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In this paper, a series of new ruthenium complexes of the general formula [Ru(NS)(dpphpy)(dppb)]PF6(Ru1–Ru3), where dpphpy = diphenyl-2-pyridylphosphine, NS ligands = 2-thiazoline-2-thiol (tzdt, Ru1), 2-mercaptopyrimidine (pySm, Ru2), and 4,6-diamino-2-mercaptopyrimidine (damp, Ru3), and dppb = 1,4-bis(diphenylphosphino)butane, were synthesized and characterized by elemental analysis, spectroscopic techniques (IR, UV/visible, and 1D and 2D NMR), and X-ray diffraction. In the characterization, the correlation between the phosphorus atoms and their respective aromatic hydrogen atoms of the compounds in the assignment stands outs, by 1H–31P HMBC experiments. The compounds show anticancer activities against A549 (lung) and MDA-MB-231 (breast) cancer cell lines, higher than the clinical drug cisplatin. All of the complexes are more cytotoxic against the cancer cell lines than against the MRC-5 (lung) and MCF-10A (breast) nontumorigenic human cell lines. For A549 tumor cells, cell cycle analysis upon treatment with Ru2showed that it inhibits the mitotic phase because arrest was observed in the Sub-G1 phase. Additionally, the compound induces cell death by an apoptotic pathway in a dose-dependent manner, according to annexin V-PE assay. The multitargeted character of the compounds was investigated, and the biomolecules were DNA, topoisomerase IB, and proteasome, as well as the fundamental biomolecule in the pharmacokinetics of drugs, human serum albumin. The experimental results indicate that the complexes do not target DNA in the cells. At low concentrations, the compounds showed the ability to partially inhibit the catalytic activity of topoisomerase IB in the process of relaxation of the DNA plasmid. Among the complexes assayed in cultured cells, complex Ru3was able to diminish the proteasomal chymotrypsin-like activity to a greater extent.

In this study, half-sandwich Ru(II) complexes containing acylthiourea ligands of the general type [Ru(η6-p-cymene)(PPh3)(S)Cl]PF6(1m–6m) and [Ru(η6-p-cymene)(PPh3)(S–O)]PF6(1b–6b) where S/S–O = N’,N’-disubstituted acylthiourea were synthesized and characterized (via elemental analyses, IR spectroscopy, 1H NMR spectroscopy, 13C{1H} NMR spectroscopy, and X-ray diffractometry), and their cytotoxic activity was evaluated. The different coordination modes of the acylthiourea ligands, monodentately via S (1m–6m) and bidentately via S,O (1b–6b), to ruthenium were modulated from different synthetic routes. The cytotoxicity of the complexes was evaluated in five human cell lines (DU-145, A549, MDA-MB-231, MRC-5, and MCF-10A) by MTT assay. The IC50values for prostate cancer cells (2.89–7.47 μM) indicated that the complexes inhibited cell growth, but that they were less cytotoxic than cisplatin (2.00 μM). Unlike for breast cancer cells (IC50= 0.28–0.74 μM) and lung cancer cells (IC50= 0.51–1.83 μM), the complexes were notably more active than the reference drug, and a remarkable selectivity index (SI 4.66–19.34) was observed for breast cancer cells. Based on both the activity and selectivity, complexes 5band 6b, as well as their respective analogous complexes in the monodentate coordination 5mand 6m, were chosen for further investigation in the MDA-MB-231 cell line. These complexes not only induced morphology changes but also were able to inhibit colony formation and migration. In addition, the complexes promoted cell cycle arrest at the sub-G1phase inducing apoptosis. Interaction studies by viscosity measurements, gel electrophoresis, and fluorescence spectroscopy indicated that the complexes interact with the DNA minor groove and exhibit an HSA binding affinity.

Three new acesulfamate salts, NaC4H4NO4S, RbC4H4NO4S and CsC4H4NO4S, were prepared by reactions in aqueous solutions and thoroughly characterized. Their crystal and molecular structures were determined by single crystal X-ray diffraction methods. They crystallize in the monoclinic space group P21/awith a= 7.2518(2), b= 8.9414(4), c= 10.5929(4) Å, β= 99.951(3)°, V= 676.52(4) Å3for the Na salt; a= 7.4663(3), b= 9.6962(4), c= 10.4391(4) Å, β= 95.150(3)°, V= 752.68(5) Å3for the Rb salt and a= 7.5995(4), b= 9.9439(4), c= 10.8814(6) Å, β= 91.298(5)°, V= 822.08(7) Å3for the Cs salt, and Z= 4 molecules per unit cell. The three compounds are isotypic to each other and to the previously reported potassium salt. The metal ions are in irregular polyhedral coordination with six neighboring acesulfamate anions through their nitrogen and carbonyl and sulfoxide oxygen atoms. The FTIR spectra of the compounds were also recorded and are briefly discussed.

