Synthesis of organosoluble polyamides with bulky triaryl imidazole pendent group

New unsymmetrical diamine monomer containing triaryl imidazole pendent group, 4-[4-（4,5-diphenyl-1H-imidazol-2-y1）phe- noxy]-1,3-benzenediamine, was synthesized via aromatic substitution reaction of 1-chloro-2,4-dinitrobenzene with 4-（4,5- diphenyl-1H-imidazol-2-y1）pbenol, followed by palladium-catalyzed hydrazine reduction. This new monomer was further confirmed by FT-IR, IH NMR and ^13C NMR. Novel polyamides having pendant triaryl imidazole group were prepared by the phosphorylation polycondensation of four commercially aromatic dicarboxylic acids with the prepared diamine. Inherent viscosities of polyamides were in the range 0.42-0.53 dL/g indicating formation of medium molecular weight polymers. Polyamides exhibited glass-transition temperature （Tg） in the range 236-265 ℃. These polymers are essentially amorphous and were soluble in polar aprotic solvents such as DMF, NMP, DMAc. The 10% weight loss temperatures in air atmosphere, measured by TGA were in the range 350-373 ℃ indicating their good thermal stabilities. ？2009 Mousa Ghaemy. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

COPOLYMERIZATION OF CARBON DIOXIDE AND CYCLOHEXENE OXIDE CATALYZED BY ALUMINUM PORPHYRIN-QUATERNARY AMMONIUM SALT IN THE PRESENCE OF BULKY LEWIS ACID

Chloro(5,10,15,20-tetraphenyl-porphyrinato)-aluminum/tetraethylammonium bromide(Et4NBr)in combination with bulky Lewis acid was used for the copolymerization of CO_2 and cyclohexene oxide(CHO).Bulky Lewis acid having substituents at the ortho positions of the phenolate ligands,like methylaluminum bis(2,6-di-tert-butyl-4-methylphenolate), significantly shortened the induction period and raised the catalytic activity,the corresponding turnover frequency reached 44.9 h^(-1)in 9 h,which was 23.8% higher than th...

D-A-π-A organic dyes with fluorenyl-substituted bulky donor for efficient dye-sensitized solar cells

Improving light-harvesting efficiency and suppressing interfacial charge recombination are of paramount importance to the development of Cu(Ⅱ/Ⅰ)redox shuttle-based dye-sensitized solar cells(DSSCs).Here,we present a rational molecular engineering on D-A-π-A organic sensitizers featuring with fluorenyl-substituted bulky donor(HY57,HY60,and HY61)for Cu(Ⅱ/Ⅰ)mediated DSSCs.By gradually enhancing conjugation and rigidity of theπ-spacer and auxiliary acceptor moieties,the light-harvesting and electron-injection efficiencies can be simultaneously improved.The large size of fluorenyl-substituted arylamine donor together with abundant alkyl chains decorated on the molecular structures assist dense assembly of dye monolayer at surface of nanocrystalline TiO2,which largely suppress interfacial charge recombination losses.When applied in Cu(Ⅱ/Ⅰ)mediated DSSCs,the combination of an auxiliary acceptor of phenanthrene-fused-quinoxaline(PFQ)and aπ-spacer of cyclopentadithiophene(CPDT)in dye HY61 results in a simultaneous enhancement in short-circuit current(JSC)and open-circuit voltage(VOC),thus improving the power conversion efficiency(PCE)from 7.3%for reference dye HY59 to 10.3%for HY61.This study demonstrates that rigid and fused building block is promising towards constructing highly efficient organic sensitizers.

Can we triumph over locally advanced cervical cancer with colossal para-aortic lymph nodes? A case report

BACKGROUND Para-aortic lymph nodes(PALNs)are common sites for the regional spread of cervical squamous cell carcinoma(SCC).CASE SUMMARY We report the case of a 36-year-old woman who presented with cervical SCC with multiple bulky PALNs,largest measured 4.5 cm×5 cm×10 cm.The patient was treated with radical intent with definitive chemoradiation using sequential doseescalated adaptive radiotherapy,followed by maintenance chemotherapy.The patient achieved a complete response;she has been doing well since the completion of treatment with no evidence of the disease for 2 years.CONCLUSION Regardless of the size of PALN metastases of cervical carcinoma origin,it is still treatable(with radical intent)via concurrent chemoradiation.Adaptive radiotherapy allows dose escalation with minimal toxicity.

