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The title mol­ecular salt, C5H12NO+·C4BN4− or (C5H12NO)[B(CN)4], was obtained as single crystals by slow evaporation of a solution of the compound in aceto­nitrile over several weeks. The asymmetric unit contains two (S)-alanine ethyl ester cations and two tetra­cyanidoborate anions, which are linked by N—H...N hydrogen bonds. The compound exhibits a relatively low melting point of 110°C and shows a solid–solid phase transition near room temperature (Ts–s = 29°C) on the basis of DSC measurements.

Four new salts with low melting points of the general formula (EMIm)[NiBr3(L)] (EMIm = 1-ethyl-3-methyl-imidazolium) with L = N-methylimidazole (NMIm), N-methylbenzimidazole (NMBIm), quinoline (quin), and triphenylphosphane (PPh3) were prepared and characterized by means of elemental analysis, IR, NMR, and UV–vis spectroscopy. Magnetic properties were deduced from NMR data using the EVANS method. All four compounds are paramagnetic with magnetic moments close to the spin-only values of the tetrahedrally coordinated Ni(II) ion. Molecular and crystal structures were obtained by single crystal X-ray diffraction investigations. Melting points are determined to have values between 110 °C, (EMIm)[NiBr3(NMIm)] and 168 °C, (EMIm)[NiBr3(PPh3)]. They exceed the maximum temperature required to call them “Ionic Liquids”. Decomposition has been found to occur above 200 °C and to depend largely on the type of organic ligand coordinated to Ni(II).

Four new low melting salts, “Ionic Liquids” consisting of the [CrIII(NCS)4(Phen)]− complex monoanion and imidazolium based cations A, with A = 1-ethyl-3-methylimidazolium (EMIm), 1-butyl-3-methylimidazolium (BMIm), 1,3-dimethyl-2,4,5-triphenylimidazolium (DML), and 1,2,3,4,5-pentamethyl-imidazolium (PMIm), were investigated. Single-crystal X-ray investigations established the structures of the four compounds. (EMIm)[Cr(NCS)4(Phen)] (I): triclinic, $$P\bar 1$$ , a = 8.1382(6), b = 10.4760(8), c = 16.003(1) A, α = 90.330(4)°, β = 94.759(4)°, γ = 107.305(4)°, Z = 2, R 1(F)/wR 2(F 2) = 0.0650/0.1770; (BMIm)[Cr(NCS)4(Phen)] (II): triclinic, $$P\bar 1$$ , a = 8.5545(4), b = 9.8620(4), c = 16.6762(6) A, α = 92.503(2)°, β = 97.517(2)°, γ = 91.249(2)°, Z = 2, R 1(F)/wR 2(F 2) = 0.0393/0.0848; (DML)[Cr(NCS)4(Phen)] · C3H6O (III): triclinic, $$P\bar 1$$ , a = 11.0475(9), b = 13.589(1), c = 14.582(1) A, α = 83.013(4)°, β = 87.116(4)°, γ = 70.333(5)°, Z = 2, R 1(F)/wR 2(F 2) = 0.0407/0.1023; (PMIm)[Cr(NCS)4(Phen)] · C3H6O (IV): orthorhombic, Pbca, a = 17.379(1), b = 16.514(1), c = 22.304(1) A, Z = 8, R 1(F)/wR 2(F 2) = 0.0460/0.1107 (in addition III and IV contain co-crystallized acetone molecules). Each compound was characterized by elemental analysis, NMR, IR, und UV-Vis spectroscopy. Magnetic properties were derived from NMR investigations (EVANS method). All four compounds are paramagnetic with effective magnetic moments of spin-only CrIII. Melting points were obtained from DSC measurements. All melting points are higher than required for “Ionic Liquids”, but nevertheless “low” for molten salts.