The crystal structures of heptamethylenediammonium bis(saccharinate) monohydrate, [H3N - (CH2)7 -NH3](sac)2·H2O (1) and octamethylenediammonium bis(saccharinate) hemihydrate, [H3N- (CH2)8-NH3](sac)2·0.5H2O (2), were determined by single-crystal X-ray diffraction methods. Compound 1 crystallizes in the triclinic space group P1¯ with 2 molecules per unit cell, and 2 in the monoclinic space group P21/a with Z = 4. The saccharinate moiety is planar in both compounds presenting bonding characteristics comparable to those found in other saccharinate salts. The ionic crystals are further stabilized by an extensive H-bonding network, which links the anions and cations into an infinite three-dimensional supramolecular assembly. The FTIR spectra of the adducts are briefly discussed in comparison with those of the constituent molecules.

A series of palladium(II) thiosaccharinates with triphenylphosphane (PPh3), bis(diphenylphosphanyl)methane (dppm), and bis(diphenylphosphanyl)ethane (dppe) have been prepared and characterized. From mixtures of thiosaccharin, Htsac, and palladium(II) acetylacetonate, Pd(acac)2, the palladium(II) thiosaccharinate, Pd(tsac)2(tsac: thiosaccharinate anion) (1) was prepared. The reaction of 1with PPh3, dppm, and dppe leads to the mononuclear species Pd(tsac)2(PPh3)2·MeCN (2), [Pd(tsac)2(dppm)] (3), Pd(tsac)2(dppm)2(4), and [Pd(tsac)2(dppe)]·MeCN (5). Compounds 2, 4, and 5have been prepared also by the reaction of Pd(acac)2with the corresponding phosphane and Htsac. All the new complexes have been characterized by chemical analysis, UV/Vis, IR, and Raman spectroscopy. Some of them have been also characterized by NMR spectroscopy. The crystalline structures of complexes 3, and 5have been studied by X‐ray diffraction techniques. Complex 3crystallizes in the monoclinic space group P21/nwith a= 16.3537(2), b= 13.3981(3), c= 35.2277(7) Å, β= 91.284(1)°, and Z= 8 molecules per unit cell, and complex 5in P21/nwith a= 10.6445(8), b= 26.412(3), c= 15.781(2) Å, β= 107.996(7)°, and Z= 4. In compounds 3and 5, the palladium ions are in a distorted square planar environment. They are closely related, having two sulfur atoms of two thiosaccharinate anions, and two phosphorus atoms of one molecule of dppm or dppe, respectively, bonded to the PdIIatom. The molecular structure of complex 3is the first reported for a mononuclear PdII‐dppm‐thionate system.

The reaction of the bis(thiosemicarbazone) of dimethyl pyridine-2,6-diyl diketone, H2DAPTSC, with PbMe2(OAc)2, PbMePh(OAc)2 or PbPh2(OAc)2 in MeOH afforded the complexes [PbMe2(DAPTSC)], [PbMePh(DAPTSC)] or [PbPh2(DAPTSC)] (in the first two cases together with [Pb(DAPTSC)]). X-ray crystallography of the Pb(IV) complexes showed that the metal has a pentagonal bipyramidal coordination sphere. The N3,S2-bound DAPTSC2– anion occupied the equatorial plane and the organic groups were in the apical positions. These compounds retain the same coordination mode in DMSO solution. DAPTSC2– is also N3,S2-bound in [Pb(DAPTSC)], a complex with a stereochemically active PbII lone pair. The reaction of PbPh2Cl2 with H2DAPTSC, also in methanol at room temperature, afforded [PbPh2(H2DAPTSC)]2[PbPh2Cl4]Cl2·6CH3OH. X-ray crystallography of this centrosymmetric complex showed it to consist of two [PbPh2(H2DAPTSC)]2+ cations of similar structure to the neutral [PbR2(DAPTSC)] complexes, together with a trans-octahedral [PbPh2Cl4]2– anion and two Cl– anions. This compound decomposes in DMSO solution, probably evolving to H2DAPTSC and PbPh2Cl2(DMSO)n. In order to evaluate the changes undergone by H2DAPTSC under metallation, the X-ray structure of the free molecule was also determined.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

