A single liquid chromatography–quadrupole time‐of‐flight mass spectrometric method for the quantification of total antibody,antibody‐conjugated drug and free payload of antibody–drug conjugates

A single hybrid affinity‐captured‐LC‐TOF‐MS/MS method was developed and applied for the quantification of total antibody, antibody conjugated drug and free payload of antibody drug conjugate (ADC). Adcetris®, a valine–citrulline monomethyl auristatin E conjugated ADC, was used as a model ADC compound. A quadratic regression (weighted 1/concentration) was used to fit calibration curves over the concentration range 30.65–613.00 ng/mL with an equation y = ax² + bx + c for the antibody‐conjugated drug of Adcetris®. The qualification run met the acceptance criteria of ±25% accuracy and precision values for quality control samples. For the analysis of total antibody, a signature peptide (TTPPVLDSDGSFFLYSK, molecular weight 1874) was used after affinity capture using magnetic beads and on‐bead trypsin digestion. A quadratic regression (weighted 1/concentration) was used to fit calibration curves over the concentration range 5.00–100.00 μg/mL with an equation y = ax² + bx + c for total antibody. For free payload analysis of monomethyl auristatin E, a protein precipitation method followed by LC‐TOF‐MS/MS analysis was used. A quadratic regression (weighted 1/concentration) was used to fit calibration curves over the concentration range 1.01–2200 ng/mL with an equation y = ax² + bx + c for free payload. Pharmacokinetic study samples and in vitro stability samples in rat were successfully analyzed by this a hybrid affinity‐captured‐LC‐TOF‐MS/MS method. This single platform method is a useful complementary method for the pharmacokinetics study of ADC with valine–citrulline linker at the early drug discovery stage.     

Synthesis,Crystal, and Electronic Structure of the New Ternary Zintl Phase Eu2–xMg2–yGe3 (x = 0.1; y = 0.5)

The new ternary phase Eu_2–xMg_2–yGe₃ (x = 0.1, y = 0.5) was obtained by solid‐state synthesis and the structure determined by means of Single Crystal X‐ray Diffraction. The compound crystallizes with the orthorhombic space group Cmcm (no. 63) having structural features of the low‐temperature modification of LaSi. The crystal structure contains two different types of germanium anions: isolated Ge^4– and $\rm^{2}_{\infty}$ [Ge^2–x–y] chains. The cation substructure is partially disordered and is best represented assuming a split position. The chemical bonding is well represented by the Zintl‐Klemm concept. Resistivity measurements reveal that the compound is metallic. DFT band structure calculations were carried out on the ideal stoichiometric compound Eu₂Mg₂Ge₃, showing that this model (x = 0; y = 0) would be also metallic as a consequence of the ecliptic stacking of anions. Susceptibility and specific heat measurements evidence the presence of weak, and probably frustrated, antiferromagnetic interactions between disordered europium atoms.     

Distinct Diffusion in Macromolecule‐Solvent Mixtures

Summary: The specificity of interactions between pairs of molecules cannot be explicitly given by experimental transport coefficients such as intra‐ or mutual diffusion coefficients. But a microscopic interpretation of the transport properties exists, where distinct diffusion coefficients (DDCs) are related to preferential, correlated motion among distinct molecules. Since in general the DDCs do not play the role of an indicator for molecular self‐association phenomena if not compared with some appropriate standard, here we propose DDCs of hard spheres at the second order of volume fraction as new standard coefficients. The analysis based on these novel DDCs is designed to study intermolecular interaction between macromolecule and solvent. Comparisons of the novel non‐ideal with previous ideal reference states were done, and their combined use is shown to reinforce information conveyed by the usual velocity correlation analysis. The comparison of novel hard sphere standards with real DDCs, corresponding to an homologous chemical series of poly(ethylene glycol)‐water mixtures, provides a look at this polymer‐solvent mixture in a dilute and semi‐dilute regime.

Comparison between real (calculated by using Equation (5)–(7) and experimental data) and hard‐sphere based distinct diffusion coefficients for PEG 200 (1: Dequation/tex2gif-stack-1.gif; 2: Dequation/tex2gif-stack-2.gif and 3: Dequation/tex2gif-stack-3.gif).     