A series of eight new 1-alkyl-3-methylimidazolium derived salts with the pseudotetrahedral CoII-based complex anion, [CoIIBr3quin]−, quin = quinoline, and 1-alkyl-3-methylimidazolium cations, AlkMIm, Alk = ethyl, n-butyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, allyl, and propargyl; M = methyl, was synthesized. The melting point of each compound was measured to see if they are designated as metal-containing ionic liquids (magnetic ionic liquids). Each compound was further characterized by elemental analysis, NMR, IR, and UV/vis spectroscopy. From NMR investigations, information about the magnetic behavior was derived using the EVANS method. It has been found that every compound is paramagnetic with effective magnetic moments of spin-only CoII. The solid state structures of the compounds (AlkMIm)[CoIIBr3quin] with Alk = ethyl, n-butyl, n-hexyl, and n-nonyl were established by single-crystal X-ray diffraction techniques with regard to finding correlations between thermal and structural properties: (EMIm)[CoBr3...

A series of 9 new Reineckate salts, A[CrIII(NCS)4(NH3)2] with various large organic cations A = tetraalkylammonium, [R4N]+, R = n-butyl, n-dodecyl; 1-alkyl-3-methylimidazolium, (RMIm)+: R = methyl, ethyl, iso-propyl, n-butyl, and n-hexyl; A = 1,3-dimethyl-2,4,5-triphenylimidazolium and A = 1,2,3,4,5-pentamethylimidazolium was synthesized. The melting point of each compound was measured to see if any belongs to the group of metal-containing Ionic Liquids with low melting points. Each compound was further characterized by elemental analysis, NMR, IR, and UV/Vis spectroscopy. From NMR investigations information about the magnetic behavior was derivedusing the Evans method. It has been found that every compound is paramagnetic with effective magnetic moments of spin-only CrIII. The structures of the Reineckates with A = tetra-n-butyl-ammonium, tetra-n-dodecyl-ammonium, 1-ethyl-3-methylimidazolium, and 1,2,3,4,5-pentamethylimidazolium were determined by single-crystal X-ray diffraction measurements: (nBu4N)[Cr(NCS)4(NH3)2]: monoclinic, C2/c (no. 15), a = 12.0818(8), b = 10.2425(8), c = 24.222(2) A, β = 98.324(3)°, Z = 4, R1(F)/wR2(F2) = 0.0332/0.0871; {(C12H25)4N}[Cr(NCS)4(NH3)2]·0.85H2O: triclinic, P (no. 2), a = 8.4049(1), b = 20.1525(4), c = 20.7908(4) A, α = 67.487(1)°, β = 81.328(1)°, γ = 78.040(1)°, Z = 2, R1(F)/wR2(F2) = 0.0533/0.1343; (EMIm)[Cr(NCS)4(NH3)2]: orthorhombic, Pbcm (no. 57), a = 8.765(2), b = 15.888(3), c = 14.191(3) A, Z = 4, R1(F)/wR2(F2) = 0.0466/0.1271; (PeMIm)[Cr(NCS)4(NH3)2]: monoclinic, P21/n (no. 14), a = 6.0817(2), b =13.9811(5), c = 25.2902(9) A, β = 90.075(2)°, Z = 4, R1(F)/wR2(F2) = 0.0405/0.1111.

The alkylation of 2,4,5-trimethyl-1H-imidazole with 1-bromobutane gives 1,3-dibutyl-2,4,5-trimethyl-imidazolium bromide, (DBTMIm)Br (1), from which the hexafluoridophosphate, (DBTMIm)[PF6] (2), the tetrabromidocobaltate(II), (DBTMIm)2[CoBr4] (3), and the tetrabromidonickelate(II), (DBTMIm)2[NiBr4] (4) were obtained as pure salts by ion exchange, or addition reactions, respectively. Properties of these four salts with the completely alkylated imidazolium cation were investigated with respect to question of their use as Ionic Liquids or Molten Salts. The IR, UV/Vis, and NMR spectra were recorded. Thermal data were derived from DSC (differential scanning calorimetry) measurements. The structures of compounds 2, 3, and 4 were determined by single-crystal X-ray diffraction. Compound 2 crystallizes in the monoclinic space group C2/c (no. 15), a = 15.531(1), b = 8.4749(8), c = 28.181(3) A, β = 103.681(2)°, Z = 8, R1(F)/wR2(F2) = 0.0594/0.1592; Compounds 3 and 4 are isostructural with orthorhombic symmetry, space group Pbcn (no. 60), Z = 4; 3: a = 14.6782(5), b = 15.0768(6), c = 16.1524(6) A, R1(F)/wR2(F2) = 0.0267/0.0620; 4: a = 14.6931(9), b = 15.139(1), c = 16.1508(9) A, R1(F)/wR2(F2) = 0.0296/0.0657. The three structurally characterized salts contain isolated complex anions and DBTMIm cations. 3 and 4 are paramagnetic with effective magnetic moments slightly above those expected for the corresponding spin-only systems.

