Methanol from CO2 by organo-cocatalysis: CO2 capture and hydrogenation in one process step.

Carbon dioxide chemically bound to alcohol-amines was hydrogenated to methanol under retrieval of these industrially used CO2 capturing reagents. The energetics of the process can be seen as a partial cancellation of the exothermic heat of reaction of the hydrogenation with the endothermic one of the CO2 release from the capturing reagent. The process provides a means to significantly improve the energy efficiency of CO2 to methanol conversions.

5,5'-(Ethyne-1,2-di-yl)diisophthalic acid dimethyl sulfoxide tetra-solvate.

In the title compound, C18H10O8·4C2H6OS, the mid-point of the triple bond of the main mol-ecule is located on a special position, i.e. about an inversion center. The carboxyl groups are twisted slightly out of the planes of the aromatic rings to which they are attached, making dihedral angles of 24.89 (1) and 7.40 (2)°. The cystal packing features strong O-H⋯O hydrogen bonds, weaker C-H⋯O inter-actions and O⋯S contacts [3.0981 (11) Å] and displays channel-like voids extending along the a-axis direction which contain the dimethyl sulfoxide solvent mol-ecules.

High-separation performance of chromatographic capillaries coated with MOF-5 by the controlled SBU approach.

Recently developed MOF surface-coating techniques, the controlled SBU approach (CSA) for the generation of MOF-5, and the use of self-assembled monolayers have been combined to generate a wall-bonded, crosslinked stationary phase for gas chromatographic capillary columns displaying excellent performance in the separation of natural gas components. The chromatographic performance of this new type of column has been compared to the state-of-the-art solution for this separation problem, namely a coated silica column of the porous layer open tubular (PLOT) type. Chromatographic parameters such as separation, resolution, and tailing factors, as well as plate numbers and heights in the case of isothermal operation, have been determined. Kinetic and thermodynamic parameters characterizing the analyte-stationary phase interaction have been determined for various C1-C4 analytes.

Poly[(µ4-2,5-dimethoxybenzene-1,4-dicarboxylato)manganese(II)] and its zinc(II) analogue: three-dimensional coordination polymers containing unusually coordinated metal centres.

The title compounds, [Mn(C(10)H(8)O(6))](n) and [Zn(C(10)H(8)O(6))](n), are isomorphous coordination polymers prepared from 2,5-dimethoxyterephthalic acid (H(2)dmt) and the respective metal(II) salts. Both complexes form three-dimensional metal-organic frameworks with each M(II) centre bridged by four 2,5-dimethoxyterephthalate (dmt(2-)) anions, resulting in the same type of network topology. The asymmetric unit consists of one M(II) cation on a twofold axis and one half of a dmt(2-) anion (located on a centre of inversion). In the crystal structure, the M(II) centres are coordinated in a rather unusual way, as there is a distorted tetrahedral inner coordination sphere formed by four carboxylate O atoms of four different dmt(2-) anions, and an additional outer coordination sphere formed by two methoxy and two carboxylate O atoms, with each of the O atoms belonging to one of the four different dmt(2-) anions forming the inner coordination sphere. Consideration of both coordination spheres results in a super-dodecahedral coordination geometry for the M(II) centres. Besides the numerous M(II)···O interactions, both structures are further stabilized by weak C-H···O contacts.

Little change but great effect: varying supramolecular interactions in 2,5-dimethoxyterephthalic acid and 2,5-diethoxyterephthalic acid.

The title terephthalic acid derivatives, namely 2,5-dimethoxyterephthalic acid, C(10)H(10)O(6), (I), and 2,5-diethoxyterephthalic acid, C(12)H(14)O(6), (II), exhibit nearly planar molecular structures, with maximum deviations from the least-squares planes calculated for all non-H atoms of 0.0418 (6) and 0.0902 (10) Å for (I) and (II), respectively. The molecules of both title compounds contain an inversion centre and thus the asymmetric unit of both crystal structures consists of only half a molecule. It is a remarkable fact that a comparatively small change in the substitution of the terephthalic acid [dimethoxy in (I) versus diethoxy in (II)] causes major differences in the dominating supramolecular interactions. While in (II) the packing structure is stabilized by typical intermolecular hydrogen-bonded carboxylic acid dimer interactions, the carboxyl group in (I) forms an unusual intramolecular hydrogen bond with the O atom of the neighbouring methoxy group.

Main-group and transition-element IRMOF homologues.

A simple two-component procedure was developed to synthesize not only classical zinc-based IRMOFs represented by MOF-5 but also the cobalt and beryllium homologues of this most prominent MOF. The procedure is the first manifestation of mirroring the IRMOF series with other metal centers taken from main-group as well as transition-metal elements. Because of the existence of many suitable precursors, the procedure promises the generation of a large number of IRMOF homologues. Since the IRMOF series together with the MIL series is the MOF group with the largest number of representatives, the possibility of choosing the metal centers of the secondary building units from an extended set will tremendously expand the number of obtainable structures in a predictive, crystal-engineering-type way. Use of metal centers other than zinc will allow the addition of new features to the existing IRMOF structures, such as magnetic properties in the example of cobalt.

Degradation of selected (bio-)surfactants by bacterial cultures monitored by calorimetric methods.

