title: Synthesis and vibrational circular dichroism of enantiopure chiral oxorhenium(V) complexes containing the hydrotris(1-pyrazolyl)borate ligand.
abstract: The infrared and vibrational circular dichroism (VCD) spectra of six chiral oxorhenium(V) complexes, bearing a hydrotris(1-pyrazolyl)borate (Tp) ligand, have been investigated. These complexes are promising candidates for observation of parity violation (symmetry breaking due to the weak nuclear force). New chiral oxorhenium complexes have been synthesized, namely, [TpReO(eta2-O(CH3)CH2CH2O-O,O)] (4a and 4b) diastereomers and [TpReO(eta2-N(CH3)CH2CH2O-N,O)] (5) and [TpReO(eta2-N(tBu)CH2CH2O-N,O)] (6) enantiomers. All compounds could be obtained in enantiomerically pure form by using either column chromatography or HPLC over chiral columns. VCD spectroscopy of these compounds and of [TpReO(eta2-N(CH3)CH(CH3)CH(Ph)O-N,O)] (2) and [TpReO(eta2-N(CH2)3CHCO2-N,O)] (3) (with chiral bidentate ligands derived, respectively, from ephedrine and proline) were studied. This allowed the absolute configuration determination of all compounds together with their conformational analysis, by comparing calculated and experimental spectra. This is the first VCD study of rhenium complexes which further demonstrates the applicability of VCD spectroscopy in determining the chirality of inorganic complexes.
authors.affiliation: Department of Chemistry, Syracuse University, Syracuse, New York 13244, USA.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Lassen
authors.forename: Laure
authors.initials: L
authors.lastname: Guy
authors.forename: Iyad
authors.initials: I
authors.lastname: Karame
authors.forename: Thierry
authors.initials: T
authors.lastname: Roisnel
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vanthuyne
authors.forename: Christian
authors.initials: C
authors.lastname: Roussel
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Cao
authors.forename: Rosina
authors.initials: R
authors.lastname: Lombardi
authors.forename: Jeanne
authors.initials: J
authors.lastname: Crassous
authors.forename: Teresa B
authors.initials: TB
authors.lastname: Freedman
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Nafie
mesh_terms: D000465:Algorithms; D001881:Borates / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002942:Circular Dichroism / Q000379:methods; D008024:Ligands; D008956:Models, Chemical; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D011720:Pyrazoles / Q000737:chemistry; D012211:Rhenium / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013237:Stereoisomerism
chemical_list: D001881:Borates; D008024:Ligands; D009942:Organometallic Compounds; D011720:Pyrazoles; D012211:Rhenium