The reaction of the CuIIand NiIIcomplexes of saccharin with dicyandiamide (cyanoguanidine, cnge) in methanol produces the addition of methanol to the nitrile moiety of this molecule. Furthermore, the product of the reaction coordinates the metal centers generating two new complexes containing saccharinate as the counter anion. The crystal structures of [Cu(cnge‐OCH3)2](sac)2and of [Ni(cnge‐OCH3)2](sac)2·2H2O (cnge‐OCH3= 1‐amidino‐O‐methylurea) were solved by single crystal X‐ray diffractometry. Both complexes crystallize in the triclinic space group ${\rm P}{\bar 1}$and the metallic cations present a quite similar centrosymmetric planar conformation. The complexes were characterized by means of electronic and infrared spectroscopy and also their magnetic and thermal behavior was investigated.

Abstract A series of cis-{RuCl2(PPh3)2[4,4'-(X)2-2,2'-bipy]} [cis-chlorines; X=-H, -Me, -SMe, and (-Cl,-Me)] complexes have had their structures determined by single crystal X-ray diffraction. The geometry of these complexes, also determined in CH2Cl2 solution by 31P{1H}-n.m.r. spectroscopy, showed that the chemical shifts for the phosphorus atoms are slightly dependent on the pKa of the 4,4'-(-X)2-2,2'-bipy ligands.

The reactions of several derivatives of 1,2,5‐thiadiazole 1,1‐dioxide [3,4‐diphenyl‐(1a), 3,4‐bis(p‐methoxyphenyl)‐(1b), phenanthro[9,10‐c]‐(1c) and acenaphtho[1,2‐c]‐1,2,5‐thiadiazole 1,1‐dioxide (1d), 3,4‐diphenyl‐1,2,5‐thiadiazoline 1,1‐dioxide (2a) and 4‐ethoxy‐5‐methyl‐3,4‐diphenyl‐1,2,5‐thiadiazoline 1,1‐dioxide (2b)], with reagents possessing two nucleophilic nitrogen atoms (urea, N,N′‐dimethylurea, thiourea, N‐methylthiourea, N‐ethylthiourea, N‐allylthiourea, N,N′‐diethylthiourea, N,N′‐diphenylthiourea, dithioxamide and sulfamide), were followed by cyclic voltammetry (CV) and UV–visible spectrophotometry in aprotic solvent solution. The products were isolated, characterized by IR, 1H NMR and 13C NMR methods and their structure was confirmed by single‐crystal x‐ray diffraction. Several substrate–nucleophile combinations (1a–dand 2awith some ureas and thioureas) reacted to give good yields of new compounds formed by the addition reaction of the two nitrogen atoms of the nucleophile to the two >CN— double bonds of the 1,2,5‐thiadiazole 1,1‐dioxide ring. Some systems (1a–dithioxamide and 2b–thiourea) did not react, whereas in others (e.g. 1a–sulfamide) a monoaddition equilibrium reaction was observed. Copyright © 2004 John Wiley & Sons, Ltd.

Distribution data for alkali metal picrates in the water–chloroform solvent system in the absence and in the presence of acetonitrile were used to determine the partition constants of the dissociated electrolytes in the mutually saturated solvents and the ion-pair formation constants in the water saturated organic phase. These data were compared with those previously reported in water–benzonitrile and water–dichloromethane solvent systems. The same experiments carried out in the presence of ethyl p-tert-butylcalix4arene tetraethanoate, EtCalix4, led to the calculation of distribution and extraction constants in these solvent systems. The presence of acetonitrile in the organic phase enhances significantly the extraction constant to an extent that these are the highest values so far obtained in the solvent systems investigated. This enhancement in extraction is attributed to metal complex stabilization promoted by the presence of acetonitrile in the hydrophobic cavity of the ligand. The X-ray structures of two sodium complexes picrate as the counter-ion, isolated from water saturated chloroform with and without acetonitrile are reported for the first time. In the first complex, the macro-cycle is sited on a crystallographic four-fold axis and hosts an acetonitrile solvent molecule in its calix and a sodium ion in its hydrophilic cavity. The metal is in a eight-fold Archimedean square anti-prism environment, coordinated to the phenol oxygen atom and to the carbonyl oxygen atom of the four rotationally symmetry related pendant arms. The macro-cycle of the other complex adopts a slightly distorted cone conformation and its hydrophilic cavity also hosts a sodium ion. But now the metal is in a seven-fold environment, coordinated to the four phenol oxygen atoms and to the carbonyl oxygen atoms of three pendant arms acting as bidentate ligands. The fourth, mono-dentate, pendant arm points away from the hydrophilic cavity and its terminal –CH2-CH3group interacts hydrophobically with the calix of a neighboring complex giving rise to a supra-molecular polymeric structure in the lattice.

