Solid state and solution NMR studies of some new complexes of mercury selenocyanate with imidazolidine-2-thione and its derivatives

Reactions of imidazolidine-2-thione (Imt), 1,3-diazinane-2-thione (Diaz) and 1,3-diazipane-2-thione (Diap) with mercury(II) selenocyanate in acetonitrile resulted in formation of 2?:?1 complexes. Both solid state and solution NMR, confirm the exocyclic sulfur atom to be the donor in all cases. ¹⁹⁹Hg shielding tensors and anisotropies were calculated from the solid-state NMR spectra. Based on the solid NMR data a distorted tetrahedral disposition of ligands around mercury is proposed.     

Zinc halide complexes of imidazolidine-2-thione and its derivatives: X-ray structures,solid state,solution NMR and antimicrobial activity studies

The preparation and characterization of zinc complexes of formula ZnL₂X₂ (X?=?Cl and Br), with L?=?1,3-diazinane-2-thione (Diaz), 1,3-diazipane-2-thione (Diap), imidazolidine-2-thione (Imt) and its methyl and n-propyl substituted derivatives, are described. The complexes dichlorobis(1-methylimidazolidine-2-thione-S)-zinc(II) (1) and dichlorobis(1-propylimidazolidine-2-thione-S)-zinc(II) (2) have been characterized by single-crystal X-ray methods. Both complexes adopt distorted tetrahedral geometry. Only intramolecular hydrogen bonding interactions are observed in 1 and 2. Solution and solid state ¹³C NMR show a significant shift of the C=S carbon resonance of the ligands, while other resonances are relatively unaffected, indicating that most likely the solid state structure is maintained in solution. Antimicrobial activity studies of the free ligands and their complexes show that ligands exhibit substantial antibacterial activities compared to the complexes.     

Complexation of palladium cyanide with imidazolidine-2-thione and its derivatives

Summary Pd(CN)₂ reacts with imidazolidine-2-thione (Imt), 1,3-diazinane-2-thione(Diaz), 1,3-diazipnane-2-thione (Diap) and their derivatives to yield complexes of stoichiometry [PdL₂(CN)₂] or [PdL(CN)₂] (L = Imt, Diaz or Diap and L = Imt having N-Me, Et or Pr substituents), which were characterized by elemental analysis, i.r., ¹H and ¹³C n.m.r. spectroscopy. Both mono- and bis ligand complexes are thought to be square planar with the monoligand binding to metal via sulphur (bridging) and the bis ligand via the monodentate thione group. The ¹³C enriched Pd(¹³CN)₂ complex was prepared and the ¹³C n.m.r. recorded. The C-2 resonance of ¹³C n.m.r. of Imt, Diaz or Diap complexes of the copper(I), silver(I), gold(I) and palladium(II) were compared.     

Synthesis and characterization of mixed-metal complexes of Ag/Cu and W/Mo and a complex of Ag with heterocyclic thione ligands

Reactions of AgI with salts of [WS(4)](2-) or [MoS(4)](2-) and with either imidazolidine-2-thione (Imt) or [1,3]diazepane-2-thione (Diap) give the complexes [WS(4)Ag(2)(Imt)(2)](n) and [MS(4)Ag(2)(Diap)(4)] [M = W or Mo]; in the case of Diap, corresponding Cu complexes can be obtained with CuCl instead of AgI. Decomposition of the Ag-Diap complexes during attempted recrystallization leads to the polymeric complex [AgI(Diap)](n). The monomeric mixed-metal Diap complexes contain edge-sharing WS(4) and AgS(4) tetrahedra, the Diap ligands being terminally bonded to Ag through sulfur. The mixed-metal W-Ag-Imt complex is a chain polymer with two different environments for the WS(4) unit and three different coordination environments for Ag, one of which is an unprecedented AgS(5) square-based pyramid; Imt ligands are terminally coordinated to Ag. [AgI(Diap)](n) has a complex polymeric chain structure with three different distorted tetrahedral environments for Ag, direct Ag-Ag bonding, both bridging and terminal I, and all Diap ligands bridging pairs of Ag atoms. All the crystal structures feature N-H[...]S or N-H[...]I hydrogen bonding. The complexes have also been characterised by infrared, UV-Vis and (1)H and (13)C NMR spectroscopy.     

Complexations of Hg(CN)(2) with imidazolidine-2-thione and its derivatives: solid state, solution NMR and antimicrobial activity studies

The preparation and characterization of new mercuric complexes of formula L(2)Hg(CN)(2) with L being imidazolidine-2-thione (Imt) and its substituted derivatives, 1,3-diazinane-2-thione (Diaz), 1,3-diazipane-2-thione (Diap), are described. The solution and solid-state (13)C NMR show a significant shift of the CS carbon resonance of the ligands, while the other resonances are relatively unaffected, indicating that most likely the solid-state structure is maintained in solution as well. The principal components of the (199)Hg shielding tensors were determined from solid-state NMR data. Antimicrobial activity studies of the free ligands and their complexes show that ligands exhibit substantial antibacterial activities compare to their Hg(II) complexes.     