Molecular and supramolecular ionic aggregates HxOyz in organic and organometallic crystalline hydrates

Ionic aggregates of the form H_xO_y^z (z≠ 0) have been characterized during an analysis of 245 crystal structures extracted from the Cambridge Structural Database [Allen (2002). Acta Cryst. B 58 , 380–388]. A systematic nomenclature is proposed for these species. Three modes of hydrogen bonding are described, characterized in part by the distance between contiguous O atoms: normal (NHB; O...O = 2.6–3.0 Å), charge assisted (CAHB; O...O = 2.5 Å) and molecular (MHB; O...O = 2.4 Å). The three modes are consistent with previous reports, our experimental results, and quantum‐chemical‐optimized geometries and energetics. No evidence is presented concerning the possible existence or stability of these aggregates in solution. Rather, emphasis is placed on the necessity in crystal structure analysis to develop thoroughly existing hydrogen‐bonded networks, ignorance of which can lead to erroneous crystal structure models and other physico‐chemical data associated with composition and charge balance.     

Ethylene/1‐hexene copolymers synthesized with a single‐site catalyst: Crystallization analysis fractionation,modeling, and reactivity ratio estimation

A series of poly(ethylene‐co‐1‐hexene) samples made with rac‐ethylene bis(indenyl)zirconium dichloride/methylaluminoxane were analyzed by crystallization analysis fractionation (CRYSTAF). The nine samples had comonomer contents of 0–4.2 mol % 1‐hexene with a narrow range of molecular weights (34,000–39,000 g/mol). Because all the copolymer samples had narrow, unimodal chemical composition distributions, they were ideal as calibration standards for CRYSTAF. A linear calibration curve was constructed relating the peak crystallization temperature from CRYSTAF operated at a cooling rate of 0.1 °C/min and the comonomer content as determined by ¹³C NMR. Reactivity ratios for ethylene and 1‐hexene were estimated by the fitting of reactant liquid‐phase compositional data to the Mayo–Lewis equation. It was found that a value of the 1‐hexene reactivity ratio could not be unequivocally determined from the set of samples analyzed because the range of comonomer incorporation was too narrow. Stockmayer's bivariate distribution was used to model the fractionation process in CRYSTAF, and although a good fit to experimental CRYSTAF profiles was attained, the model did not fully describe the underlying crystallization phenomena. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2595–2611, 2002     

Molecular weight dependent structure and charge transport in MAPLE‐deposited poly(3‐hexylthiophene) thin films

In this work, poly(3‐hexylthiophene) (P3HT) films prepared using the matrix‐assisted pulsed laser evaporation (MAPLE) technique are shown to possess morphological structures that are dependent on molecular weight (MW). Specifically, the structures of low MW samples of MAPLE‐deposited film are composed of crystallites/aggregates embedded within highly disordered environments, whereas those of high MW samples are composed of aggregated domains connected by long polymer chains. Additionally, the crystallite size along the side‐chain (100) direction decreases, whereas the conjugation length increases with increasing molecular weight. This is qualitatively similar to the structure of spin‐cast films, though the MAPLE‐deposited films are more disordered. In‐plane carrier mobilities in the MAPLE‐deposited samples increase with MW, consistent with the notion that longer chains bridge adjacent aggregated domains thereby facilitating more effective charge transport. The carrier mobilities in the MAPLE‐deposited simples are consistently lower than those in the solvent‐cast samples for all molecular weights, consistent with the shorter conjugation length in samples prepared by this deposition technique. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 652–662     

2D l‐Di‐toluoyl‐tartaric acid Lanthanide Coordination Polymers: Toward Single‐component White‐Light and NIR Luminescent Materials

A series of five l ‐di‐p‐toluoyl‐tartaric acid (l ‐DTTA) lanthanide coordination polymers, namely {[Ln₄K⁴ L₆(H₂O)_x]?yH₂O}_n, [Ln=Dy ( 1 ), x=24, y=12; Ln=Ho ( 2 ), x=23, y=12; Ln=Er ( 3 ), x=24, y=12; Ln=Yb ( 4 ), x=24, y=11; Ln=Lu ( 5 ), x=24, y=12] have been isolated by simple reactions of H₂L (H₂L= L ‐DTTA) with LnCl₃?6 H₂O at ambient temperature. X‐ray crystallographic analysis reveals that complexes 1 – 5 feature two‐dimensional (2D) network structures in which the Ln³⁺ ions are bridged by carboxylate groups of ligands in two unique coordinated modes. Luminescent spectra demonstrate that complex 1 realizes single‐component white‐light emission, while complexes 2 – 4 exhibit a characteristic near‐infrared (NIR) luminescence in the solid state at room temperature.     

