A Nanosized Porous Supramolecular Lead(II)-'-phenyl(pyridin-2-yl)methylene--phenylthiosemicarbazide Aggregate, Obtained Under Electrochemical Conditions.

A novel nanosized porous supramolecular nonanuclear complex [Pb(HL)Cl(ClO)](ClO)·15HO(solvent) (·15HO(solvent)) is reported that was synthesized by electrochemical oxidation of a Pb anode under the ambient conditions in a CHCN:MeOH solution of '-phenyl(pyridin-2-yl)methylene--phenylthiosemicarbazide (), containing [N(CH)]ClO as a current carrier. The supramolecular aggregate of is enforced by a myriad of Pb···S tetrel bonds (TtBs) established with the thiocarbonyl sulfur atoms of adjacent species, which have been also analyzed by DFT calculations via 2D maps of ELF, Laplacian and RDG properties. Moreover, Pb···Cl TtBs with the central Cl anion, and Pb···O TtBs with the three oxygen atoms of the ClO anion, were revealed.

Palladium(II) and Platinum(II) Complexes Bearing ONS-Type Pincer Ligands: Synthesis, Characterization and Catalytic Investigations.

This work describes the synthesis of eight new Pd(II) and Pt(II) complexes with the general formula [M(TSC)Cl], where TSC represents the 4N-monosubstituted thiosemicarbazone derived from 2-acetylpyridine N-oxide with the substituents CH (H4MLO), CH (H4ELO), phenyl (H4PLO) and (CH) (H4DMLO). These complexes have been characterized by elemental analysis, molar conductivity, IR spectroscopy, H, C, Pt and ESI-MS. The complexes exhibit a square planar geometry around the metallic center coordinated by a thiosemicarbazone molecule acting as a donor ONS-type pincer ligand and by a chloride, as confirmed by the molecular structures of the complexes, [Pd(4ELO)Cl] () and [Pd(4PLO)Cl] (), determined by single-crystal X-ray diffraction.

Synthesis, Structural Characterisation, and Electrochemical Properties of Copper(II) Complexes with Functionalized Thiosemicarbazones Derived from 5-Acetylbarbituric Acid.

The reaction between 5-acetylbarbituric acid and 4-dimethylthiosemicarbazide or 4-hexamethyleneiminyl thiosemicarbazide produces 5-acetylbarbituric-4-dimethylthiosemicarbazone (HAcbDM) and 5-acetylbarbituric-4N-hexamethyleneiminyl thiosemicarbazone (HAcbhexim). Eight new complexes with different copper(II) salts have been prepared and characterized using elemental analysis, molar conductance, UV-Vis, ESI-HRMS, FT-IR, magnetic moment, EPR, and cyclic voltammetry. In addition, three-dimensional molecular structures of [Cu(HAcbDM)(HO)](NO)·HO (), [Cu(HAcbDM)(HO)]ClO (), and [Cu(HAcbHexim)Cl] () were determined by single crystal X-ray crystallography, and an analysis of their supramolecular structure was carried out.

Silver(I) Octanuclear Complexes Containing '-(4-Oxotiazolidin-2-Iliden)picolinohydrazonamide and Nitrate as Bridge Ligands. An Example of Solvatomorphism?

The versatile coordination chemistry of (2Z,'E)-'-(4-oxothiazolidin-2-ylidene)picolinohydrazonamide (HAmDHotaz) facilitated the synthesis of new complexes with different silver(I) salts. This paper describes the synthesis and characterization, through elemental analysis and spectroscopic techniques (when solubility permits), of a series of compounds that illustrate the coordinative and structural diversity achievable with the HAmDHotaz ligand. Five silver clusters containing the [Ag(AmDHotaz)] nucleus were structurally analyzed by single-crystal X-ray diffraction and were found to exhibit solvomorphism.

Supramolecular Nature of Multicomponent Crystals Formed from 2,2'-Thiodiacetic Acid with 2,6-Diaminopurine or N9-(2-Hydroxyethyl)adenine.

The synthesis and characterization of the multicomponent crystals formed by 2,2'-thiodiacetic acid (Htda) and 2,6-diaminopurine (Hdap) or N9-(2-hydroxyethyl)adenine (9heade) are detailed in this report. These crystals exist in a salt rather than a co-crystal form, as confirmed by single crystal X-ray diffractometry, which reflects their ionic nature. This analysis confirmed proton transfer from the 2,2'-thiodiacetic acid to the basic groups of the coformers.