Two new, large 1,3,5-triazine-based ligands with only N-donor functions were synthesized as well as the Co(II) salt [Co(DHPTBenz)2](Br1.7(OH)0.3) · 4.8H2O (DHPTBenz = 2,4-bis-(2-diphenylmethylene)-hydrazinyl-6-piperidin-1-yl-1,3,5-triazine). Single crystal X-ray structures of the Co(II) complex, DHPTBenz, and 2,4-dichloro-6-(piperidin-1-yl)-1,3,5-triazine (DCPT) have been determined. The last compound was used as starting material for the tridentate DHPTBenz ligand. Spectroscopic data of the ligand and the starting materials are reported. The Co(II) ion in the complex is distorted octahedrally coordinated by six N atoms of two DHPTBenz ligands. One N atom of the triazine ring of each ligand bonds axially with short distances of 1.953(3) A and 1.954(3) A, respectively, whereas two of the hydrazine-N atoms of two ligands form the equatorial plane with an average Co–N bond distance of 2.313 A. The complex cation has a slightly elongated, nanometer-scaled ball shape with the longest diameter of 1.82 nm.

The new Zirconium(IV) coordination compound [Ph4P]2[(ZrCl4Py)2O] (Ph = phenyl, Py = pyridine) was synthesized by dissolving ZrCl4, [Ph4P]Cl and a stoichiometric amount of NaOH/Na mixture in pyridine or pyridine/organic solvent mixtures. The title phase was obtained as colourless crystals. The crystal structure of [Ph4P]2[(ZrCl4Py)2O] was determined. It crystallizes monoclinic, P21/c, Z = 4, a = 13.412(2), b = 13.461(2), c = 16.442(3) A, β = 102.72(1)°. The structure consists of isolated tetraphenylphosphonium cations and [(ZrCl4Py)2O]2− complex anions. The centrosymmetric complex anion contains a linear Zr–O–Zr bridge. Each Zr atom is coordinated by one oxygen dianion, the N atom of one pyridine ring and four chloro ligands in a distorted octahedral geometry. The Raman spectrum of [Ph4P]2[(ZrCl4Py)2O] is also reported. Most of the observed frequencies can be assigned to vibrations of the tetraphenylphosphonium cations and the pyridine rings.

The molecule of the title compound, C5H8O2, a low-melting α,β-unsaturated carboxylic acid, is essentially planar [maximum displacement = 0.0239 (13) Å]. In the crystal, molecules are linked into centrosymmetric dimersviapairs of O—H...O hydrogen bonds.

In order to investigate the potential ionic liquid properties of Reineckate-analogue materials, four new salts, consisting of the heteroleptic [Cr(NCS)(4)(bipy)](-) complex anion and imidazolium-based cations A(+) = 1-ethyl-3-methylimidazolium, 1-n-butyl-3-methylimidazolium, pentamethylimidazolium, and 1,3-dimethyl-2,4,5-triphenylimidazolium, were investigated. Their structures were established by single-crystal X-ray diffraction. The compounds are paramagnetic with effective magnetic moments in the range of those expected by the number of unpaired spins of the chromium(III) ion. All melting points are above 100 °C, which prevents us from calling these compounds "ionic liquids". Nevertheless, they are low for salts of this constitution and may be useful for molten salt reactions. Cyclic voltammetry measurements show no reversible electron-transfer steps.

The crystal structure of the title compound, C6H10O2, an α,β-unsaturated carboxylic acid, displays carboxylic acid inversion dimers linked by pairs of O—H...O hydrogen bonds. The packing is characterized by layers of acid dimers. All the non-H atoms of the (E)-hex-2-enoic acid molecule lie almost in the same plane (r.m.s. deviation for the non-H atoms = 0.018 Å).

The title compound, C6H7N3, has an ethylene group connecting an imidazole ring and a –CN group. These groups are in a staggered conformation. The shortest intermolecular contact is found between the imidazole N atom and a –CH2– group of a neighboring molecule.