Distribution data for alkali metal picrates in the water–chloroform solvent system in the absence and in the presence of acetonitrile were used to determine the partition constants of the dissociated electrolytes in the mutually saturated solvents and the ion-pair formation constants in the water saturated organic phase. These data were compared with those previously reported in water–benzonitrile and water–dichloromethane solvent systems. The same experiments carried out in the presence of ethyl p-tert-butylcalix(4)arene tetraethanoate, EtCalix(4), led to the calculation of distribution and extraction constants in these solvent systems. The presence of acetonitrile in the organic phase enhances significantly the extraction constant to an extent that these are the highest values so far obtained in the solvent systems investigated. This enhancement in extraction is attributed to metal complex stabilization promoted by the presence of acetonitrile in the hydrophobic cavity of the ligand. The X-ray structures of two sodium complexes (picrate as the counter-ion), isolated from water saturated chloroform with and without acetonitrile are reported for the first time. In the first complex, the macro-cycle is sited on a crystallographic four-fold axis and hosts an acetonitrile solvent molecule in its calix and a sodium ion in its hydrophilic cavity. The metal is in a eight-fold Archimedean square anti-prism environment, coordinated to the phenol oxygen atom and to the carbonyl oxygen atom of the four rotationally symmetry related pendant arms. The macro-cycle of the other complex adopts a slightly distorted cone conformation and its hydrophilic cavity also hosts a sodium ion. But now the metal is in a seven-fold environment, coordinated to the four phenol oxygen atoms and to the carbonyl oxygen atoms of three pendant arms acting as bidentate ligands. The fourth, mono-dentate, pendant arm points away from the hydrophilic cavity and its terminal –CH₂-CH₃ group interacts hydrophobically with the calix of a neighboring complex giving rise to a supra-molecular polymeric structure in the lattice.

The crystal structures of [Tl(tsac)] (1) and [Tl(tsac)(ophen)] (2) (tsac = anion of thiosaccharin; ophen = 1, 10 phenanthroline) have been determined at 116 K by single crystal X‐ray diffractometry. Complex 1crystallizes in the monoclinic space group P21/a with Z = 4 and complex 2in the monoclinic space group C2/c with Z = 8.In both complexes TIis coordinated to a thiosaccharinate anion through its sulphur and nitrogen atoms. A distorted eight fold coordination sphere around the cation in complex 1is completed with two other longer Tl‐S bonds and four Tl···O contacts with five symmetry related neighbouring thiosaccharinate anions. A phenanthroline molecule acting as a bidentate ligand through its nitrogen atoms completes a four‐fold coordination around the metal atom in complex 2. The infrared spectra of both complexes were also recorded and their most important features discussed on the basis of its structural peculiarities.

The reaction of 2, 6‐diacetylpyridine bis(thiosemicarbazone) (H2DAPTSC) with dimethylthallium hydroxide yielded the complexes [(TlMe2)2(DAPTSC)] and [TlMe2(HDAPTSC)]. The structure of [TlMe2(HDAPTSC)], determined by X‐ray diffractometry, exhibits a hitherto unknown coordination mode of the HDAPTSC—anion in which its deprotonated thiosemicarbazone chain coordinates one metal atom through its sulphur and hydrazinic N atoms while a second metal atom is weakly coordinated through the S atom of the undeprotonated thiosemicarbazone chain. Each thallium atom is coordinated in both ways, with the result that the [TlMe2(HDAPTSC)] units are linked in infinite helical chains in the direction of the baxis.

We report the molecular structure and a single crystal EPR study at 9.8 and 33.9 GHz of a new copper(II) compound with the amino acid L-Glutamine, Cu[NH2CO2CH(CH2)2CONH2]2. The Cu^II ion is in an elongated octahedral environment equatorially trans-coordinated by two glutamine molecules acting as bidentate ligands through the nitrogen atom and one oxygen atom of each amino acid group, and axially by two carboxylate oxygen atoms of two neighboring glutamine molecules. Copper ions are arranged in layers connected by syn-anti carboxylate bridges that provide equatorial and apical ligands to the copper ions. Neighboring layers are connected by long chemical paths, which include two amino acid side chains connected by H bonds. Single crystal EPR spectra show a single exchange-collapsed resonance at both microwave frequencies for any magnetic field orientation. The evaluation of the molecular g-tensor from the angular variation of the EPR line position yielded g⊥ = 2.051 and g|| = 2.248, which indicates a dx²−y² ground orbital for the Cu ions. The angular variation of the EPR line width displays a contribution that is typical of a 2-D magnetic system, and another contribution depending on the microwave frequency, which is attributed to the incomplete collapse of the resonances corresponding to magnetically nonequivalent copper ions. A quantitative analysis of the line width data allowed us to estimate a mean exchange coupling constant |J/k| = 0.42(2) K, which is assigned to the syn-anti carboxylate chemical path that connects neighboring copper ions within a layer. The results are discussed and compared with those observed in similar systems. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

