Alkali metal halogenides coordination compounds with hexamethylenetetramine

Six coordination compounds: [Li(H₂O)₄]⁺·hmta·Cl^?, [Li(H₂O)₄]⁺·hmta·I^?, [Na(H₂O)₄(hmta)] ²⁺₂ ·2H₂O·2Br^?, [Na(H₂O)₄(hmta)] ²⁺₂ ·2H₂O·2I^?, [K(H₂O)(hmta)I] _n and [Rb(H₂O)(hmta)I] _n , have been synthesized and characterised by IR spectroscopy, thermogravimetry coupled with differential thermal analysis, elemental analysis and X-ray crystallography. Both the sodium compounds are isostructural in a solid state, an isostructurality is also observed between compounds containing potassium and rubidium iodides. The sodium compounds exist as dimers (dinuclear core of the complex ion is created by two sodium cations and two water molecules). The molecules of potassium and rubidium compounds are assembled to the two dimensional hybrid nets. The each potentially multifunctional ligand (the hmta) exists in the outer coordination sphere in lithium compounds, acts in a monodentate mode in sodium compounds and in bidentate-bridging modes in potassium and rubidium compounds. The lithium ions are four coordinated, and the sodium, potassium and rubidium ions are six coordinated. Thermal analyses show that the investigated compounds decompose gradually with the formation of alkali metal halides which, during the further heating, are totally removed or they undergo partial decomposition to oxides.

     

The Synthesis of Zinc(II) and Cadmium(II) 2,4-Dichlorophenoxyacetates in Water–Methanol Environment. Structure and Properties of Polymeric [Zn(2,4-D)2(MeOH)2]n and [Cd(2,4-D)2(H2O)2]n

Abstract  

The zinc(II) and cadmium(II) 2,4-dichlorophenoxyacetate salts were synthesized in mixed water–methanol environment and characterized by elemental analysis, IR spectrometry and thermal analysis coupled with mass spectrometry. The crystal structures were determined by X-ray crystallography (compound 1, [C₁₈H₁₈Cl₄O₈Zn] _n : monoclinic, P2₁/c, a = 19.094, b = 7.378, c = 8.008, α = 90.00, β = 101.134, γ = 90.00, V = 1106.95; compound 2, [C₁₆H₁₄Cl₄O₈Cd] _n : monoclinic, P2₁/c, a = 17.730, b = 7.293, c = 8.060, α = 90.00, β = 95.18, γ = 90.00, V = 1037.9). The structural and some thermal data about the presented cadmium salt were previously reported (Song et al. Acta Crystallogr E 62:m2397, 2006; Kobylecka et al. Thermochim Acta 482:49, 2009).     

The structure and thermal behaviour of sodium and potassium multinuclear compounds with hexamethylenetetramine

Sodium and potassium thiocyanate complex compounds of formulae [Na(hmta)(H₂O)₄]₂²⁺·2SCN⁻ (1) and [K₂(hmta)(SCN)₂] _n (2) have been synthesized and characterised by IR spectroscopy, thermogravimetry coupled with differential thermal analysis, elemental analysis and X-ray crystallography. Each sodium and potassium cation is six co-ordinated, the sodium by one monofunctional hmta molecule, three terminal water molecules and two bridging water molecules, and the potassium by two bridging tetrafunctional hmta molecules and four bridging tetrafunctional thiocyanate ions. The coordination polyhedra of the central atoms can be described as distorted tetragonal bipyramids. The complex cations and anions of (1) are interconnected by multiple intramolecular O(water)—H···N(hmta/NCS) and O(water)—H···S hydrogen bonds to the three dimensional net. In each complex cation the intramolecular O–H···O hydrogen bonds link two terminal water molecules bonded to two metal cations. The compound (2) forms the three dimensional hybrid network in which the classical two-dimensional coordination polymers are linked by inorganic SCN⁻ spacers to the third-dimension. Thermal analyses show that the compounds decompose gradually in three (for 1) and two (for 2) steps with formation of Na₂SO₄ and K₂S as the final products, respectively, for 1 and 2.     

Conformation of Sterically Hindered 4-Methyl-2-oxo-2-trityl-1,3,2-dioxaphosphorinane in the Solid State and the Solution

Abstract  

The cis- and trans-2-methyl-2-oxo-2-trityl-1,3,2-dioxaphosphorinanes were obtained in the Arbuzov reaction of 2-methoxy-4-methyl-1,3,2-dioxaphosphorinane with trityl chloride. The NMR spectra (¹H, ¹³C and ³¹P) in solution indicated that trans isomer exists in the form of two noncongruent molecules and it adopts two different conformations: a halfchair and a sofa, while the cis isomer exists as the mixed half/chair–sofa conformer. The compounds crystallise as a pure chiral forms and as a racemates. The solid state structural studies show that NMR data are consistent with the single crystal X-ray analysis, but the conformation existing in the crystal structure is more complex than it can be supposed on sole NMR determination. Crystal data: cis-isomer chiral form: space group P3₂, a = 8.782, b = 8.782, c = 21.680, α = 90.00, β = 90.00, γ = 120.00, V = 1448.0; cis-isomer racemate: space group Pca2₁, a = 16.773, b = 8.491, c = 27.006, α = 90.00, β = 90.00, γ = 90.00, V = 3846.2; trans-isomer racemate: space group Cc, a = 16.133, b = 8.388, c = 16.158, α = 90.00, β = 117.20, γ = 90.00, V = 1944.8; trans-isomer chiral form: space group P 1, a = 8.397, b = 9.003, c = 14.944, α = 80.76, β = 74.38, γ = 63.31, V = 971.1).     

Determination of polyphenols in Mentha longifolia and M. piperita field-grown and in vitro plant samples using UPLC-TQ-MS

Nine polyphenols in the aerial parts of Mentha longifolia have been separated by chromatographic techniques. Their structures have been confirmed by HPLC/electrospray ionization-MS/MS. The compounds identified included rosmarinic acid, salvianolic acid L, dedihydro-salvianolic acid, luteolin-glucuronide, luteolin-diglucuronide, luteolin-glucopyranosyl-rhamnopyranoside, and eriodictyol-glucopyranosyl-rhamnopyranoside. The extracts of M. longifolia and M. piperita field plants, in vitro plants, callus tissues, and cell suspension cultures were profiled, and their polyphenol composition was compared in different tissues and quantified using ultra-performance column liquid chromatography (UPLC)/triple-quadrupole-MS in the selected-ion recording detection mode. Determination of desired compounds was based on calibration curves obtained for standards, which were previously isolated from M. longifolia aerial parts. The UPLC profiles revealed considerable differences in the synthesis of secondary metabolites among samples coming from field plants, in vitro plants, callus tissues, and cell suspension cultures. Plant tissues coming from field cultivation (for both M. piperita and M. longifolia) contained several phenolic compounds (flavonoids and phenolic acids), whereas plants from in vitro conditions, callus tissues, and suspension cultures contained only a few of them. Rosmarinic acid dominated in all of these samples. These results show that under in vitro conditions, the metabolism of phenolics undergoes a fundamental change.