The reactions of diphenylcarbazide and diphenylcarbazone with cations : Part IV. Cations of Mn,Fe, Co,Ni, Cu,Zn, Cd,Sn And Pb

Of the cations mentioned in the title, only Pb(IV) and Sn(IV) do not react with diphenylcarbazone. The compositions of the carbazone complexes were determined by Job's method; the formula proved to be M(HD)_n according to the valence of the cation. Diphenylcarbazide forms metal complexes only after its oxidation to diphenylcarbazone. Oxidation of carbazide by the metal ion itself occurs with copper(II) and iron(III).     

(4,4′‐Bipyridine)mercury(II) Coordination Polymers,Syntheses, and Structures

Mercury(II) complexes with 4,4′‐bipyridine (4,4′‐bipy) ligand were synthesized and characterized by elemental analysis, and IR, ¹H‐ and ¹³C‐NMR spectroscopy. The structures of the complexes [Hg₃(4,4′‐bipy)₂(CH₃COO)₂(SCN)₄]_n ( 1 ), [Hg₅(4,4′‐bipy)₅(SCN)₁₀]_n ( 2 ), [Hg₂(4,4′‐bipy)₂(CH₃COO)₂]_n(ClO₄)_2n ( 3 ), and [Hg(4,4′‐bipy)I₂]_n ( 4 ) were determined by X‐ray crystallography. The single‐crystal X‐ray data show that 2 and 4 are one‐dimensional zigzag polymers with four‐coordinate Hg‐atoms, whereas 1 is a one‐dimensional helical chain with two four‐coordinate and one six‐coordinate Hg‐atom. Complex 3 is a two‐dimensional polymer with a five‐coordinate Hg‐atom. These results show the capacity of the Hg‐ion to act as a soft acid that is capable to form compounds with coordination numbers four, five, and six and consequently to produce different forms of coordination polymers, containing one‐ and two‐dimensional networks.     

Quantum chemical studies on the role of water microsolvation in interactions between group 12 metal species (Hg2+, Cd2+, and Zn2+) and neutral and deprotonated cysteines

Interactions of group 12 metal(II) species (Hg²⁺, Cd²⁺, Zn²⁺, Hg(H₂O) _n ²⁺ , Cd(H₂O) _n ²⁺ , and Zn(H₂O) _n ²⁺ (n?=?1, 2) with neutral (RSH), deprotonated (RS^?), and doubly deprotonated cysteine species (abbreviated as ??H₂cys??, ??Hcys^???, and ??cys^2???, respectively) are examined with the Becke three-parameter Lee?CYang?CParr (B3LYP) hybrid functional after preliminary screening in a conformation analysis with the Parameterized Model number 3 (PM3) semiempirical method. Effects of water on aqueous solution are evaluated by microsolvation and polarized continuum model (PCM) approaches. In the most stable conformations of M(H₂cys)²⁺ and M(Hcys)⁺ complexes (M?=?Hg²⁺, Cd²⁺, and Zn²⁺), the SH group of the cysteine moiety is already deprotonated and undergoes strong binding with the metal ion. Among Hg(H₂cys)²⁺ complexes, cysteine complexes of Hg²⁺ without deprotonation of the SH group and mercury(II) carboxylato-type structures are at least 83 and 117?kJ/mol less stable in energy than the most stable complex (B3LYP/6-311++G(d,p)-SDD+d+f//B3LYP/6-31G(d)-SDD+d). Although Zn²⁺ binds more strongly than Hg²⁺ to a H₂cys molecule at the high-level CCSD(T)/6-311++G(d,p)-SDD+d+f//B3LYP/6-311++G(d,p)-SDD+d+f level, [Hg(H₂O)₂]²⁺ is stronger than [Zn(H₂O)₂]²⁺ because the deformation of [Zn(H₂O)₂]²⁺ required to bind to cys is much more than in [Hg(H₂O)₂]²⁺. Complexes with a deprotonated cysteine, M(Hcys)⁺ and M(cys), prefer a multidentate structure.     

