Interesting Reactivity in the Thermolysis and Photolysis of 2,3-Diphenyl-1-naphthol

Abstract  2,3-Diphenyl-1-naphthol (1) undergoes two unexpected reactions under different conditions. Compound (1) was heated in DMSO-d₆ and underwent a Pummerer type thermal reaction to give two isomeric products, 1-(methylthio)methoxy-2,3-diphenyl naphthol-d₅ which crystallized in the space group with a = 7.1610(9) ?, b = 11.2795(15) ?, c = 12.8905(17) ?, α = 114.049(2)°, β = 96.589(2)°, and γ = 102.945(2)°, and 2-(methylthio)methyl-2,3-diphenyl 1(2H)-naphthalenone-d₅ which crystallized in the space group with a = 8.5981(5) ?, b = 10.4374(6) ?, c = 11.1078(6) ?, α = 78.748(2)°, β = 67.709(2)°, and γ = 83.184(2)°. Photolysis (254 nm) of (1) resulted in 2,2′,3,3′-tetraphenyl-1,1′-bi-2-naphthol which crystallized in the space group P2₁/c with a = 26.3616(11) ?, b = 10.1707(4) ?, c = 23.3376(9) ?, and β = 99.034(2)°. Graphical Abstract  When 2,3-diphenyl-1-naphthol was heated in DMSO-d₆ two unexpected isomers, 1-(methylthio)methoxy-2,3-diphenyl naphthol-d₅ and the racemate 2-(methylthio)methyl-2,3-diphenyl 1(2H)-naphthalenone-d₅ were produced. Photolysis in THF at 254 nm led to the unexpected product 2,2′,3,3′-tetraphenyl-1,1′-bi-2-naphthol. All structures were elucidated by X-ray crystallography.      

Poly(alkylene-H-phosphonate)s obtained by direct esterification and oxidation of hypophosphorous acid with ethylene glycol

This paper presents for the first time the synthesis of poly(alkylene-H-phosphonate)s by one-pot tandem reaction of hypophosphorous acid and ethylene glycol. Zirconium oxychloride was used as esterification catalyst, Nickel vinylphosphonate, Nickel sulfate, Nickel chloride hexahydrate were used as transfer hydrogenation catalyst. Nickel vinylphosphonate was synthesized in our laboratory and used for the first time as catalyst in this process. The compounds were characterized by ¹H-NMR, ¹³C-NMR and ³¹P-NMR spectroscopy. Molar masses were determined by SEC-MALLS technique and depend on the catalyst used. The obtained poly(alkylene-H-phosphonate)s have molar masses between 1.50 and 11.85 kDa, higher than those obtained by other methods mentioned in the literature.     

A combined solid-state NMR and X-ray crystallography study of the bromide ion environments in triphenylphosphonium bromides

Multinuclear ((31)P and (79/81)Br), multifield (9.4, 11.75, and 21.1 T) solid-state nuclear magnetic resonance experiments are performed for seven phosphonium bromides bearing the triphenylphosphonium cation, a molecular scaffold found in many applications in chemistry. This is undertaken to fully characterise their bromine electric field gradient (EFG) tensors, as well as the chemical shift (CS) tensors of both the halogen and the phosphorus nuclei, providing a rare and novel insight into the local electronic environments surrounding them. New crystal structures, obtained from single-crystal X-ray diffraction, are reported for six compounds to aid in the interpretation of the NMR data. Among them is a new structure of BrPPh(4), because the previously reported one was inconsistent with our magnetic resonance data, thereby demonstrating how NMR data of non-standard nuclei can correct or improve X-ray diffraction data. Our results indicate that, despite sizable quadrupolar interactions, (79/81)Br magnetic resonance spectroscopy is a powerful characterisation tool that allows for the differentiation between chemically similar bromine sites, as shown through the range in the characteristic NMR parameters. (35/37)Cl solid-state NMR data, obtained for an analogous phosphonium chloride sample, provide insight into the relationship between unit cell volume, nuclear quadrupolar coupling constants, and Sternheimer antishielding factors. The experimental findings are complemented by gauge-including projector-augmented wave (GIPAW) DFT calculations, which substantiate our experimentally determined strong dependence of the largest component of the bromine CS tensor, δ(11), on the shortest Br-P distance in the crystal structure, a finding that has possible application in the field of NMR crystallography. This trend is explained in terms of Ramsey's theory on paramagnetic shielding. Overall, this work demonstrates how careful NMR studies of underexploited exotic nuclides, such as (79/81)Br, can afford insights into structure and bonding environments in the solid state.     

