Synthesis of poly(ω‐pentadecalactone)‐b‐poly(acrylate) diblock copolymers via a combination of enzymatic ring‐opening and RAFT polymerization techniques

Herein the first reported preparation of diblock copolymers of the polyethylene‐like polyester poly(ω‐pentadecalactone) (PPDL) via a combination of enzymatic ring‐opening polymerization (eROP) and reversible addition‐fragmentation chain‐transfer (RAFT) polymerization techniques is described. PPDL was synthesized via eROP using Novozyme 435 as a catalyst and a bifunctional initiator/chain transfer agent (CTA) appropriate for the eROP of ω‐pentadecalactone (PDL) and RAFT polymerization of acrylic and styrenic monomers. Chain growth of the PPDL macro‐CTA was performed to prepare acrylic and styrenic diblock copolymers of PPDL, and demonstrates a facile, metal‐free, and “greener” alternative to preparing acrylic diblock copolymers of polyethylene (PE). Diblock copolymer architecture was substantiated via analysis of ¹H NMR spectroscopic, UV‐GPC chromatographic, DSC onset crystallization (T_c), and MALDI‐ToF mass spectrometric data. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3326–3335     

Solubility of N2 in poly(α‐n‐hexyl‐β,L‐aspartate): Temperature and force‐field dependence

The solubility of N₂ in poly(α‐n‐hexyl‐β,L ‐aspartate), a stereoregular poly(β‐peptide), was investigated with atomistic Monte Carlo simulations. The structure of this material is intermediate between that of polymers able to form a three‐dimensional crystal lattice and that of liquid‐crystalline polymers with a biphasic distribution. The dependence of the calculated solubility coefficients on both the parameters of the force field and the temperature was examined. The results are compared with recently reported experimental data. Furthermore, the motion of the penetrant molecules within the polymer matrix was analyzed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2928–2936, 2003     

Synthesis and properties of the ionomer diblock copolymer poly(4‐vinylbenzyl triethyl ammonium bromide)‐b‐polyisobutene

A new amphiphilic diblock copolymer containing an ionomer segment, poly[(4‐vinylbenzyl triethyl ammonium bromide)‐co‐(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)]‐b‐polyisobutene [poly(4‐VBTEAB)‐b‐PIB], was synthesized by the chemical modification of poly(4‐methylstyrene)‐b‐polyisobutene [poly(4‐MSt)‐b‐PIB]. First, the 4‐methylstyrene moiety in poly(4‐MSt)‐b‐PIB was brominated with azobisisobutyronitrile as an initiator at 60 °C in CCl₄, and then the highly reactive benzyl bromide groups were ionized by a reaction with triethylamine in a toluene/isopropyl alcohol (80/20 v/v) mixture at about 85 °C to produce the ionomer diblock copolymer poly(4‐VBTEAB)‐b‐PIB. The solubility of the ionomer block copolymer was quite different from that of the corresponding poly[(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)]‐b‐polyisobutene {poly[(4‐MSt)‐co‐(4‐BrMSt)]‐b‐PIB}. Transmission electron microscopy observations demonstrated that all three diblock copolymers had microphase‐separation structures in which polyisobutene (PIB) domains existed in the continuous phase of the poly(4‐methylstyrene) segment or its derivative segment matrix. Dynamic mechanical thermal analysis measurements showed that poly[(4‐MSt)‐co‐(4‐BrMSt)]‐b‐PIB had two glass‐transition temperatures (T_g's), ?56 °C for the PIB segment and 62 °C for the poly[(4‐MSt)‐co‐(4‐BrMSt)] domain, whereas poly(4‐VBTEAB)‐b‐PIB showed one T_g at ?8 °C of the PIB domain; T_g of the poly[(4‐vinylbenzyl triethyl ammonium bromide)‐co‐(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)] domain was not observable because of the strong ionic interactions resulting in a higher T_g and a retention of modulus up to 124 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2755–2764, 2003     