Zinc(II), cadmium(II) and mercury(II) complexes of 4,6-dimethyl-pyrimidine-2(1H)-one

The following zinc(II), cadmium(II) and mercury(II) complexes of 4,6-dimethylpyrimidine-2(1H)-one (L) have been prepared and investigated by conductometric,IR and Raman methods: MX₂L₂ (M = Zn, X = Cl, Br(CHCl₃, I(CHCl₃, CF₃COO; M = Cd, X = Cl, Br CF₃COO; M = Hg, X = Cl, CF₃COO), Cd₂I₄L₃, Hg₃X₆L₂ (X = Cl, Br), Hg₃X₆L₄(X = Br, I), MX₂L₄·6H₂O (M = Zn, Cd, X = CIO₄, BF₄; M = Hg, X = CIO₄. The ligand is principally bonded through the unprotonated nitrogen atom and in some complexes also through the carbonylic oxygen atom. The zinc halide complexes are tetrahedrally coordinated, the trifluoroacetate ion is coordinated as a monodentate ligand.     

Thermal studies on metal complexes of 5-nitrosopyrimidine derivatives

The following Zn(II), Cd(II), Hg(II) and Hg(I) complexes of 4-amino-1,6-dihydro-2-methylthio-5-nitroso-6-oxopyrimidine (MTH) have been prepared and their thermal behaviour studied by TG and DSC techniques: Zn(MT)₂·3H₂O, Cd(MT)·H₂O. Cd(MTH)Cl₂, Hg(MTH)Cl₂ and Hg₂(MT)(NO₃). The dehydration and dehalogenation enthalpy values were calculated.     

The crystal structures of two Mercury Perrhenates

The mercury perrhenates with the empirical formulas HgReO₄ and Hg₂ReO₅ were prepared by annealing powdered mixtures of mercury(II)oxide and mercury(II)metaperrhenate Hg(ReO₄)₂ in sealed silica tubes. Their crystal structures were determined from single-crystal X-ray data. HgReO₄ crystallizes dimeric with nearly linear O₃Re? O? Hg? Hg? O? ReO₃ molecular units and Hg₂ReO₅ has a solid state structure, where Hg(I) and Hg(II) together with oxygen atoms form 14-membered rings, which are condensed to two-dimensionally infinite polycationic nets of composition (Hg₂²⁺ · 2 HgO)_n. These nets are separated from each other by tetrahedral ReO₄^? anions.     

Fe–Hg Interactions and P Chemical Shifts in [Fe(CO)3 (PPh2R)2(HgCl2)] (R=pym, fur, py, thi)

In order to study the effects of R group on Fe–Hg interactions and 31P chemical shifts, the structures of mononuclear complexes Fe(CO)₃(PPh₂R)₂ (R=pym:1, fur: 2, py: 3,thi: 4; pym=pyrimidine, fur=furyl, py=pyridine, thi=thiazole) and binuclear complexes [Fe(CO)₃(PPh₂R)₂(HgCl₂)] (R=pym: 5, fur: 6, py: 7, thi: 8) were studied using the density functional theory (DFT) PBE0 method. The 31P chemical shifts were calculated by PBE0-GIAO method. Nature bond orbital (NBO) analyses were also performed to explain the nature of the Fe–Hg interactions. The conclusions can be drawn as follows: (1) The complexes with nitrogen donor atoms are more stable than those with O or S atoms. The more N atoms there are, the higher is the stabilility of the complex. (2) The Fe–Hg interactions play a dominant role in the stabilities of the complexes. In 5 or 6, thereisa σ-bond between Fe and Hg atoms. However, in 7 and 8, the Fe–Hg interactions act as σ_P–Fe→n_Hg and σ_C–Fe→n_Hg delocalization. (3) Through Fe→Hg interactions, there is charge transfer from R groups towards the P, Fe, and Hg atoms, which increases the electron density on P nucleus in binuclear complexes. As a result, compared with their mononuclear complexes, the 31P chemical shifts in binuclear complexes show some reduction.     