23Na double-rotation NMR of sodium nucleotides leads to the discovery of a new dCMP hendecahydrate

Obtaining definitive information concerning the coordination environment of sodium ions which balance the negative charges found in nucleotides is a challenging task. We show that high resolution 1D and 2D (23)Na NMR spectra of sodium nucleotides obtained in the solid state with the use of double-rotation (DOR) provide valuable structural information. Sensitive spin diffusion homonuclear correlation experiments are used to establish the relative proximities of various pairs of crystallographically distinct Na sites and to assign the spectral resonances. Additionally, the DOR sidebands are simulated to obtain coordination information which is complementary to that obtained using multiple-quantum magic-angle spinning NMR spectra. These experiments led us to discover a new hendecahydrate of deoxycytidine monophosphate (dCMP), the structure of which is confirmed via single-crystal X-ray diffraction. This hydrate crystallizes reproducibly when deuterated water is used exclusively in the preparation process.     

A Combined Solid‐State NMR and X‐ray Crystallography Study of the Bromide Ion Environments in Triphenylphosphonium Bromides

Multinuclear (³¹P and ^79/81Br), multifield (9.4, 11.75, and 21.1 T) solid‐state nuclear magnetic resonance experiments are performed for seven phosphonium bromides bearing the triphenylphosphonium cation, a molecular scaffold found in many applications in chemistry. This is undertaken to fully characterise their bromine electric field gradient (EFG) tensors, as well as the chemical shift (CS) tensors of both the halogen and the phosphorus nuclei, providing a rare and novel insight into the local electronic environments surrounding them. New crystal structures, obtained from single‐crystal X‐ray diffraction, are reported for six compounds to aid in the interpretation of the NMR data. Among them is a new structure of BrPPh₄, because the previously reported one was inconsistent with our magnetic resonance data, thereby demonstrating how NMR data of non‐standard nuclei can correct or improve X‐ray diffraction data. Our results indicate that, despite sizable quadrupolar interactions, ^79/81Br magnetic resonance spectroscopy is a powerful characterisation tool that allows for the differentiation between chemically similar bromine sites, as shown through the range in the characteristic NMR parameters. ^35/37Cl solid‐state NMR data, obtained for an analogous phosphonium chloride sample, provide insight into the relationship between unit cell volume, nuclear quadrupolar coupling constants, and Sternheimer antishielding factors. The experimental findings are complemented by gauge‐including projector‐augmented wave (GIPAW) DFT calculations, which substantiate our experimentally determined strong dependence of the largest component of the bromine CS tensor, δ₁₁, on the shortest Br? P distance in the crystal structure, a finding that has possible application in the field of NMR crystallography. This trend is explained in terms of Ramsey’s theory on paramagnetic shielding. Overall, this work demonstrates how careful NMR studies of underexploited exotic nuclides, such as ^79/81Br, can afford insights into structure and bonding environments in the solid state.     

Simultaneous Spectrophotometric Determination of Rare-Earth and Transition Elements Using Partial Least-Squares (PLS) Multivariate Calibration

A spectrophotometric method for the simultaneous determination of rare-earth and transition elements in synthetic superconductors, [(La_{1 – x} Eu _x )_1.82Sr_0.18CuO₄], by the use of 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) as chelating agent was developed. The influence of chemical variables affecting the reaction was studied. A partial least-squares (PLS) multivariate calibration procedure was used to assess the data obtained from several calibration solutions measured over the wavelengths range 400–700 nm. The concentration range for Cu was (1–12) × 10^–6 mol/L, while the range for the rare-earth elements La and Eu was (2–8) × 10^–6 mol/L. The relative errors in the determinations were less than 5% in most cases.     

Catalytic synthesis of tricyclic quinoline derivatives from the regioselective hydroamination and C-H bond activation reaction of benzocyclic amines and alkynes

The cationic ruthenium-hydride complex [(PCy3)2(CO)(CH3CN)2RuH]+BF4- (1) was found to be an effective catalyst for the regioselective coupling reaction of benzocyclic amines and terminal alkynes to form the tricyclic quinoline derivatives. The scope of the reaction was explored by using the catalytic system Ru3(CO)12/NH4PF6. The catalytically active cationic ruthenium-acetylide complex [(PCy3)2(CO)(CH3CN)2RuCCPh]+BF4- was isolated from the reaction of 1 with phenylacetylene.