Structure and properties of terbium(III) dipivaloylmethanate and its adducts with Bipy and Phen

The complex of terbium(III) with dipivaloylmethane (2,2,6,6-tetramethylheptane-3,5-dione = Htmhd) [Tb(tmhd)₃]₂ (1) and two its adducts with bipyridyl (Bipy) and phenanthroline (Tb(tmhd)₃·Bipy (2) and Tb(tmhd)₃·Phen (3)) are synthesized and analyzed by single crystal X-ray diffraction. The crystals of [Tb(tmhd)₃]₂ (1) belong to the monoclinic crystal system: P2₁/n space group, a = 12.2238(2) Å, b = 27.6369(5) Å, c = 21.8740(4) Å, β = 105.146(1)°, V = 7133.0(2)ų, Z = 4; the crystals of Tb(tmhd)₃·Bipy (2) and Tb(tmhd)₃·Phen (3) belong to the triclinic crystal system with unit cell parameters: (2) \(P\bar 1\) space group, a = 11.0554(6) Å, b = 12.2761(7) Å, c = 17.7096(8) Å, α = 77.457(2)°, β = 85.557(2)°, γ = 69.659(2)°, V = 2199.8(2) ų, Z = 2; (3) \(P\bar 1\) space group, a = 10.8814(3) Å, b = 12.2852(4) Å, c = 18.3590(6) Å, α = 80.463(1)°, β = 87.587(1)°, γ = 68.640(1)°, V = 2253.6(1) ų, Z = 2. The structures of the complexes are molecular and involve isolated [Tb₂(tmhd)₆] (1), Tb(tmhd)₃·Bipy (2), and Tb(tmhd)₃·Phen (3) molecules. The thermal properties of the obtained terbium complexes are studied by TG-DTA.     

Supramolecular Heteroleptic Copper(II) Carboxylates: Synthesis,Spectral Characterization,Crystal Structures,and Enzyme Inhibition Assay

Two new complexes of substituted phenyl acetic acids with CuSO₄ · 5H₂O and 2,2′-bipyridine (Bipy) with formula [CuL(Bipy)₂]L · nH₂O, where L = 2-ClC₆H₄CH₂COO^– (I), 2-CH₃-3-NO₂C₆H₃CH₂COO^– (II) and n = 3 (I); 4 (II), have been synthesized. These complexes have been characterized by elemental analysis, FT-IR and X-ray crystal diffraction (CIF file CCDC nos. 1487707 (I), 1487708 (II)). Both complexes are mononuclear and crystallize in the triclinic space group P1?. In both complexes two molecules of Bipy bind equatorially with metal atom and one molecule of substituted phenyl acetic acid binds at axial position giving rise to a distorted five coordinated geometry around copper atom, while the second oxygen atom of carboxylate ligand appears to occupy the sixth position resulting in highly distorted six coordination environments around metal center in both complexes. However, another molecule of substituted phenyl acetic acid along with water molecules lies as co-crystal within the crystal lattice. Two bipyridine molecules in both complexes are lying in different planes and are oriented at dihedral angle of 63.89(8)° and 74.99(11)° in complexes I and II, respectively. Extensive hydrogen bonding because of water molecules present in crystal lattice plays a vital role in the formation of the 3D structure. Additionally, other weak interactions such as π–π interactions markedly influence the supramolecular structure. An investigation of DNA binding ability of both complexes using UV-visible spectroscopy and anti-diabetic capacity is also presented. Results revealed that synthesized complexes bind with SSDNA through intercalation as well as groove binding mode with K_b values of 2.45 × 10⁴ and 7.72 × 10³ M^–1 for complex I and II, respectively. Complex II strongly inhibits in-vitro α-glucosidase with IC₅₀ value of 30.4 μM, while complex I moderately inhibits in-vitro α-amylase with IC₅₀ value of 69.9 μM. Acarbose was employed as standard in both assays.     