Three one‐dimensional coordination polymers based on 1,1′‐bis(pyridin‐4‐ylmethyl)‐2,2′‐bi‐1H‐benzimidazole and HgX2 (X = Cl,Br and I)

A new 2,2′‐bi‐1H‐benzimidazole bridging organic ligand, namely 1,1′‐bis(pyridin‐4‐ylmethyl)‐2,2′‐bi‐1H‐benzimidazole, C₂₆H₂₀N₆, L or (I), has been synthesized and used to create three new one‐dimensional coordination polymers, viz.catena‐poly[[dichloridomercury(II)]‐μ‐1,1′‐bis(pyridin‐4‐ylmethyl)‐2,2′‐bi‐1H‐benzimidazole], [HgCl₂(C₂₆H₂₀N₆)]_n, (II), and the bromido, [HgBr₂(C₂₆H₂₀N₆)]_n, (III), and iodido, [HgI₂(C₂₆H₂₀N₆)]_n, (IV), analogues. Free ligand L crystallizes with two symmetry‐independent half‐molecules in the asymmetric unit and each L molecule resides on a crytallographic inversion centre. In structures (II)–(IV), the L ligand is also positioned on a crystallographic inversion centre, whereas the Hg centre resides on a crystallographic twofold axis. Compound (I) adopts an anti conformation in the solid state and forms a two‐dimensional network in the crystallographic bc plane viaπ–π and C—H...π interactions. The three Hg^II coordination complexes, (II)–(IV), have one‐dimensional zigzag chains composed of L and HgX₂ (X = Cl, Br and I), and the Hg^II centres are in a distorted tetrahedral [HgX₂N₂] coordination geometry. Complexes (III) and (IV) are isomorphous, whereas complex (II) displays an interesting conformational difference from the others, i.e. a twist in the flexible bridging ligand.     

Organoselenium/Tellurium-Bearing Macroacyclic and Cyclic Ligand Systems and Their Complexation Reactions

Abstract

A series of phenol-substituted acyclic Schiff bases, 2,6-{RE(CH₂) _n N═C(CH₃)}₂-C₆H₂(4-CH₃)(OH), (E = Te: R = C₆H₅, n = 2(L _a), 3(L _b); R = C₆H₄-4-OCH₃, n = 2(L _c), 3(L _d); E = Se: R = C₆H₅, n = 2(L _e), 3(L _f)), of the type E₂N₂O have been synthesized by condensation of 2,6-diacetyl-4-methylphenol with arylchalcogenoalkylamines. This ligand framework is useful for designing molecular complexes with a variety of coordination modes depending upon the nature of the central metal atom. The reactivity of the tellurium-bearing macroacyclics ligands towards Zn(II), Cd(II), and Hg(II) has been examined. The ligands L _a?L _d with Zn(II) and Cd(II), and only L _a and L _b with Hg(II) form complexes of composition M₂X₄L, (X = Cl or Br), whereas L _c and L _d with Hg(II) give products of composition HgBr₂L. The modes of ligand interaction with Zn(II) and Cd(II) are different than that with Hg(II).

Following a multistep reaction involving abstraction of bridged Br atoms and subsequent addition of more ligand, the mercury complex, Hg₂Br₄L has been used for developing metallocyclic system of the type [Hg₂Br₂L₂]²⁺. The latter has been found to encapsulate Zn(II) and Cd(II) to give multimetallic systems.     

硫、氮双齿配体与Cd(II)和Hg(II)配合物的合成与表征

以HMFC[(反)-肉桂酰基二茂铁缩(S)-甲基二硫代碳酰腙]与HBFC[(反)-肉桂酰基二茂铁缩(S)-苄基二硫代碳酰腙]两种Schiff碱分别与醋酸镉[Cd(OAc)₂•2H₂O]、醋酸汞[Hg(OAc)₂]反应, 合成了6个未见文献报道的配合物Cd(MFC)₂•H₂O, Cd(MFC)•OAc, Cd(BFC)₂, Hg(MFC)₂, Hg(MFC)•OAc, Hg(BFC)₂, 考察了其物理性质, 并利用元素分析、IR, ¹H NMR及摩尔电导表征了其组成、可能结构, 推断了配位过程. 结果表明: 这两种Schiff 碱都是反式双齿配体, 经烯硫醇化并失去质子后, 以负硫离子与过渡金属离子形成共价键, 氮原子与中心金属离子形成配位键.     