Bond dissociation energies and the Hammett correlation,Part 1: Remotely substituted aromatic compounds and vitamin E

Four hundred and seventy nine experimental values of X? Z bond dissociation energies (BDEs) of para‐, ortho‐, meta‐, and multisubstituted aromatic compounds were reproduced by the following simple equations: Here X represents a wide variety of univalent atoms or groups; Y is one or several various remote substituents; and Z represents an oxygen, nitrogen, carbon, or sulfur atom. DH⁰(X? ZC₅H₆) is a known reference/anchor point for a series of X? Z bonds. E_sr is the remote conjugation energy between the substituents and the reaction center (broken bond), and can be expressed as a Hammett‐type correlation. σ⁺(Y) is the Brown–Okamoto constant of a substituent Y or the sum of several substituent constants. The Hammett slope or reaction constant ρ is a linear function of the difference between the covalent potentials V_x(Z) and V_x(X). It has been found that and The set of equations are very powerful for the prediction of BDEs, chemical reactivity, and reaction center (or active site) in antioxidants, nutrients, pharmaceuticals, toxicants, carcinogens, and explosives. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 453–466, 2002     

Angle‐resolved XPS of fluorinated and semi‐fluorinated side‐chain polymers

Angle‐resolved XPS data (elemental quantification and high‐energy‐resolution C 1s) are presented for ten polymers with side‐chains of the form ? OCO(CF₂)_yF, ? COO(CH₂)₂OCO(CF₂)_yF (y = 1, 2, 3) and ? COO(CH₂)_x(CF₂)_yF (x = 1, y = 1, 2, 3; x = 2, y = 8). Particular attention was paid to charge compensation and speed of data acquisition, with co‐addition from multiple fresh samples to give spectra with good energy resolution and good signal‐to‐noise ratio free from the effects of x‐ray‐induced degradation. Water contact angles for the polymers are also reported. The XPS data demonstrate preferential surface segregation of fluorine‐containing groups for all but the shortest side‐chain polymer, where the ? OCOCF₃ side‐chain either does not surface segregate or is too short for surface segregation to be detectable by angle‐resolved XPS. In the other polymers studied the relative positions of functional groups in the side‐chains correlate with the angle‐resolved behaviour of the corresponding C 1s components. This shows that the surface side‐chains are oriented towards the polymer surface. For the ? COO(CH₂)₂OCO(CF₂)_yF (y = 1) side‐chain, the angle‐resolved C 1s data suggest reduced ordering and linearity compared with y = 2 and 3. For any particular series of polymers, e.g. ? COO(CH₂)_x(CF₂)_yF, the water contact angles increase with y, consistent with burying of the hydrophilic ester groups as y increases. For any particular value of y the sequence of water contact angles is ? COO(CH₂)_x(CF₂)_yF > ? OCO(CF₂)_yF ～ ? COO(CH₂)₂OCO(CF₂)_yF, suggesting greater ordering and density of fluorocarbon species at the surface of the ? COO(CH₂)_x(CF₂)_yF side‐chain polymers compared with the other polymers studied. For the ? COO(CH₂)₂(CF₂)₈F polymer a water contact angle of 124° is measured, which is greater than that of poly(tetrafluoroethene). The ? COO(CH₂)₂OCO(CF₂)F polymer is unusual in that it shows a particularly low water contact angle (83° ), suggesting that the probe fluid is able to sense both ester groups, consistent with the reduced ordering of the side‐chain detected by angle‐resolved XPS. Copyright © 2004 John Wiley & Sons, Ltd.     

Effect of Li2O Addition on the Preparation of (Y2‐yLiy)Ti2O7‐y

A new series of (Y_2‐yLi_y)Ti₂O_7‐y having an ordered pyrochlore phase was prepared by a solid state reaction method with a solid solution range of 0.05 ≥ y ≥ 0.10. Unit cell parameters obtained by the Rietveld refinement method shows that the a‐axis decreases linearly with increasing the amount of Li ion addition, indicating the successful incorporation of the Li ion into unit cell. The average x‐fractional coordinate of the O(1) site depends on the ionic radius ratio of r(A³+)/r(Ti⁴⁺) in the A₂Ti₂O₇ with a pyrochlore phase. The Ti K‐edge XANES spectra of the (Y_2‐yLi_y)Ti₂O_7‐y show that the valence of the Ti ions is slightly less than 4 so that Ti is in the mixed valence state. Average particle size increases with increasing the amount of extra Li ion addition, which acts as a flux to lower the melting point of the materials.     