Syntheses,crystal structures,and properties of two supramolecules based on methoxyphenyl imidazole dicarboxylates

Two cobalt(II) and cadmium(II) complexes, [Co(H₂DMOPhIDC)₂(H₂O)₂] ? 2H₂O (H₃DMOPhIDC = 2-(3,4-dimethoxyphenyl)-1H-imidazole-4,5-dicarboxylic acid) (I), [Cd(H₂MOPhIDC)₂-(Phen)] ? C₂H₅OH (H₃MOPhIDC = 2-(3-dimethoxyphenyl)-1H-imidazole-4,5-dicarboxylic acid, Phen = 1,10-phenanthroline) (II), have been hydro(solvo)thermally synthesized by employing two kinds of organic ligands, H₃DMOPhIDC or H₃MOPhIDC, respectively. The molecular structures of I and II have been characterized by IR spectra, elemental analyses and single-crystal X-ray diffraction (CIF files CCDC nos. 935845 (I), 935846 (II)). Both complexes show three-dimensional supramolecular structures supported by intermolecular H-bonds. Furthermore, the thermogravimetric and photoluminescent properties of two complexes have been investigated as well.     

Biomimetic oxidation of catechol employing complexes formed in situ with heterocyclic ligands and different copper(II) salts

In the present work, catecholase activity is presented. The complexes were prepared by condensation of the organic ligand pyrazolyl L ₁ –L ₄ and copper(II) ion in situ. The pyrazolyl compounds L ₁ –L ₄ used in this study are: L ₁ is (3,5-dimethyl-pyrazol-1-ylmethyl)-(4-methyl-pyridin-2-yl)-pyrazol-1-ylmethyl-amine; L ₂ is 1-{4-[(3,5-dimethyl-pyrazol-1-ylmethyl)-pyrazol-1-ylmethyl-amino]-phenyl}-ethanone; L ₃ is 1-{4-[(3,5-dimethyl-pyrazol-1-ylmethyl)-[1,2,4]triazol-1-ylmethyl-amino]-phenyl}-ethanone, and L ₄ is 2-[(3,5-dimethyl-pyrazol-1-ylmethyl)-[1,2,4]triazol-1-ylmethyl-amino]-6-methyl-pyrimidin-4-ol, and copper ions salts Cu(II) are (Cu(CH₃COO)₂, CuCl₂, Cu(NO₃)₂ and CuSO₄). In order to determine factors influencing the catecholase activity of these complexes, the effect of ligand nature, ligand concentration, nature of solvent and nature of counter anion has been studied. The best activity of catechol oxidation is given by the combination formed by one equivalent of ligand L ₂ and one equivalent of Cu(CH₃COO)₂ in methanol solvent which is equal to 9.09 µmol L^?1 min^?1. The Michaelis–Menten model is applied for the best combination, to obtain the kinetic parameters, and we proposed the mechanism for oxidation reaction of catecholase.     

Synthesis and Structure of Different-Metal Different-Ligand Germanium(IV) and Cobalt(II) or Copper(II) Complexes with 1-Hydroxyethylidenediphosphonic Acid and 1,10-Phenanthroline

Different-metal different-ligand complexes [{Co(Phen)₃}₂{Co(Phen)(H₂O)₄}₂][{Ge(μ-OH)(μ- Hedp)}₆Cl₂] (I), [{Cu(Phen)₂(H₂O)}₂(HPhen)₂][Ge(μ-OH)(μ-Hedp)]₆ · 20H₂O (II) (H₄Hedp = 1-hydroxyethylidenediphosphonic acid, Phen = 1,10-phenanthroline) were synthesized and studied by X-ray diffraction. According to X-ray diffraction data (CIF files CCDC nos. 1573112 (I), 1573113 (II)), compounds I and II are cation–anion type complexes in which the anions are represented by {[Ge(μ-OH)(μ-Hedp)]⁶}^6– and, in the case of I, two additional Cl^– ions, while the cations are [Co(Phen)₃]²⁺, [Co(Phen)(H₂O)₄]²⁺ in I and [Cu(Phen)₂(H₂O)]²⁺, HPhen⁺ in II. In the crystals of compounds I and II, the cations, anions, and water molecules are combined by numerous intermolecular hydrogen bonds, giving rise to a 3D network.     