Cyclometalated platinum(Ⅱ) complexes with sterically bulky camphor-derived groups as β-diketonate ancillary ligand:a new route to efficiently reducing π-π interactions and Pt-Pt interactions

A new series of mono-cyclometalated square planar platinum(Ⅱ) complexes have been synthesized and the single-crystal X-ray structures of complex 1 and 2 have been determined.The complexes have the general formula ppyPt(O^O),where ppy is 2-phenylpyridyl,and O^O is β-diketonate ancillary ligands with the acyl substituent group in position 3 of(D)-(+)-camphor.Although,like the many Pt(Ⅱ) complexes with square-planar geometry,these complexes have plane stacking modes in crystal structure,the sterically bulky camphor-derived groups compel extensive slipping of the molecular stacking planes,resulting in the negligible overlapping of the aromatic ring fragments between molecules and the considerable Pt-Pt distance.The resolved spectra and a little shifted emission in solid state of complexes show that there is significant reduction of π-π interactions and Pt-Pt interactions,and suggest these complexes may be good candidates for doped phosphorescent organic light emitting diodes(PhOLEDs) and even for nondoped PhOLEDs.

AlkB recognition of a bulky DNA base adduct stabilized by chemical cross-linking

E.coli AlkB is a direct DNA/RNA repair protein that oxidatively reverses N1 alkylated purines and N3 alkylated pyrimidines to regular bases.Previous crystal structures have revealed N1-methyl adenine(1-meA) recognition by AlkB and a unique base flipping mechanism,but how the AlkB active site can accommodate bulky base adducts is largely unknown.Employing a previously developed chemical cross-linking technique,we crystallized AlkB with a duplex DNA containing a caged thymine base(cagedT).The structure revealed a flexible hairpin lid and a reorganized substrate recognition loop used by AlkB to accommodate cagedT.These observations demonstrate,at the molecular level,how bulky DNA adducts may be recognized and processed by AlkB.

Novel Organic Dyes Based on Bulky Tri（triphenylamine）-Substituted Styrene for Dye-Sensitized Solar Cells

Three novel donor-n-acceptor （D-π-A） metal-free organic dyes （TB, TS and TF） based on tri（triphenylamine）- substituted styrene as donor with various conjugated linkers （benzene, thiophene and furan） were synthesized, characterized and used for the application of dye-sensitized solar cells （DSSCs）. Under the same condition, The photo-to-electrical conversion efficiency of the DSSCs sensitized with TB, TS and TF reach 1.84%, 4.10% and 4.52%, respectively, which are lower than that sensitized with RI （5.02%） with one triphenylamine unit. The results suggest that these bulky donor-based sensitizers are unfavorable to DSSCs.

Bulky nanodiamond-confined synthesis of sub-5 nanometer ordered intermetallic Pd_(3)Pb catalysts

Modulation of geometric and electronic structures of supported Pd-based catalysts by forming atomically ordered intermetallic phases enables an effective way to optimize catalytic performance.However,the synthesis of small-sized Pd-based intermetallic nanoparticle catalysts with improved mass-based activity remains formidable challenges,since high-temperature annealing generally required for atom ordering inevitably leads to severe metal sintering and thus large crystallites.Here,we present a bulky nanodiamond-confined method to prepare sub-5 nm Pd_(3)Pb intermetallic nanocatalysts by mitigating metal sintering at high temperatures,which is induced by the electronic interactions between metal and defect-rich graphene shells reinforced by diamond cores in the bulky nanodiamond support.The prepared small-sized Pd_(3)Pb intermetallic catalyst displays a high activity with a turnover frequency of 932 h−1 for the semihydrogenation of phenylacetylene under mild conditions(room temperature,3 bar H_(2)),along with a high selectivity of>96%to styrene near the complete conversion of phenylacetylene.

Tetrahydrobenzo[5]helicenediol derivatives as additives for efficient proline-catalyzed asymmetric List-Lerner-Barbas aldol reactions of bulky aldehyde substrates

Tetrahydrobenzo[5]helicenediol（THB-[5]HDIOL） derivatives as additives for the efficient prolinecatalyzed asymmetric List-Lerner-Barbas（LLB） aldol reactions of bulky aldehyde substrates was described. It was found that with dibromo-substituted helical diols P-4 a/M-4 a as additives, the prolinecatalyzed LLB aldol reaction of 9-anthraldehyde and acetone gave the product in 83% yield and 99% ee.Transition state models revealed an edge-to-face p-p stacking between the anthracenyl group in TS（R）and the phenyl group of the additive, which might result in the high enantioselectivity.