Synthesis and characterization of mesogen‐jacketed liquid‐crystal polymers based on 2,5‐bis(4′‐alkoxyphenyl)styrene

A series of novel mesogen‐jacketed liquid‐crystal polymers, poly[2,5‐bis(4′‐alkoxyphenyl)‐styrene] (P‐n, n = 1–11), were prepared via free‐radical polymerization of newly synthesized monomers, 2,5‐bis(4′‐alkoxyphenyl)styrene (M‐n, n = 1–11). The influence of the alkoxy tail length on the liquid‐crystalline behaviors of the monomers and the polymers was investigated with differential scanning calorimetry (DSC), thermogravimetry, polarized optical microscopy (POM), and wide‐angle X‐ray diffraction (WAXD). The monomers with n = 1–4, 9, and 11 were monotropic nematic liquid crystals. All other monomers exhibited enantiotropic nematic properties. Their melting points (T_m's) decreased first as n increased to 6, after which T_m increased slightly at longer spacer lengths. The isotropic–nematic transition temperatures decreased regularly with increasing n values in an odd–even way. The glass‐transition temperatures (T_g's) of the polymers first decreased as the tail lengths increased and then leveled off when n ≥ 7. All polymers were thermally stable and entered the mesophase at a temperature above T_g. Upon further heating, no mesophase‐to‐isotropic melt transition was observed before the polymers decomposed. WAXD studies indicated that an irreversible order–order transition for the polymers with short tails (n ≤ 5) and a reversible order–order transition for those with elongated tails (n ≥ 6) occurred at a temperature much higher than T_g. However, such a transition could not be identified by POM and could be detected by DSC only on heating scans for the polymers with long tails (n ≥ 7). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1454–1464, 2003     

Poly(1,4‐cyclohexylenedimethylene 1,4‐cyclohexanedicarboxylate): Influence of stereochemistry of 1,4‐cyclohexylene units on the thermal properties

A series of poly(1,4‐cyclohexylenedimethylene 1,4‐cyclohexanedicarboxylate) (PCCD) samples, characterized by different cis/trans ratio of the 1,4‐cyclohexanedicarbonyl unit, have been synthesized and analyzed by thermogravimetry (TGA), calorimetry (DSC), and X‐ray diffraction (WAXD). The thermal stability results are good and are not affected by the stereochemistry of the 1,4‐cyclohexylene units. On the other hand, the thermal transitions are notably influenced by the cis/trans content. With the increment of the trans content the polymer changes from completely amorphous to semicrystalline material. T_g, T_m, and crystallinity increase. These results suggest that the trans configuration induces a better chain packing and higher symmetry, improving the crystallizability of the samples. The effect of the molecular structure on the thermal properties is analyzed by using a statistical approach. From the effective correlations found between stereochemistry of the C₆ rings and transition temperatures it is possible to extrapolate that the configuration of 1,4‐cyclohexylene ring deriving from 1,4‐cyclohexanedicarboxylic acid or dimethyl 1,4‐cyclohexanedicarboxylate results to be the main element responsible for the thermal properties. This is due to the high rigidity of the 1,4‐cyclohexanedicarbonyl unit with respect to 1,4‐cyclohexanedimethyleneoxy unit, deriving from the diol. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 619–630, 2008     

Helical polyacetylenes carrying 2,2,6,6‐tetramethyl‐1‐piperidinyloxy and 2,2,5,5‐tetramethyl‐1‐pyrrolidinyloxy moieties: Their synthesis,properties, and function

