Relationship between solid state structure and solution stability of copper(ii)-hydroxypyridinecarboxylate complexes

The complementary solid state/solution studies of the systematic series of bioactive ligands 3-hydroxy- 1-methyl-4-pyridinecarboxylate (L1), 3-hydroxy-1,2,6-trimethyl-4-pyridinecarboxylate (L2), 4-hydroxy-1- methyl-3-pyridinecarboxylate (L3), 4-hydroxy-1,6-dimethyl-3-pyridinecarboxylate (L4), 4-hydroxy-1-(2- hydroxyethyl)-6-methyl-3-pyridinecarboxylate (L5) and 4-hydroxy-1-(2-carboxyethyl)-6-methyl-3- pyridinecarboxylate (L6) with copper(II) have been performed in order to design efficient chelating drugs for the treatment of metal overloading conditions. Single crystals of [Cu(L1)2(H2O)]3H2O (1) (monomer) with axial water coordination, [Cu2(L2)4]6H2O (2) and [Cu2(L3)4]4H2O (3) (cyclic dimers), where pyridinolato and carboxylato oxygens, respectively, act as linkers between adjacent copper complexes, [Cu(L4)2]n3H2O (4) (1D polymer) and [Cu3(L5)6]18H2O (5) (trimer), constructed using two square-pyramidal and one elongated octahedral Cu(II) complexes have been determined by SXRD. The bidentate coordination mode of the ligands has been found preferentially with cis arrangements in 1 and 2 and trans arrangements in 3\u20135. The solution speciation and complex stability of aqueous solutions have been studied by pH-dependent electron paramagnetic resonance spectroscopy resulting in the detection of solely monomeric [CuL]+ and [CuL2] complexes. The stability order obtained for the [CuL]+ complexes could be correlated with the deprotonation constants of their hydroxyl group (log bLH) reflecting that the higher acidity increases the complex stability in the order L2 o L1 E L6 o L4 E L5 o L3. This stability order elucidates the different axial linkers in the cyclic dimers 2 and 3. DFT quantum-chemical calculations support the effect of the electron distribution on the established stability order

Supramolecular morphotropy of calixarene inclusion compounds

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Isostructurality of co-crystals of an ester substituted dinitro calixarene host

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Synthesis, structural, DFT, and cytotoxicity studies of Cu^II and Ni^II complexes with 3-aminopyrazole derivatives

Template synthesis of N,N′-bis(4-acetyl-5-methylpyrazole-3-yl) formamidine (ampf) was performed starting from 4-acetyl-3-amino-5-methylpyrazole (aamp) and CH(OC2H5)3 in methanol in the presence of CuCl2, Cu(NO3)2, or Ni(NO 3)2. The ligand was isolated in coordinated form as [Cu(ampf)Cl2], [Cu(ampf)(MeOH)(NO3)2]MeOH, and [Ni(ampf)(MeOH)2(NO3)]NO3 correspondingly. The compounds were characterized by elemental analysis, Fourier-transform IR and electronic spectroscopy, thermal analysis, single-crystal X-ray diffraction, and quantum chemical (density functional theory) calculations. The density functional theory calculations provided information on the metalligand interactions in the complexes and assisted the assignment of the FT-IR spectra. The antiproliferative activity of the complexes and the ligand precursor, aamp, was tested against human myelogenous leukaemia K562, colon adenocarcinoma HT29, and cervix carcinoma HeLa. © 2010 CSIRO

X-ray crystal structures and isostructurality calculation of calix[4]arenes with lower rim propyl and carboxylic acid or mixed carboxylic acid and ester substituents involving solvent complexes with methanol and ethanol

X-ray crystal structures of two calix[4]arenes are reported. They feature aside from two distal n-propyl units, two ethyl acetate or mixed ethyl acetate and acetic acid groups as the characteristic substituents of the lower rim hydroxylic hydrogens. The structures are compared by making use of isostructurality calculations. In case of the semi-ester, solvates with methanol and ethanol as the guest solvents are involved. The carboxy function of the semi-ester does not form a dimer but an intramolecular hydrogen bond to a propoxy group. The solvates can be described as isostructural in spite of the different solvent molecules