Synthesis of thionato(trimethylphosphine)gold(I) complexes

Summary New compounds of formula [AuL(PMe₃)]Cl [L = imidazolidine-2-thione (Imt), 1,3-diazinane-2-thione (Diaz), 1,3-diazepine-2-thione (Diap) and their derivatives] have been synthesized and characterized by elemental analysis, and i.r., ¹³C- and ³¹P-n.m.r. spectroscopies. The Diap ligand, which incorporates the thione in a seven-membered heterocyclic ring, binds more strongly to Au^I compared to its Diaz (six-membered ring) and Imt (five-membered ring) analogues.     

Mixed ligand palladium(II) and platinum(II) complexes of tertiary diphosphines and benz-1,3-imidazoline-2-thione,benz-1,3-oxazoline-2-thione or benz-1,3-thiazoline-2-thione

Palladium(II) and platinum(II) complexes containing the mixed ligands tertiary diphosphines Ph₂P(CH₂) _n PPh₂, (n = 1–4) and benz-1,3-imidazoline-2-thione, benz-1,3-oxazoline-2-thione or benz-1,3-thiazoline-2-thione have been prepared and characterized by elemental analysis, magnetic susceptibility, molar conductance and i.r. spectral data. ³¹P–{¹H}-n.m.r. data have been applied to characterize the produced linkage isomers.     

Transition metal complexes with thiosemicarbazide-based ligands. Part LVI: Nickel(II) complex with 1,3-diphenylpyrazole-4-carboxaldehyde thiosemicarbazone and unusually deformed coordination geometry

Synthesis of a new nickel(II) complex, [Ni(Ph₂PzTSC-H)₂] with 1,3-diphenylpyrazole-4-carboxaldehyde thiosemicarbazone (Ph₂PzTSC), is described. The compounds have been characterized by elemental and thermal analysis, molar conductivity and spectral (UV–Vis, IR, ¹H NMR, and ¹³C NMR) measurements. In the case of complex the magnetic measurement has been also performed. Crystal and molecular structures of both the free ligand and the complex have been determined by single crystal X-ray analysis. It was found that the ligand coordinates in a bidentate NS fashion, in its deprotonated thioenolato form. The cis-square-planar geometry of the complex is significantly distorted tetrahedrally. The Cambridge Structural Database (CSD) study has been performed to obtain geometrical and structural informations on similar nickel(II) complexes in order to compare structural data.     

Luminescent silver nitrate complexes of bis[2-(diphenylphosphano)phenyl]ether (DPEphos): Crystal structure of [Ag(DPEphos)(py2SH)2]NO3

Heteroleptic silver(I) nitrate complexes containing the bis[2-(diphenylphosphano)phenyl]ether (DPEphos) ligand and the heterocyclic thioamides pyridine-2(1H)-thione (py2SH), pyrimidine-2(1H)-thione (pymtH), 4,6-dimethylpyrimidine-2(1H)-thione (dmpymtH), 1,4,5,6-tetrahydropyrimidine-2-thione (thpymtH) or 1,3-imidazolidine-2-thione (imtH₂) have been synthesized and characterized by IR and UV-Vis spectroscopy, elemental analyses and melting point determinations. The complexes can be obtained by the addition of the thioamide ligand to an AgNO₃-diphosphane adduct in dichloromethane/ethanol solution. The molecular structure of [Ag(DPEphos)(py2SH)₂]NO₃ complex has been established by single-crystal X-ray diffraction. The structure features a tetrahedral silver(I) center with two phosphorus atoms from the chelating diphos ligand, and the exocyclic sulfur atom of two heterocyclic thioamide units. Intense blue-green emission is observed in the region 470-483 nm for all the complexes in the solid state and in solution at ambient temperature.     

Rhodium(III) and cadmium(II) complexes based on the polypyridyl ligand 2,3,5,6-tetrakis(2-pyridyl)pyrazine (tppz)

Tppz (2,3,5,6-tetrakis(2-pyridyl)pyrazine) complexes [Rh(tppz)(bpy)Cl][PF₆]₂.acetylacetone (bpy = 2,2′-bipyridine) and [{CdCl₂}₂(μ-tppz)].ethylene glycol have been synthesized and characterized by elemental analyses, IR, ¹H NMR, cyclic voltammetry, photoluminescence and electronic spectral studies. Solid state structures of both complexes have been determined by single-crystal X-ray crystallography. The structural determination shows that the dinuclear Cd(II) complex, [{CdCl₂}₂(μ-tppz)], is a 1D coordination polymer. An ORTEP drawing of [Rh(tppz)(bpy)Cl][PF₆]₂.acetylacetone shows that the coordination geometry around the Rh(III) center is a distorted octahedron. [{CdCl₂}₂(μ-tppz)] displays intraligand ¹(π–π^*) fluorescence and can potentially serve as a photoactive material. For the mononuclear Rh(III) complex, only a two-electron reduction process occurs at the metal with the elimination of Cl⁻ ligand. The emission of this complex is assigned as πd^* phosphorescence.     