Synthesis,characterization and extraction properties of calix[4]crown with amine units and study of its complexes with Cu(II)

In this work, we have focused on the synthesis of p-tert-butyl calix[4]crown with amine units (H ₃ L) as a class of selective receptors for metal ions. The macrocyclic ligand (H ₃ L) with N₂O₇ donors was synthesized via condensation between 1,3-diaminocalix[4]arene and 2-[3-(2-formylphenoxy)-2-hydroxypropoxy] benzaldehyde, followed by reduction of the Schiff base product in situ with sodium borohydride, then it was characterized by FT-IR, ¹H NMR and X-ray crystallography. Two Cu(II) complexes were prepared from the reaction of H ₃ L with Cu(II) salts (CuX₂, X = ClO₄ ^? and Cl^?). FT-IR, UV–Vis, elemental analysis, molar conductivity and cyclic voltammetry techniques were used for study and characterization of these complexes. On the basis of liquid–liquid extraction experiments, ligand H ₃ L indicated good affinity toward Pb²⁺ and Cu²⁺.     

Two naphthoate-based lead(II) complexes with different limited-nuclear motifs: Syntheses,crystal structures,and fluorescent properties

Two new naphthoate-based lead(II) complexes, [Pb(NA)₂(2,2’-Bipy)] (I) and [Pb₂(NA)₄(4,4’- Bipy)] (II) (NA–= 1-naphthoate, 2,2’-Bipy = 2,2’-bipyridine, and 4,4’-Bipy = 4,4’-bipyridine) (CIF files CCDC nos. 664900 (I), 664899 (II)) have been hydrothermally synthesized by varying the N-heterocyclic coligands. Structural analyses reveal that the two complexes possess different limited-nuclear motifs, the former one owns mononuclear unit and the last complex exhibits centrosymmetric binuclear motif bridged by 4,4’-Bipy connector. The coordination numbers of Pb(II) metal centers in I and II are four and five, respectively. The NA^– anions in both complexes show the same binding modes, it is obvious that the bipyridyl coligands in the present mixed-ligands system are responsible for the dissociation or dimerization of mononuclear structural units and the binding numbers of the metal ion. In both complexes, the 6s lone pair of electrons of Pb²⁺ has a stereochemistry activity resulting the distribution of the Pb–O and Pb–N bonds in a hemisphere. Furthermore, both of the two compounds are linked to 2D network by intermolecular C–H···O hydrogen bonding and π···π stacking interactions, exhibiting strong fluorescent emissions resulting from the NA^?-based intraligand charge transfer at room temperature, which can be hopefully used as fluorescent materials.     

Synthesis,crystal structures,characterization and antitumor activities of two copper(II) complexes of a sulfonamide ligand

An N-sulfonamide (HL = N-(5-(4-methoxyph-enyl)-[1, 3, 4]–thiadiazole–2-yl)-naphtalenesulfonamide) and two of its Cu(II) complexes, [Cu(L)₂(py)₂] (C1) and [Cu(L)(phen)₂](L)1.25(MeOH) (C2), were synthesized. The X-ray crystal structures of the complexes have been determined. In complex C1, the copper atom is four-coordinated, forming a CuN₄ chromophore, while in complex C2, the copper atom is five-coordinated, forming a CuN₅ chromophore. The ligand acts as monodentate, coordinating the metal through a single thiadiazole N atom. The molecules from the reaction medium (pyridine and phenanthroline) are also involved in coordination to the copper atoms. The complexes have a square planar (C1) and slightly distorted square pyramidal (C2) geometries. The compounds were characterized by physicochemical and spectroscopic methods. Nuclease activity studies of the complexes confirm their capacity to cleave DNA. Both complexes also have SOD-like activity, but weaker than the native Cu₂Zn₂SOD activity. Cytotoxicity studies were carried out on melanoma cell line B16F10 and on normal retinal epithelial cell line (D407) and confirmed that C2 inhibits the growth of B16F10 cells, in a dose-dependent manner. Also, C2 displays a cytoselective profile, since it is not toxic to the D407 cell line. The results of the cell cytotoxicity studies are in concordance with the DNA cleavage and SOD mimetic activity studies and indicate that complex C2 has a high biological activity.     

