The microwave spectrum of the PH2 radical

Three rotational transitions, 1₁₀ ← 1₀₁, 2₂₀ ← 2₁₁, and 3₃₀ ← 3₂₁, of the PH₂ radical in the ground vibronic state were observed in the mm-wave region, by using a source-frequency modulation spectrometer with a 1-m-long free space cell. The PH₂ radical was generated directly in the cell by glow discharge in a mixture of phosphine and oxygen. Thirty four fine and hyperfine components were measured for the three transitions. An analysis of the observed spectra, combined with far-infrared and mid-infrared laser magnetic resonance spectra and laser-induced fluorescence spectra obtained by other works, improved the rotational and spin-rotation interaction constants in precision. The observed hyperfine structure gave the magnetic hyperfine coupling constants for both P and H nuclei and also the P nuclear spin-rotation interaction constants.     

Infrared diode laser spectroscopy of the NS radical

The v = 1 ← 0 vibration-rotation bands of the NS radical in the $\text{X}{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and $\text{X}{}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ electronic states were observed by using a tunable diode laser. From the least-squares analysis the band origins were determined to be 1204.2755(12) and 1204.0892(19) cm^?1, respectively, for $\text{X}{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and $\text{X}{}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$. The rotational and centrifugal distortion constants and the internuclear distance in the X²Π electronic state were obtained as follows: B_e = 0.775549(10) cm^?1, D_e = 0.00000129(33) cm^?1, and $\text{r}{}_{\mathrm{e}}\text{= 1.49403(4)}\text{A}\text{?}$, with three standard deviations indicated in parentheses.     

Hyperfine coupling constants of NCO in ÃΣ by sub-Doppler spectroscopy

Molecular constants including ¹⁴N hyperfine coupling constants of the NCO radical in the òΣ⁺(000) state have been determined precisely by using the microwave-optical double resonance (MODR) and intermodulated fluorescence (IMF) techniques, where the band was pumped by a dye laser. The results are B = 12 056.559(41), D = 0.0045(16), γ = 22.06(17), b = 430.4(12), c = 80.3(28), and eQq = 2.6(36), all in MHz with one standard error in parentheses. It was found that, because the òΣ⁺ state closely approximates a coupling case (b_βS), MODR did not provide any precise value for the Fermi contact term, but this constant was determined accurately by combining the MODR spectrum with the IMF spectrum.     

The microwave spectrum of the DO2 radical

The a-type N = 1 ← 0,2 ← 1, and 3 ← 2 and the b-type 1₁₁ ← 2₀₂, 2₁₂ ← 3₀₃, 3₁₃ ← 4₀₄, 6₀₆ ← 5₁₅, and 7₀₇ ← 6₁₆ transitions, 14 in total, of the DO₂ free radical in the ground vibronic state were observed by microwave spectroscopy in the frequency region up to 200 GHz. The DO₂ radical was generated in a free-space absorption cell by a DC discharge in a mixture of CH₃OD and O₂. From the observed spectra the rotational constants, centrifugal distortion constants, spin-rotation coupling constants, and magnetic hyperfine coupling constants were determined with good precision. The hyperfine coupling constants of DO₂ were determined by the present work for the first time. A comparison of the in-plane components of the dipole-dipole interaction tensor of DO₂ with those of HO₂ made it possible to determine the off-diagonal component T_ab, and thus the principal values and the principal axes of the tensor.     

A novel synthesis of benzofuran and related compounds. I. The vilsmeier reaction of phenoxyacetonitriles

A novel synthesis of 2-benzofurancarboxylic acid derivatives by the Vilsmeier reaction of phenoxyacetonitriles is described.     

