title: Configuration Control in the Synthesis of Homo- and Heteroleptic Bis(oxazolinylphenolato/thiazolinylphenolato) Chelate Ligand Complexes of Oxorhenium(V): Isomer Effect on Ancillary Ligand Exchange Dynamics and Implications for Perchlorate Reduction Catalysis.
abstract: This study develops synthetic strategies for N,N-trans and N,N-cis Re(O)(LO-N)2Cl complexes and investigates the effects of the coordination spheres and ligand structures on ancillary ligand exchange dynamics and catalytic perchlorate reduction activities of the corresponding [Re(O)(LO-N)2](+) cations. The 2-(2'-hydroxyphenyl)-2-oxazoline (Hhoz) and 2-(2'-hydroxyphenyl)-2-thiazoline (Hhtz) ligands are used to prepare homoleptic N,N-trans and N,N-cis isomers of both Re(O)(hoz)2Cl and Re(O)(htz)2Cl and one heteroleptic N,N-trans Re(O)(hoz)(htz)Cl. Selection of hoz/htz ligands determines the preferred isomeric coordination sphere, and the use of substituted pyridine bases with varying degrees of steric hindrance during complex synthesis controls the rate of isomer interconversion. The five corresponding [Re(O)(LO-N)2](+) cations exhibit a wide range of solvent exchange rates (1.4 to 24,000 s(-1) at 25 °C) and different LO-N movement patterns, as influenced by the coordination sphere of Re (trans/cis), the noncoordinating heteroatom on LO-N ligands (O/S), and the combination of the two LO-N ligands (homoleptic/heteroleptic). Ligand exchange dynamics also correlate with the activity of catalytic reduction of aqueous ClO4(-) by H2 when the Re(O)(LO-N)2Cl complexes are immobilized onto Pd/C. Findings from this study provide novel synthetic strategies and mechanistic insights for innovations in catalytic, environmental, and biomedical research.
authors.affiliation: Department of Civil and Environmental Engineering, Colorado School of Mines , Golden, Colorado 80401, United States.
authors.forename: Jinyong
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Chemistry and Biochemistry, The Ohio State University , Columbus, Ohio 43210, United States.
authors.forename: Dimao
authors.initials: D
authors.lastname: Wu
authors.affiliation: Pure Storage Inc., Mountain View, California 94041, United States.
authors.forename: Xiaoge
authors.initials: X
authors.lastname: Su
authors.forename: Mengwei
authors.initials: M
authors.lastname: Han
authors.forename: Susana Y
authors.initials: SY
authors.lastname: Kimura
authors.forename: Danielle L
authors.initials: DL
authors.lastname: Gray
authors.forename: John R
authors.initials: JR
authors.lastname: Shapley
authors.affiliation: Department of Chemistry and School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Mahdi M
authors.initials: MM
authors.lastname: Abu-Omar
authors.affiliation: Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Werth
authors.affiliation: Department of Civil and Environmental Engineering, Colorado School of Mines , Golden, Colorado 80401, United States.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Strathmann
mesh_terms: D002384:Catalysis; D002614:Chelating Agents / Q000737:chemistry*; D007536:Isomerism; D008024:Ligands; D010472:Perchlorates / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D012211:Rhenium / Q000737:chemistry*
chemical_list: D002614:Chelating Agents; D008024:Ligands; D010472:Perchlorates; D012211:Rhenium; C494474:perchlorate