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Assembly of Protonated Tetramethylpyrazine (TMP) in Triiodide. Vibrational Spectra and DFT Simulations

Sobczyk L., Bator G., Sawka-Dobrowolska W., Nowicka-Scheibe J., Grech E., Pawlukojć A.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 5

957-963

EN

In the complex of tetramethylpyrazine (TMP) with HI3 two protonated molecules of TMP form the assembly of composition (TMP×H+)2TMP(I3 - )2. The X-ray structure, determined at 100 K, shows the +N-H×××N hydrogen bonds markedly shorter than those found previously [13] at room temperature (2.828 ni s. 2.894 A). The DFT calculations for isolated cation yield the value of 3.038 capital A, ring that reflects the soft ness of the hydroen bond potential. The calculations of vibrational frequencies for crystalline state reflect very well the IR spectra. This relates particularly to the ni (NH+) mode. A remark able discrepancy is observed when calculations are performed for isolated assemblies.

2

Structure and Vibrational Spectra of the 1:1 Squaric Acid (H2SQ) – Tetramethylpyrazine (TMP) Adduct

Nowicka-Scheibe J., Grech E., Sawka-Dobrowolska W., Bator G., Sobczyk L.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 5-6

643-652

EN

The crystal structure of the title complex was determined at 100 K by X-ray diffraction. It consists of double ionized dimeric (HSQ)2 2 species and protoned TMPH+ cations. Strong charge assisted (OHO)– and (NHO)+ hydrogen bonds are the main factor of crystal packing. A wealth of unconventional C–HO and C–HN relatively short bridges should be emphasized. Particularly important are the latter ones binding two adjacent TMPH+ cations. The structure is well manifested in the IR and Raman spectra, particularly in the region of (OH) and (NH) as well as of (C=O) frequencies. The complexation of TMPleads to a marked change in the low and high frequency vibrations of the methyl groups. An anomaly on the DSC runs has been found at 163/175 K (cooling/ heating) which can be assigned to the freezing of the methyl group rotations. No change of the crystal symmetry is observed at this temperature.

3

Magnetic ordering processes in manganese(II) di(hydrogen malonate) dihydrate complex studied by ESR spectroscopy

Marczyński S., Typek J., Grech E., Kołodziej B.

Materials Science Poland

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2006

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Vol. 24, No. 4

1139--1144

EN

A new manganese complex of malonic acid CH2(COOH) 2źMnCO3źH2O was synthesized. Temperature dependence of the electron spin resonance (ESR) spectrum of Mn(II) was investigated in the 4.2-295 K. temperature range. The obtained ESR spectra were successfully fitted by using a Lorentzian-shape function. The fitting revealed existence of about 2% of a spurious phase of the manganese(II) complex. Strong magnetic interactions have been observed in the investigated temperature range with expected magnetic phase transition at TN approximately equals 2.5 K. The integrated intensity, linewidth and resonance field of the ESR spectrum have shown that the spin dynamical fluctuations essentially influence the magnetic system. An anomalous behaviour of the ESR resonance field parameter has been observed below 100 K. and with decreasing temperature the resonance field shifted to higher magnetic fields.

4

Electron spin resonance study of copper(II) hydrogenmalonate dihydrate complex

Marczyński S., Typek J., Guskos N., Grech E., Kołodziej B.

Materials Science Poland

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2006

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Vol. 24, No. 4

1077--1085

EN

Copper(II) hydrogenmalonate dihydrate complex has been studied by using the electron spin resonance (ESR) method. Numerically deconvoluted ESR spectra of Cu(II) ions have been investigated at 4.2-295 K temperature range. The powder ESR spectrum has been described by three g-factors and additionally 1.5% of the existing spurious phases of a copper(II) complex has been revealed. The temperature dependence of the integrated ESR intensity has shown a Curic-Weiss type behaviour, consisting of two terms with different Curie-Weiss temperatures. The observed ferromagnetic interactions suggest the presence of two different paramagnetic species. It is proposed that the [Cu(H2O) 4][Cu(mal)2(H2O)2] copper(II) dimer complex is responsible for the low-temperature (T less than or equal 50 K) behaviour of the investigated sample.

