SPANphos

SPANphos
Names
	Preferred IUPAC name (4,4,4′,4′,6,6′-Hexamethyl-3,3′,4,4′-tetrahydro-2,2′-spirobi[[1]benzopyran]-8,8′-diyl)bis(diphenylphosphane)
Identifiers
CAS Number	556797-94-5 ;
3D model (JSmol)	Interactive image;
PubChem CID	12103420;
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Properties
Chemical formula	C47H46O2P2
Molar mass	704.814 g/mol
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
	(what is ?)
	Infobox references

SPANphos is an organophosphorus compound used as a ligand in organometallic and coordination chemistry. The compound is a rare example of a trans-spanning ligand and rigidly links mutually trans coordination sites. By virtue of its C₂-symmetric backbone, SPANphos forms a chiral cavity over the face of a square planar complexes, e.g. in MCl₂(SPANphos) (M = Pd, Pt).

Structure of PtCl₂(SPANphos)^[1]

Synthesis[]

SPANphos can be prepared synthesized from relatively inexpensive reagents. In the first step 4,4,4',4',6,6'-hexamethyl-2,2'-spirobichromane is prepared via an acid-catalyzed reaction of p-cresol and acetone. The resultant spirocycle is halogenated with N-bromosuccinimide followed by lithium-bromide exchange using n-BuLi. Treatment of the resulting dilithio compound with chlorodiphenylphosphine completes the synthesis.^[1]

Preparation of SPANphos from p-cresol

References[]

^ Jump up to: ^a ^b Z. Freixa, M. S. Beentjes, G. D. Batema, C. B. Dieleman, G. P. F. v. Strijdonck, J. N. H. Reek, P. C. J. Kamer, J. Fraanje, K. Goubitz and P. W. N. M. Van Leeuwen (2003). "SPANphos: A C₂-Symmetric trans-Coordinating Diphosphane Ligand". Angewandte Chemie International Edition. 42 (11): 1322–1325. doi:10.1002/anie.200390330. PMID 12645065.CS1 maint: multiple names: authors list (link)

[Freixa-1] Jump up to: ^a ^b Z. Freixa, M. S. Beentjes, G. D. Batema, C. B. Dieleman, G. P. F. v. Strijdonck, J. N. H. Reek, P. C. J. Kamer, J. Fraanje, K. Goubitz and P. W. N. M. Van Leeuwen (2003). "SPANphos: A C₂-Symmetric trans-Coordinating Diphosphane Ligand". Angewandte Chemie International Edition. 42 (11): 1322–1325. doi:10.1002/anie.200390330. PMID 12645065.CS1 maint: multiple names: authors list (link)

[1]