Mercury(II) complexes of pyrrolidinedithiocarbamate,crystal structure of bis{[μ2-(pyrrolidinedithiocarbamato-S,S ′)(pyrrolidinedithiocarbamato-S,S ′)mercury(II)]}

Mercury(II) complexes of pyrrolidinedithiocarbamate (PDTC) having the general formula [Hg(PDTC)X] (X = Cl^?, SCN^?, and CN^?) and [Hg(PDTC)₂] have been prepared and characterized by elemental analysis, IR, and NMR. The crystal structure of [Hg(PDTC)₂] has also been determined by X-ray crystallography, showing that the complex is a centrosymmetric dimer, [Hg₂(PDTC)₄] (bis[µ²-(pyrrolidinedithiocarbamato-S,S′)(pyrrolidinedithiocarbamato-S,S′)mercury(II)]) (1). The solid-state structure of 1 contains two crystallographically equivalent Hg(II) centers in a distorted tetrahedron.     

Halide-directed Assembly of Mercury(II) Coordination Polymers for Electrochemical Biosensing Toward Penicillin

Three 1D/2D Hg^II coordination polymers (CPs), namely {[Hg₃(L)₂Cl₆](H₂O)}_n ( 1 ), [Hg(L)Br₂]_n ( 2 ), and [Hg(L)I₂]_n ( 3 ) were prepared by assembly of 3,4-bis(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (L) with different inorganic Hg^II salts (i.e. HgCl₂, HgBr₂ or HgI₂). Single-crystal X-ray diffraction analysis reveals two types of bimetallic subunits [(Hg)₂C₆N₄] and [(Hg)₂C₁₂N₆] in CP 1 , which are further extended to a 2D coordination network. Both of CPs 2 and 3 show 1D zigzag arrays bridged by L ligands. Notably, the L ligands take the (η⁴, μ₄) coordination fashion in 1 but (η², μ₂) binding mode in 2 and 3 . The structural differences of CPs 1 – 3 indicate that the L ligand can adjust its coordination fashions to meet the requirements of Hg^II centers, relying on the presence of distinct halide anions. In addition, 1 can be applied to fabricate an electrochemical biosensor for the detection of penicillin.     

Synthesis and structural studies of new Mannich base ligands and their metal complexes

The new Mannich bases bis(1,4-diphenylthiosemicarbazide methyl) phosphinic acid H₃L¹ and bis(1,4-diphenylsemicarbazide methyl) phosphinic acid H₃L² were synthesised from the condensation of phosphinic acid, formaldehyde with 1,4-diphenyl thiosemicarbazide and 1,4-diphenylsemicarbazide, respectively. Monomeric complexes of these ligands, of general formulae K₂[Cr^III(L ⁿ )Cl₂], K₃[Mn^II(L ⁿ )Cl₂] and K[M(L ⁿ )] (M = Co(II), Ni(II), Cu(II), Zn(II) or Hg(II); n = 1, 2), are reported. The mode of bonding and overall geometry of the complexes were determined through physico-chemical and spectroscopic methods. These studies revealed octahedral geometries for the Cr(III), Mn(II) complexes, square planar for Co(II), Ni(II) and Cu(II) complexes and tetrahedral for the Zn(II) and Hg(II) complexes.     