H(N3)dap (Hdap = 2,6-Diaminopurine) Recognition by Cu(EGTA): Structure, Physical Properties, and Density Functional Theory Calculations of [Cu(μ-EGTA)(μ-H(N3)dap)(HO)]·7HO.

Reactions in water between the Cu(µ-EGTA) chelate (EGTA = ethylene-bis(oxyethyleneimino)tetraacetate(4-) ion) and Hdap in molar ratios 1:1 and 1:2 yield only blue crystals of the ternary compound [Cu(μ-EGTA)(μ-H(N)dap)(HO)]·7HO (), which has been studied via single-crystal X-ray diffraction and various physical methods (thermal stability, spectral and magnetic properties), as well as DFT theoretical calculations. In the crystal, uncoordinated water is disordered. The tetranuclear complex molecule also has some irrelevant disorder in an EGTA-ethylene moiety.

The Copper(II)-Thiodiacetate (tda) Chelate as Efficient Receptor of N9-(2-Hydroxyethyl)Adenine (9heade): Synthesis, Molecular and Crystal Structures, Physical Properties and DFT Calculations of [Cu(tda)(9heade)(HO)]·2HO.

Considering that Cu(tda) chelate (tda: dithioacetate) is a receptor for adenine and related 6-aminopurines, this study reports on the synthesis, molecular and crystal structures, thermal stability, spectral properties and DFT calculations related to [Cu(tda)(9heade)(HO)]·2HO () [9heade: N9-(2-hydroxyethyl)adenine]. Concerning the molecular recognition of (metal chelate)-(adenine synthetic nucleoside), represents an unprecedented metal binding pattern (MBP) for 9heade. However, unprecedentedly, the Cu(tda)-9heade molecular recognition in is essentially featured in the Cu-N1(9heade) bond, without any N6-H⋯O(carboxyl tda) interligand interaction.

Experimental and Theoretical Evidence of a Pb⋅⋅⋅Pb Ditetrel Bond Without a σ-Hole.

The crystal structure of a newly synthesized compound, [PbL(Ac)] , (where L=2 (amino(pyrazin-2-yl) methylene) hydrazinecarbothioamide, Ac=acetate anion) exhibits a close contact between pairs of Pb atoms, suggesting a ditetrel bond, in addition to two Pb⋅⋅⋅O tetrel bonds, and two C-H⋅⋅⋅O H-bonds. The presence of this ditetrel bond as an attractive component is confirmed by various quantum chemical methods. This novelty of this particular bond is its existence even in the absence of a σ-hole on the Pb atom, which is typically considered a prerequisite for a bond of this type.

Deciphering the H-Bonding Preference on Nucleoside Molecular Recognition through Model Copper(II) Compounds.

The synthetic nucleoside acyclovir is considered an outstanding model of the natural nucleoside guanosine. With the purpose of deepening on the influence and nature of non-covalent interactions regarding molecular recognition patterns, three novel Cu(II) complexes, involving acyclovir (acv) and the ligand receptor N-(2-hydroxyethyl)ethylenediamine (hen), have been synthesized and thoroughly characterized. The three novel compounds introduce none, one or two acyclovir molecules, respectively.

Structural basis and effect of copper(II) complexes with 4-oxo-thiazolidine ligands on DNA binding and nuclease activity.

Seven novel Copper(II) complexes, namely [Cu(Am4DHotaz)(HO)](ClO) (1), [Cu(Am4DHotaz)(NO)(MeOH)]·HO (2), [Cu(Am4Motaz)(HO)](ClO)·0.83HO (3), [Cu(Am4Motaz)(NO)]NO·MeOH (4), [Cu(Am4Eotaz)(NO)](NO)·2HO (5), [Cu(Am4Eotaz)(ClO)](ClO) (6) and [Cu(Am4Eotaz)(ClO)(HO)](ClO) (6a) (HAm4DHotaz = N'-(4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide, Am4Motaz = N'-(3-methyl-4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide and Am4Eotaz = N'-(3-ethyl-4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide), have been successfully synthesized and characterized by several physicochemical techniques and, for 1-6 complexes, single crystal X-ray diffraction. Having the structural data as a base, complexes 1, 2 and 3 exhibited square pyramidal to square pyramidal slightly distorted geometry, whereas 4, 5 and 6 an intermediate between square pyramidal and trigonal bipyramidal.

Molecular and supramolecular recognition patterns in ternary copper(II) or zinc(II) complexes with selected rigid-planar chelators and a synthetic adenine-nucleoside.

