Dioxygen Reactivity of Copper(I) Complexes with Tetradentate Tripodal Ligands Having Aliphatic Nitrogen Donors: Synthesis, Structures, and Properties of Peroxo and Superoxo Complexes

Oxygenation of copper(I) with tetradentate tripodal ligands (L) comprised of a tris(aminoethyl)amine (tren) skeleton having sterically bulky substituent(s) on the terminal nitrogens has been investigated, where L = tris(N-benzylaminoethyl)amine (LH,Bn), tris(N-benzyl-N-methylaminoethyl)amine (LMe,Bn), or tris(N,N-dimethylaminoethyl)amine (LMe,Me). All the copper(I) complexes reacted with dioxygen at low temperatures to produce superoxocopper(II) and/or trans-(μ-1,2-peroxo)-dicopper(II) complexes depending on the steric bulkiness of the terminal nitrogens and the reaction conditions. The reaction of a copper(I) complex [Cu(LH,Bn)]+ at −90 °C in acetone resulted in the formation of a superoxo complex [Cu(LH,Bn)(O2)]+ as a less stable species and a peroxo complex [{Cu(LH,Bn)}2(O2)]2+ as a stable species. The structures of [Cu(LH,Bn)]ClO4 and [{Cu(LH,Bn)}2(O2)](BPh4)2·8(CH3)2CO were determined by X-ray crystallography. [{Cu(LH,Bn)}2(O2)]2+ has a trans-(μ-1,2-peroxo)-dicopper(II) core with a trigonal bipyramidal structure. The O–O bond distance is 1.450(5) Å with an intermetallic Cu···Cu separation of 4.476(2) Å. The resonance Raman spectrum of [{Cu(LH,Bn)}2(O2)]2+ measured at −90 °C in acetone-d6 showed a broad ν(O–O) band at 837–834 cm−1 (788 cm−1 for an 18O labeled sample) and two ν(Cu–O) bands at 556 and 539 cm−1, suggesting the presence of two peroxo species in solution. [Cu(LMe,Bn)]+ also produced both superoxo and trans-μ-1,2-peroxo species, [Cu(LMe,Bn)(O2)]+ and [{Cu(LMe,Bn)}2(O2)]2+. At a lower concentration of [Cu(LMe,Bn)]+ (∼0.24 mM) and higher dioxygen concentration (P(O2) = ∼1 atm), the superoxo species is predominantly formed, whereas at a higher concentration of [Cu(LMe,Bn)]+ (∼1 mM) and lower dioxygen concentration (P(O2) = ∼0.02 atm) the formation of the peroxo species is observed. The resonance Raman spectrum of [Cu(LMe,Bn)(O2)]+ (∼1 mM) in acetone-d6 at ∼−95 °C exhibited a ν(O–O) band at 1120 cm−1 (1059 cm−1 for an 18O labeled sample) and that of [{Cu(LMe,Bn)}2(O2)]2+ (∼3 mM) in acetone-d6 at ∼−90 °C showed two ν(O–O) bands at 812 and 797 cm−1 (767 and 753 cm−1 for an 18O labeled sample), respectively. A similar observation was also made for [{Cu(LMe,Me)}2(O2)]2+. Relationships between the energies of the LMCT and d–d transitions and those of the ν(O–O) and ν(Cu–O) stretching vibrations and the steric constraints in the Cu(II)–(O22−)–Cu(II) core are discussed

Heterogeneity between Two α Subunits of α₂β₂ Human Hemoglobin and O₂ Binding Properties: Raman, ¹H Nuclear Magnetic Resonance, and Terahertz Spectra

Following a previous detailed investigation of the β subunit of α₂β₂ human adult hemoglobin (Hb A), this study focuses on the α subunit by using three natural valency hybrid α­(Fe²⁺-deoxy/O₂)­β­(Fe³⁺) hemoglobin M (Hb M) in which O₂ cannot bind to the β subunit: Hb M Hyde Park (β92His → Tyr), Hb M Saskatoon (β63His → Tyr), and Hb M Milwaukee (β67Val → Glu). In contrast with the β subunit that exhibited a clear correlation between O₂ affinity and Fe²⁺–His stretching frequencies, the Fe²⁺–His stretching mode of the α subunit gave two Raman bands only in the T quaternary structure. This means the presence of two tertiary structures in α subunits of the α₂β₂ tetramer with T structure, and the two structures seemed to be nondynamical as judged from terahertz absorption spectra in the 5–30 cm^–1 region of Hb M Milwaukee, α­(Fe²⁺-deoxy)­β­(Fe³⁺). This kind of heterogeneity of α subunits was noticed in the reported spectra of a metal hybrid Hb A like α­(Fe²⁺-deoxy)­β­(Co²⁺) and, therefore, seems to be universal among α subunits of Hb A. Unexpectedly, the two Fe–His frequencies were hardly changed with a large alteration of O₂ affinity by pH change, suggesting no correlation of frequency with O₂ affinity for the α subunit. Instead, a new Fe²⁺–His band corresponding to the R quaternary structure appeared at a higher frequency and was intensified as the O₂ affinity increased. The high-frequency counterpart was also observed for a partially O₂-bound form, α­(Fe²⁺-deoxy)­α­(Fe²⁺-O₂)­β­(Fe³⁺)­β­(Fe³⁺), of the present Hb M, consistent with our previous finding that binding of O₂ to one α subunit of T structure α₂β₂ tetramer changes the other α subunit to the R structure

Interrelationship among Fe–His Bond Strengths, Oxygen Affinities, and Intersubunit Hydrogen Bonding Changes upon Ligand Binding in the β Subunit of Human Hemoglobin: The Alkaline Bohr Effect