Palladacycles incorporating a carboxylate-functionalized phosphine ligand: syntheses,characterization and their catalytic applications toward Suzuki couplings in water

A series of acetato-bridged [C^X]-type (C = aryl carbanion, X = N, P) palladacycles (1–5) of the general formula [Pd(μ-CH₃COO)(C^X)]₂ were synthesized as metal precursors via slightly modified procedures. However, in the case of complex 5 with Dpbp (Dpbp = 2′-(diphenylphosphino-κP)[1,1′-biphenyl]-2-yl-κC) as the supporting C^P ligand, an unexpected dinuclear complex [Pd(μ-CO₂)(Dpbp)]₂ (6) was obtained as a by-product and structurally determined by X-ray crystallography. The reactions of complexes 1–4 with 2-(diphenylphosphino)benzoic acid conveniently afforded four carboxylate-functionalized phosphine complexes [Pd(C^N)(Dpb)] (Dbp = 2-(diphenylphosphino-κP)benzoato-κO, 7–10), two of which (9/10) are newly synthesized in the present work and have been fully characterized. A comparative catalytic study revealed that complex [Pd(Ppy)(Dpb)] (7) (Ppy = 2-(2-pyridinyl-κN)phenyl-κC) is the best performer in Suzuki cross-couplings in H₂O. In addition, complex 7 exhibits much better catalytic activity compared to the non-functionalized phosphine equivalent [Pd(OAc)(PPh₃)(Ppy)] (11), which clearly indicates the superiority of incorporating a carboxylate-functionalized phosphine ligand into the palladacycles. A preliminary mechanistic study uncovered a different precatalyst initiation pathway compared to other known analogues of catalyst precursors.     

Supramolecular homobimetallic <Emphasis Type="Italic">bis</Emphasis>-diorganotin(IV) complexes of ditopic oxygen nitrogen donor ligand: synthesis,spectroscopic characterization,crystal structure and biological screening

Six new homobimetallic bis-diorganotin(IV) complexes: [Me₂Sn]₂L (1), [Et₂Sn]₂L (2), [n-Bu₂Sn]₂L (3), [Ph₂Sn]₂L (4), [Oct₂Sn]₂L (5) and [n-BuClSn]₂L (6) (H ₄ L=N¹′, N⁶′-bis(2-hydroxybenzylidene)adipodihydrazide) have been synthesized and structurally characterized by means of elemental analysis, mass spectroscopy, FT-IR, NMR (¹H, ¹³C{¹H}, ¹¹⁹Sn) and single-crystal X-ray diffraction. Spectroscopic studies indicate coordination of the ligand to the diorganotin(IV) moieties via iminolic oxygen, nitrogen and phenolic oxygen atoms generating pentacoordinated tin centers. Single-crystal X-ray analysis of (1) revealed homobimetallic nature of complex with dimethyltin moieties oriented in trans-conformation. The ligand is non-planar with each Sn atom in a distorted square pyramidal coordination geometry. Packing diagrams suggest the essential role of C–H^…N and C–H^…O interactions in generating supramolecular assembly. The ligand and complexes were screened for in vitro antimicrobial activity and cytotoxicity. Compound (4) exhibits highest cytotoxicity.     

Crystal structure of Co(III) α-dimethylglyoximates with imidazole

Two new dimethylglyoximate complexes [Co(DmgH)₂(Im)Cl] (I) and (ImH)[Co(DmgH₂)₂Cl₂] (II), where DmgH^? is the dimethylglyoxime residue and Im is the imidazole molecule, are synthesized. The composition and structure of the crystals are determined from the elemental analysis, IR spectra, and single crystal X-ray diffraction. Complex I is molecular, containing the Im molecule as a coordinated ligand; complex II is of the ionic type with (ImH)⁺ involved as an outer-sphere organic cation. The mode of component packing in the crystals mainly depends on the imidazole position in the compounds.     