Four ternary metal-complexes with Cu(II) or Zn(II), 2,6-pyridine-dicarboxylate (pdc) or glycyl-glycinate (GG) and the synthetic nucleoside 9-(2-hydroxyethyl)adenine (9heade) have been synthesized and studied by single-crystal X-ray diffraction and other physical methods. Relevant supramolecular assemblies found in the solid state structures have been further studied using density functional theory (DFT) calculations. In addition, the energetic features of the non-covalent interactions as well as the cooperativity effects have been calculated and characterized using the non-covalent interaction plot computational tool.

New sulfonamide complexes with essential metal ions [Cu (II), Co (II), Ni (II) and Zn (II)]. Effect of the geometry and the metal ion on DNA binding and nuclease activity. BSA protein interaction.

Mixed divalent Cu, Co, Ni and Zn complexes containing the new sulfonamide ligand N-(2-(pyridin-2-yl)ethyl)quinoline-8-sulfonamide (HQSEP) were prepared and characterized by physico-chemical techniques. The tetracoordinate [Cu(QSEP)X] [X = Br (1), Cl (2)] compounds present a seesaw geometry (τ = 0.56 (1) and 0.

Hexanuclear CuO-3Cu triazole-based units as novel core motifs for high nuclearity copper(ii) frameworks.

The asymmetric 3,5-disubstituted 1,2,4-triazole ligand HV (5-amino-3-picolinamido-1,2,4-triazole) by reaction with an excess of Cu(ii) perchlorate (Cu : HV being 12 : 1) has produced a novel hexanuclear {Cu(μ-O/H)(HV/V)} fragment, with one triangular Cu(μ-O/H) group connected to three peripheral single Cu(ii) ions through a -- bridging mode of the ligand, which is the building block of the three structures described here: one hexanuclear, [Cu(μ-O)(HV)(ClO)(HO)]·8HO (1), one dodecanuclear, [Cu(μ-O)(V)(ClO)(HO)](ClO)·6HO (2), and one tetradecanuclear 1D-polymer, {[Cu(μ-OH)(V)(HV)(ClO)(HO)](ClO)·14HO} (3), the last two containing hexanuclear subunits linked by perchlorato bridges. The Cu-Cu av. intra-triangle distance is 3.

Probing the effect of N-alkylation on the molecular recognition abilities of the major groove N7-binding site of purine ligands.

The study of the metal binding pattern of N-methyladenines (1-, 3-, 7- or 9-Meade) towards Cu-iminodiacetate-like chelates is addressed on the basis of XRD crystal structures of sixteen novel ternary compounds. Except for three compounds, all others feature an square-based Cu(II) coordination, type 4 + 1, and the efficient cooperation of a CuN7 bond with an intra-molecular N6-H⋯O(coord. carboxylate) interligand interaction as the major metal-binding pattern.

Design and synthesis of methyl 2-{[4-phenyl-5-(pyridin-2-yl)-4H-1,2,4-triazol-3-yl]sulfanyl}acetate (phpy2NS) as a ligand for complexes of Group 12 elements: structural assessment and hydrogen-bonded supramolecular assembly analysis.

The reaction of 2-cyanopyridine with N-phenylthiosemicarbazide afforded 2-[amino(pyridin-2-yl)methylidene]-N-phenylhydrazine-1-carbothioamide (Ham4ph) and crystals of 4-phenyl-5-(pyridin-2-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (pyph3NS, 1, CHNS). Crystals of methyl 2-{[4-phenyl-5-(pyridin-2-yl)-4H-1,2,4-triazol-3-yl]sulfanyl}acetate (phpy2NS, 2, CHNOS), derived from 1, were obtained by the reaction of Ham4ph with chloroacetic acid, followed by the acid-catalyzed esterification of the carboxylic acid with methyl alcohol. Crystals of bis(methanol-κO)bis(methyl 2-{[4-phenyl-5-(pyridin-2-yl)-4H-1,2,4-triazol-3-yl-κN,N]sulfanyl}acetato)zinc(II)/cadmium(II) hexabromidocadmate(II), [ZnCd(CHNOS)(CHOH)][CdBr] or [ZnCd(phpy2NS)(MeOH)][CdBr], 3, and dichlorido(methyl 2-{[4-phenyl-5-(pyridin-2-yl)-4H-1,2,4-triazol-3-yl-κN,N]sulfanyl}acetato)mercury(II), [HgCl(CHNOS)] or [Hg(phpy2NS)Cl], 4, were synthesized using ligand 2 and CdBr or HgCl, respectively.

