

Diphosphines