Recurrent motifs in pharmaceutical cocrystals involving glycolic acid: X-ray characterization, Hirshfeld surface analysis and DFT calculations

Crystallization studies on some pyridinecarboxamides and methylated xanthines with glycolic acid as coformer, were carried out on formation of synthons and their influence on stability and solubility, the energy landscape and stabilization energies.

Characterization and biological activities of two copper(II) complexes with diethylenetriamine and 2,2'-bipyridine or 1,10-phenanthroline as ligands

Two new mixed ligand copper(II) complexes with diethylenetriamine, 2,2'-bipyridine and 1,10-phenanthroline have been synthesized. The crystal and molecular structures of [Cu(dien)(phen)](ClO(4))(2) and [Cu(dien)(bipy)](BF(4))(2) (dien=diethylenetriamine, phen=1,10-phenanthroline, bipy=2,2'-bipyridine) were determined by X-ray crystallography from single crystal data. These two complexes have similar structures. The EPR spectral data also suggest that these complexes have distorted square pyramidal geometry about copper(II). Anti-microbial and superoxide dismutase activities of these complexes have also been measured. They show the higher SOD activity than the corresponding simple Cu(II)-dien/Cu(II)-PMDT (PMDT=N,N,N',N',N''-pentamethyldiethylenetriamine) complexes because of a strong axial bond of one of the nitrogen atoms of the alpha-diimine. Both the complexes have been found to cleave plasmid DNA in the presence of co-reductants such as ascorbic acid and glutathione.

Ternary copper(II) complexes with N-carboxymethyl-l-prolinato(2−) ion and imidazole or creatinine: A comparative study of the interligand interactions influencing the molecular recognition and stability

The compounds {[Cu(CMP)(Him)].H(2)O}(n) (I) and [Cu(CMP)(crea)H(2)O].3H(2)O (II) were synthesized and characterized by X-ray diffraction, thermal, spectral and magnetic methods (CMP=N-carboxymethyl-;l-prolinato(2-) ion, Him=imidazole and crea=creatinine). Appropriate structural comparison with other compounds such as {[Cu(CMP)(H(2)O)].H(2)O}(n), [Cu(crea)(2)Cl(2)] and [Cu(dipeptide)(crea)(H(2)O)(x)].nH(2)O (x=0 or 1) have been made in order to prove that crea can act as an imidazole-like ligand (because it is able to promote the same fac- to mer-CMP tridentate conformational change in copper(II) complexes) as well as to discuss the interligand interactions which control the 'Cu(CMP) complex-crea, molecular recognition processes. In contrast to that found in related ternary complexes, we have concluded that direct CMP-crea interligand interactions are missing in the Cu-CMP-crea complex due to the inappropriate correspondence between the donor and/or acceptor H-bonding properties of these ligands. CMP can only act as H-acceptor by its two terminal carboxylate group, and crea can display H-donor and H-acceptor roles by its exocyclic -NH(2) and O moieties, respectively. That promotes the reinforcement of the Cu-N(crea) bond by a bridge -N-H(crea)...O(aqua) (2.867(3)A, 176.4 degrees).

X-ray, spectral and biological (antimicrobial and superoxide dismutase) studies of oxalato bridged CuII–NiII and CuII–ZnII complexes with pentamethyldiethylenetriamine as capping ligand

X-band electron spin resonance (ESR) and electronic spectra of oxalatobridged heterodinuclear Cu-Ni and Cu-Zn complexes, viz., [(PMDT)Cu-Ox-Ni(PMDT)](BPh(4))(2).2CH(3)CN and [(PMDT)Cu-Ox-Zn(PMDT)](BPh(4))(2).2CH(3)CN, where PMDT=pentamethyldiethylenetriamine, Ox=oxalate ion have been described. Complex [(PMDT)Cu-Ox-Ni(PMDT)](BPh(4))(2).2CH(3)CN has been structurally characterized. This complex crystallizes in the monoclinic space group, C(2) (No. 5) with the unit parameters a=20.445(4) A, b=14.884(3) A, c=23.174(5) A, alpha=90 degrees, beta=102.693(4) degrees, gamma=90 degrees, V=6880(2) A(3) and Z=4. The structure refined to R=0.0354 and R(w)=0.0853 for 21,109 reflections with I>2 sigma(I) using 765 parameters, shows the presence of a MN(3)O(2) chromophore in a distorted trigonal-bipyramidal (TBP) heterometallic complex with oxalate dianion. Taking with an equatorial Cu-O=2.137(8) A and an axial Cu-O=1.961(6) A coordination site at Cu(II) ion and equatorial Ni-O=2.178(7) A and axial Ni-O=1.994 (9) A coordination site at Ni(II) ion. The Cu-Ni distance is 5.3532(9) A and Cu-C(2)O(4)-Ni unit is planar. The [(PMDT)Cu-Ox-Ni(PMDT)](2+) shows the ESR spectrum of the antiferromagnetic spin exchange with each dinuclear delocalization of the unpaired electron over the unit and spin-doublet ground state which demonstrates the Cu-Ox-Ni core. Antimicrobial and superoxide dismutase (SOD) activities of these complexes have also been measured.