Molecular organization in MAPLE‐deposited conjugated polymer thin films and the implications for carrier transport characteristics

The morphological structure of poly(3‐hexylthiophene) (P3HT) thin films deposited by both Matrix Assisted Pulsed Laser Evaporation (MAPLE) and solution spin‐casting methods are investigated. The MAPLE samples possessed a higher degree of disorder, with random orientations of polymer crystallites along the side‐chain stacking, π–π stacking, and conjugated backbone directions. Moreover, the average molecular orientations and relative degrees of crystallinity of MAPLE‐deposited polymer films are insensitive to the chemistries of the substrates onto which they were deposited; this is in stark contrast to the films prepared by the conventional spin‐casting technique. Despite the seemingly unfavorable molecular orientations and the highly disordered morphologies, the in‐plane charge carrier transport characteristics of the MAPLE samples are comparable to those of spin‐cast samples, exhibiting similar transport activation energies (56 vs. 54 meV) to those reported in the literature for high mobility polymers. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 39–48     

High-efficient calculation of the interaction energies between dissimilar double layers for Na2SO4-type asymmetric electrolytes at y 0 > y d > 0

Several rapidly convergent series for highly efficient calculation of the interaction energies between dissimilar double layers for Na₂SO₄-type electrolytes at y ₀ > y _d > 0 are derived, the accurate numerical results are given, and several approximate expressions are obtained for y ₀ ≪ 1. The number of the series terms required to obtain the interaction energies with six significant digits via the use of the series derived is no more than 2 when the dimensionless surface potential of double layers y ₀ ≤ 20. The interaction energies between dissimilar double layers for NaCl-or Na₂SO₄-type electrolytes are remarkably affected by the value of y _d,, but the interaction energies for Na₂SO₄-type electrolytes are hardly affected by the value of y ₀. The present results can also be applied to CaCl₂-type electrolytes at y ₀ < y _d < 0. The text was submitted by the authors in English.     

Highly Emissive Self‐Trapped Excitons in Fully Inorganic Zero‐Dimensional Tin Halides

The spatial localization of charge carriers to promote the formation of bound excitons and concomitantly enhance radiative recombination has long been a goal for luminescent semiconductors. Zero‐dimensional materials structurally impose carrier localization and result in the formation of localized Frenkel excitons. Now the fully inorganic, perovskite‐derived zero‐dimensional Sn^II material Cs₄SnBr₆ is presented that exhibits room‐temperature broad‐band photoluminescence centered at 540 nm with a quantum yield (QY) of 15±5 %. A series of analogous compositions following the general formula Cs_4?xA_xSn(Br_1?yI_y)₆ (A=Rb, K; x≤1, y≤1) can be prepared. The emission of these materials ranges from 500 nm to 620 nm with the possibility to compositionally tune the Stokes shift and the self‐trapped exciton emission bands.     

Preparation and characterization of N‐methyl‐substituted polyurethane

We prepared N‐methyl‐substituted polyurethanes with different substitution degrees from sodium hydride, methyl p‐toluene sulfonate, and polyether–polyurethane containing poly(oxytetramethylene) glycol, 4,4′‐diphenylmethane diisocyanate, and 1,4‐butanediol. The chemical structures were characterized with Fourier transform infrared and ¹H NMR. To investigate the effects of the N‐substitution degree on the morphology, thermal stability, and mechanical properties, we used differential scanning calorimetry, thermogravimetric analysis, and a universal testing machine. As the substitution degree increased, the new free (1708 cm^?1) and bonded (1650 cm^?1) carbonyl peaks increased. There was no bonded carbonyl peak in fully substituted polyurethane because the urethane groups had no hydrogen. At a small substitution degree, we observed a slight increase in the glass‐transition temperature and decrease in the endotherms of soft‐segment and hard‐segment domains due to the decrease in the hard‐segment domain and the increase in the urethane groups in the soft‐segment domain. The hard‐segment domain decreased and then disappeared as the N‐methyl substitution degree increased. These changes in the morphology resulted (1) in decreased modulus and tensile strength for the films because of the decrease in physical crosslinking points and (2) improved thermal stability as the substitution degree increased. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4077–4083, 2002     

Solid polymer electrolytes. IV. Preparation and characterization of novel crosslinked epoxy‐siloxane polymer complexes as polymer electrolytes