Novel 1D Mn(II) complexes containing aromatic dicarboxylic acids

Three Mn(II) complexes of [MnL(Bipy)(H₂O)] _n (I), [Mn₃(Phen)₂(HL)₂(L)₂]n (II), and [Mn(Phen)₂(HL)(OH)] (III), where L = 4,4′-(2-acetylpropane-1,3-diyl)dibenzoic acid, Bipy = 2,2′-bipyridine, and Phen = 1,10-phenanthroline, were hydrothermally synthesized and characterized by single crystal X-ray diffractions, infrared spectroscopy, thermogravimetric analyses, and magnetic analyses. Complexes I and II are one dimensional (1D) coordination polymers which can form the supramolecules with the help of the intermolecular hydrogen bond interactions. Finally, the landé factors are simulated by magentochemical analysis to be 2.15 and 1.80 for I and II with S = 5/2, respectively.     

Synthesis of copper(II) and zinc(II) complexes with chalcone–thiosemicarbazone hybrid ligands: X-ray crystallography,spectroscopy and yeast activity

Four chalcone–thiosemicarbazones (C-TSCs) of the type 2-((E)-3-(4-R-phenyl)-1-phenylallylidene)-N-phenylhydrazinecarbothioamide, where R?=?Cl (HL1), NO₂ (HL2), CH₃ (HL3) or CN (HL4), were prepared in good yields from the reaction of the respective chalcone with 4-phenyl-3-thiosemicarbazide and HCl in EtOH. Reaction of HL with CuCl₂·2H₂O or ZnCl₂ in the presence of Et₃N afforded the complexes [M(L)₂], M?=?Cu(II) or Zn(II). X-ray diffraction analysis revealed that the ligands coordinate in their deprotonated form, in a bidentate fashion through the iminic nitrogen and sulfur atoms. Yeast activities of the compounds were tested, where the ligand HL4 was the most damaging derivative, exhibiting cell viability at about 50%. On the other hand, lipid peroxidation assays revealed that the ligand HL1 was able to better induce membrane damage compared to the other compounds. It has been found that coordination with Cu(II) and Zn(II) did not increase the biological activities of the C-TSCs.     

Hydrothermal synthesis, crystal structures, and properties of two Co(II) complexes based on 4-bromoisophthalic acid and N-donor ligands

Two new Co(II) complexes, [Co₂(H₂O)(Bipy)₂(Bript)₂] _n (I) and [Co(H₂O)(Phen)(Bript)] · H₂O (II), where H₂Bript = 4-bromoisophthalic acid, Bipy = 2,2??-bipyridine, and Phen = 1,10-phenanthroline, have been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. Complex I has binuclear units in which two Co²⁺ ions are bridged by two carboxylate groups and a coordinaiod-water molecule, and the binuclear units are connected by Bript to generate a 1D helical chain. These 1D helical chains are further linked by ????? stacking interactions to form a 3D supramolecular network, while complex II has a 2D layer motif. In I and II, there exists extensive hydrogen bonding interactions. The thermal behavior of the two corresponding complexes have briefly been investigated.     

Hydrides,alkalides, and halides of calcium metal chain: electronic structure and NLO property

The ground state structure and stability of linear calcium chains Ca _n X ₂ , XCa _n Y (X,Y?=?H, Li, Na, K; n?=?1–8), Ca ₈ Y ₂ , and Ca ₈ XY (X?=?H, K; Y?=?F, Cl, Br) have been calculated at the B3LYP/6-311++G(d,p) level. The hyperpolarizabilities of these metal complexes are calculated by employing B2PLYP, BHHLYP, and CAM-B3LYP functionals. The electron correlation at the MP2, CCSD, and CCSD(T) levels and the effect of basis set on the second hyperpolarizability of some representative molecules are also examined. Among the chosen functionals, the CAM-B3LYP method with POL basis set shows fair agreement with the CCSD(T)/POL γ _zzzz . The chosen species are found to be sufficiently stable. The dialkalide calcium chains possess larger magnitude of linear polarizability and second hyperpolarizability compared to dihydrides and dihalides. The highest value of first hyperpolarizability has been obtained for the complex Ca ₈ HK. Among the investigated metal complexes, the substantially larger second hyperpolarizability is obtained for alkalides, Ca ₈ LiK, Ca ₈ NaK, Ca ₈ K ₂ in which charge transfer is significantly larger. The calculated transition energy and transition moment associated with the most crucial electronic transition play a significant role in modulating the magnitude of hyperpolarizabilities. The TD-CAMB3LYP calculated transition energy shows increasing red shift following the power law ?E _ng  =?bn ^?c with c value varying in the order Ca _n H ₂ >> Ca _n Li ₂ = Ca _n Na ₂ ≥ Ca _n K ₂ . The most interesting feature is that no saturation limit of γ can be realized on increasing the length of calcium metal chains but ?E _ng approaches to a limiting value for n?→?∞.     

