Synthesis and vibrational circular dichroism of enantiopure chiral oxorhenium(V) complexes containing the hydrotris(1-pyrazolyl)borate ligand.
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.
Lassen
Peter R
PR
Department of Chemistry, Syracuse University, Syracuse, New York 13244, USA.
Guy
Laure
L
Karame
Iyad
I
Roisnel
Thierry
T
Vanthuyne
Nicolas
N
Roussel
Christian
C
Cao
Xiaolin
X
Lombardi
Rosina
R
Crassous
Jeanne
J
Freedman
Teresa B
TB
Nafie
Laurence A
LA
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
D001881:Borates; D008024:Ligands; D009942:Organometallic Compounds; D011720:Pyrazoles; D012211:Rhenium