The molecular structure of diosgenone, a natural steroidal sapogenin, closely related to diosgenin and isolated from Solanum nudum, was solved by single crystal X-ray diffractometry at 120 K and refined by full-matrix least-squares to an agreement factor, R1 = 0.054. It crystallizes in the monoclinic space group P21, with a = 15.1870(4) Å , b = 7.2710(2) Å , c = 21.2840(6) Å , ß= 99.251(1) °, and four molecules in the unit cell (Z = 4). The results constitute the first structural report on a steroidal sapogenin from the diosgenin group.

In an attempt to obtain new square grid polymers we could prepare the copper(II) complex [Cu(4, 4'‐bipy)2(H2O)2](sac)2· DMF (4, 4'‐bipy = 4, 4'‐bipyridine; sac = anion of saccharin; DMF = dimethylformamide). Its structure was determined by single crystal X‐ray diffraction methods. It crystallizes in the orthorhombic space group Pcnb(a= 14.4994(2), b= 15.8128(3), c= 16.6850(2) Å, Z = 4) and is a square grid polymer with the saccharinate anions sandwiched between the complex layers and the DMF molecules filling the square holes. UV‐vis, diffuse reflectance and IR spectra, room temperature magnetic susceptibility and the thermal behaviour were also investigated.

The oxidation of thiosalicylic acid in methanol into 2‐sulfonatobenzoic acid was successfully achieved by the reaction with pyridine‐N‐oxide in aerobic media containing a copper(II) catalysts. The 100 K structure of the tetraphenylphosphonium 2‐sulfonatobenzoic acid [P(C6H5)4]C6H4SO3COOH (I) has been determined by X ray diffraction methods. The anion shows a novel conformation with a strong intramolecular COOH · · · OSO2bond. The oxidation reaction also produces [P(C6H5)4]2[Cu2Cl6] (II), as assessed by single crystal X‐ray measurements. When water is added to the reaction medium, the compound Iis reformed. Nevertheless, instead of compound II, chloro tetrapyridine‐N‐oxide copper(II) chloride monohydrate [Cu(C5H5NO)4Cl]Cl · H2O (III) is obtained. The crystal structure of this new copper complex has been determined and is also reported here. The copper ion is in a CuO4Cl pyramidal coordination with the oxygen atoms of four C5H5NO ligands at the square basis (average Cu—O distance of 1.98(1) Å) and a chlorine ion (d(Cu—Cl) = 2.4585(4) Å) at the pyramid apex. Vibrational studies of the three compounds have been performed. Compound IIIhas also been characterized by diffuse reflectance and UV‐vis spectroscopy and by its thermal and magnetic behavior.

The preparation of oxovanadium(IV, V) coordination compounds with 2‐acetylpyridine‐2‐furanoylhydrazone (Hapf) is described. [VO(apf)(acac)] was prepared from oxovanadium(IV) diacetylacetonate [VO(acac)2] by reaction with Hapf in methanol or dichloromethane. The complex is paramagnetic and its EPR spectrum is consistent with an octahedral coordination for the vanadium(IV) atom. Voltammetry studies of [VO(apf)(acac)] indicate an irreversible oxidation, in agreement with the chemical behavior of the compound in solution. The vanadium(IV) complex undergoes slow oxidation in alcoholic solution, losing the acetylacetonate ligand to form [VO2(apf)] and [V2O2(μ‐O)2(apf)2]. The crystal structures of these last compounds were determined by X‐ray diffraction methods. [V2O2(μ‐O)2(apf)2] crystallizes monoclinic [P21/c, Z = 2, a= 817.400(10), b= 1650.90(3), c= 984.70(2) pm, β= 112.7190(10)°]. The crystal structure consists of dimeric units, in which two μ‐oxo ligands subtend asymmetric bridges between the vanadium atoms in a very distorted octahedral coordination.