Intramolecular "Aryl-metal chelate ring" pi,pi-interactions as structural evidence for metalloaromaticity in (aromatic alpha,alpha'-diimine)-copper(II) chelates: molecular and crystal structure of aqua(1,10-phenanthroline)(2-benzylmalonato)copper(II) three-hydrate

By reaction of Cu(2)CO(3)(OH)(2), 2-benzylmalonic acid (H(2)Bzmal), and 1,10-phenanthroline (phen), [Cu(Bzmal)(phen)(H(2)O)] x 3H(2)O (compound 1) has been obtained and characterized by thermal, spectral, magnetic, and X-ray diffraction methods. The molecular structure of 1 is remarkably similar to that of [Cu(Bzmal)(bipy)(H(2)O)] x 2H(2)O (compound 2, bipy = 2,2'-bipyridine). In both complexes, the aryl(Bzmal) ring produces an unexpected pi,pi-stacking interaction with the Cu(II)-(aromatic alpha,alpha'-diimine) chelate ring, at an average distance d(pi)(-)(pi) of 3.40 A, involving roughly parallel and smoothly slipped rings. This insight is discussed as new structural evidence for metalloaromaticity of Cu(II)-(aromatic alpha,alpha'-diimine) chelate rings. Interestingly, 1 recognizes itself by a weak intermolecular pi,pi-stacking interaction between aryl(Bzmal) ligands to give pairs of complex molecules. In contrast, there is an intermolecular pyridyl-pyridyl pi,pi-stacking interaction also forming pairs of complex molecules in 2.

cis-Dichloro(alpha,omega-diamino carboxylate ethyl ester)palladium(II) as Palladium(II) versus Platinum(II) Model Anticancer Drugs: Synthesis, Solution Equilibria of Their Aqua, Hydroxo, and/or Chloro Species, and in Vitro/in Vivo DNA-Binding Properties

cis-Dichloro(d,l-2,3-diaminopropionate ethyl ester)palladium(II), cis-[Pd(Etdap)Cl(2)] (I), and cis-dichloro(d,l-2,4-diaminobutyrate ethyl ester)palladium(II), cis-[Pd(Etdab)Cl(2)] (II), were synthesized and characterized by elemental analysis, IR spectroscopy, and TG-DTA thermal analysis. The equilibrium model and log beta(pqr) constants of hydrolytic species of I and II were also investigated by potentiometric methods (I = 0.15 M (NaClO(4)) and 37 degrees C). Aqueous solutions of cis-[Pd(Etdaa)(H(2)O)(2)](ClO(4))(2) (Etdaa = Etdap (III) or Etdab (IV)) were prepared by stoichiometric reaction of I or II with AgClO(4). Thus, log beta(pqr) of the corresponding cis-aquahydroxo (pqr = 1,0,-1) and di(&mgr;-hydroxo) (pqr = 2,0,-2) species were obtained from E(H(+)) data of alkalimetric titrations of solutions of III or IV. Such constants were then used as fixed values to obtain log beta(pqr)() of chloro-containing species (cis-dichloro (1,2,0), cis-chloroaqua (1,1,0), and cis-chlorohydroxo (1,1,-1)) from E(H(+)) and E(Cl(-)) data pairs simultaneously obtained by titration of solutions of III or IV with NaOH and NaCl. All log beta(pqr) were fitted by the SUPERQUAD program. Appropriate log beta(pqr)() sets give good simulations of experimental titration curves and several species distribution diagrams. In addition the interaction of I and/or II with DNA in vitro and in vivo was studied by various methods. UV spectral data and melting and renaturation curves indicate that both compounds destabilize the DNA helicoidal structure. Compound II disrupts in vivo the structure and transcription process of polytene chromosomes of Drosophila hydei.

