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Electronic Structure of Ru2(II,II) Oxypyridinates: Synthetic, Structural, and Theoretical Insights into Axial Ligand Binding
- Source :
- Inorganic Chemistry, Inorganic Chemistry, American Chemical Society, 2015, pp. 8571-8589. ⟨10.1021/acs.inorgchem.5b01241⟩
- Publication Year :
- 2015
- Publisher :
- HAL CCSD, 2015.
-
Abstract
- Reduction of (4,0)-Ru2(chp)4Cl (1) (chp = 6-chloro-2-oxypyridinate) with Zn or FeCl2 yields a series of axial ligand adducts of the Ru2(II,II) species Ru2(chp)4(L), with L = tetrahydrofuran (2), dimethyl sulfoxide (DMSO; 3), PPh3 (4), pyridine (5), or MeCN (6). Zn reduction in noncoordinating solvents such as toluene or CH2Cl2 leads to the dimeric species [Ru2(chp)4]2 (7) or [Ru2(chp)4]2(ZnCl2) (8), whereas addition of strongly σ-donating ligands such as CO causes cleavage of the Ru-Ru bond. Density functional theory (DFT) models of these complexes, the axially free species, and the axial adducts of several other potential ligands (H2O, NH3, CH2Cl2, S-bound DMSO, N2, and CO) indicate that these compounds can be divided into three distinct categories, based on their Ru-Ru bond length and electronic structure. Compounds 2, 3, 5, 6, 7, and 8, the hypothetical axially free species, and adducts of H2O and NH3 fit in Category 1 with a (δ*)(2)(π*)(2) ground state, as indicated by their electronic spectra, magnetic properties, and Ru-Ru bond distances. However, compound 4 and the CH2Cl2 adduct (Category 2) show a pseudo-Jahn-Teller distortion and spectroscopic signs of δ*/π* orbital mixing suggestive of a new electronic ground state intermediate between the (δ*)(2)(π*)(2) and (δ*)(1)(π*)(3) configurations. Category 3 consists of the hypothetical adducts of N2, S-bound DMSO, and CO, all of which are predicted to have a (δ*)(1)(π*)(3) configuration. Electronic spectra were recorded and assigned using time-dependent DFT, allowing assignment of a band in the 10,000-13,000 cm(-1) range as the δ → π* transition. The axial ligand's π-acid character heavily influences the δ*-π* gap, and thereby the ground-state electronic configuration, but not the axial ligand binding strength, which is dictated more by the σ-donor character of the ligands. Thus, this work greatly expands the number of axial ligand adducts known for Ru2(II,II) complexes supported by N,O-donor ligands and provides a predictive theoretical framework for their stability and electronic structures.
- Subjects :
- Ligand
Stereochemistry
Synthetic
Structure
Electronic structure
[CHIM.MATE]Chemical Sciences/Material chemistry
Toluene
3. Good health
Adduct
Inorganic Chemistry
Bond length
Crystallography
chemistry.chemical_compound
chemistry
Oxypyridinates
Pyridine
Axial Ligand Binding
Density functional theory
Physical and Theoretical Chemistry
Tetrahydrofuran
Subjects
Details
- Language :
- English
- ISSN :
- 00201669 and 1520510X
- Database :
- OpenAIRE
- Journal :
- Inorganic Chemistry, Inorganic Chemistry, American Chemical Society, 2015, pp. 8571-8589. ⟨10.1021/acs.inorgchem.5b01241⟩
- Accession number :
- edsair.doi.dedup.....05ef0981d89f97ce94ceee91e014d51b