Intermolecular interactions between σ- and π-holes of bromopentafluorobenzene and pyridine: computational and experimental investigations.

The characters of σ- and π-holes of bromopentafluorobenzene (C6F5Br) enable it to interact with an electron-rich atom or group like pyridine which possesses an electron lone-pair N atom and a π ring. Theoretical studies of intermolecular interactions between C6F5Br and C5H5N have been carried out at the M06-2X/aug-cc-pVDZ level without and with the counterpoise method, together with single point calculations at M06-2X/TZVP, wB97-XD/aug-cc-pVDZ and CCSD(T)/aug-cc-pVDZ levels. The σ- and π-holes of C6F5Br exhibiting positive electrostatic potentials make these sites favorably interact with the N atom and the π ring of C5H5N with negative electrostatic potentials, leading to five different dimers connected by a σ-holen bond, a σ-holeπ bond or a π-holeπ bond. Their geometrical structures, characteristics, nature and spectroscopy behaviors were systematically investigated. EDA analyses reveal that the driving forces in these dimers are different. NCI, QTAIM and NBO analyses confirm the existence of intermolecular interactions formed via σ- and π-holes of C6F5Br and the N atom and the π ring of C5H5N. The experimental IR and Raman spectra gave us important information about the formation of molecular complexes between C6F5Br and C5H5N. We expect that the results could provide valuable insights into the investigation of intermolecular interactions involving σ- and π-holes.

Insights into the Diels-Alder Reaction between 3-Vinylindoles and Methyleneindolinone without and with the Assistance of Hydrogen-Bonding Catalyst Bisthiourea: Mechanism, Origin of Stereoselectivity, and Role of Catalyst.

The Diels-Alder reaction between 3-vinylindoles and methyleneindolinone can proceed both under catalyst-free conditions and with bisthiourea as the catalyst. The reaction with bisthiourea is much faster and results in higher stereoselectivity of the product. The reaction mechanism, origin of stereoselectivity, and role of the catalyst were elaborated based on quantum mechanical calculations and theoretical methods of reactivity indices, NCI, QTAIM, and distortion/interaction models. In the uncatalyzed reaction, the two C-C bonds that are formed undergo conversion from noncovalent to covalent bonding via a concerted asynchronous mechanism. The weak intermolecular interactions formed in the transition state play important roles. The difference between the interaction and distortion energies is responsible for the stereoselectivity. In the catalyzed reaction, bisthiourea induces both the diene and dienophile to approach it via weak intermolecular interactions, which greatly lowers the energy barrier of the reaction and leads to the product with excellent stereoselectivity. The possible pathways of this reaction were explored, which suggested that the formation of the two C-C bonds goes through either a stepwise or concerted asynchronous mechanism. These results detail the reaction mechanism and shed light on both the significant role of the bisthiourea catalyst and the origin of stereoselectivity for this type of Diels-Alder reaction and related ones.

Photo-induced versatile aliphatic C-H functionalization via electron donor-acceptor complex.

The ability to selectively introduce diverse functionality onto hydrocarbons is of substantial value in the synthesis of both small molecules and pharmaceuticals. In this endeavour, as a photocatalyst- and metal-free process, the electron donor-acceptor (EDA) strategy has not been well explored. Here we report an approach to aliphatic carbon-hydrogen bond diversification through an EDA complex constituted by HCl and SIV=O groups. As an efficient hydrogen atom transfer (HAT) reagent, chlorine radical can be produced via a proton-coupled electron transfer process in this system. Based on this unusual path, a photo-promoted versatile aliphatic C-H functionalization is developed without photo- and metal-catalysts, including thiolation, arylation, alkynylation, and allylation. This conversion has concise and ambient reaction conditions, good functional group tolerance, and substrate diversity, and provides an alternative solution for the high value-added utilization of bulk light alkanes.

Sequential chemoradiotherapy with gemcitabine and cisplatin for locoregionally advanced nasopharyngeal carcinoma.

We investigated a new chemoradiotherapy (CRT) regimen for locoregionally advanced nasopharyngeal carcinoma (NPC). A total of 240 patients were randomly assigned to three different CRT regimens: sequential CRT [1 cycle chemotherapy + Phase I radiotherapy (RT) + 1 cycle chemotherapy + Phase II RT + 2 cycles chemotherapy] with a cisplatin-gemcitabine (GC) regimen (800 mg/m(2) gemcitabine on Days 1 and 8 and 20 mg/m(2) cisplatin on Days 1-5, every 4 weeks) (sGC-RT); sequential chemoradiotherapy with a cisplatin-fluorouracil (PF) regimen (20 mg/m(2) DDP and 500 mg/m(2) 5-FU on Days 1-5, every 4 weeks) (sPF-RT) and cisplatin-based concurrent chemoradiotherapy plus adjuvant PF chemotherapy (Con-RT + PF). The complete response rate was higher in the sGC + RT group than in the other two groups (98.75% vs. 92.50%, p < 0.01). The 3-year overall survival (OS), disease-free survival (DFS) and distant metastasis-free survival (DMFS) rates in the sGC-RT group were significantly higher than those observed in the Con-RT group (OS, 95.0% vs. 76.3%, p < 0.001; DFS, 89.9% vs. 67.5%, p < 0.001; DMFS, 92.5% vs. 76.0%, p = 0.004) and in the sPF + RT group (OS, 95.0% vs. 73.6%, p < 0.001; DFS, 89.9% vs. 63.3%, p < 0.001; DMFS, 92.5% vs. 74.7%, p = 0.002). There were no significant differences in 3-year OS, DFS and MFS rates between the Con-RT and the sPF-RT groups. The GC-RT group experienced more hematologic toxicity, constipation and rash; however, there were no differences in late RT toxicity between the groups. These results demonstrate that a sGC-RT regimen is effective and well tolerated in patients with locoregionally advanced NPC.