2,2,6,6‐Tetramethyl‐1‐piperidinyloxy (TEMPO)‐ and 2,2,5,5‐tetramethyl‐1‐pyrrolidinyloxy (PROXYL)‐containing (R)‐1‐methylpropargyl TEMPO‐4‐carboxylate ( 1 ), (R)‐1‐methylpropargyl PROXYL‐3‐carboxylate ( 2 ), (rac)‐1‐methylpropargyl PROXYL‐3‐carboxylate ( 3 ), (S)‐1‐propargylcarbamoylethyl TEMPO‐4‐carboxylate ( 4 ), and (S)‐1‐propargyloxycarbonylethyl TEMPO‐4‐carboxylate ( 5 ) (TEMPO, PROXYL) were polymerized to afford novel polymers containing the TEMPO and PROXYL radicals at high densities. Monomers 1–3 and 5 provided polymers with moderate number‐average molecular weights of 8200–140,900 in 49–97% yields in the presence of (nbd)Rh⁺[η⁶‐C₆H₅B^?(C₆H₅)₃], whereas 4 gave no polymer with this catalyst but gave polymers possessing low M_n (3800–7500) in 56–61% yield with [(nbd)RhCl]₂‐Et₃N. Poly( 1 ), poly( 2 ), and poly( 4 ) took a helical structure with predominantly one‐handed screw sense in THF and CHCl₃ as well as in film state. The helical structure of poly( 1 ) and poly( 2 ) was stable upon heating and addition of MeOH, whereas poly( 4 ) was responsive to heat and solvents. All of the free radical‐containing polymers displayed the reversible charge/discharge processes, whose capacities were in a range of 43.2–112 A h/kg. In particular, the capacities of poly( 2 )–poly( 5 )‐based cells reached about 90–100% of the theoretical values regardless of the secondary structure of the polymer, helix and random. Poly( 1 ), poly( 2 ), and poly( 4 ) taking a helical structure exhibited better capacity tolerance towards the increase of current density than nonhelical poly( 3 ) and poly( 5 ) did. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5431–5445, 2007     

The Crystal and Molecular Structure of γ‐P4S6

The crystal and molecular structure of γ‐P₄S₆ was determined from single‐crystal X‐ray diffraction. It crystallizes monoclinically in the space group P2₁/m (No. 11) with a = 6.627(3) Å, b = 10.504(7) Å, c = 6.878(3) Å, β = 90.18(4)°, V = 478.8(4) ų, and Z = 2. The structure consists of cage‐like P₄S₆ molecules with C_S symmetry arranged with the topology of a cubic close packing.     

Synthesis,one‐ and two‐photon properties of poly[9,10‐bis(3,4‐bis(2‐ethylhexyl‐oxy)phenyl)‐2,6‐anthracenevinylene‐alt‐N‐octyl‐3,6‐/2,7‐carbazolevinylene]

The synthesis, one‐ and two‐photon absorption (TPA) and emission properties of two novel 2,6‐anthracenevinylene‐based copolymers, poly[9,10‐bis(3,4‐bis(2‐ethylhexyloxy)phenyl)‐2,6‐anthracenevinylene‐alt‐N‐octyl‐3,6‐carbazolevinyl‐ene] ( P1 ) and poly[9,10‐bis(3,4‐bis(2‐ethylhexyloxy)phenyl)‐2,6‐anthracenevinyl‐ene‐alt‐N‐octyl‐2,7‐carbazolevinylene] ( P2 ) were reported. The as‐synthesized polymers have the number‐average molecular weights of 1.56 × 10⁴ for P1 and 1.85 × 10⁴ g mol^?1 for P2 and are readily soluble in common organic solvents. They emit strong bluish‐green one‐ and two‐photon excitation fluorescence in dilute toluene solution (? _P1 = 0.85, ? _P2 = 0.78, λ_em( P1 ) = 491 nm, λ_em( P2 ) = 483 nm). The maximal TPA cross‐sections of P1 and P2 measured by the two‐photon‐induced fluorescence method using femtosecond laser pulses in toluene are 840 and 490 GM per repeating unit, respectively, which are obviously larger than that (210 GM) of poly[9,10‐bis‐(3,4‐bis(2‐ethylhexyloxy) phenyl)‐2,6‐anthracenevinylene], indicating that the poly(2,6‐anthracenevinylene) derivatives with large TPA cross‐sections can be obtained by inserting electron‐donating moieties into the polymer backbone. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 463–470, 2010     

