Band 80, Heft 5

In work of the mid-19th century, it has been shown that the physical properties of cellulose and related materials are changed drastically upon their immersion in “aqueous zinc chloride solutions”, followed by washing to remove the salt and drying the resulting fabric, whose chemical composition did not change, but had a different structure. It was soon recognized that the process worked only at very high concentrations of zinc chloride, but it was only in the last decade that the “solutions” were finally identified to be in fact ionic liquids with an optimum performance for the trihydrate ZnCl 2 (H 2 O) 3 which is built up of [Zn(H 2 O) 6 ] 2+ cations and [ZnCl 4 ] 2− anions, both in the solid state and in the melt, and which has a melting point of 6.5 °C. The production of Vulcanised Fibre has long been an important industrial process based on the treatment of cellulose with zinc chloride following established protocols. In the present paper the consequences of the ionic liquid concept for the underlying processes are discussed on the molecular level, proposing a sequence of reversible reactions, which allow the reorganization of the cellulose structure under surprisingly mild conditions. Due to its advantageous properties as a biomaterial, the all-cellulose, self-reinforced composite is currently being rediscovered for newly considered applications within several industries such as the construction industry as one example. Its strength, lightweight and plasticity present unique opportunities for architectural as well as structural applications.

Although the first hydroxy substituted triphenlymethane dyes were prepared at the beginning of the 19th century, they found, other than their amino-substituted derivatives, surprisingly less scientific and practical interest hitherto. Only triphenylmehane dyes derived from salicylic acid and some of its derivatives received practical importance as Mordant Dyes. To close this gap, we have prepared and characterized few hydroxy-substituted triphenlymethane dyes by starting from appropriate phenols and using different synthetic routes. The structure of the hydroxy-substituted triphenlymethane dyes prepared are confirmed by means of mass spectra and 1 H NMR spectra. Their colors vary with the acidity of the solutions and is originated by a stepwise protonation of the oxygen moieties at their triphenylmethane cores.

Tetragonal Ga 5 Na 1– x B 12 O 26– x (OH) x ( x  = 0.12) was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 12.4 GPa/1,280 °C. The compound crystallizes in the space group I 4 1 / acd (no. 142) with lattice parameters of a =  11.0884(6) and c =  21.730(2) Å. The crystal structure has been determined by single-crystal X-ray diffraction and revealed an occupation with Na + of about 88 % of the cuboctahedral cavity formed by condensed [BO 4 ] tetrahedra in the related homeotypic structure of Ga 5 B 12 O 25 (OH). The structure refinement is additionally supported by infrared spectroscopy (IR) and energy-dispersive X-ray (EDX) investigations.

We report on the synthesis an structural characterization of 16 new tetrelides RE -(Rh,Ir)-(Si,Ge), the phosphides Sm 4 Rh 13 P 9 , Sm 4 Ir 13 P 9 , Gd 4 Ir 13 P 9 and Yb 4 Ir 13 P 9 and the arsenide Eu 4 Ir 13 As 9 , which crystallize with the orthorhombic Ho 4 Ir 13 Ge 9 type. The structure of Gd 4 Ir 13 Ge 9 was refined from single-crystal X-ray diffractometer data: space group Pmmn , a = 397.76(2), b = 1,120.97(6), c = 1,935.52(10) pm, w R 2 = 0.0683, 2,537 F 2 values and 90 refined variables. The iridium and germanium atoms in Gd 4 Ir 13 Ge 9 build up a three-dimensional [Ir 13 Ge 9 ] polyanionic network which is stabilized by Ir–Ge (240–260 pm) and Ir–Ir (274–294 pm) bonding interactions. The three crystallographically independent gadolinium sites fill large channels within the [Ir 13 Ge 9 ] polyanionic network. They have hexagonal prismatic coordination with additional atoms capping the rectangular faces. The structural chemistry of the Ho 4 Ir 13 Ge 9 type is compared to the hexagonal phases RE 4 Co 13 (Si,P) 9 ( RE = Sm, Gd–Er), U 4 Fe 13 P 9 and the auride Sr 4 In 13 Au 9 . Magnetic susceptibility data of Tb 4 Ir 13 Ge 9 show Curie-Weiss behavior with an experimental magnetic moment of 10.4(1) µ B  Tb atom −1 . Tb 4 Ir 13 Ge 9 is ordered antiferromagnetically at T N = 4.7(1) K and undergoes two successive metamagnetic steps.

The compound described in a previous report [Ru 2 (CO) 4 ( µ -H)( µ -P t Bu 2 )( µ -dppa)] [dppa = bis(diphenylphosphanyl)amine, 1 ] crystallizes from acetone/ethanol as a solvate stabilized in the solid by an intermolecular hydrogen bonding between the NH function of the dppa ligand and an ethanol molecule (Mayer, T.; Böttcher, H.-C. Polyhedron 2013 , 50 , 507−511). Surprisingly, by the use of n -pentane as the antisolvent during crystal growth for X-ray diffraction purposes an isomer of compound 1 was obtained. A deprotonation of the NH function within the dppa ligand in 1 occurred accompanied by an intramolecular oxidative addition of the proton towards the diruthenium core resulting in the novel compound [Ru 2 (CO) 4 ( µ -H) 2 ( µ -P t Bu 2 )( µ -dppa−H)] ( 2 ), [(dppa−H) = [dppa−H + ] −  = Ph 2 PNPPh 2 − , bis(diphenylphosphanyl)amide]. By dissolution of solid 2 in polar solvents a transformation back to 1 (reductive elimination) occurred as clearly indicated in solution by the NMR data for complex 1 . Therefore, compound 2 has been characterized only in the solid state by elemental analysis, IR spectroscopy, mass spectrometry and single-crystal X-ray diffraction.

Anthracene- d - and l -phenylalanine compounds ( d - 1 , l - 1 ) were obtained in high yields by the condensation reactions of 9-anthraldehyde with d - and l -phenylalanine and reduction with sodium borohydride. Both compounds d - 1 and l - 1 show luminescence in solution and solid states, exhibiting dual-state emission property. Solid samples of  d - 1 and l - 1 exhibit mechanochromic luminescence enhancement with grinding. In respect of chiroptical property, d - 1 and l - 1 display mirror-image circular dichroism spectra in solution, and solid samples in KBr pellets exhibit circularly polarized luminescence with a dissymmetry factor of −1.4 × 10 −4 /6.0 × 10 −4 , respectively. The two compounds can differentiate enantiomers of free amino acids such as phenylalanine, lysine, glutamic acid and folic acid, in aqueous phase.

The bromination of the electron-deficient 2,2′-dicyano-6,6′-difluorobiphenyl with elemental bromine in HNO 3 /H 2 SO 4 produces mainly 3,3′-dibromobiphenyl ( 1 ) and 3-nitro-3′-bromobiphenyl ( 2 ) in a total yield of 70 %. Compound 1 reacts with carbazole to yield the 3,3′-dibromo-6,6′-di(9 H -carbazol-9-yl)-[1,1′-biphenyl]-2,2′-dicarbonitrile ( 6 ). The structures of the products have been studied by spectroscopic methods and X-ray diffraction, as well as DFT calculations. The optical properties of some of the compounds have been investigated by UV/Vis or fluorescene spectrocopy, which show that compound 6 has Thermally Activated Delayed Fluorescence (TADF) and Aggregation-Induced Emission (AIE) properties (i.e. Aggregation-Induced Delayed Fluorescence, AIDF). These biphenyl products may find potential applications in the field of organic photofunctional materials.