5

On a New Unexpected Benzoxazino-Benzoxazine Derivative

Nowicka-Scheibe J., Sośnicki J. G., Grech E., Głowiak T., Sobczyk L.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 11

1419-1426

EN

The reaction between 2-amino-5-nitrophenol and 1,2-cyclohexanedione in ethanol leads to formation, in addition to corresponding propellane, of 3. The X-ray diffraction, NMR and IR studies allowed to solve the structure of molecules. It has been shown that planar nitrobenzoxazine groups are oriented to each other perpendicularly with a chair conformation of the cyclohexyl unit. The possible mechanism of reaction leading to 3 is discussed.

6

Dimerization of 1,8-Diaminonaphthalene. DFT Theoretical, Ifra-red, raman and Inelastic Neutron Scattering Studies

Majerz I., Pawlukojć A., Sobczyk L., Grech E., Nowicka-Scheibe J.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 2-3

409-417

EN

Infra-red (IR), Raman (R) and inelastic neutron scattering (INS) studies were performed on solid 1,8-diaminonaphthalene. Calculations by using HF and DFT methods showed that very good reproduction of the dimeric structure found in the solid state yields the DFT method on the B3LYP/6-31G** level. The characteristic motif of dimers is an eight-membered ring with two intramolecular (highly bent) and two intermolecular N-H___Nhydrogen bridges. The four outer N-H groups remain non-bonded. This leads to a complicated pattern of vibrational spectra. No agreement between calculated and experimental (IR, R) spectra in the range of (NH2) vibrations was found.Arelatively good coincidence of experimental and theoretically predicted spectra is observed in the middle and low frequency regions, especially when analysing the INS spectra for dimeric species. The dimerization leads to a marked change in modes connected with torsional vibrations of NH2 groups.

7

Crystal and Molecular Structures of Model Schiff-Mannich Bases

Woźniak K., Grech E., Szady-Chełmieniecka A.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 5

717-728

8

Intermolecular (OHO)- hydrogen bond formed by a hydroxyquinoline derivative

Wiench J. W., Stefaniak L., Grech E.

Bulletin of the Polish Academy of Sciences. Chemistry

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1999

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Vol. 47, No. 1

67-75

EN

(1)H, (13)C, (14)N, (15)N, (17)0, and (19)F NMR data are presented for HTFMQ and its complexes with DMAN in 2 .land 1 : 1 molar ratios. GIAO-CHF molecular orbital calculations for the [1H] and [4H] forms of the free molecule and its anion are also performed. The results show that the [4H] form of HTFMQ predominates in acetonitrile solutions. In both complexes with DMAN, HTFMQ forms a semi-anion containing an intermolecular hydrogen bond.

9

X-ray, IR and (1)H NMR studies of 1:1 adduct of 1,8-bis(dimethylamino)naphthalene (DMAN) and 1,1-cyclobutanedicarboxylic acid (CBDC)

Bartoszczak-Adamska E., Grech E., Jaskólski M.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 2

347-354

EN

The crystal and molecular structure of the title compound has been determined by X-ray analysis. This compound crystallizes in the P2-1/c space group with cell parameters: a= 9.325(2), b=15.158(3), c=14.102(3) A, beta=106.40(3)degree and with four C14H19N(+/2)xC6H7O(-/4) formula units in the unit cell. The structure contains DMANH(+) cations with a short asymmetric intramolecular N-H...N hydrogen bond (N...N 2.595(2) A) and CBDC(-) monoanions with a short intramolecular O-H...O hydrogen bond (O...) 2.412(3) A). The ionic character of he very strog (NHN)(+) and moderately strong (OHO)(-) hydrogen bonds has been derived from IR spetroscopy. The (1)H NMR spectrum measured in acetonitrile solution is similar to that in the solid state.