Quasi-aromatic Möbius Metal Chelates.

We report the design as well as structural and spectroscopic characterizations of two new coordination compounds obtained from Cd(NO)·4HO and polydentate ligands, benzilbis(pyridin-2-yl)methylidenehydrazone (L) and benzilbis(acetylpyridin-2-yl)methylidenehydrazone (L), in a mixture with two equivalents of NHNCS in MeOH, namely [Cd(SCN)(NCS)(L)(MeOH)] (1) and [Cd(NCS)(L)(MeOH)] (2). Both L and L are bound via two pyridyl-imine units yielding a tetradentate coordination mode giving rise to the 12 π electron chelate ring. It has been determined for the first time (qualitatively and quantitatively), using the EDDB electron population-based method, the HOMA index, and the ETS-NOCV charge and energy decomposition scheme, that the chelate ring containing Cd can be classified as a quasi-aromatic Möbius motif.

Molecular recognition between adenine or 2,6-diaminopurine and copper(II) chelates with N,O2,S-tripodal tetradentate chelators having thioether or disulfide donor groups.

Five novel ternary copper(II) complexes with the N,O2,S-tripodal tetradentate chelators N,N-bis(carboxymethyl)-S-benzylcysteaminate(2-) ion (BCBC) or N,N,N',N'-tetrakis(carboxymethyl)cystaminate(4-) ion (TCC) and adenine (Hade), 2,6-diaminopurine (Hdap), 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen) as co-ligand were synthesized and characterized by X-ray diffraction and other physical methods: [Cu2(BCBC)2(μ2-N3,N7-H(N9)ade)(H2O)2]·H2O (1), [Cu2(BCBC)2(μ2-N7,N9-H(N3)dap)(H2O)2]·4H2O (2), [Cu2(μ2-TCC)(H(N9)ade)2(H2O)2]·10H2O (3), [Cu2(μ2-TCC)(bpy)2]·15H2O (4) and [Cu2(μ2-TCC)(phen)2]·14H2O (5). The crystal structure of H4TCC·3H2O was also determined. All ternary Cu(II) complexes have molecular structures.

Lights and shadows in the challenge of binding acyclovir, a synthetic purine-like nucleoside with antiviral activity, at an apical-distal coordination site in copper(II)-polyamine chelates.

Several nucleic acid components and their metal complexes are known to be involved in crucial metabolic steps. Therefore the study of metal-nucleic acid interactions becomes essential to understand these biological processes. In this work, the synthetic purine-like nucleoside acyclovir (acv) has been used as a model of guanosine recognition with copper(II)-polyamine chelates.

Two novel ternary dicopper(II) μ-guanazole complexes with aromatic amines strongly activated by quantum dots for DNA cleavage.

Two novel (μ-guanazole)-bridged binuclear copper(II) complexes with 1,10-phenanthroline (phen) or 2,2'-bipyridine (bipy), [Cu2(μ-N2,N4-Hdatrz)(phen)2(H2O)(NO3)4] (1) and [Cu2(μ-N1,N2-datrz)2(μ-OH2)(bipy)2](ClO4)2 (2) (Hdatrz = 3,5-diamino-1,2,4-triazole = guanazole), have been prepared and characterized by X-ray diffraction, spectroscopy, and susceptibility measurements. Compounds 1 and 2 differ in the aromatic amine, which acts as a coligand, and in the Cu···Cu'-bridging system. Compound 1, which contains two mono-bridged copper ions, represents the first example of a discrete Cu-(NCN-trz)-Cu' complex.

Molecular recognition modes between adenine or adeniniun(1+) ion and binary M(II)(pdc) chelates (MCoZn; pdc=pyridine-2,6-dicarboxylate(2-) ion).

Mixed ligand M(II)-complexes (MCoZn) with pyridine-2,6-dicarboxylate(2-) chelator (pdc) and adenine (Hade) have been synthesized and studied by X-ray diffraction and other spectral and thermal methods: [Cu(pdc)(H(N9)ade)(H2O)] (1), [Cu2(pdc)2(H2O)2(μ2-N3,N7-H(N9)ade)]·3H2O (2), trans-[M(pdc)(H(N9)ade)(H2O)2]·nH2O for MCo (3-L, 3-M, 3-H) or Zn (4-L, 4-H), where n is 0, 1 or 3 for the 'lowest' (L), 'medium' (M) and 'highest' (H) hydrated forms, and the salt trans-[Ni(pdc)(H2(N1,N9)ade)(H2O)2]Cl·2H2O (5). In all the nine compounds, both neutral and cationic adenine exist as their most stable tautomer and the molecular recognition pattern between the metal-pdc chelates and the adenine or adeninium(1+) ligands involves the MN7 bond in cooperation with an intra-molecular N6H⋯O(coordinated carboxylate) interligand interaction. In addition the dinuclear copper(II) compound (2) has the CuN3 bond and the N9H⋯O(coord.