[A study of the effect of interstitial (125)I seed implantation on ward nurses' hemogram and relevant protection investigations].

OBJECTIVE: To analyze the blood picture changes of the ward nurses who nurse the patients received (125)I seeds implantation. METHODS: 32 ward nurses who nurse the patients for (125)I seeds implantation were involved in the experimental group, the control group included 32 ward nurses from the medical oncology never exposed to (125)I seeds. The WBC count, hemoglobin concentration and platelet counts from the two groups were analyzed statistically, respectively. 30 patients received (125)I seeds implantation were selected randomly and γ-ray dose from the unshielded group and lead rubber cloth covering group was detected at a distance of 0, 15, 30, 50, 100 cm from patient body surface and at different angles. RESULTS: No significant statistical difference was found between the two groups of WBC count, hemoglobin concentration and platelet count (7.1 ± 1.7 vs 6.8 ± 2.0, 132 ± 11 vs 136 ± 11, 236 ± 57 vs 242 ± 61) . The measured radiation dose was close to the natural background dose (10.2-10.8 µSv/h) at a distance of 50 cm from the body surface [ (12.7 ± 4.3) µSv/h] and the same as after 0.125 mm lead equivalent (Pb) rubber cloth shield protection[ (11.2 ± 3.1) µSv/h]. CONCLUSION: Interstitial (125)I seed implantation is safe on the blood picture of the ward nurses after taking appropriate protective measures.

Sequential Catalytic Annulations: Divergent Synthesis of Heterocycles through a Radical [1,4]-Oxygen Shift.

A radical [1,4]-oxygen-atom transfer has been realized by the reaction of linear alkyne-tethered ketoximes and ethynylbenziodoxolones (EBX) under sequential catalytic conditions. Mechanism studies indicate that the O atom transfer experiences a cascade O atom radical cyclization/alkynylation/N-O bond photocleavage and subsequent N,O-diradical rearrangement. By the diversification of catalytic sequences, a series of structurally important 3H-pyrrol-3-ones and chlorinated furo[3,2-b]pyrroles are divergently synthesized along with an O atom shift under the catalysis of Cu/Ir photosensitization and Cu/Ir photosensitization/AlCl3, respectively.

Linear σ-hole⋯CO⋯σ-hole intermolecular interactions between carbon monoxide and dihalogen molecules XY (X, Y=Cl, Br).

Carbon monoxide can interact with two dihalogen molecules XY (X, Y=Cl, Br) in the form of X(Y)⋯COX(Y)⋯CO⋯X(Y)X(Y) trimeric complex, and their nature and characteristics were investigated at MP2/aug-cc-pVDZ level without and with counterpoise method, together with single point calculations at CCSD(T)/aug-cc-pVDZ level. The optimized geometries, stretching modes and interaction energies of a series of X(Y)⋯COX(Y)⋯CO⋯X(Y)X(Y) trimeric complexes were obtained and discussed. The cooperativity in these complexes was evaluated. EDA analyses reveal that the electrostatic interaction is the dominant net driving force in each trimer, but the contributions of other interactions like exchange, dispersion and polarization interactions are also important. QTAIM and NCI analyses confirm the existence of attractive halogen-bonding interactions. Additionally, EDDMF analysis was employed for the component dimers of these trimers, which indicates that the formation of halogen-bonding interactions is closely related to the charge shift and the rearrangement of electronic density in the formation of these complexes. The results would provide valuable insight into for these linear halogen bonds.

Adverse reactions and their management in the treatment of malignant tumors using cytokine-induced killer cells.

OBJECTIVE: To identify the causes and the corresponding management of adverse reactions during the treatment of malignant tumors using cytokine-induced killer cells. METHODS: From January 2012 to December 2012, 441 patients received a total of 1,393 autologous cytokine-induced killer cell transfusion cycles in our department. The adverse reactions after the procedures were observed (assessed using the National Cancer Institute Common Toxicity version 2.0), and targeted care and health education were delivered by nurses. RESULTS: All treatment sessions were successfully completed, and the following adverse reactions were found: grade 1/3 fever in 1.36% (19/1,393) patients; grade 2/3 fever in 0.86% (12/1,393) patients; grade 2/3 chills in 0.65% (9/1,393) patients; and grade 1/3 dizziness in 0.29% (4/1,393) patients. CONCLUSIONS: After timely intervention of the adverse reactions, all patients were treated successfully. The best timing of the CIK cell therapy for cancer patients is when the tumor burden, or the number of tumor cells, reaches the minimal level after the end of surgery, chemotherapy and radiation therapy.