Wieslaw Lasocha

Synthesis and structural investigation of 6,13-dichloroacylated tetraaza[14]annulene nickel(II) complexes

Abstract The reactions of the tetraaza[14]annulene Ni(II) complex (1) with chloroacyl chlorides afforded the 6,13-dichloroacylated complexes 2 and 3. By a demetallation procedure the metal free ligand of 2 was obtained. The crystal structure of the adduct 2·C6H5CH3 has been determined by the single-crystal X-ray diffraction method.

Fine refinement of solid state structure of racemic form of phospho-tyrosine employing NMR Crystallography approach

We present step by step facets important in NMR Crystallography strategy employing O-phospho-dl-tyrosine as model sample. The significance of three major techniques being components of this approach: solid state NMR (SS NMR), X-ray diffraction of powdered sample (PXRD) and theoretical calculations (Gauge Invariant Projector Augmented Wave; GIPAW) is discussed. Each experimental technique provides different set of structural constraints. From the PXRD measurement the size of the unit cell, space group and roughly refined molecular structure are established. SS NMR provides information about content of crystallographic asymmetric unit, local geometry, molecular motion in the crystal lattice and hydrogen bonding pattern. GIPAW calculations are employed for validation of quality of elucidation and fine refinement of structure. Crystal and molecular structure of O-phospho-dl-tyrosine solved by NMR Crystallography is deposited at Cambridge Crystallographic Data Center under number CCDC 1005924.

SELENOMALTOL -SYNTHESIS, SPECTROSCOPY AND THEORETICAL CALCULATIONS

- Synthesis and structure of the seleno derivative of maltol (selenomaltol) is described. Structural and energetical properties of possible selenomaltol structures have been calculated at the B1LYP/6-311++G(d,p) level. The lowest energies are always predicted for the keto-enol tautomer. To verify obtained results several standard experimental methods, namely: elemental analysis, mass spectrometry, infrared and NMR spectroscopies and X-ray crystallography have been used. Investigation of IR and NMR spectra clearly indicate that the oxygen atom of exocyclic keto group on maltol was replaced by selenium. Experimental crystallographic results support this conclusion.

X-ray powder diffraction investigation of green earth pigments

Laboratory X-ray powder diffraction was used to investigate mineralogical compositions of green pigments labeled by suppliers as “green earths.” It was found that glauconite and celadonite—minerals historically considered as the main ingredient of this pigment—were present only in Bohemian green earth, green earth from Thuringen (glauconite), and Bavarian green earth (celadonite). Other investigated pigments consist of mineralogical-component minerals with added synthetic organic colorants. The obtained results may be useful for scientists, restorers, and artists in proper choices of the pigments they use in their works.

New binucleating Schiff base NiII and CuII complexes—synthesis, spectral properties and crystal structure

Abstract Four novel oxamide type ligands have been obtained by reaction of “half units” 1–4 and oxalyl chloride. They were used to prepare corresponding related binuclear CuII and NiII complexes. The products obtained were characterized by elemental analysis, MS, IR and NMR spectra and X-ray single crystal analysis.

X-ray powder diffraction structural studies of lithol red pigments

Lithol reds belong to the group of azo pigments which were popular artists’ pigments at the beginning of the twentieth century. Under the name lithol red pigment, one can find a family of sodium (PR 49), barium (PR 49:1), calcium (PR 49:2), and strontium (PR 49:3) salts of diazotised Tobias (2-naphthylamine-1-sulphonic) acid coupled with 2-naphthol. The colour of the pigment ranges from yellowish red (sodium salt) to bluish red (strontium salt), depending on the metal cation. The main drawback of lithol red is its very poor lightfastness, which has profound implications for its artistic use (e.g. Mark Rothko’s Seagram and Harvard Murals) [1].

On the grounds of icons from National Museum in Krakow

Among various types of cultural heritage objects, icons belong to the most interesting and not too often investigated group. Similarly to the investigations of easel paintings, only tiny amounts of samples taken from icons can be available for scientific studies. In the literature very few technical papers on icons can be found, so there is a shortage of information for comparative studies in this subject.