10

FT-IR and NMR stedies of proton sponge character of Cis-1,2-bis(diethylaminomethyl)cyclohexane

Brzezinski B., Grech E., Klimkiewicz J., Schroeder G., Stefaniak L., Urjasz H.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 2

284-291

EN

Cis-1,2-bis(diethylaminomethyl)cyclohexane (DEAMCH) was synthesized and its pK-a values in acetonitrile were measured. Dual behevioral of DEAMCH was observed in the reaction with various acids: HClO4, 4-tert-butylphenol, 4-cyanophenol and pentachlorophenol (PCP) in acetonitrile and acetone-d-6 solutions, respectively, when studied by FT-IR as well as (1)H, (13)C and (15)N NMR spectroscopy. An intramolecular NHN(+) hydrogen bond was found in 1:1 complex of DEAMCH with HClO4 in solution. This hydrogen bond was, however, weaker than those previously observed in other protonated proton sponges. In complexes of DEAMCH with 4-cyanophenol both NHN(+) intramolecular hydrogen bond and structurally symmetrical intermolecular homoconjugated (OHO)(-) hydrogen bonds were formed. These properties of DEAMCH demonstrate its proton sponge like character. On the other hand, in complexes of DEAMCH with more acidic phenol such as PCP intermolecular hydrogen-bonded complexes are formed, in which the OH protons are localized at the amino groups. For these O(-)...HN(+) hydrogen bonds a strongly asymmetrical double minimum proton potential with the well at the N atom is present, characteristic of complexes having no proton sponge like character.

11

Crystal and molecular structure of 2-(N,N-diethylamino)-methyl-4-bromo-6-formylphenol

Woźniak K., Anulewicz R., Grech E., Szady A.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 2

460-469

EN

Structural and spectroscopic properties of solid 2-(N,N-diethylamino)-methyl-4-bromo-6-formylphenol have been investigated. There are two molecules of the title compound in the independent part of the unit cell with only minor structural differences. This is an example of a Mannich base containing a neutral [O-H...N] intramolecular hydrogen bonding. Single crystal X-ray diffraction shows that the title molecule is dominated by neutral Kekule structures. Being involved in a strong intramolecular [O-H...N] hydrogen bonding, 2-(N,N-diethylamino)-methyl-4-bromo-6-formylphenol forms its crystal lattice by means of different types of weak intermolecular [C-H...O], and C-H...Br hydrogen bonds.

12

Comparison of the molecular structures of 1,5-bis(p-toluenesulphonamido)-2,4,6,8-tetranitronaphthalene and its dianion in the bispyridinium salt

Olejnik Z., Lis T., Grech E., Nowicka-Scheibe J.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 7

1255-1268

EN

1,5-Bis(p-toluenesulphonamido)-2,4,6.8-tetranitronaphthalene (1,5-TSATNN) [alternative name: N,N'-(2,4,6,8-tetranitronaphthalene-1,5-diyl)-bis(p-toluenesulphonamide)] crystalized from acetic acid or pyridine with three molar equivalents of solvent. The compound with pyridine is shown to be a 1:1 adduct of bispyridinium salt. Substantial differences between molecular geometries of 1,5-TSATNN and its dianion are found. Naphthalene cores are distorted from planarity in quite different modes and the neutral and deprotonated p-tosylamide groups adopt different rotational conformations. A significant delocalization of the negative charge, observed as shortening of the S-N and N(amide)-C bonds, as well as evidence of conjugation between the amide and nitro groups are found in the dianion.

13

N NMR study of three proton sponges and some of their salts

Klimkiewicz J., Stefaniak L., Grech E., Brzeziński B., Webb G. A.

Bulletin of the Polish Academy of Sciences. Chemistry

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1998

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Vol. 46, No. 1

75-78

EN

15N NMR data are reported for the three proton sponges DMAMN, DMAMB and DEAMB together with some of their salts with HNO3 and HC104. Low temperature 15N measurements on the monoperchlorate salts reveal the presence of a (N-H-N)+ structure from the values observed for 1J(15N-1H). The diperchlorate salts show monoprotonation of each nitrogen atom.