Cis-Dichloro(diaminosuccinate diethyl ester)palladium (II) as Pd(II)/Pt(II) model compound for DNA-binding and antitumor properties: solution equilibria of their aqua-, hydroxo-, and/or chloro-species

Cis-Dichloro(diaminosuccinic acid)palladium(II), cis-[Pd(H2dasa)Cl2] (I), or cis-dichloro(diaminosuccinate diethyl ester)palladium(II), cis-[Pd(Et2dasa)Cl2] (II) reacts with two equivalents of AgClO4 to give insoluble Pd(dasa) or an aqueous solution of [Pd(Et2dasa) (H2O)2](ClO4)2, respectively. Three solutions of this salt were titrated with NaOH (I = NaClO4 (0.15M),37 degrees C), and 133 E(H+) data (3.5 < or = pH < or = 7) were treated by SUPERQUAD to fit log beta pqr of cis-aquahydroxo-(pqr = 10-1, -5.25(3)) and di-mu-hydroxo-species (20-2, -6.55(1)). At pH > 7 the ester hydrolysis prevents the calculation of log beta 10-2 for the cis-dihydroxo-complex. Another three solutions of such salt were titrated (I = 0.15M (NaClO4), 37 degrees C) with NaOH and NaCl simultaneously using two potentiometric systems (which measure H+ or Cl-). From 147 E(H+) and E(Cl-) data pairs and the above fixed log beta pqr, SUPERQUAD calculations yield log beta pqr for cis-chloro-aqua (pqr = 110, 3.65(1)), cis-chloro-hydroxo (11-1, -2.68 (4)), and cis-dichloro-species (120, 5.86(3)). Simulated and experimental titrations are in good agreement. Circular dichroism spectra of native DNA and drug:DNA complexes suggest that cis-Pd(H2dasa) and cis-Pd(Et2dasa) chelate moieties induce an opening and rotation of the stacked bases in the double helix. This finding is explained by the abundance of each one and of the total neutral and charged species of II in the tested CD solution.

cis-dichloro-palladium(II) complexes with diaminosuccinic acid and its diethyl ester: synthesis, molecular structure, and preliminary DNA-binding and antitumor studies

The reactions of K2PdCl4 with meso-diaminosuccinic acid (H2dasa) in 0.1 M HCl or its diethyl ester dihydrochloride Et2dasa.2HCl in neutralized aqueous solution yield cis-[Pd(H2dasa)Cl2](I) and cis-[Pd(Et2dasa)Cl2](II), respectively. These products were characterized by elemental analysis, IR spectroscopy, and TG-DTA thermal analysis. The crystal of II is monoclinic, space group C2/c (a = 14.292(5), b = 14.636(5), c = 13.435(5) A, beta = 98.08(2) degrees, Z = 8, R = 0.041 and wR = 0.06). The Pd(II) atom exhibits a roughly square planar coordination with two Pd-N bonds (Et2dasa) (2.014(2) and 2.049(7) A) and two cis-imposed Pd-Cl bonds (2.294(2) and 2.303(2) A). Compound I reacts with 2,2'-bipyridine in neutral aqueous solution to give [Pd(2,2'-bipy)(dasa)].3H2O(III) in a process of cis-chloride substitution by 2,2'-bipy as a model N-heterocyclic chelating entity. The molecular and crystal structure of III is also reported. It was observed that both cis-dichloro-Pd(II) complexes having Pd(H2dasa) (acidic) and Pd-(Et2dasa)(esterified) chelate entities induce conformational changes in the covalent closed circular (ccc) form of pUC8 plasmid. Both compounds were assayed for antitumor activity in vitro against MDA-MB 468 and HL-60 human cancer cell lines. The results show that compounds I and II have values of ID50 lower than those of K2PdCl4, and also lower than those of diaminoacid ligands (meso-diaminosuccinic acid and meso-diaminosuccinate diethyl ester). Thus it is likely that the imposed cis-coordination of the chelating H2dasa or Et2dasa to the Pd(II) center increases the biological activity of these palladium(II) complexes.