Synthesis and structure of [Hg2(L)2(NO3)2] (L = (4-nitrophenyl)pyridin-2-ylmethyleneamine); a theoretical study on Hg–Hg bond in this and in linear Hg2X2 (X = F, Cl, Br, I, Ph) complexes

A new binuclear mercury(I) complex, [Hg₂(L)₂(NO₃)₂] (L = (4-nitrophenyl)pyridin-2-ylmethyleneamine), 1, has been synthesized and characterized by CHN analyses, IR, UV–vis spectroscopy and X-ray crystal structure analysis. The complex contains a metal–metal bonded core, [Hg–Hg]²⁺, in which a single bidentate imine ligand is coordinated to each mercury atom. The Hg atoms have an additional interaction with the oxygen atom of the NO₃ ^? ion. Theoretical studies show that the interaction energy between the two {Hg(L)NO₃} fragments is about 45–59 kcal/mol depending on the level of calculation. The Mayer-Mulliken and Wiberg bond indices (WBI) for Hg–Hg bond at different levels of theory are about 0.75–0.88 and 0.60–0.70, respectively, and are significantly larger than that for Hg–N and Hg–O bonds. The NBO calculations by using different methods and basis sets also show that the S character in Hg–Hg bond is very large (94.65–97.81 %). All above data for this complex are compared with those for linear Hg₂X₂ (X = F,Cl, Br, I, Ph) complexes. Interestingly, the bond order for Hg–Hg bond in complex 1 is comparable with that for Hg₂F₂ and larger than those in above linear complexes. This is consistent with the experimental data indicating that the Hg–Hg bond in 1 is shorter than that in all above complexes, except Hg₂F₂.     

Effect of terminal groups on the relative stability of linear mercury clusters

The problem of stabilizing the linear clusters of mercury by terminal groups is discussed in terms of the MNDO method for the following model and real compounds: Hg_n (I), Hg_nCl₂ (II) and Hg_n(AlCl₄)₂ (III) with n=2–4. It is shown that the terminal acceptor groups stabilize the linear mercury chains. It is established that in systems (II) and (III), unlike in (I), the highest occupied molecular orbitals are bonding. Mordoviya State University. Institute of Organoelement Compounds, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 4, pp. 623–629, July–August, 1995. Translated by I. Izvekova     

One‐dimensional coordination polymers generated from a new triazole bridging ligand and HgX2 (X = Cl,Br and I): characterization and luminescent properties

The new 4‐amino‐1,2,4‐triazole asymmetric bridging ligand 4‐amino‐5‐(pyridin‐3‐yl)‐3‐[4‐(pyridin‐4‐yl)phenyl]‐4H‐1,2,4‐triazole (L) has been used to generate three novel isomorphic one‐dimensional coordination polymers, viz. catena‐poly[[tris[dichloridomercury(II)]‐bis{μ₃‐4‐amino‐5‐(pyridin‐3‐yl)‐3‐[4‐(pyridin‐4‐yl)phenyl]‐4H‐1,2,4‐triazole}] acetonitrile monosolvate], {[Hg₃Cl₆(C₁₈H₁₄N₆)₂]·CH₃CN}_n, (I), and the bromido, {[Hg₃Br₆(C₁₈H₁₄N₆)₂]·CH₃CN}_n, (II), and iodido, {[Hg₃I₆(C₁₈H₁₄N₆)₂]·CH₃CN}_n, (III), analogs. The asymmetric ligand acts as a tridentate ligand to coordinate the three different Hg^II centers (two of which are symmetry‐related). Two ligands and two symmetry‐related Hg^II centers form centrosymmetric rectangular units which are linked into one‐dimensional chains via the other unique Hg atoms, which sit on mirror planes. The chains are elaborated into a three‐dimensional structure via interchain hydrogen bonds. The acetonitrile solvent molecules are located in ellipsoidal cavities. The luminescent character of these three coordination complexes was investigated in the solid state.     

New homoleptic metal complexes of Schiff bases derived from 2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-one

New bidentate Schiff-base ligands 2-(2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-ylidene)hydrazinecarbothioamide HL¹ and 2-(2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-ylidene)hydrazinecarboxamide HL² were synthesized from the condensation of 2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-one with thiosemicarbazide and semicarbazide, respectively. Homoleptic complexes of these ligands, of general formula K[Cr(L ⁿ )₂Cl₂], K₂[Mn(L ⁿ )₂Cl₂], K₂[Fe(L¹)₂Cl₂] and [M(L ⁿ )₂] (where M = Co(II), Ni(II) Cu(II), Zn(II), Cd(II), and Hg(II) ions; n = 1 or 2) are reported. The mode of bonding and overall geometry of the complexes were determined through IR, UV-Vis, NMR and mass spectral studies, magnetic moment measurements, elemental analysis, metal content, and conductance. These studies revealed octahedral geometry for Cr(III), Mn(II), and Fe(II) complexes, square planar for Cu(II), Co(II), and Ni(II) complexes and tetrahedral for Zn(II), Cd(II), and Hg(II) complexes.     

