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Six N-alkylpyridinium salts [CnPy](2)[MCl4] (n = 4 or 12 and M = Co, Cu, Zn) were synthesized, and their structure and thermal properties were studied. The [C4Py](2)[MCl4] compounds are monoclinic and crystallize in the space group P2(1)/n. The crystals of the longer chain analogues [C12Py](2)[MCl4] are triclinic and crystallize in the space group P (1) over bar. Above the melting temperature, all compounds are ionic liquids (ILs). The derivatives with the longer C12 chain exhibit liquid crystallinity and the shorter chain compounds only show a melting transition. Consistent with single-crystal analysis, electron paramagnetic resonance spectroscopy suggests that the [CuCl4](2-) ions in the Cu-based ILs have a distorted tetrahedral geometry.
Six N-alkylpyridinium salts [CnPy](2)[MCl4] (n = 4 or 12 and M = Co, Cu, Zn) were synthesized, and their structure and thermal properties were studied. The [C4Py](2)[MCl4] compounds are monoclinic and crystallize in the space group P2(1)/n. The crystals of the longer chain analogues [C12Py](2)[MCl4] are triclinic and crystallize in the space group P (1) over bar. Above the melting temperature, all compounds are ionic liquids (ILs). The derivatives with the longer C12 chain exhibit liquid crystallinity and the shorter chain compounds only show a melting transition. Consistent with single-crystal analysis, electron paramagnetic resonance spectroscopy suggests that the [CuCl4](2-) ions in the Cu-based ILs have a distorted tetrahedral geometry.
We report on a new series of isoreticular frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate (IFP-14, IFP=imidazolate framework Potsdam) that form one-dimensional, microporous hexagonal channels. Varying R in the 2-substitued linker (R=Me (IFP-1), Cl (IFP-2), Br (IFP-3), Et (IFP-4)) allowed the channel diameter (4.01.7 angstrom), the polarisability and functionality of the channel walls to be tuned. Frameworks IFP-2, IFP-3 and IFP-4 are isostructural to previously reported IFP-1. The structures of IFP-2 and IFP-3 were solved by X-ray crystallographic analyses. The structure of IFP-4 was determined by a combination of PXRD and structure modelling and was confirmed by IR spectroscopy and 1H MAS and 13C CP-MAS NMR spectroscopy. All IFPs showed high thermal stability (345400?degrees C); IFP-1 and IFP-4 were stable in boiling water for 7 d. A detailed porosity analysis was performed on the basis of adsorption measurements by using various gases. The potential of the materials to undergo specific interactions with CO2 was investigated by measuring the isosteric heats of adsorption. The capacity to adsorb CH4 (at 298 K), CO2 (at 298 K) and H2 (at 77 K) at high pressure were also investigated. In situ IR spectroscopy showed that CO2 is physisorbed on IFP-14 under dry conditions and that both CO2 and H2O are physisorbed on IFP-1 under moist conditions.
By varying reaction parameters for the syntheses of the hydrogen-bonded metal-imidazolate frameworks (HIF) HIF-1 and HIF-2 (featuring 14 Zn and 14 Co atoms, respectively) to increase their yields and crystallinity, we found that HIF-1 is generated in two different frameworks, named as HIF-1a and HIF-1b. HIF-1b is isostructural to HIF-2. We determined the gas sorption and magnetic properties of HIF-2. In comparison to HIF-1a (Brunauer-Emmett-Teller (BET) surface area of 471m(2) g(-1)), HIF-2 possesses overall very low gas sorption uptake capacities [BET(CO2) surface area=85m(2) g(-1)]. Variable temperature magnetic susceptibility measurement of HIF-2 showed antiferromagnetic exchange interactions between the cobalt(II) high-spin centres at lower temperature. Theoretical analysis by density functional theory confirmed this finding. The UV/Vis-reflection spectra of HIF-1 (mixture of HIF-1a and b), HIF-2 and HIF-3 (with 14 Cd atoms) were measured and showed a characteristic absorption band centered at 340nm, which was indicative for differences in the imidazolate framework.