Polymolybdates and Peroxomolybdates: Candidates for Catalysts in Industry

Progress in catalysis depends on a full understanding of the role of the individual components of catalytic materials. Crystallographic studies offer insight into crystal structure, which enables the rational selection of reagents and better planning of the syntheses of novel materials and catalysts. In this paper we have studied the process of the oxidation of hydrocarbons and terpenes with oxygen from the air. Processes of this type are important in so-called “Green Chemistry.” Their application can reduce the amount of environmentally harmful pollutants formed through conventional oxidation based on nitric acid. While investigating the catalytic activity of peroxoand polymolybdates(VI) in the oxidation of cycloalkanes, we found a number of intriguing relationships. To explain them, we designed, synthesized and solved the crystal structures of the family of new peroxomolybdates, tri-, octaand pentamolybdates of amines. Both single crystal and polycrystalline materials were investigated using laboratory as well as synchrotron radiation. Next, we used these compounds as catalysts in certain interesting for industry processes (e.g. oxidation of cyclic hydrocarbons). We have concluded that: − The activity of peroxocompounds is enhanced by the coordination of N-oxide groups to Mo atoms. − The activity of anionic polymeric trimolybdates decreases when ‘surface of polymeric fiber’ is blocked by cations. − The anionic layers of pentamolybdates are separated by cations of variable size. The distance between layers plays a role similar to that of the size of channels in zeolites. Summary: Peroxomolybdates and polyoxomolybdates show great prospects for new industrial uses (besides cracking and desulfurization).

Octamolybdates – promising materials for industry and medicine

desirable to attach organic functionalities covalently to the surface of polyoxoanions. As part of a broad program centered on the functionalization of polyoxometalates, we have been interested in the derivatisation of Lindqvist type polyoxoanions with organosilyl moieties. The condensed polyoxometalate (nBu4N)4[(TaW5O18)2O] which is synthesized by reacting [TaW5O19] with BuSnCl3, crystallises in the orthorhombic system, space group Pbnb with lattice parameters a = 15.7981(14), b = 17.939(3), c = 35.216(6)Å, V= 9980 Å and Z = 4. The crystallographic study of(nBu4N)4[(TaW5O18)2O] shows that the dimer is composed from two polyoxoanions fragments linked by linear Ta-O-Ta bridge. Such a linkage readily reacts with organosilyl (Lewis electrophilic reagents), such as RR’ 2SiOH (R = R’ = Et, iPr, OtBu, Ph; R = tBu, R’ = Me) to yield monomeric plenary Lindqvist derivatives (nBu4N)2[W5O18Ta(O)SiR’R2]. These derivatives are characterized in the solid state by IR and in solution by multinuclear NMR (C, Si, W). The crystallographic study of (nBu4N)2[(W5O18Ta(O)SiPh3)]indicates that {SiPh3} is grafted on the surface of the polyanion through the terminal Ot-Ta oxygen atom.

X-ray powder diffraction investigations of phenol derivatives

The X-ray powder diffraction patterns of three phenol derivatives—2-chlorophenol, 2,6-dichloro-4-nitrophenol, and 2,6-dichloro-phenoloindophenol tetrahydrate—were collected and the lattice parameters of these compounds were determined. The measurement for 2-chlorophenol was carried out at 250 K in a low-temperature chamber; this compound crystallizes in hexagonal system with a=1.59602(8) nm, c=0.59761(7) nm, space group P6 or P6 3 /m. Investigated at room temperature, 2,6-dichloro-4-nitrophenol and 2,6-dichloro-phenoloindophenol tetrahydrate crystallize in the triclinic system with the unit cell parameters refined to a=0.8169(2) nm, b=1.6637(6) nm, c=0.7440(1) nm, α=96.6(3)°, β=116.19(2)°, γ=78.68°, and space group P-1(2), and a=0.7792(3) nm, b=1.2795(4) nm, c=0.7256(3) nm, α=91.17(5)°, β=96.93(4)°, γ=85.41(3)°, and space group P-1(2), respectively.