Syntheses,Characterization, and Crystal Structures of a Dinuclear Complex and Coordination Polymer of Mercury(II) with Schiff Base Ligands containing N3 and N4 Donors

Two dinuclear mercury(II) iodide compounds, [Hg₂(L)(I)₄] ( 1 ) and [(L′)Hg(μ‐I)₂HgI₂]_n ( 2 ) [L = N,N′‐bis(phenyl(pyridin‐2‐yl)methylene)propane‐1,2‐diamine and L′ = N‐(phenyl(pyridin‐2‐yl)methylene)propane‐1,2‐diamine] were synthesized and characterized. The molecular structures of [Hg₂(L)(I)₄] ( 1 ) and [(L′)Hg(μ‐I)₂HgI₂]_n ( 2 ), which were determined by single‐crystal X‐ray diffraction, indicate that each Hg^II in 1 has a distorted tetrahedral environment around the metal atom with a HgN₂I₂ chromophore, whereas in 2 one mercury(II) atom adopts a distorted tetrahedral arrangement with a HgI₄ chromophore and the other has a distorted square pyramidal environment with HgN₃I₂ chromophore. In the solid state, compound 2 consists of a 1D coordination polymer structure.     

Possibilities of tetra-, penta-, and hexacoordination in quantum-chemical simulation of mechanism of formation and stereoisomerization of bisligand azomethine complexes of Zn(II), Cd(II), and Hg(II)

The competition between tetra-, penta-, and hexacoordination with the MN₂O₂, MN₂O₂X, and MN₂O₂X₂ (X = S, Se) coordination nodes, respectively, during the formation of bisligand Zn(II), Cd(II), and Hg(II) complexes with bi- and tridentate heterocyclic azomethines has been studied by means of quantumchemical DFT simulation of the complex formation and further stereoisomerization. It has been found that pentacoordination was favorable for the Cd(II) and Hg(II) complexes, whereas the Zn(II) complexes are tetracoordinate.     

Molecular Docking,DFT Calculations,Effect of High Energetic Ionizing Radiation,and Biological Evaluation of Some Novel Metal (II) Heteroleptic Complexes Bearing the Thiosemicarbazone Ligand

New Pb(II), Mn(II), Hg(II), and Zn(II) complexes, derived from 4-(4-chlorophenyl)-1-(2-(phenylamino)acetyl)thiosemicarbazone, were synthesized. The compounds with general formulas, [Pb(H₂L)₂(OAc)₂]ETOH.H₂O, [Mn(H₂L)(HL)]Cl, [Hg₂(H₂L)(OH)SO₄], and [Zn(H₂L)(HL)]Cl, were characterized by physicochemical and theoretical studies. X-ray diffraction studies showed a decrease in the crystalline size of compounds that were exposed to gamma irradiation (γ-irradiation). Thermal studies of the synthesized complexes showed thermal stability of the Mn(II) and Pb(II) complexes after γ-irradiation compared to those before γ–irradiation, while no changes in the Zn(II) and Hg(II) complexes were observed. The optimized geometric structures of the ligand and metal complexes are discussed regarding density functional theory calculations (DFT). The antimicrobial activities of the ligand and metal complexes against several bacterial and fungal stains were screened before and after irradiation. The Hg(II) complex has shown excellent antibacterial activity before and after γ-irradiation. In vitro cytotoxicity screening of the ligand and the Mn(II) and Zn(II) complexes before and after γ-irradiation disclosed that both the ligand and Mn(II) complex exhibited higher activity against human liver (Hep-G2) than Zn(II). Molecular docking was performed on the active site of MK-2 and showed good results.