Configurationally homogeneous diastereomers of a linear hexa(tertiary phosphine): enantioselective self-assembly of a double-stranded parallel helicate of the type (P)-[Cu(3)(hexaphos)(2)](PF(6))(3).
Three configurationally homogeneous diastereomers of the linear hexa(tertiary phosphine) Ph(2)PCH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)PPh(2) (hexaphos) have been isolated in enantiomerically pure form, namely (R,S,S,R)-, (R,S,S,S)-, and (S,S,S,S)-hexaphos. The strongly helicating (R,S,S,R)-(-) form of the ligand combines with copper(I) ions to generate by stereoselective self-assembly the P enantiomer of a parallel helicate of the type [Cu(3)(hexaphos)(2)](PF(6))(3), which has been characterized by x-ray crystallography. Theoretical modeling of the cation indicates that it is the relationship between the helicities of the two 10-membered rings containing the three copper ions, each of which has the twist-boat-chair-boat conformation, and the configurations of the three chiral, tetrahedral copper stereocenters of P configuration that determines the stereochemistry of the parallel and double alpha-helix conformers of the double-stranded trinuclear metal helicate.
Bowyer
Paul K
PK
Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 0200, Australia.
Cook
Vernon C
VC
Gharib-Naseri
Nahid
N
Gugger
Paul A
PA
Rae
A David
AD
Swiegers
Gerhard F
GF
Willis
Anthony C
AC
Zank
Johann
J
Wild
S Bruce
SB
D002412:Cations; D002851:Chromatography, High Pressure Liquid; D018360:Crystallography, X-Ray; D008024:Ligands; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D010720:Phosphines / Q000737:chemistry*; D011487:Protein Conformation; D013237:Stereoisomerism; D013997:Time Factors
D002412:Cations; D008024:Ligands; D046911:Macromolecular Substances; D010720:Phosphines; C044646:phosphine