Homo‐ and random copolymerizations of ω‐pentadecalactone with ε‐caprolactone using isothiourea‐based dual catalysis

In this study, the catalytic behavior of dual catalysis based on isothioureas (ITUs) for ring‐opening polymerization (ROP) of macrolactone ω‐pentadecalactone (PDL) and its copolymerization with ε‐caprolactone (CL) has been investigated in detail. In the presence of benzyl alcohol (BnOH) initiator, 2,3,6,7‐tetrahydro‐5H‐thiazolo[3,2‐a]pyrimidine (THTP) acted as a representative organic compound, which coupled with magnesium halides (MgX₂) as cocatalysts and catalyzed the polymerization in toluene at 70 °C. Under suitable conditions, an array of polymers with controlled molecular weights and relatively narrow molecular weight distributions were synthesized. The formation of homopolymers and copolymers with different architectures was verified using GPC, DSC, NMR, and matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐ToF) mass. The MALDI‐ToF mass spectrometry (MS) analysis of poly(ω‐pentade‐calactone) (PPDL) provided direct evidence for the successful initiation of ROP of PDL using BnOH to obtain linear PPDL with a very small amount of oligomer. The NMR analysis indicated that the arrangements of PDL and CL units in the copolymer chains were completely random. The thermal stability of copolymers was composition dependent and increased with the increase in the content of PDL unit. Furthermore, the proposed polymerization mechanism is a dual catalytic mechanism. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019     

Crystalline Structure of Mangiferin,a C‐Glycosyl‐Substituted 9H‐Xanthen‐9‐one Isolated from the Stem Bark of Mangifera indica

The crystalline structure of mangiferin (=2‐β‐D ‐glucopyranosyl‐1,3,6,7‐tetrahydroxy‐9H‐xanthen‐9‐one; 1 ), a biologically active xanthenone C‐glycoside, isolated from the stem bark of Mangifera indica (Anacardiaceae), was unambiguously determined by single‐crystal X‐ray diffraction (XRD). The crystal structure is summarized as follows: triclinic, P1, a=7.6575(5), b=11.2094(8), c=11.8749(8) Å, α=79.967(5), β=87.988(4), γ=72.164(4)°, V=955.3(1) ų, and Z=2. The structure also shows two molecules in the asymmetric unit cell and five crystallization H₂O molecules. The packing is stabilized by several intermolecular H‐bonds involving either the two symmetry‐independent mangiferin molecules 1a and 1b , or the H₂O ones.     

Synthesis of well‐defined,soluble poly(3‐alkyl‐4‐benzamide) by chain‐growth condensation polymerization

Well‐defined poly(3‐alkyl‐4‐benzamide) was synthesized by means of chain‐growth condensation polymerization of phenyl 3‐octyl‐4‐(4‐octyloxybenzyl(OOB)amino)benzoate ( 1c ) from initiator 2 , followed by removal of the OOB groups on amide nitrogen of poly 1c . Polymerization of 1c with phenyl 4‐(trifluoromethyl)benzoate ( 2b ) in the presence of 1,1,1,3,3,3‐hexamethyldisilazide (LiHMDS) and LiCl in THF at ?10 °C gave poly 1c with a narrow molecular weight distribution (M_w/M_n ≤ 1.08) and a well‐defined molecular weight (M_n = 4480–12,700) determined by the feed ratio of monomer to initiator (from 10 to 30). The OOB groups of poly 1c were removed with H₂SO₄ to give the corresponding N‐unsubstituted poly(p‐benzamide) (poly 1c′ ) with low polydispersity. The solublity of poly 1c′ in polar organic solvents was dramatically higher than that of poly(p‐benzamide), demonstrating that introduction of an alkyl group on the aromatic ring is very effective for improving the solubility of poly(p‐benzamide). © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 360–365     