The subjects of the article are investigations concerning the ability of both Rhodococcus opacus 1CP and mixed bacterial cultures to use selected surfactants as sole carbon and energy source. In a comparative manner the biosurfactants rhamnolipid, sophorolipid and trehalose tetraester, and the synthetic surfactant Tween 80 were examined. Particular emphasis was put on a combinatorial approach to determine quantitatively the degree of surfactant degradation by applying calorimetry, thermodynamic calculations and mass spectrometry, HPLC as well as determination of biomass. The pure bacterial strain R. opacus was only able to metabolize a part of the synthetic surfactant Tween 80, whereas the mixed bacterial cultures degraded all of the applied surfactants. Exclusive for the biosurfactant rhamnolipid a complete microbial degradation could be demonstrated. In the case of the other surfactants only primary degradation was observed.

Hexakis(N,N-dimethyl-formamide-κO)cobalt(II) bis-(perchlorate).

The asymmetric unit of the title complex, [Co(DMF)(6)](ClO(4))(2) (DMF = N,N-dimethyl-formamide, C(3)H(7)NO), consists of two half complex cations with the Co(2+) metal ions located on centers of inversion and two perchlorate anions. In the crystal packing, each Co(2+) ion is coordinated by six mol-ecules of DMF in a slightly distorted octa-hedral geometry. The crystal structure is mainly stabilized by coordinative, ionic and C-H⋯O hydrogen-bonding inter-actions.

Calorimetric investigations into the starvation response of Pseudomonas putida growing on phenol and glucose.

AIMS: To investigate the stress response during nutrient deprivation, particularly with regard to the application of phenol as growth substrate of Pseudomonas putida with calorimetric measurements as a new method. METHODS AND RESULTS: The online and noninvasive measurement of the thermal power P(0) permits the detection of microbial activity during the starvation period. While the results of the investigations with phenol reveal a significant loss of activity as a function of the temporal nutrient dosage, only a small loss of activity was detected by using glucose. Microbiological methods (colony forming units (CFU) and activity of catechol-2,3-dioxygenase) showed a loss of the enzyme activity at a constant CFU. The introduction of a simple decay parameter k(D) in the kinetic description of the growth process on phenol was sufficient for the successful kinetic modelling. CONCLUSIONS: The combination of calorimetric measurements and the determination of the enzymatic activity proved the loss of activity of Ps. putida during the deprivation of the substrate phenol. SIGNIFICANCE AND IMPACT OF THE STUDY: The initial heat power (P(0)) proves to be a suitable parameter for the characterization of the physiological state of the culture and can be used for the regulation of nutrient supply in biotechnological process development.

Proton and water activity-controlled structure formation in zinc carboxylate-based metal organic frameworks.

The contributions of terephthalic acid and Zn(2+)-coordinated water in N,N-diethylformamide (DEF) to the overall proton activity in the synthesis of MOF-5 (Zn4O(BDC)3, BDC = 1,4-benzenedicarboxylate) were quantitatively determined by combined electrochemical and UV-vis spectroscopic measurements. Structural transformations of zinc carboxylate-based metal organic frameworks due to their exposure to environments with variable water concentrations and the chemical means necessary to revert these transitions have been investigated. It was found that the water-induced structural transition of MOF-5 to the hydroxide structure Zn3(OH)2(BDC)2 x 2 DEF (MOF-69c) can be reverted by a thermal treatment of the obtained compound and its subsequent exposure to anhydrous DEF. MOF-5 syntheses from simple carboxylates as well as a water-free synthesis based on nitrate decomposition are presented. The latter demonstrates that nitrate can serve as the sole source for the oxide ion in MOF-5.

Large pores generated by the combination of different inorganic units in a zinc hydroxide ethynylene diisophthalate MOF.

An ethynylene diisophthalic acid linker molecule was synthesized and used to form a zinc carboxylate-based metal organic framework (MOF) with very large pores and unit cell volume resulting from the unusual combination of structurally different inorganic units forming the secondary building blocks (SBUs). The structure is the first zinc hydroxide carboxylate structure where the inorganic units do not form layers or ribbons but isolated islands. The structure forms true pores with a significantly narrowed pore entry similar to zeolites. The pores are, thus, not created simply by intersecting channels as in most other MOF structures. Although the pore shape is highly asymmetric the spherical free volume is with 10.8 A still large. The stability of the SBUs in respect to exchange and removal of coordinated solvent molecules is investigated.

Gaseous species as reaction tracers in the solvothermal synthesis of the zinc oxide terephthalate MOF-5.

Gaseous species emitted during the zinc oxide/zinc hydroxide 1,4-benzenedicarboxylate metal organic framework synthesis (MOF-5, MOF-69c) have been used to investigate the reaction scheme that leads to the framework creation. Changes of the gas-phase composition over time indicate that the decomposition of the solvent diethylformamide occurs at least via two competing reaction pathways that can be linked to the reaction's overall water and pH management. From isotope exchange experiments, we deduce that one of the decomposition pathways leads to the removal of water from the reaction mixture, which sets the conditions when the synthesis of an oxide-based (MOF-5) instead of an hydroxide-based MOF (MOF-69c) occurs. A quantitative account of most reactants and byproducts before and after the MOF-5/MOF-69c synthesis is presented. From the investigation of the reaction intermediates and byproducts, we derive a proposal of a basic reaction scheme for the standard synthesis zinc oxide carboxylate MOFs.