Effects of Bulky LATP in PEO-based Hybrid Solid Electrolytes

Solid polymer electrolytes(SPEs) have been considered as the spotlight in recent years due to their high safety, non-flammability and good flexibility. Nonetheless, high crystallinity of polymer matrix leads to low ionic conductivity at ambient conditions and retards the practical applications of SPEs. Herein, we report hybrid solid electrolytes(HSE) containing bulky LATP in poly(ethylene oxide)(PEO) matrix, which significantly enhances the electrochemical properties. LATP has been easily obtained by an accessible solid-state method. The solid electrolyte based on 20 wt% LATP in PEO polymer matrix(abbreviated as PEO-20) exhibits an ionic conductivity of 2.1 ×10-5 S·cm-1 at 30 ℃, an order of magnitude higher than 2.9 × 10-6 S·cm-1 of the pristine PEO solid electrolyte(abbreviated as PEO-0), mainly resulting from the decline of crystallinity in polymer matrix. The electrochemical window of PEO-20 can reach 4.84 V at room temperature, compared with 4.40 V for PEO-0, which could be compatible with high-voltage cathode materials.

Efficient Semi‑Transparent Wide‑Bandgap Perovskite Solar Cells Enabled by Pure‑Chloride 2D‑Perovskite Passivation

Wide-bandgap(WBG)perovskite solar cells suffer from severe non-radiative recombination and exhibit relatively large opencircuit voltage(V_(OC))deficits,limiting their photovoltaic performance.Here,we address these issues by in-situ forming a well-defined 2D perovskite(PMA)_(2)PbCl_(4)(phenmethylammonium is referred to as PMA)passivation layer on top of the WBG active layer.The 2D layer with highly pure dimensionality and halide components is realized by intentionally tailoring the side-chain substituent at the aryl ring of the post-treatment reagent.First-principle calculation and single-crystal X-ray diffraction results reveal that weak intermolecular interactions between bulky PMA cations and relatively low cation-halide hydrogen bonding strength are crucial in forming the well-defined 2D phase.The(PMA)_(2)PbCl_(4)forms improved type-I energy level alignment with the WBG perovskite,reducing the electron recombination at the perovskite/hole-transport-layer interface.Applying this strategy in fabricating semi-transparent WBG perovskite solar cells(indium tin oxide as the back electrode),the V_(OC)deficits can be reduced to 0.49 V,comparable with the reported state-of-the-art WBG perovskite solar cells using metal electrodes.Consequently,we obtain hysteresis-free 18.60%-efficient WBG perovskite solar cells with a high V_(OC)of 1.23 V.

Role of Neoadjuvant Chemotherapy in Treatment of Cervical Cancer: A Case Series of Thirty-Eight Patients Treated at Bangabandhu Sheikh Mujib Medical University in Dhaka, Bangladesh

Background: Cervical cancer is the second most common malignancy of women in Bangladesh. Surgery is the mainstay of treatment of patients with early invasive cancer confined to cervix. While the five-year survival rate after surgery for stage IB1 disease exceeds 90%, it is only 60% - 70% for stage IB2 and IIA2 (tumor size > 4 cm). To improve the outcome of treatment, two to three cycles of Neoadjuvant Chemotherapy (NACT) has been evaluated as a treatment strategy in stage IB2 and IIA2 diseases. Objectives: This study aimed to evaluate the role of neoadjuvant chemotherapy (NACT) followed by Radical Surgery (RS) among the patients with early bulky cervical cancer (Stage IB2 & IIA2) to reduce the tumor size to achieve radical resectibility. Methods: This study was carried out at the Gynaecological Oncology Division of the Department of Obstetrics and Gynecology at Bangabandhu Sheikh Mujib Medical University (BSMMU) during the period July 2015 to December 2015. Thirty-eight patients with early bulky cervical cancer without any prior medical or surgical treatment received NACT using intravenous paclitaxel 175 mg/m2 and cisplatin 75 mg/m2 followed by radical surgery. The primary outcome measure assessed the response to NACT to reduce the size of the tumor. Secondary outcome measures assessed the resectibility of tumor and compared the preoperative clinical stage to the postoperative pathological stage. This study also assessed the relationship of intraoperative and postoperative complications including the adverse effects of postoperative radiotherapy and chemoradiotherapy. Results: Clinical response to NACT was 94.7% (84.2% complete response + 10.5% partial response). Progressive disease was found in two cases (5.3%). Duration of surgery was less than 2 hours in 81.6% cases and greater than 3 hours in 13.2% cases only. All women lived 5 to 10 hours away from Dhaka and could not return for in person follow-up. It was possible to get telephone follow-up on twenty-four women (63%). Seven (29%) had died from their cancers within one year of their surgery. Seventeen women were alive and disease free two years after completeion of their treatment. Conclusion: NACT is a feasible approach for improving the resectability of early stage bulky cervical cancer at BSMMU.

