Enzymatic Polymerization of Furan-2,5-Dicarboxylic Acid-Based Furanic-Aliphatic Polyamides as Sustainable Alternatives to Polyphthalamides.

Furan-2,5-dicarboxylic acid (FDCA)-based furanic-aliphatic polyamides can be used as promising sustainable alternatives to polyphthalamides (semiaromatic polyamides) and be applied as high performance materials with great commercial interest. In this study, poly(octamethylene furanamide) (PA8F), an analog to poly(octamethylene terephthalamide) (PA8T), is successfully produced via Novozym 435 (N435)-catalyzed polymerization, using a one-stage method in toluene and a temperature-varied two-stage method in diphenyl ether, respectively. The enzymatic polymerization results in PA8F with high weight-average molecular weight (M̅(w)) up to 54000 g/mol.

Enzymatic synthesis of biobased polyesters using 2,5-bis(hydroxymethyl)furan as the building block.

2,5-Bis(hydroxymethyl)furan is a highly valuable biobased rigid diol resembling aromatic monomers in polyester synthesis. In this work, it was enzymatically polymerized with various diacid ethyl esters by Candida antarctica Lipase B (CALB) via a three-stage method. A series of novel biobased furan polyesters with number-average molecular weights (M(n)) around 2000 g/mol were successfully obtained.

On the "tertiary structure" of poly-carbenes; self-assembly of sp3-carbon-based polymers into liquid-crystalline aggregates.

The self-assembly of poly(ethylidene acetate) (st-PEA) into van der Waals-stabilized liquid-crystalline (LC) aggregates is reported. The LC behavior of these materials is unexpected, and unusual for flexible sp(3)-carbon backbone polymers. Although the dense packing of polar ester functionalities along the carbon backbone of st-PEA could perhaps be expected to lead directly to rigid-rod behavior, molecular modeling reveals that individual st-PEA chains are actually highly flexible and should not reveal rigid-rod induced LC behavior.

Enzyme-catalyzed synthesis of unsaturated aliphatic polyesters based on green monomers from renewable resources.

Bio-based commercially available succinate, itaconate and 1,4-butanediol are enzymatically co-polymerized in solution via a two-stage method, using Candida antarctica Lipase B (CALB, in immobilized form as Novozyme® 435) as the biocatalyst. The chemical structures of the obtained products, poly(butylene succinate) (PBS) and poly(butylene succinate-co-itaconate) (PBSI), are confirmed by 1H- and 13C-NMR. The effects of the reaction conditions on the CALB-catalyzed synthesis of PBSI are fully investigated, and the optimal polymerization conditions are obtained.

Light-Induced Bistability in Iron(III) Spin-Transition Compounds of 5 X-Salicylaldehyde Thiosemicarbazone (X=H, Cl, Br).

The iron(III) spin-crossover compounds [Fe(Hthsa)(thsa)]⋅H O (1), [Fe(Hth5Clsa)(th5Clsa) ]⋅H O (2), and [Fe(Hth5Brsa)(th5Brsa) ]⋅H O (3) (H thsa=salicylaldehyde thiosemicarbazone, H th5Clsa=5-chlorosalicylaldehyde thiosemicarbazone, and H th5Brsa=5-bromosalicylaldehyde thiosemicarbazone) have been synthesized and their spin-transition properties investigated by magnetic susceptibility, Mössbauer spectroscopy, and differential scanning calorimetry measurements. The three compounds exhibit an abrupt spin transition with a thermal hysteresis effect. The more polarizable the substituent on the salicylaldehyde moiety, the more complete is the transition at room temperature with an increased degree of cooperativity.

4-(4-Ethyl-phenyl-diazen-yl)phenol.

The crystal structure of the title compound, C(14)H(14)N(2)O, determined at 100 K, shows that the mol-ecules are not planar in the solid state, in contrast to other diazene (azobenzene) derivatives. The dihedral angle between the planes of the two aromatic rings is 42.32 (7)°.

Study of neutral Fe(III) complexes of pyridoxal-N-substituted thiosemicarbazone with desolvation-induced spin-state transformation above room temperature.

The preparation and characterization of two new neutral ferric complexes with desolvation-induced discontinuous spin-state transformation above room temperature are reported. The compounds, [Fe(Hthpy)(thpy)].CH3OH.

Two new polymorphs of diphenyl(4-pyridyl)methyl methacrylate.

The title compound (D4PyMA), C(22)H(19)NO(2), exhibits polymorphism after crystallization by slow evaporation from a binary mixture of chloroform and hexane. Long needle-like crystals have an orthorhombic structure (space group Fdd2), with one molecule in the asymmetric unit, while small tablet-like crystals exhibit a monoclinic crystal structure (space group P2(1)/n), in which two independent but chemically identical molecules comprise the asymmetric unit. The bond lengths and angles are normal, while the torsion angles around the -C-O- bond linking the diphenyl(4-pyridyl)methyl and methacrylate groups show the flexibility of the molecule by way of packing effects.