Chain‐growth condensation polymerization approach to synthesis of well‐defined polybenzoxazole: Importance of higher reactivity of 3‐amino‐4‐hydroxybenzoic acid ester compared to 4‐amino‐3‐hydroxybenzoic acid ester

Application of chain‐growth condensation polymerization (CGCP) to obtain well‐defined polybenzoxazole (PBO) was examined. CGCP of both phenyl 3‐{(2‐methoxyethoxy)methoxy (MEM‐oxy)}‐4‐(octylamino)benzoate ( 1b ) (para‐substituted monomer) and phenyl 4‐MEM‐oxy‐3‐(octylamino)benzoate ( 3b ) (meta‐substituted monomer) was examined in the presence of metal disilazide base and phenyl 4‐nitro‐ or methylbenzoate 2 as an initiator. Polymerization of the latter monomer, but not the former, afforded polymer with controlled molecular weight based on the feed ratio of monomer to initiator and with a narrow molecular weight distribution. Accordingly, monomer 3c , in which the octyl group on the amino nitrogen of 3b was replaced with a 4‐(octyloxy)benzyl (OOB) group, was polymerized in the presence of lithium 1,1,1,3,3,3‐hexamethyldisilazide (LiHMDS), phenyl 4‐methylbenzoate ( 2b ), and LiCl in THF at 0 °C to yield poly 3c with well‐defined molecular weight (M_n = 4520–9080) and low polydispersity (M_w/M_n ≤ 1.11). Treatment of poly 3c with trifluoroacetic acid simultaneously removed the MEM and OOB groups, affording poly(o‐hydroxyamide) (poly 4 ) without scission of the amide linkages. Cyclodehydration of poly 4 proceeded at 350 °C to yield PBO (poly 5 ), which was insoluble in organic solvents and acids. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1730–1736     

Assembly and Crystal Structure of a Novel 1—D Coordination Polymer of Copper（Ⅱ）with Thiocyanate and 4—Cyanopyridine

A novel one‐dimensional coordination polymer, Catena‐poly [bis(4‐cyano‐pyridyl) copper(II)‐di‐thiocyanate], ¹_∞ [Cu^II‐(cypy)₂(μ_N.S‐SCN)₂] (cypy = 4‐cyano‐pyridyl), was synthesized in a solution reaction of Cu(NO₃)₂·3H₂O, 4‐cyano‐pyridine and KSCN in mole ratio of 1:2:2 at room temperature. Its crystal structure was determined by single‐crystal X‐ray diffraction. The crystal belongs to monoclinic crystal system, space group P2₁/c with cell parameters a = 1.0719(2), b = 1.8441(4), c =0.9144(2) nm, β = 110.49(3)° and Z = 4. A full‐matrix least‐squares refinement gave R₁ = 0. 0393 and wR₂= 0.0916 for 1554 reflections having 1 >2σ(I). The crystal is thermally stable up to approximately 170 °C.     

A New Copper(II) Complex with the N,N′‐Tetra(antipyryl‐4‐methyl)‐1,2‐ethanediamine (TAMEN) Ligand: [Cu(TAMEN)](ClO4)2·H2O·DMF

The synthesis of the Mannich base N,N′‐tetra(antipyryl‐4‐methyl)‐1,2‐ethanediamine (TAMEN) ( 1 ), its crystal structure as well as the synthesis and the crystal structure of the copper complex [Cu(TAMEN)](ClO₄)₂·H₂O·DMF ( 2 ) are reported. C₅₀H₅₆N₁₀O₄·2C₂H₅OH (TAMEN·2EtOH) crystallizes with triclinic symmetry, space group , lattice parameters: a = 877.3(1), b = 1078.1(1), c = 1433.3(2) pm, α = 71.93(1), β = 82.16(1), γ = 84.54(1)° and Z = 1. The copper complex [Cu(TAMEN)](ClO₄)₂·H₂O·DMF also crystallizes with triclinic symmetry, space group , lattice parameters: a = 1279.2(2), b = 1485.6(2), c = 1513.6(2) pm, α = 98.04(1), β = 101.24(1), γ = 94.66(1)° and Z = 2. The copper(II) atom is six‐coordinate with an elongated pseudo‐octahedral geometry due to a strong Jahn‐Teller effect.     