The trans-K{[FeCl(NO0)(cyclam)]·[FeCl(NO+)(cyclam)]₂}(PF₆)₆ complex was prepared from the reaction of trans-[Fe(cyclam)Cl₂]Cl and nitric oxide. The molecular structure of the complex was determined by X-ray diffraction (space group P2₁/c; a = 10.3560(3) Å; b = 17.7110(6) Å; c = 17.9480(6) Å; β = 91.052(2)°). Crystal and spectroscopic evidence indicates the existence of two independent complexes with participation of different forms of nitric oxide: NO+ and NO0. The IR spectrum shows the presence of two ν(NO) stretching modes at 1863 and 1610 cm−1 which are characteristic of these NO species, respectively. Upon reduction by zinc amalgam, the ν(NO+) band at 1863 cm−1 disappears and the band at 1610 cm−1 becomes more intense. The EPR measurements indicate the presence of the NO0 group. No signal for paramagnetic species of Fe(iii) was observed.

The crystal structures of two salts of bis­(thio­urea)­gold(I) complexes, namely bis­(thio­urea‐κS)­gold(I) chloride, [Au(CH4N2S)2]Cl, (I), and bis­[bis­(thio­urea‐κS)­gold(I)] sulfate, [Au(CH4N2S)2]2SO4, (II), have been determined. The chloride salt, (I), is isomorphous with the corresponding bromide salt, although there are differences in the bonding. The AuIion is located on an inversion centre and coordinated by two symmetry‐related thio­urea ligands through the lone pairs on their S atoms [Au—S 2.278 (2) Å and Au—S—C 105.3 (2)°]. The sulfate salt, (II), crystallizes with four independent [Au(CH4N2S)2]+cations per asymmetric unit, all with nearly linear S—Au—S bonding. The cations in (II) have similar conformations to that found for (I). The Au—S distances range from 2.276 (3) to 2.287 (3) Å and the Au—S—C angles from 173.5 (1) to 177.7 (1)°. These data are relevant in interpreting different electrochemical processes where gold–thio­urea species are formed.

Saccharinate complexes of the fourteen trivalent lanthanide cations and YIIIwere prepared by reaction between the respective lanthanide carbonates and saccharin in aqueous solution. Their crystal structures were determined by single crystal X‐ray diffractometry. They represent three different structural types. The first family, of composition [Ln(sac)(H2O)8](sac)2�H2O (sac = anion of saccharin; Ln = La, Ce, Pr, Nd.Sm, Eu), belongs to the monoclinic space group P21/c with Z = 4 and the LnIIIcation is in a tricapped trigonal prismatic environment with nine‐fold oxygen coordination. The second group of composition [Ln(sac)2(H2O)6]‐(sac)(Hsac)�4H2O with Ln = Gd, Dy, Ho, Er, Yb, Lu, and Y, pertains to the triclinic P1¯‐ space group, with Z = 2 and constitutes a new example of complexes containing simultaneously saccharin and its anion in the lattice. The TmIIIand TbIIIcompounds, which are also triclinic (space group P1¯‐ and Z = 2) present two closely related structures conformed by three and two [Ln(sac)(H2O)7]2+crystallographically independent complexes, respectively, with the [Tm(sac)(H2O)7]3(sac)6�9H2O and [Tb(sac)(H2O)7]2(sac)4�6H2O composition. For all the heavier lanthanides (Gd‐Lu) and yttrium the cation presents eight‐fold oxygen coordination, with the ligands at the corners of a slightly distorted square Archimedean antiprism.

Several new 1,2,5-oxadiazole N -oxide derivatives and some deoxygenated analogues were synthesized to be tested as potential selective hypoxic cell cytotoxins. Compounds prepared were designed in order to gain insight into the mechanism of action of this kind of cytotoxin. Compounds were tested in oxia and hypoxia and they proved to be non-selective. 3-Cyano- N 2 -oxide-4-phenyl-1,2,5-oxadiazole showed the best cytotoxic activity in oxia. The cytotoxicity observed for these derivatives could be explained in terms of the electronic characteristics of the 1,2,5-oxadiazole substituents. Electrochemical and ESR studies were performed on the more cytotoxic derivative.