Regulation of the oxygen affinity of human adult hemoglobin (Hb A) at high pH, known as the alkaline Bohr effect, is essential for its physiological function. In this study, structural mechanisms of the alkaline Bohr effect and pH-dependent O₂ affinity changes were investigated via ¹H nuclear magnetic resonance and visible and UV resonance Raman spectra of mutant Hbs, Hb M Iwate (αH87Y) and Hb M Boston (αH58Y). It was found that even though the binding of O₂ to the α subunits is forbidden in the mutant Hbs, the O₂ affinity was higher at alkaline pH than at neutral pH, and concomitantly, the Fe–His stretching frequency of the β subunits was shifted to higher values. Thus, it was confirmed for the β subunits that the stronger the Fe–His bond, the higher the O₂ affinity. It was found in this study that the quaternary structure of α­(Fe³⁺)­β­(Fe²⁺-CO) of the mutant Hb is closer to T than to the ordinary R at neutral pH. The retained Aspβ94–Hisβ146 hydrogen bond makes the extent of proton release smaller upon ligand binding from Hisβ146, known as one of residues contributing to the alkaline Bohr effect. For these T structures, the Aspα94–Trpβ37 hydrogen bond in the hinge region and the Tyrα42–Aspβ99 hydrogen bond in the switch region of the α₁–β₂ interface are maintained but elongated at alkaline pH. Thus, a decrease in tension in the Fe–His bond of the β subunits at alkaline pH causes a substantial increase in the change in global structure upon binding of CO to the β subunit

Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) of the major salivary glands : an assessment of the optimal number and combination of b-values

Purpose: To examine the optimal number and combination of b-values in intravoxel incoherent motion (IVIM) diffusionweighted imaging (DWI) of the major salivary glands. Material and methods: IVIM-DWI was performed on 10 healthy volunteers using 13 b-values (low b-values: 0-100 s/mm2; high b-values: 200-1000 s/mm2). The IVIM parameters and apparent diffusion coefficient of the bilateral major salivary glands were calculated using 13 b-values and were considered the standard values. We sequentially reduced the number of b-values to 10, 8, 6, and 5. The parameters in each combination were calculated. The standard values were compared with the parameters from each reduced b-value in IVIM-DWI. The Wilcoxon signed-rank test was used to determine whether there were any differences between the parameters in each combination. Bonferroni correction was conducted for multiple comparisons. Results: There were no significant differences between the standard values and parameters from the 2 combinations of 6 b-values. However, significant differences were observed between the standard values and parameters from some combinations of only 2 low or only 2 high b-values. Conclusions: IVIM-DWI of the major salivary glands could be performed using a minimum of 6 b-values. However, they should contain 3 low and 3 high b-values

Revisiting Smectic E Structure through Swollen Smectic E Phase in Binary System of 4‑Nonyl-4′-isothiocyanatobiphenyl (9TCB) and <i>n</i>‑Nonane

Thermodynamic and diffraction analyses were performed to establish the phase diagram for a binary system between 4-<i>n</i>-nonyl-4′-isothiocyanatobiphenyl (9TCB) and <i>n</i>-nonane. The swollen SmE structure is identified in the binary system. Upon swelling, a characteristic two-dimensional herringbone array is maintained whereas the layer spacing of SmE structure increases with the content of <i>n</i>-nonane. Considering the difficulties in explaining the experimental findings based on the traditional model of SmE structure, a new model, lamellar with two types of sublayers consisting of aromatic core and alkyl chain moieties, is proposed

A case of clear cell adenocarcinoma arising from the urethral diverticulum: Utility of urinary cytology and immunohistochemistry

Carcinomas rarely arise from the urethral diverticulum. In this report, we present a case of clear cell adenocarcinoma arising from the urethral diverticulum. A 42-year-old woman complained of bloody discharge and lower back pain. Imaging studies showed a tumor involving the region surrounding the urethra and cystourethroscopy showed papillary and villous tumors in the urethral diverticula. Cytology of the urine sediment showed papillary or spherical clusters of atypical cells, some of which had clear abundant cytoplasm and formed mirror ball-like clusters, suggesting adenocarcinoma. Although histological diagnosis was indeterminate by biopsy and transurethral resection (TUR) because of absence of stromal invasion, surgically resected specimen via cysturethrectomy revealed that the tumor was clear cell carcinoma. Urinary cytological findings and immunohistochemical analysis for CD15, Ki-67, and p53 might be useful for accurate diagnosis of clear cell adenocarcinoma that arises from the urethral diverticulum when sufficient materials are not available by biopsy and TUR

Association between personality traits and glycemic control after inpatient diabetes education

Aims: The longitudinal effect of personality traits on glycemic control is unclear. This prospective observational study explored the relationship between personality traits and glycemic control in patients with uncontrolled diabetes after inpatient diabetes education. Methods: Patients with diabetes mellitus (HbA1c ≥ 7.5%, measured by high-performance liquid chromatography) who received inpatient diabetes education were scored on the Big Five personality traits: neuroticism, extraversion, openness, agreeableness, and conscientiousness. Multiple linear analysis was used to determine whether any personality traits were independently associated with HbA1c on admission and HbA1c change from admission to 1, 3, and 6 months after discharge. Results: One hundred seventeen participants (mean age 60.4 ± 14.5 years; 59.0% male) were enrolled. HbA1c values on admission and 1, 3, and 6 months after discharge were 10.2 ± 2.1%, 8.3 ± 1.4%, 7.6 ± 1.4%, and 7.7 ± 1.5%, respectively. Multiple linear analysis showed that no personality traits were associated with HbA1c on admission. Neuroticism was negatively associated with the HbA1c change from admission to 3 months (β = −0.192, P = 0.025) and 6 months after discharge (β = −0.164, P = 0.043). Conclusions: Neuroticism was associated with good long-term glycemic control after inpatient diabetes education