(Acetato‐κO)aqua(1H‐imidazole‐κN3)(picolinato‐κ2N,O)copper(II) 0.87‐hydrate: a Z′> 1 structure

The crystal structure of the title compound, [Cu(C₆H₄NO₂)(C₂H₃O₂)(C₃H₄N₂)(H₂O)]·0.87H₂O, has a square‐pyramidal‐coordinated Cu^II centre (the imidazole is trans to the picolinate N atom, the acetate is trans to the picolinate –CO₂ group and the aqua ligand is in a Jahn–Teller‐elongated apical position) and has two symmetry‐independent molecules in the unit cell (Z′ = 2), which are connected through complementary imidazole–picolinate N—H...O hydrogen bonding. The two partially occupied solvent water molecules are each disordered over two positions. The disordered solvent water molecules, together with pseudosymmetry elements, support the notion that a crystal structure with multiple identical chemical formula units in the structural asymmetric unit (Z′ > 1) can represent a crystal `on the way', that is, a kinetic intermediate form which has not yet reached its thermodynamic minimum. Neighbouring molecules form π–π stacks between their imidazole and picolinate N‐heterocycles, with centroid–centroid distances in the range 3.582 (2)–3.764 (2) Å.     

Syntheses and properties of new aromatic polybenzoxazoles bearing ether and phenylethylidene or 1‐phenyl‐2,2,2‐trifluoroethylidene linkages

Two new bis(ether acyl chloride)s, 1,1‐bis[4‐(4‐chloroformylphenoxy)phenyl]‐1‐phenylethane and 1,1‐bis[4‐(4‐chloroformylphenoxy)phenyl]‐1‐phenyl‐2,2,2‐trifluoroethane, were prepared from readily available reagents. Aromatic polybenzoxazoles with both ether and phenylethylidene or 1‐phenyl‐2,2,2‐trifluoroethylidene linkages between phenylene units were obtained by a conventional two‐step procedure including the low‐temperature solution polycondensation of the bis(ether acyl chloride)s with three bis(o‐aminophenol)s, yielding poly(o‐hydroxyamide) precursors, and subsequent thermal cyclodehydration. The intermediate poly(o‐hydroxyamide)s exhibited inherent viscosities of 0.39–0.98 dL/g. All of the poly(o‐hydroxyamide)s were amorphous and soluble in polar organic solvents such as N,N‐dimethylacetamide, and most of them could afford flexible and tough films via solvent casting. The poly(o‐hydroxyamide)s exhibited glass‐transition temperatures (T_g's) of 129–194 °C and could be thermally converted into corresponding polybenzoxazoles in the solid state at temperatures higher than 300 °C. All the polybenzoxazoles were amorphous and showed an enhanced T_g but a dramatically decreased solubility with to respect to their poly(o‐hydroxyamide) precursors. They exhibited T_g's of 216–236 °C through differential scanning calorimetry and were stable up to 500 °C in nitrogen or air, with 10% weight‐loss temperatures being recorded between 538 and 562 °C in nitrogen or air. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 914–921, 2003     

Synthesis and Crystal Structure of α‐ThTe3

The binary thorium tritelluride, α‐ThTe₃, was synthesized by solid‐state methods at 1223 K. From a single‐crystal X‐ray diffraction study the material crystallizes in the TiS₃ structure type with two formula units in space group C²_2h–P2₁/m of the monoclinic system in a cell with lattice constants a = 6.1730 (4) Å, b = 4.3625(3) Å, c = 10.4161(6) Å, and β = 97.756(3)° (at 100 K). The asymmetric unit of this compound comprises one Th atom and three Te atoms each with site symmetry m. Each Th atom is coordinated to eight Te atoms in a bicapped trigonal‐pyramidal arrangement. Th–Te distances range from 3.1708(4) Å to 3.2496(6) Å. The structure features a Te–Te interaction 2.7631(8) Å in length, which is typical for a Te–Te single bond. Thus α‐ThTe₃ may be charge balanced and formulated as Th⁴⁺Te^2–Te₂^2–.     