A modified method for the synthesis of 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra(benzoyl)methoxycalix(4)arene (1) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra(acetoyl)methoxycalix(4)arene (2) using 18-crown-6 as phase transfer catalyst is reported. Ligand 1 was structurally (1H NMR and X-ray crystallography) and thermodynamically characterised. An account of the steps required for the formulation of an equation representative of the complexation process involving metal cations and macrocycles is given using as an illustrative example the interaction of 1 with the Na(I) cation. Thus, detailed thermodynamics of this system are first reported taking into account the solution properties of the reactants and the product in various solvents with the aim of assessing quantitatively the medium effect on the complexation process. The sodium:monoacetonitrile:1 complex was isolated and its molecular structure was determinated from X-ray diffraction data. The calix now adopts a more symmetric cone conformation than the free ligand and its hydrophobic cavity is filled with an acetonitrile solvent molecule. The hydrophilic pocket hosts the sodium cation which is in an eight-fold coordination with the four ethereal oxygen atoms [average d(Na–O) = 2.45(4) Å] and the four carbonyl oxygen atoms [average d(Na–O) = 2.51(4) Å] forming the corners of a distorted Archimedean square antiprism. The key structural features relevant to the complexation process are discussed. 1H NMR and conductance measurements have been used to assess the interaction of 1 and 2 with alkali metal cations. Final conclusions are given. Attention is drawn about the relevance of detailed thermodynamic studies on cation complexation processes involving calixarene derivatives. This is discussed within the context of selectivity and the factors controlling it in solution processes.

Summary.:  The crystal structure of the title complex, [Cd(tsac)2(H2O)], has been determined by single crystal X-ray diffraction methods. It crystallizes in the monoclinic space group C2/c (a = 12.236(3), b = 8.919(3), c = 16.655(3) �, β = 96.18(2)�, Z = 4). The molecular structure was solved from 1705 independent reflections with I > σ(I) and refined to R 1 = 0.0489. Infrared and Raman spectra of the complex were recorded and are briefly discussed. Its thermal behaviour was investigated by thermogravimetry and differential thermal analysis.

Two new Cu(II) complexes of stoichiometry [Cu(L-dipept)], containing as ligands the dipeptides L-alanine-L-valine and L-alanine-L-phenylalanine were prepared. They were characterized by single crystal X-ray diffractometry, and infrared and electronic spectroscopy. Both crystallize in the orthorhombic space group P212121with Z = 4. The Cu(II) ion has essentially the same elongated pyramidal coordination, being equatorially cis coordinated by a N2O2arrangement of ligand atoms and axially by a carbonyl oxygen atom. The compounds show rather similar polymeric structures that differ from each other basically in the dihedral angle between adjacent N2O2planes. The infrared and electronic spectra are briefly discussed on the basis of the structural characteristics of the complexes. Superoxide dismutase-like activity was tested for both compounds.

The crystal structure of the complexes [Cu(sac)2(bzim)2(H2O)] (1) and [Cu(sac)2(bzim)(H2O)(EtOH)] · 2 EtOH (2) (sac = saccharinate anion; bzim = benzimidazole; EtOH = ethanol) was determined by single crystal X‐ray diffractometry. Complex 1crystallizes in the monoclinic C2/c space group with Z = 8 whereas complex 2belongs to the triclinic P1 space group with Z = 2. Room temperature magnetic susceptibilities as well as electronic and IR spectra of both complexes were discussed. Their thermal behaviour was investigated by means of TG and DTA methods.

Acetoacetanilide- and methylacetoacetate thiosemicarbazones (HTSC¹ and HTSC², respectively) react with cadmium(II) acetate in methanol, giving complexes containing the ligand 2-[amino(thioxo)methyl]-5-methyl-2,3-dihydro-1H-3-pyrazolonate (L^–). An X-ray diffraction study of the structures of HTSC¹, HTSC², HL, and [CdL2Py], identified the main structural changes in the cyclization process. Additionally, the coordination of the metal in the complexes [CdL(AcO)] · 2 MeOH and [CdL2] · 3 H2O was analyzed using IR spectroscopy in the solid state and ¹H-, ¹³C-, and ¹¹³Cd-NMR spectroscopy in solution. On reaction with aqueous trifluoroacetic acid, both complexes releases the free pyrazolone, which can be easily isolated.

