A Rare Example of Four-Coordinate Nonoxido Vanadium(IV) Alkoxide in the Solid State: Structure, Spectroscopy, and Magnetization Dynamics.
Danilo StinghenMatteo AtzoriCaprici M FernandesRonny R RibeiroEduardo L de SáDavi F BackSiddhartha O K GieseDavid L HughesGiovana G NunesElena MorraMario ChiesaRoberta SessoliJaísa Fernandes SoaresPublished in: Inorganic chemistry (2018)
The distorted tetrahedral [V(OAd)4] alkoxide (OAd = 1-adamantoxide, complex 1) is the first homoleptic, mononuclear vanadium(IV) alkoxide to be characterized in the solid state by X-ray diffraction analysis. The compound crystallizes in the cubic P4̅3 n space group with two highly disordered, crystallographically independent molecules in the asymmetric unit. Spin Hamiltonian parameters extracted from low temperature X- and Q-band electron paramagnetic resonance (EPR) experiments performed for polycrystalline samples of 1, both in the concentrated (bulk) form and diluted in the diamagnetic [Ti(OAd)4] analogue, reveal a fully axial system with g z < g x, g y and A z ≫ A x, A y. Complex 1 has also been characterized by alternate current susceptometry with varying temperature (3-30 K) and static magnetic field (up to 8.5 T), showing field-induced slow relaxation of the magnetization with relaxation times ranging from ca. 3 ms at 3 K to 0.02-0.03 ms at 30 K, in line with relevant results described recently for other potential molecular quantum bits. Pulsed EPR measurements, in turn, disclosed long coherence times of ca. 4 μs at temperatures lower than 40 K, despite the presence of the H-rich ligands. The slow spin relaxation in 1 is the first observed for a tetracoordinate nonoxido vanadium(IV) complex, and results are compared here to those generated by square-pyramidal VIV(O)2+ and trigonal prismatic V4+ with oxygen donor atom sets. Considering that the number of promising d1 complexes investigated in detail for slow magnetization dynamics is still small, the present work contributes to the establishment of possible structural/electronic correlations of interest to the field of quantum information processing.
Keyphrases
- solid state
- single molecule
- molecular dynamics
- mass spectrometry
- multiple sclerosis
- energy transfer
- density functional theory
- ms ms
- atomic force microscopy
- living cells
- room temperature
- electron microscopy
- high glucose
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- high resolution
- gene expression
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- single cell
- risk assessment
- peripheral blood
- health information
- magnetic resonance
- protein kinase
- climate change
- magnetic resonance imaging
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- sensitive detection
- crystal structure
- fluorescent probe
- transition metal
- data analysis