14140-04-6Relevant articles and documents
Light-Induced Self-Nitrosation of Polycyclic Phenols with Nitrosamine. Excited State Proton Transfer
Chow, Yuan L.,Wu, Zheng-Zhi
, p. 5260 - 5267 (1987)
Photoexcitation of polycyclic phenols in the presence of N-nitrosodimethylamine caused the self-nitrosation of the phenols to give 1,2- or 1,4-quinone monooximes.With use of naphthols as models, the key step of the photonitrosation was shown to be a dual sensitization process from the lowest singlet excited state of naphthols by proton transfer followed by energy migration within an exciplex to cause the known homolysis of the nitrosamine; it is assumed that the resulting radical species undergo nitrosation of naphtholates.The crucial requirement of the excited state proton transfer (ESPT) reaction is established by quenching of the photonitrosation by general bases, such as water and TEA, with quenching rate constants close to those of naphthol fluorescence by these bases.
Synthesis and physicochemical properties of 9,10-phenanthrenequinone monoxime and its nitro derivatives
Linko,Soldatkina,Zaitsev,Ryabov,Sokol
, p. 1095 - 1099 (1999)
Phenanthrenequinone monoxime and its mono-, di-, and trinitro derivatives were synthesized. The acidity constants and their variation with the number and position of nitro groups were determined. The electronic and IR spectra of the nitro compounds were studied. The bands in the electronic spectra were assigned based on quantum-chemical calculations in the Pariser-Parr-Pople approximation. Correlations between the pKa values and some calculated characteristics of the compounds under study were found.
Oximato-Based Ligands in 3 d/4 f-Metal Cluster Chemistry: A Family of {Cu3Ln} Complexes with a "propeller"-like Topology and Single-Molecule Magnetic Behavior
Worrell, Anne,Sun, Di,Mayans, Julia,Lampropoulos, Christos,Escuer, Albert,Stamatatos, Theocharis C.
supporting information, p. 13944 - 13952 (2018/10/31)
The organic chelating and bridging ligands 9,10-phenanthrenedione-9-oxime (phenoxH) and 9,10-phenanthrenedione-9,10-dioxime (phendoxH2) were synthesized and subsequently employed for the first time in heterometallic 3d/4f-metal cluster chemistry. The general reaction between CuCl2·2H2O, LnCl3·6H2O, phenoxH, and NEt3 in a 1:2:2:4 molar ratio, in a solvent mixture comprising MeCN and MeOH, afforded brown crystals of a new family of [Cu3LnCl3(phenox)6(MeOH)3] clusters (Ln = Gd (1), Tb (2), Dy (3)) that possess an unprecedented [Cu3Ln(μ-NO)6]3+ "propeller"-like core. Complexes 1-3 are the first {Cu3Ln} clusters in which the outer CuII and the central LnIII atoms are solely bridged by diatomic oximato bridges. The {Cu-N-O-Ln} bridging units are very distorted with torsion angles spanning the range 35.5-48.9° and 25.2-55.6° in 1 and 2, respectively. As a result, complexes 1-3 are antiferromagnetically coupled, in agreement with previously reported magnetostructural criteria for oximato-bridged Cu/Ln complexes. The magnetic susceptibility data for all complexes were nicely fit to an isotropic spin Hamiltonian (for 1) or a Hamiltonian that accounts for the spin of the CuII atoms, the spin component of the LnIII, the spin-orbit coupling (λ), an axial ligand-field component around the LnIII atoms (Δ), and the Zeeman effect (for the anisotropic 2 and 3). The resulting fit parameters were J = -1.34 cm-1 and g = 2.10 (1), J = -1.42 cm-1, gCu = 2.10, and Δ = -26.3 cm-1 (2), and J = -1.70 cm-1, gCu = 2.05, and Δ = -38.1 cm-1 (3). The reported fitting procedure, implemented in the PHI program, is here used for the first time. Even if this method is only valid in high-symmetry Ln environments, when it is properly used allows a very simple and efficient method to obtain the exchange parameters. In light of the negative anisotropy, compounds 2 and 3 were found to exhibit frequency-dependent tails of out-of-phase signals in the presence of a small external dc field, characteristic of the slow magnetization relaxation of a single-molecule magnet. By using the Kramers-Kronig equations, the effective energy barriers (Ueff) were derived and reported as Ueff = 10.1 and 5.4 cm-1 for 2 and 3, respectively.