The title compound, a new example of an inorganic ester-like complex, was characterized by spectroscopic and X-ray crystallographic methods. It crystallizes in the triclinic space group P1 (a=9.413(2), b=10.595(3), c=11.783(2) Å, α=103.59(2), β=101.98(2), γ=99.40(2)°, Z=2). The structure was solved employing 2902 independent reflections with I>2σ(I) by direct and Fouriermethods and refined by a full-matrix least-squares fit to R1=0.049. Infrared and Ramanspectra of the solid compound and the electronic absorption spectra of its acetonitrilic and ethanolic solutions were recorded and are briefly discussed. Die Titelverbindung, ein neues Beispiel eines anorganischen esterähnlichen Komplexes, wurde mit spektroskopischen und Röntgen-Einkristall-Methoden charakterisiert. Sie kristallisiert in der triklinen Raumgruppe P1 (a=9.413(2), b=10.595(3), c=11.783(2) Å, α=103.59(2), β=101.98(2), γ=99.40(2)°, Z=2). Die Struktur wurde aus 2902 unabhängigen Reflexen mit I>2σ(I) durch direkte und Fourier-Methoden gelöst und durch einen least-squares fitzu R1=0.049 verfeinert. Die Infrarot- und Ramanspektren des Festkörpers und die Elektronen-absorptionsspektren seiner Lösungen in Acetonitril und Ethanol wurden aufgenommen und werden kurz besprochen.

An additive thermodynamic contribution of pendant arms to the complexation of calixarene derivatives with mercuryii in acetonitrile is for the first time demonstrated.

The title compound, tetrakis(μ‐3,4,5‐triethoxy­benzoato‐κ2O:O′)­bis­[(pyrazine‐κN)­rhodium(II)](Rh—Rh), [Rh2(C13H17O5)4(C4H4N2)2], crystallizes on an inversion centre in the triclinic space group . The equatorial carboxyl­ate ligands bridge the two RhIIatoms, giving a binuclear lantern‐like structure. The pyrazine mol­ecules occupy the two axial coordination sites. The phenyl rings are tilted by ca10° with respect to the attached carboxyl­ate groups. The pyrazine planes have a torsion angle of ca19° around the Rh—N bond with respect to the plane of the nearer carboxyl­ate group and are not coplanar with the Rh—Rh bond.

The title compound, catena‐poly[[tetrakis(μ‐decanoato‐κ2O:O′)diruthenium(II,III)(Ru—Ru)]‐μ‐octanesulfonato‐κ2O:O′], [Ru2(C10H19O2)4(C8H17O3S)], is an octane­sulfonate derivative of the mixed‐valence complex diruthenium tetradecanoate. The equatorial carboxyl­ate ligands are bidentate, bridging two Ru atoms to form a dinuclear structure. Each of the two independent dinuclear metal complexes in the asymmetric unit is located at an inversion centre. The octane­sulfonate anion bridges the two dinuclear units through axial coordination. The alkyl chains of the carboxyl­ate and sulfonate ligands are arranged in a parallel manner. The global structure can be seen as infinite chains of polar moieties separated by a double layer of non‐polar alkyl groups, without interdigitation of the alkyl chains.

The reaction of 1,2-diphenylethanedione (“benzil”) with cyclopentadiene in the presence of sodium methoxide unexpectedly afforded a novel 2,3,7-triphenyl derivative of the bicyclic cyclopenta[c]pyran. The structure was elucidated by physical methods (IR, UV/VIS, 1H-NMR, 13C-NMR MS) and a single-crystal X-ray analysis.

The octahedral title compound, [Ru(C2H5O)(NO)(NO2)2(C6H16N2)], crystallizes in the rhombohedral space group P31with an ethoxy ligand axially coordinated transto the nitro­syl ligand. The RuIIion is equatorially coordinated by a tetramethylethylenediamine group acting as a bidentate ligand, and to two nitro moieties whose planes are tilted with respect to the mean equatorial plane. Each nitro­gen ligand bonded to the metallic centre has a different hybridization state.

The crystal structure of the title compound, [Hg(C11H8N)(C12H22PS2)], consists of mol­ecules in which the Hg atom is coordinated strongly to the C atom in position 2 of the phenyl group and to one of the di­thio­phosphinate S atoms, and at longer distances to the pyridine N atom and the other S atom. The C—Hg—S fragment involving the S atom more strongly bound to Hg is almost linear [C—Hg—S = 178.9 (3)°].

An electrochemical cell [Cu₍₊₎&z.sfnc;MeCN + H₄L&z.sfnc;Pt₍₋₎] (H₄L = title ligand), yielded powdery [Cu₂(L)(H₂O)]_n and crystalline Cu₃(H₂L)(L)·2H₂O; the crystal structure of the latter shows an unusual helicate with an isosceles triangle core assembled by two μ-phenoxo bridges [Cu···Cu 3.413(3) and 3.858(3) Å], in which tetracoordinated Cu ions are in tetrahedrally distorted square planar environments.

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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.