The microwave spectrum of the SF radical

The rotational spectrum of the SF radical in the ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state was observed by using a source-modulation microwave spectrometer with a 1-m-long discharge cell. The SF radical was generated directly in the cell by a dc discharge in an $\text{OCS}\text{CF}{}_4$ mixture. A previous measurement of the microwave spectrum in the ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ state was also extended to higher-J transitions. The least-squares analysis of all the observed spectral lines gave the B₀ rotational constant and the D₀ centrifugal distortion constant to be 16 576.9140(46) and 0.02924(10) MHz, respectively, where the values in parentheses denote 2.5 times the standard deviations. The Λ-doubling constant p_v was found to be extremely small, 3.409(44) MHz, and it was presumed that contributions of ²Σ⁺ and ²Σ^? states to the Λ doubling cancel each other. All the four fluorine hyperfine coupling constants were also determined, from which the spin density on the F atom was calculated to be 0.13.     

Polycyclic N-heterocyclic compounds. XLIV. Synthesis of the novel B,D-Dihomo-11,13,15-triazasteroidal skeleton and their effect on reserpine-induced hypothermia and inhibitory activity on platelet aggregation

Synthesis of benzo[3,4]cyclohepta[1,2-e]pyrimido[1,2-c]pyrimidines, corresponding to the B,D-dihomo-11,13,15-triazasteroidal skeleton as a novel ring system is described. Their effects on reserpine-induced hypothermia in mice and inhibitory activity against collagen-induced platelet aggregation were also investigated.     

A Myoglobin Functional Model Composed of a Ferrous Porphyrin and a Cyclodextrin Dimer with an Imidazole Linker

A 1:1 inclusion complex (Fe^IIPImCD) of 5,10,15,20‐tetrakis‐ (4‐sulfonatophenyl)porphinatoiron(II) (Fe^IIP) and an O‐methylated β‐cyclodextrin dimer with an imidazole linker (ImCD) was found to bind dioxygen in aqueous solution. The half‐saturation pressure of dioxygen (P_1/2^O2) is 1.7 torr at 25 °C, which is 10 times lower than that for a previous myoglobin functional model (hemoCD) with a pyridine linker. Meanwhile, the half‐life of oxygenated Fe^IIPImCD is 3 h, which is 10 times shorter than that of oxygenated hemoCD. The covering of the iron(II) center by a microscopic environment is essential for preventing autoxidation of oxygenated ferrous porphyrin, which is promoted by nucleophilic attack of H₂O and/or nucleophiles such as inorganic anions. Due to structural requirements, covering of the Fe^II center of Fe^IIPImCD is insufficient compared with the case of hemoCD. As a result, water molecules can penetrate more easily the cleft of the O₂–Fe^IIPImCD complex and act as an autoxidation inducer. This structure also causes poorer selectivity against carbon monoxide (M=1040). In contrast, the dioxygen affinity of Fe^IIPImCD is much higher than that of hemoCD because the imidazole moiety is a stronger electron donor than pyridine.     

Spontaneous copolymerization of 4-methylene-1,3-dioxolanes with maleic anhydride

The copolymerization of methylenedioxolanes, such as 4-methylene-1,3-dioxolane (I) and 2,2-dimethyl-4-methylene-1,3-dioxolane (II), with maleic anhydride (Manh) gives rise spontaneously to the alternating copolymers by the participation of charge-transfer (CT) complexes. The formation of CT complexes I-Manh and II-Manh was ascertained by UV and NMR spectroscopies. The equilibrium constants (K) could not be determined but were assumed to be small (K ? 1). For comparison with these systems an investigation of I-dimethyl maleate (DMM) and II-DMM systems was carried out to estimate K values 0.115 and 0.157 L/mol, respectively. To clarify the copolymerization mechanism I-Manh-acryronitrile was terpolymerized. Consequently it was concluded that the spontaneous copolymerization of I-Manh and II-Manh systems is effected by the CT complex monomer mechanism.     

Chemical studies of the radical scavenging mechanism of bisorbicillinol using the 1,1-diphenyl-2-picrylhydrazyl radical

A potent antioxidant, bisorbicillinol, which is a member of the bisorbicillinoid family isolated from the culture broth of Trichoderma sp. USF-2690, produces a stable radical-terminated symmetric dimer by donating two hydrogen atoms to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical.