Coordination Chemistry of potentially S,N,N py -Tridentate Thiosemicarbazones with the {Re(CO)3 } + fragment and formation of hemiaminal derivatives

Nine potentially S,N,Npy-tridentate thiosemicarbazones (HL) derived from pyridine-2-carbaldehyde or 1-(2-pyridyl)ethanone have been prepared and fully characterized. The X-ray crystal structures of six of them and two hydrochlorides were determined and analyzed. The reaction of the [ReX(CH3CN)2(CO)3]/[ReX(CO)5] (X = Cl and Br) precursors with these ligands yielded different kinds of compounds: the adducts [ReX(HL)(CO)3], in which the ligands were S,N-bidentate; the trinuclear species [Re3Cl2(L23)(HL23)(CO)9]; and the thiosemicarbazonate compounds [Re(L)(CO)3], where the ligand is S,N,Npy-tridentate. Besides, the reaction in methanol or ethanol of the thiosemicarbazones derived from aldehydes yielded S,N,Npy-tridentate hemiaminal cationic [Re(HLOR)(CO)3]X and neutral [Re(LOMe)(CO)3] complexes after the coordinated ligand underwent addition of the alcohol group to the imine bond. The reactivity of the complex [ReX(HL)(CO)3] in MeOH and NEt3 led to the formation of dinuclear [Re2(L)2(CO)6], where the thiosemicarbazonate is again S,N-bidentate. The influence that the substituents on the thiosemicarbazone ligands have on the stability of the complexes and the effect of the reaction medium on the resulting compounds have been analyzed.Agencia Estatal de Investigación | Ref. PID2019-110218RB-I00Universidade de Vigo/CISU

Coordination modes of hydrazone and acyl-hydrazone ligands containing a pyridine group with the {Re(CO)3}+ fragment

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGFour acyl-hydrazones derived from 5-hydroxypicolinohydrazide and 4-hydroxybenzaldehyde (HL11), 2-fluoro-4-hydroxybenzaldehyde (HL12), 2,4-dihydroxybenzaldehyde (HL13) or 2-pyridinecarboxaldehyde (HL14) and two hydrazones derived from 2-hydrazino pyridine and 4-dimethylaminobenzaldehyde (HL21) or 4-diethylamino-2-hydroxybenzaldehyde (HL22) were synthesized and their X-ray structures determined. Twelve rhenium(I) complexes of formula [ReX(HLn)(CO)3] (X = Cl, Br) were obtained by treating these ligands with [ReX(CH3CN)2(CO)3], and the structures of some representative compounds were determined by X-ray diffraction. The coordination geometry around rhenium(I) can be described as octahedral, with three carbon atoms in a fac configuration, the halogen atom and two nitrogen atoms from the hydrazone chain and the pyridine group, respectively. The carbonyl group of the acyl-hydrazone ligands does not participate in coordination in any of complexes HL11–HL14. The coordination mode of the ligands in all complexes could be established by comparing the IR and 1H NMR spectra. Formation of the hydrazonate complexes only proved possible with the derivatives of HL22. A study of the corresponding single crystal showed the presence of the dimer [Re2(L22)2(CO)6], in which the phenolate group of the ligand of the dimer partner coordinates to rhenium after deprotonation. This same group is used to bind to the rhenium atom of the dimer partner at the position released by the halide.Agencia Estatal de Investigación | Ref. PID2019-110218RB-I0

New α-keto acid-derived hydrazone ligands and their reaction with the {Re(CO)3}+

Two hydrazone ligands derived of phenylglyoxylic acid (HL1) and 4-hydroxyphenylpyruvic acid (HL2) were synthesized and their zwitterionic structures were determined by X-ray diffraction. The rhenium(I) complexes of formula [ReCl(HLn)(CO)3] were obtained by reaction of the ligands with [ReCl(CH3CN)2(CO)3]. The formation of the hydazonate complexes were also achieved. In the case of HL1 the trimetic complex [Re3(L1)3(CO)9] was isolated by using a basic medium. On the other hand, from storage of a solution of the [ReCl(HL2)(CO)3] complex, crystals of the [Re2(L2)2(CO)6] dimer could be obtained for their structural analysis by X-ray diffraction. The study of the crystalline structures is included. The coordination geometry around rhenium(I) can be described as octahedral with three carbon atoms in fac configuration. In all complexes a five-membered chelate ring is formed including two nitrogen atoms from the hydrazone chain and the pyridine group. In the mononuclear complexes the carboxylic group does not participates in the coordination but acts as a bridge to form the polynuclear compounds. The coordination mode of the ligands in all the complexes could be corroborated by comparative studies of the experimental and calculated (DFT) IR spectra.Agencia Estatal de Investigación | Ref. PID2019-110218RB-I00Agencia Estatal de Investigación | Ref. RED2022-134091-TUniversidade de Vigo/CISU

Synthesis, characterization, and cytotoxicity studies of N-(4-methoxybenzyl) thiosemicarbazone derivatives and their ruthenium(II)-p-cymene complexes

The reaction of [Ru2Cl2(μ-Cl)2(η6-p-cymene)2] with two thiosemicarbazones obtained by the condensation of N-(4-methoxybenzyl) thiosemicarbazide and 1,4-hydroxy-3-methoxyphenyl)ethan-1-one (HL1) or 2-fluoro-4-hydroxybenzaldehyde (HL2) was studied. The cationic complexes of formula [RuCl(η6-p-cymene)(HL)]+ were isolated as solid chloride and trifluoromethylsulfate (TfO) salts. A study of the solid state and NMR spectra suggests the presence in the material of two isomers that differ in the configuration in the iminic bond, C2=N3, of the coordinated thiosemicarbazone in the triflate salts and only the E isomer in the chloride. An X-ray study of single crystals of the complexes supports this hypothesis. The thiosemicarbazone ligand coordinates with the ruthenium center through the iminic and sulfur atoms to form a five-membered chelate ring. Furthermore, the isolation of single crystals containing the thiosemicarbazonate complex [Ru2(μ-L2)2(η6-p-cymene)2]2+ suggests the easy labilization of the coordinated chloride in the complex. The redox behavior of the ligands and complexes was evaluated by cyclic voltammetry. It seems to be more difficult to oxidize the complex derived from HL1 than HL2. The ability of the complexes to inhibit cell growth against the NCI-H460, A549 and MDA-MB-231 lines was evaluated. The complexes did not show greater potency than cisplatin, although they did have greater efficacy, especially for the complex derived from HL1.Ministerio de Ciencia e Innovación | Ref. PID2019-110218RB-I0

Complexos metálicos con uso potencial na imaxe do receptor de estróxenos

Los radiocomplejos con afinidad por el receptor de estrógeno (RE) pueden ser usados en diagnosis de enfermedades hormonodependientes y tumorales en las que se produce la soabreexpresión de esta proteína. En la presente tesis se abordará el diseño, síntesis y caracterización de complejos metálicos con ligandos portando grupos –OH o –NR 2 , además de grupos quelatantes. Se espera que una vez unidos al metal se produzca su orientación para potenciar la unión al RE de forma similar al estradiol o raloxifeno (agonistas de RE). Esta hipótesis se validará mediante la determinación de los valores de K i frente al RE.Os radiocomplexos con afinidade polo receptor de estróxeno (RE) poden usarse na diagnose de enfermedades hormonodependentes e tumorais. Na presente tese abordarase o diseño, síntese e caracterización de complexos metálicos con ligandos portadores de grupos –OH ou –NR 2, ademáis de grupos quelatantes. Espérase que una vez unidos ó metal prodúzase a orientación para potenciar a unión ó RE de maneira similar ó estradiol ou raloxifeno (agonistas de RE). Esta hipótese validarase mediante a determinación dos valores de K i frente ó RE.Radioactive complexes with selective affinity to estrogen receptor (ER) can be used in tumor and hormone-dependent diseases diagnosis. In the present work, design, synthesis and characterization of metal complexes with ligands including –OH or –NR 2 groups furthermore of chelating groups will be carried out. We expect an arrangement of the former groups after metal coordination and, the link to the ER, similarly to estradiol or raloxifene, will be optimized. This hypothesis will be validated by determining the corresponding Ki by ER

Crystal structure of N-(4-hydroxybenzyl)acetone thiosemicarbazone

The structure of the title compound, C11H15N3OS, shows the flexibility due to the methylene group at the thioamide N atom in the side chain, resulting in the molecule being non-planar. The dihedral angle between the plane of the benzene ring and that defined by the atoms of the thiosemicarbazide arm is 79.847 (4)°. In the crystal, the donor–acceptor hydrogen-bond character of the –OH group dominates the intermolecular associations, acting as a donor in an O—H...S hydrogen bond, as well as being a double acceptor in a centrosymmetric cyclic bridging N—H...O,O′ interaction [graph set R22(4)]. The result is a one-dimensional duplex chain structure, extending along [111]. The usual N—H...S hydrogen-bonding association common in thiosemicarbazone crystal structures is not observed

A monoclinic polymorph of 1,2-bis[(1-methyl-1H-tetrazol-5-yl)sulfanyl]ethane (BMTTE)

The synthesis and crystal structure of a monoclinic (P21/c) polymorph of the title compound, C6H10S2N8, are reported. The molecule has pseudo-twofold rotational symmetry, with the tetrazole rings being inclined to one another by 5.50 (6)°. In the crystal, molecules are linked by C—H...N hydrogen bonds, forming chains propagating along [101] and enclosing R22(20) ring motifs. The chains are linked by offset π–π interactions involving the tetrazole rings [intercentroid distances vary from 3.3567 (7) to 3.4227 (7) Å], forming layers parallel to the ac plane. The crystal structure of the triclinic polymorph (P\overline{1}) has been described previously [Li et al. (2011). Acta Cryst. E67, o1669]

Crystal structure of fac-tricarbonylchloridobis(4-hydroxypyridine)rhenium(I)–pyridin-4(1H)-one (1/1)

The asymmetric unit of the title compound, [ReCl(C5H5NO)2(CO)3]·C5H5NO, contains one molecule of the complex fac-[ReCl(4-pyOH)2(CO)3] (where 4-pyOH represents 4-hydroxypyridine) and one molecule of pyridin-4(1H)-one (4-HpyO). In the molecule of the complex, the Re atom is coordinated to two N atoms of the two 4-pyOH ligands, three carbonyl C atoms, in a facial configuration, and the Cl atom. The resulting geometry is slightly distorted octahedral. In the crystal structure, both fragments are associated by hydrogen bonds; two 4-HpyO molecules bridge between two molecules of the complex using the O=C group as acceptor for two different HO– groups of coordinated 4-pyOH from two neighbouring metal complexes. The resulting square arrangements are extented into infinite chains by hydrogen bonds involving the N—H groups of the 4-HpyO molecule and the chloride ligands. The chains are further stabilized by π-stacking interactions

Synthesis, Characterization, and Cytotoxicity Studies of N-(4-Methoxybenzyl) Thiosemicarbazone Derivatives and Their Ruthenium(II)-p-cymene Complexes

The reaction of [Ru2Cl2(μ-Cl)2(η6-p-cymene)2] with two thiosemicarbazones obtained by the condensation of N-(4-methoxybenzyl) thiosemicarbazide and 1,4-hydroxy-3-methoxyphenyl)ethan-1-one (HL1) or 2-fluoro-4-hydroxybenzaldehyde (HL2) was studied. The cationic complexes of formula [RuCl(η6-p-cymene)(HL)]+ were isolated as solid chloride and trifluoromethylsulfate (TfO) salts. A study of the solid state and NMR spectra suggests the presence in the material of two isomers that differ in the configuration in the iminic bond, C2=N3, of the coordinated thiosemicarbazone in the triflate salts and only the E isomer in the chloride. An X-ray study of single crystals of the complexes supports this hypothesis. The thiosemicarbazone ligand coordinates with the ruthenium center through the iminic and sulfur atoms to form a five-membered chelate ring. Furthermore, the isolation of single crystals containing the thiosemicarbazonate complex [Ru2(μ-L2)2(η6-p-cymene)2]2+ suggests the easy labilization of the coordinated chloride in the complex. The redox behavior of the ligands and complexes was evaluated by cyclic voltammetry. It seems to be more difficult to oxidize the complex derived from HL1 than HL2. The ability of the complexes to inhibit cell growth against the NCI-H460, A549 and MDA-MB-231 lines was evaluated. The complexes did not show greater potency than cisplatin, although they did have greater efficacy, especially for the complex derived from HL1