TY - JOUR
T1 - Redox-Dependent Metal−Metal Bonding in Trinuclear Metal Chains
T2 - Probing the Transition from Covalent Bonding to Exchange Coupling
AU - Obies, Mohammed
AU - Perkins, Nicholas R.
AU - Arcisauskaite, Vaida
AU - Heath, Graham A.
AU - Edwards, Alison J.
AU - McGrady, John E.
N1 - Publisher Copyright:
© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2018/4/6
Y1 - 2018/4/6
N2 - The synthesis and physical properties of two new cationic tri-metallic chains, [(PEt3)3RuCl3M′Cl3Ru(PEt3)3]1+, M′=Rh and Ir are reported. These are isostructural with a previously reported 17-electron all-ruthenium analogue, but replacing a d5 RuIII ion in the central position with d6 RhIII/IrIII has a significant impact on the nature of the metal-metal interactions. All three materials have been characterized electrochemically at the 18-, 17- and 16-electron levels. X-ray crystallography and spectroelectrochemistry, complemented by electronic structure analysis at the DFT and CASPT2 levels, indicate that whilst the presence of a RuIII ion in the center of the chain allows multi-center covalent bonding to develop, a closed-shell RhIII/IrIII ion pushes the system towards the exchange-coupled limit, where the outer Ru centers are only weakly interacting. This family of three isostructural compounds reveals how changes in metal composition can have subtle effects on physical properties of systems that lie close to the localized/delocalized borderline.
AB - The synthesis and physical properties of two new cationic tri-metallic chains, [(PEt3)3RuCl3M′Cl3Ru(PEt3)3]1+, M′=Rh and Ir are reported. These are isostructural with a previously reported 17-electron all-ruthenium analogue, but replacing a d5 RuIII ion in the central position with d6 RhIII/IrIII has a significant impact on the nature of the metal-metal interactions. All three materials have been characterized electrochemically at the 18-, 17- and 16-electron levels. X-ray crystallography and spectroelectrochemistry, complemented by electronic structure analysis at the DFT and CASPT2 levels, indicate that whilst the presence of a RuIII ion in the center of the chain allows multi-center covalent bonding to develop, a closed-shell RhIII/IrIII ion pushes the system towards the exchange-coupled limit, where the outer Ru centers are only weakly interacting. This family of three isostructural compounds reveals how changes in metal composition can have subtle effects on physical properties of systems that lie close to the localized/delocalized borderline.
KW - CASSCF
KW - density functional theory
KW - metal−metal bonds
KW - spectroelectrochemistry
KW - tri-metallic
UR - http://www.scopus.com/inward/record.url?scp=85039147418&partnerID=8YFLogxK
U2 - 10.1002/chem.201704727
DO - 10.1002/chem.201704727
M3 - Article
SN - 0947-6539
VL - 24
SP - 5309
EP - 5318
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 20
ER -