Mixed-ligand copper(II)-sulfonamide complexes: effect of the sulfonamide derivative on DNA binding, DNA cleavage, genotoxicity and anticancer activity.

Four ternary complexes, [Cu(L1)2(bipy)] (1) [HL1 = N-(6-chlorobenzo[d]thiazol-2-yl)-4-methylbenzenesulfonamide], [Cu(L2)2(bipy)] (2) [HL2 = N-(benzo[d]thiazol-2-yl)-4-methylbenzenesulfonamide], [Cu(L3)2(bipy)]·1/2H2O (3) [HL3 = N-(5,6-dimethylbenzo[d]thiazol-2-yl)-4-methylbenzenesulfonamide] and [Cu(L4)2(bipy)] (4) [HL4 = N-(5,6-dimethylbenzo[d]thiazol-2-yl)benzenesulfonamide], were prepared and then characterized by X-ray crystallography, spectroscopy and magnetic measurements. Whereas the molecular structure of 1 and 2 consists of a discrete monomeric copper(II) species with a distorted square planar geometry, that of 3 and 4 consists of two independent molecules. In 3, both molecules present a different coordination geometry (distorted square planar and distorted square pyramidal) while in 4 they have an identical coordination environment (distorted square planar).

Two copper complexes from two novel naphthalene-sulfonyl-triazole ligands: different nuclearity and different DNA binding and cleavage capabilities.

Two novel naphthalene-sulfonyl-triazole ligands, 5-amino-N1-(naphthalen-3-ylsulfonyl)-1,2,4-triazole (anstrz) and 3,5-diamino-N1-(naphthalen-3-ylsulfonyl)-1,2,4-triazole (danstrz), purposely designed to interact with DNA, have been prepared for the first time and then fully characterized by (1)H, (13)C NMR, and IR spectroscopy, mass spectrometry and elemental analysis. The crystal structures of two copper complexes of these derivatives, i.e.

Structural insights on the molecular recognition patterns between N(6)-substituted adenines and N-(aryl-methyl)iminodiacetate copper(II) chelates.

For a better understanding of the metal binding pattern of N(6)-substituted adenines, six novel ternary Cu(II) complexes have been structurally characterized by single crystal X-ray diffraction: [Cu(NBzIDA)(HCy5ade)(H2O)]·H2O (1), [Cu(NBzIDA)(HCy6ade)(H2O)]·H2O (2), [Cu(FurIDA)(HCy6ade)(H2O)]·H2O (3), [Cu(MEBIDA)(HBAP)(H2O)]·H2O (4), [Cu(FurIDA)(HBAP)]n (5) and {[Cu(NBzIDA)(HdimAP)]·H2O}n (6). In these compounds NBzIDA, FurIDA and MEBIDA are N-substituted iminodiacetates with a non-coordinating aryl-methyl pendant arm (benzyl in NBzIDA, p-tolyl in MEBIDA and furfuryl in FurIDA) whereas HBAP, HCy5ade, HCy6ade and HdimAP are N(6)-substituted adenine derivatives with a N-benzyl, N-cyclopentyl, N-cyclohexyl or two N-methyl groups, respectively. Regardless of the molecular (1-4) or polymeric (5-6) nature of the studied compounds, the Cu(II) centre exhibits a type 4+1 coordination where the tridentate IDA-like chelators adopt a mer-conformation.

Solid state structures of cadmium complexes with relevance for biological systems.

This chapter provides a review of the literature on structural information from crystal structures determined by X-ray diffractometry of cadmium(II) complexes containing ligands of potential biological interest. These ligands fall into three broad classes, (i) those containing N-donors such as purine or pyrimidine bases and derivatives of adenine, guanine or cytosine, (ii) those containing carboxylate groups such as α-amino acids, in particular the twenty essential ones, the water soluble vitamins (B-complex) or the polycarboxylates of EDTA type ligands, and (iii) S-donors such as thiols/thiolates or dithiocarbamates. A crystal and molecular structural analysis has been carried out for some representative complexes of these ligands, specifically addressing the coordination mode of ligands, the coordination environment of cadmium and, in some significant cases, the intermolecular interactions.