Nickel(II) and cobalt(II) complexes with 4,5-dichloro-isothiazole-3-carboxylic acid and 1,10-phenanthroline: synthesis, crystal structures and cytotoxicity

Abstract The tendency of forming mixed carboxyl-to-oxime hydrogen bonds was tested on the series of bornane derivatives: one with the acid function only (bornane-2-endo-carboxylic acid), one with the oxime function (2,2′-diethylthiobomane-3-oxime), and one with both oxime and carboxylic functions (bornane-2-oxime-3-endo-carboxylic acid). The crystal structures of these compounds were determined by means of X-ray diffraction. In bornane-2-endo-carboxylic acid and 2,2′-diethylthiobornane-3-oxime 'homogenic' hydrogen bonds were found, and these hydrogen bonds close eight-and six-membered rings, respectively. By contrast, in bornane-2-oxime-3-endo-carboxylic acid 'heterogenic' hydrogen bonds between carboxylic and oxime bonds were found. This carboxylic-oxime, or 'carboxyoxime' system is almost always present in compounds which have both oxime and carboxylic groups; therefore it can be regarded as an element of supramolecular structures (synthon). The presence of such synthons can break the tendency of carboxylic acids and oximes towards crystallizing in centrosymmetric structures.

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Formation of isolated guest dimers vs. host-guest coordination. X-Ray crystal structures of four carboxylic acid inclusion compounds formed by roof-shaped and scissor-like host molecules

Journal of Inclusion Phenomena and Macrocyclic Chemistry ◽

10.1007/bf01041887 ◽

1990 ◽

Vol 8 (3) ◽

pp. 309-322 ◽

Cited By ~ 17

Author(s):

Ingeborg Cs�regh ◽

M�ty�s Czugler ◽

Edwin Weber ◽

Jochen Ahrendt

Keyword(s):

Carboxylic Acid ◽

Crystal Structures ◽

Inclusion Compounds ◽

X Ray ◽

Host Molecules

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Crystal structures of two 6-(2-hydroxybenzoyl)-5H-thiazolo[3,2-a]pyrimidin-5-ones

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989015011044 ◽

2015 ◽

Vol 71 (7) ◽

pp. 766-771

Author(s):

Ligia R. Gomes ◽

John Nicolson Low ◽

Fernando Cagide ◽

Fernanda Borges

Keyword(s):

Hydrogen Bond ◽

Carboxylic Acid ◽

Hydrogen Bonds ◽

Crystal Structures ◽

Dihedral Angles ◽

Stacking Interactions ◽

Mechanism Of Formation ◽

Π Stacking ◽

Heterocyclic Moiety

The title compounds, 6-(2-hydroxybenzyl)-5H-thiazolo[3,2-a]pyrimidin-5-one, C13H8N2O3S, (1), and 6-(2-hydroxybenzyl)-3-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one, C14H10N2O3S, (2), were synthesized when a chromone-3-carboxylic acid, activated with (benzotriazol-1-yloxy)tripyrrolidinylphosphonium hexafluoridophosphate (PyBOP), was reacted with a primary heteromamine. Instead of the expected amidation, the unusual title thiazolopyrimidine-5-one derivatives were obtained serendipitously and a mechanism of formation is proposed. Both compounds present an intramolecular O—H...O hydrogen bond, which generates anS(6) ring. The dihedral angles between the heterocyclic moiety and the 2-hydroxybenzoyl ring are 55.22 (5) and 46.83 (6)° for (1) and (2), respectively. In the crystals, the molecules are linked by weak C—H...O hydrogen bonds and π–π stacking interactions.

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