Crystal structure of poly(dithiotriethylene adipate)

The crystal structure of poly(dithiotriethylene adipate) has been determined through the best fitting of calculated and experimental X‐ray diffraction powder profiles. A triclinic cell was found with dimensions a = 4.942 (7) Å, b = 4.702 (2) Å, c = 20.56 (2) Å, α = 88.9 (2)°, β = 61.0 (1)°, γ = 67.8 (1)°, P‐1 space group, and one chain in the unit cell. A full extended trans conformation of the chain fitted satisfactory the experimental data, yielding to a discrepancy factor R_p = 0.073. A comparison between the crystal structures of poly(dithiotriethylene adipate) and poly (thiodiethylene adipate) is proposed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2677–2682, 2005     

Bioengineering functional copolymers. III. Synthesis of biocompatible poly[(N‐isopropylacrylamide‐co‐maleic anhydride)‐g‐poly(ethylene oxide)]/poly(ethylene imine) macrocomplexes and their thermostabilization effect on the activity of the enzyme penicillin G acylase

Stimuli‐responsive poly[(N‐isopropylacrylamide‐co‐maleic anhydride)‐g‐poly(ethylene oxide)]/poly(ethylene imine) macrobranched macrocomplexes were synthesized by (1) the radical copolymerization of N‐isopropylacrylamide and maleic anhydride with α,α′‐azobisisobutyronitrile as an initiator in 1,4‐dioxane at 65 °C under a nitrogen atmosphere, (2) the polyesterification (grafting) of prepared poly(N‐isopropylacrylamide‐co‐maleic anhydride) containing less than 20 mol % anhydride units with α‐hydroxy‐ω‐methoxy‐poly(ethylene oxide)s having different number‐average molecular weights (M_n = 4000, 10,000, or 20,000), and (3) the incorporation of macrobranched copolymers with poly(ethylene imine) (M_n = 60,000). The composition and structure of the synthesized copolymer systems were determined by Fourier transform infrared, ¹H and ¹³C NMR spectroscopy, and chemical and elemental analyses. The important properties of the copolymer systems (e.g., the viscosity, thermal and pH sensitivities, and lower critical solution temperature behavior) changed with increases in the molecular weight, composition, and length of the macrobranched hydrophobic domains. These copolymers with reactive anhydride and carboxylic groups were used for the stabilization of penicillin G acylase (PGA). The conjugation of the enzyme with the copolymers significantly increased the thermal stability of PGA (three times at 45 °C and two times at 65 °C). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1580–1593, 2003     

Kristallzucht und Strukturverfeinerung von Quecksilber(II)‐amidchlorid – HgClNH2

Crystal Growth and Refinement of the Crystal Structure of Mercury(II) Amide Chloride – HgClNH₂ Single crystals were prepared by recrystallization of HgClNH₂ from aqueous NH₃/NH₄⁺ solution at 160 °C. They were used for a single‐crystal X‐ray structure redetermination. The previously reported [W. N. Lipscomb, Acta. Crystallogr. 1951 , 4, 266.] structural topology determined on basis of X‐ray powder diffraction data is now confirmed. However, a higher symmetry is found: Space group type Pmma (instead of Pmm2), a = 6.709(1) Å, b = 4.351(1) Å, c = 5.154(1) Å, Z = 2. The crystal structure contains zig‐zag‐chains [Hg(NH₂)_2/2]⁺. Four Cl atoms complete the coordination sphere of Hg to a distorted octahedron. These share common faces and edges in layers [HgCl_4/4(NH₂)_2/2]. These layers are connected via hydrogen bonds N–H…Cl.