Synthesis,characterization and X-ray crystal structure of novel nickel Schiff base complexes and investigation of their catalytic activity in the electrocatalytic reduction of alkyl and aryl halides

Novel potentially bidentate NO Schiff base ligands, HL ¹ and HL ² derived from condensation reaction of 2′-methoxyphenyl-2-ethylamine with salicylaldehyde (HL ¹ ) and with 2-hydroxy-4-methoxybenzaldehyde (HL ² ), and their nickel complexes were synthesized and characterized by usual spectroscopic techniques such as FT-IR, UV–Vis, ¹H NMR, ¹³C NMR and elemental analysis. It was revealed that the bidentate Schiff base ligands coordinate with Ni(II) ions yielding mononuclear complexes with 1:2 (metal/ligand) stoichiometry. This result has been determined by using X-ray crystallographic technique of HL ² and the nickel complex derived from HL ¹ (Ni(II)-2L ¹ ). So, the structural studies showed that the two Ni(II) complexes adopt a square-planar geometry around the central metal ion. Cyclic voltammetry studies were investigated in 0.1 M TBAP in DMF solution and indicate that the nickel complexes show one reduction wave related to Ni(II)/Ni(I) redox couple. The electrocatalytical properties of these complexes were also studied in the same electrolyte medium. Their electrocatalytic performances have been tested toward the electroreduction reaction of bromocyclopentane and iodobenzene, showing a promoted activity in the case of the Ni(II)-2L ² complex.     

Halide copper(II) complexes of aromatic N-donor containing ligands: Structural,magnetic and reactivity studies

The preparation of four new copper(II) complexes with different N-donor ligands [CuBr₂(2-benzylpyridine)₂] (1), [CuBr₂(2-benzylpyridine)(2,2′-bipyridine)]·H₂O (2), [CuBr₂(3-methyl-2-phenylpiridine)₂] (3), [Cu(picolinate)₂]·KI (4) from copper(I) halides as starting material is described. During the preparation of compound 4 a ligand oxidation reaction took place to give the picolinate ligand starting from 2-(2-methylaminoethyl)pyridine. The complexes were characterized by elemental analyses, IR spectroscopy and crystallographic studies. Single crystal X-ray diffraction analysis of the complexes reveals their monomeric penta- and tetracoordinated nature. For all compounds, the copper(II) present a common square planar coordination except for compound 2 which is five coordinated in a quasi-square pyramidal configuration with τ of 0.29. The Cu–N distances for these compounds are in the range of 1.959(4)-2.041(3) Å, Cu–O distance was 1.961(3) Å and Cu–Br distances were in the range of 2.4052(4)-2.4381(6) Å for the square base configuration while for apical distance it was 2.6745(7) Å. Magnetic properties have been investigated for all compounds in the temperature range 2-300 K. Compound 1 shows weak antiferromagnetic intermolecular interaction.     

Copper(I) complexes of 2-(benzen-1-yl)methyleneamino-3-aminomaleonitrile and triphenylphosphine ligands: synthesis,characterization, luminescence and catalytic properties

Some mixed ligand copper(I) complexes of general formula [Cu(L)(PPh₃)₃]X (X = Cl (1), ClO₄ (2), BF₄ (3) or PF₆ (4); L = 2-(benzen-1-yl)methyleneamino-3-aminomaleonitrile) were prepared and characterized by physicochemical and spectroscopic methods. A single-crystal X-ray diffraction study of [Cu(L)(PPh₃)₃]CIO₄ (2) revealed that the copper atom is four coordinated in a distorted tetrahedral geometry. Electrochemical studies of complexes 1–4 show quasireversible redox behavior corresponding to the Cu(I)/Cu(II) couple. Room temperature luminescence is observed for all four complexes. These complexes proved to be effective catalysts for the Sonogashira coupling of terminal alkynes with aryl halides at 90 °C.     