Syntheses and Crystal Structures of Two Tin(Ⅳ) Complexes with Aminosilane Bearing Ligand

Aminosilane bearing bulky substituents on nitrogen： LH2 （L = Me2Si（NDipp＇）2, Dipp = 2,6-diisopropylphenyl） was reacted with BuLi in toluene. The resulting bulky chelating dianion Me2Si（NDipp）2 was used to synthesize the unusual spirocyclic heterotriatomic complex [MeESi（NDipp）2]ESn （1） by its reaction with SnCl4 and the bulky heterotriatomic complex Me2Si（NDipp）2SnPh2 （2） with Ph2SnC12. 1 belongs to the monoclinic system, space group P21/n with a = 13.193（2）, b = 20.663（3）, c = 20.403（3）A, β = 99.954（2）°, V = 5478.3（15） A3, C55H85.5N4Si2Sn, Mr = 977.64, Z = 4, Dc. = 1.185 Mg/m3, μ（MoKa） = 0.547 mm-1, F（000） = 2086, S = 1.000, the final R = 0.0614 and wR = 0.1322 for 14446 observed reflections （1 〉 2σ（I）） and R = 0.0797 and wR = 0.1456 for all data. 2 belongs to the triclinic system, space group P1 with a = 10.36（15）, b = 13.204（7）, c = 14.363（7） A, a = 90.214（10）, β = 106.182（7）, y = 109.854（8）°, V = 1764.4（15） A3, C38HsoN2SiSn, M,. = 681.58, Z = 2, Dc = 1.283 Mg/m^3,μ（MoKa） = 0.785 mm-1, F（000） = 712, S = 1.002, the final R = 0.0498 and wR = 0.0955 for 7533 observed reβections （I 〉 2σ（I）） and R = 0.0676 and wR = 0.1018 for all data. In the structure of 1, the tin atom is located in the spirocyclic center of the two fused four-membered SnN2Si rings. The two complexes were characterized by ^1H NMR, elemental analysis, and single-crystal X-ray structural analysis.

INFLUENCE OF PROCESSING PARAMETERS AND POWDER BINDER CONTENT ON PROPERTIES OF HIGH LOFT NONWOVEN FABRICS

In this paper, the influence of processing parameters and powder binder content was studied and analysed on the properties of high loft nonwoven fabrics mainly using statistical analysis method. The relationship between the bulkiness and the warmth retention property was also tested. The analytical results reveal that the increase of the powder content, heating temperature and pressure will affect the tensile strength of nonwovens. Moreover, there are interactions between these parameters. The compression properties only change a little for a powder binder content of 15％—20％. However, with the increase of the heating temperature and pressure, the bulkiness and compression rate will reduce significantly. For the bulk density of high loft nonwoven fabrics, there exists a heat transter mechanism of air convection, but the higher the bulkiness of nonwovens, the larger the thickness and the better the warmth retention property of nonwoven fabrics.

Extension of Highly Efficient Alcohol-promoted Rearrangement into One-pot Domino Palladium-catalyzed Carbonylation for Sterically Crowded Aromatic Six-membered Imides

Aromatic six-membered imides suffer the introduction of bulky substituents at the imide positions due to the formation of isoimides and low reactivity,preventing from the investigation of the intrinsic molecular properties.Here,we found a highly efficient alcohol-promoted rearrangement from isonaphthalimide to naphthalimide under acid or basic nonaqueous conditions,which can be regarded as model compounds for aromatic six-membered imides.We proposed two-step nucleophilic substitutions in the isomerization mechanistic pathways that were verified by the separation of a key intermediate.Furthermore,in-situ ^(1)H NMR exhibited the first-order kinetics for the isoimide loss process.Finally,the alcohol-promoted isoimide-imide rearrangement was extended to a palladium-catalyzed one-pot domino carbonylation reaction toward sterically crowded aromatic six-membered imides.