Two series of novel crosslinked siloxane‐based polymers and their complexes with lithium perchlorate (LiClO₄) were prepared and characterized by Fourier transform infrared spectroscopy, solid‐state NMR (¹³C, ²⁹Si, and ⁷Li nuclei), and differential scanning calorimetry. Their thermal stability and ionic conductivity of these complexes were also investigated by thermogravimetric and AC impedance measurements. In these polymer networks, poly(propylene oxide) chains with different molecular weights were introduced through self‐synthesized epoxy‐siloxane precursors cured with two curing agents. The glass‐transition temperature (T_g) of these copolymers is dependent on the length of the ether units. The dissolution of LiClO₄ considerably increases the T_g of the polyether segments. The dependence of the ionic conductivity was investigated as a function of temperature, LiClO₄ concentration, and the molecular weight of the polyether segments. The ion‐transport behavior was affected by the combination of the ionic mobility and number of carrier ions. The ⁷Li solid‐state NMR line shapes of these polymer complexes suggest a significant interaction between Li⁺ ions and the polymer matrix, and temperature‐ and LiClO₄ concentration‐dependent chemical shifts are correlated with ionic conductivity. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1226–1235, 2002     

The nature of structure and bonding between transition metal and mixed Si‐Ge tetramers: A 20‐electron superatom system

A novel superatom species with 20‐electron system, Si_xGe_yM⁺ (x + y = 4; M = Nb, Ta), was properly proposed. The trigonal bipyramid structures for the studied systems were identified as the putative global minimum by means of the density functional theory calculations. The high chemical stability can be explained by the strong p‐d hybridization between transition metal and mixed Si‐Ge tetramers, and closed‐shell valence electron configuration [1S²1P⁶2S²1D¹⁰]. Meanwhile, the chemical bondings between metal atom and the tetramers can be recognized by three localized two‐center two‐electron (2c‐2e) and delocalized 3c‐2e σ‐bonds. For all the doped structures studied here, it was found that the π‐ and σ‐electrons satisfy the 2(N + 1)² counting rule, and thus these clusters possess spherically double (π and σ) aromaticity, which is also confirmed by the negative nucleus‐independent chemical shifts values. Consequently, all the calculated results provide a further understanding for structural stabilities and electronic properties of transition metal‐doped semiconductor clusters. © 2016 Wiley Periodicals, Inc.     

Computation of two‐center Coulomb integrals over Slater‐type orbitals using elliptical coordinates

A general analytic formula is obtained for the two‐center Coulomb integrals over Slater‐type orbitals in elliptical coordinates. Finite series expansions are used in the evaluation of the radial part of the integrals. The analytic formula is expressed in terms of a product of the well‐known auxiliary functions A_k(p) and B_k(p) and incomplete gamma functions. Recursive relations for the computer evaluation of these functions are given as well. The recursive relations are stable and our computer results are in good agreement with the benchmark values given in the literature. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003     

Colloidal Synthesis and Charge‐Carrier Dynamics of Cs2AgSb1−yBiyX6 (X: Br,Cl; 0 ≤y ≤1) Double Perovskite Nanocrystals

A series of lead‐free double perovskite nanocrystals (NCs) Cs₂AgSb_1?yBi_yX₆ (X: Br, Cl; 0≤y≤1) is synthesized. In particular, the Cs₂AgSbBr₆ NCs is a new double perovskite material that has not been reported for the bulk form. Mixed Ag–Sb/Bi NCs exhibit enhanced stability in colloidal solution compared to Ag–Bi or Ag–Sb NCs. Femtosecond transient absorption studies indicate the presence of two prominent fast trapping processes in the charge‐carrier relaxation. The two fast trapping processes are dominated by intrinsic self‐trapping (ca. 1–2 ps) arising from giant exciton–phonon coupling and surface‐defect trapping (ca. 50–100 ps). Slow hot‐carrier relaxation is observed at high pump fluence, and the possible mechanisms for the slow hot‐carrier relaxation are also discussed.     

Linking Conformational Flexibility and Kinetics: Catalytic 1,4‐Type Friedel–Crafts Reactions of Phenols Utilizing 1,3‐Diamine‐Tethered Guanidine/Bisthiourea Organocatalysts

Herein, we present details of our conformationally flexible, 1,3‐diamine‐tethered guanidine/bisthiourea organocatalysts for chemo‐, regio‐, and enantioselective 1,4‐type Friedel–Crafts reactions of phenols. These organocatalysts show a unique stereo‐discrimination governed by the differential activation entropy (ΔΔS^≠), rather than by the differential activation enthalpy (ΔΔH^≠). Extensive kinetic analyses using Eyring plots for a series of guanidine/bisthiourea organocatalysts revealed the key structural motif in the catalysts associated with a large magnitude of differential activation entropy (ΔΔS^≠). A plausible guanidine–thiourea cooperative mechanism for the enantioselective Friedel–Crafts reaction is proposed.