Supramolecular structure,spectroscopic, thermal studies and antimicrobial activities of Schiff base complexes

Metal(II) complexes of 4-(((2-hydroxynaphthalen-1-yl)methylene)amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (HL) were prepared, and their compositions and physicochemical properties were characterized on the basis of elemental analysis, with¹HNMR, UV–Vis, IR, mass spectroscopy and thermogravimetric analysis. All results confirm that the novel complexes have a 1:1 (M:HL) stoichiometric formulae [M(HL)Cl₂] (M = Cu(II)(1), Cd(II)(5)), [Cu(L)(O₂NO)(OH₂)₂](2), [Cu(HL)(OSO₃)(OH₂)₃]2H₂O(3), [Co(HL)Cl₂(OH₂)₂]3H₂O(4), and the ligand behaves as a neutral/monobasic bidentate/tridentate forming a five/six-membered chelating ring towards the metal ions, bonding through azomethine nitrogen, exocyclic carbonyl oxygen, and/or deprotonated phenolic oxygen atoms. The XRD studies show that both the ligand and Cu(II) complex (1) show polycrystalline with monoclinic crystal structure. The molar conductivities show that all the complexes are non-electrolytes. On the basis of electronic spectral data and magnetic susceptibility measurements, a suitable geometry has been proposed. The trend in g values (g _ll > g _⊥ > 2.0023) suggest that the unpaired electron on copper has a \(d_{{x^{2} - y^{2} }}\) character, and the complex (1) has a square planar, while complexes (2) and (3) have a tetragonal distorted octahedral geometry. The molecular and electronic structures of the ligand (HL) and its complexes (1–5) have been discussed. Molecular docking was used to predict the binding between HL ligand and the receptors of the crystal structure of Escherichia coli (E. coli) (3t88) and the crystal structure of Staphylococcus aureus (S. aureus) (3q8u). The activation thermodynamic parameters, such as activation energy (E _a), enthalpy (ΔH), entropy (ΔS), and Gibbs free energy change of the decomposition (ΔG) are calculated using Coats–Redfern and Horowitz–Metzger methods. The ligand and its metal complexes (1–5) showed antimicrobial activity against bacterial species such as Gram positive bacteria (Bacillus cereus and S. aureus), Gram negative bacteria (E. coli and Klebsiella pneumoniae) and fungi (Aspergillus niger and Alternaria alternata); the complexes exhibited higher activity than the ligand.     

Addition of phenylacetylene and camphor to the complex [(dpp-bian)Eu(dme)<Subscript>2</Subscript>] (dpp-bian is the 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene dianion)

The reduction of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-bian) with an excess of europium metal in 1,2-dimethoxyethane (dme) produces a divalent europium complex with the dpp-bian dianion, [(dpp-bian)Eu(dme)₂] (1). The reactions of 1 with phenyl-acetylene and camphor proceed via protonation of the diimine ligand to form the monomeric amido-amino complexes of divalent europium — [H(dpp-bian)Eu(C≡CPh)(dme)₂] (2) and [H(dpp-bian)Eu(camphor)(dme)₂] (3), respectively. Compounds 2 and 3 were characterized by IR spectroscopy and elemental analysis. Their molecular structures were determined by X-ray diffraction. Compounds 2 and 3 were shown to be monomeric seven-coordinate europium(ii) complexes with terminal phenylethynyl and enol ligands, respectively. According to the IR spectroscopic data, the terminal ligands in complexes 2 and 3 undergo tautomerization involving backward proton transfer from the amido-amino ligand to the substrate. The magnetic moment of compound 2 (8.03 μB) remains constant in the temperature range of 4—300 К and confirms the presence of divalent europium.