Improvement of microstructure and coercivity for Nd-Fe-B sintered magnets by boundary introducing low melting point alloys

Different from the grain boundary diffusion process(GBDP),which is suitable for modifying thin magnet,a green-pressing agents permeation process(GAPP)that uses low melting point alloys was applied to the Nd-Fe-B green compact with a thickness over 15 mm to reconstruct the boundary microstructure of a sintered Nd-Fe-B magnet.The coercivity increases from 12.3 kOe for the sample free of Pr80Al20 to16.8 kOe for the sample with 2 wt%Pr80Al20.By further increasing the Pr80Al20 content to 3 wt%,the coercivity increases slightly,but the remanence and Hk/Hcj deteriorate obviously.The optimal comprehensive properties of Hcj=16.8 kOe,Br=13.4 kG and Hk/Hcj=0.975 are obtained at 2 wt%Pr80Al20,since matrix phase grains are separated by relatively continuous thin grain boundary layers,which weaken the magnetic coupling between adjacent grains.The coercivities of the samples from the GAPP that use2 wt%Pr80Al20,Pr70Al30 and Pr60Tb20Al20 alloys,respectively,can be enhanced to a large extent.However,the coercivity of the magnet reconstructed with Pr80Al20 is lower than that of the sample with Pr60Tb20Al20 but is higher than that of the sample reconstructed with Pr70Cu30 alloy.Moreover,the coercivity of the sample from the GAPP using 2 wt%Pr80Al20 is much higher than that of the sample from the GBDP,which is due to a nearly uniform boundary microstructure from the surface to the interior of the thick magnet from the GAPP,thus providing new insights into the fabrication of thick and bulky permanent magnets with high coercivity.

Solar cells sensitized by porphyrin dyes containing a substituted carbazole donor with synergistically extended absorption and suppressed the dye aggregation

To achieve high power conversion efficiency(PCE),three porphyrin sensitizers have been synthesized and explored to simultaneously enhance the photocurrent(JSC)and photovoltage(VOC).On basis of the XW4,a benzothiadiazole(BTD)unit has been introduced to afford XW57 with the aim to extend the absorption wavelength and enhance the light harvesting ability.As a result,a JSC of 13.72 mA/cm^2 has been obtained for XW57,higher than that of XW4.On this basis,XW58 has been prepared by modifying the carbazole-based donor with two bulky dihexyloxyphenyl groups,and the superior anti-aggregation character raises the VOC from 781 mV(XW4)to 844 mV.When both the BTD unit and the bulky groups are introduced to the acceptor and donor units,respectively,the resulting sensitizer XW59 exhibits a highest PCE value of 7.34%with synergistically enhanced JSC of 13.19 mA/cm^2 and VOC of 793 mV.These results provide further insight into developing high performance dye-sensitized solar cells.

Hydroalumination of diazo and azido compounds:An Al-H addition to end-on nitrogen of substrates

This paper reports the reactions of a monomeric aluminum dihydride LAlH2(L = HC[C(Me)N(Ar)]2,Ar = 2,6-i-Pr2C6H3) with diazo,azido,and terminal alkyne compounds.The reaction of LAlH2 with N2CH(SiMe3) and N3(1-Ad) occurred through an Al-H addition to end-on nitrogen to yield respective compounds LAl[N(H)N = CH(SiMe3)]2(1) and LAl[N(H)N=N(1-Ad)]2(2),while the reaction of LAlH2 with PhC≡CH occurred through a stepwise deprotonation to yield LAlH(C≡CPh)(5) and LAl-(C≡CPh)2(6),respectively.2 further reacted by N2-release to yield LAl[NH(1-Ad)][N(H)N=N(1-Ad)](3) and LAl[NH-(1-Ad)]2(4) upon the increased temperature treatment.Compounds 1-6 have been fully characterized,revealing novel reactivity patterns of LAlH2 toward different substrates under the steric influence from the bulky L ligand at Al.

Use of Silicon Substituents in the Syntheses of Natural and Non-natural Molecules

Trimethylsilyl groups have been used in our research as a director as well as a bulky and lipophilic group in our quest for natural and non-natural molecules.

Synthesis and Luminescent Properties of Iridium Complexes with Reduced Concentration Quenching Effect

Three novel cyclometalated ligands 1-benzyl-2-phenyl-lH-benzoimidazole（BPBM）, 1-（4-methoxy- benzyl）-2-（4-methoxy-phenyl）-lH-benzoimidazole（MBMPB） and 4-[2-（4-dimethylamino-phenyl）-benzoinidazol-1- ylmethyl]-phenyl-dimethyl-amine（DBPA） were designed and synthesized, and the corresponding highly efficiency green-emitting phosphorescent iridium complexes Ir（BPBM）2（acac）（1）, Ir（MBMPB）2（acac）（2） and Ir（DPBA）2（acac） （3） with acetylacetone（acac） as auxiliary ligand were also synthesized. The ligands are functionalized by bulky non-planarity substituents, thus the phosphorescent concentration quenching is substantially suppressed, and all the complexes exhibit bright photoluminescence（PL） in solid state. The photo-physical properties of the three iridium complexes were researched in detail. The results indicate that they have potential application in fabricating non-doped electrophosphorescence device.