Synthesis and structures of iron(iii) complexes based on azo derivatives of 5-oxo- and 5-thioxopyrazole

New potentially tridentate ligands, viz., 3-methyl-1-phenyl-4-(quinolin-8-ylhydrazono)pyrazol-5(1H)-one and 3-methyl-1-phenyl-4-(quinolin-8-ylhydrazono)pyrazole-5(1H)-thione (LH), and their complexes with Fe^III were synthesized. The structures of the ligands and metal chelates (FeL₂A; A = ClO₄ or FeCl₄) were studied by ¹H NMR spectroscopy and magnetochemistry. The FeL₂A complex (A = FeCl₄) was investigated by X-ray diffraction. These low-spin complexes have pseudooctahedral structures with the N₄X₂ ligand environment (X = O or S).     

Crystal structure and magnetic properties of the binuclear copper(II) complex based on 1,3-diaminopropan-2-ol N,N′-bis(3-formyl-5-<Emphasis Type="Italic">tert</Emphasis>-butylsalicylidene)

1,3-Diaminopropan-2-ol N,N′-bis(3-formyl-5-tert-butylsalicylidene) (H₃L) and the binuclear copper(II) complex based on H₃L, [Cu₂L(CH₃COO)] (I), are synthesized. The compounds are studied by IR and ¹H NMR spectroscopies, magnetochemistry, and X-ray diffraction analysis. Compared to the copper(II) complexes with 1,3-diaminopropan-2-ol N,N′-bis(salicylidene), complex I is characterized by a substantial change in the structure resulting in weakening of the antiferromagnetic exchange interaction.     

Chiral Pt(II)/Pd(II) pincer complexes that show C-H?Cl hydrogen bonding: Synthesis and applications to catalytic asymmetric aldol and silylcyanation reactions

A chiral C₂-symmetric NCN ligand, (5R,7R)-1,3-bis(6,6-dimethyl-5,6,7,8-tetrahydro-5,7-methanoquinolin-2-yl)benzene has been synthesized. A direct cyclometalation of this ligand with K₂MCl₄ (M = Pt, Pd) in dry acetic acid offered the corresponding pincer complexes, [(5R,7R)-1,3-bis(6,6-dimethyl-5,6,7,8-tetrahydro-5,7-methanoquinolin-2-yl)phenyl]platinum(II) chloride 5a and its palladium(II) analogue 5b. The Pt(II) and Pd(II) complexes 5 were characterized by NMR spectroscopy, and X-ray crystal structure analysis was done for the Pt(II) complex. The NMR data for both the complexes and X-ray crystal structural data for the chloro-Pt(II) complex indicate the existence of intramolecular C-H?Cl hydrogen bonding both in solution and in solid states. Chloride abstraction from 5a by treatment with silver triflate resulted in the corresponding triflate complex 6a, which generates the corresponding cationic aqua complex 7a in the presence of water molecules. The Pt(II) complex 6a/7a was used as asymmetric catalyst in the aldol reaction between methyl isocyanoacetate and aldehydes and also in the silylcyanation of aldehydes.     

Copper(I) complexes from copper(II) halides and 1,3-thiazohdine-2-thione

Summary Reaction of 1,3-thiazolidine-2-thione and copper(II) chloride and bromide in MeOH yields CuL₃X complexes. These react with an excess of copper(II) halide to give CuL₂X complexes. From their i.r. spectra, all the complexes seem to be S-bonded to the metal. Thev(CuCl) vibration is identified at 236 cm^–1.     

Zinc(II) and cadmium(II) <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>'-Bis(2-<Emphasis Type="Italic">N</Emphasis>-Tosylaminobenzylidene) diaminodipropyliminates: Syntheses,structures, and photoluminescence properties

Chemical and electrochemical syntheses of the zinc(II) and cadmium(II) complexes with the tetradentate Schiff base (H₂L), the condensation product of 2-N-tosylaminobenzaldehyde with diaminodipropylamine, are carried out. The structures, compositions, and properties of the synthesized metal complexes are studied by elemental analyses, IR spectroscopy, ¹H NMR, UV spectroscopy, X-ray absorption spectroscopy, and quantum-chemical calculations. The structure of the cadmium(II) complex is determined by X-ray diffraction analysis (CIF file CCDC no. 1446393). The cadmium(II) and zinc(II) complexes exhibit luminescence in a CH₂Cl₂ solution in the blue spectral range (λ_PL = 425–428 nm) with the photoluminescence quantum yields ? = 0.20 and 0.75, respectively.     

Crystal Structures and Biological Studies Two Novel Zinc Complexes Derived from <Emphasis Type="Italic">para</Emphasis>-Vanillin and Acetylacetone. Two New Precursors for Preparation ZnO Nanoparticles

In the present study, two new zinc complexes with the chemical formulas of [Zn(2-Ampy)(Acac)₂] (I) and [Zn(p-Van)₂(H₂O)₂] (II) were synthesized and characterized by FT-IR, ¹H NMR, and UV-Vis spectroscopy. Moreover, the crystal structures of the complexes were determined by X-ray diffraction technique. Single-crystal X-ray diffraction analyses (CIF files CCDC nos. 1513672 (I) and 1513673 (II)) revealed that complex I has a distorted square pyramid environment, and complex II has a distorted octahedral geometry. The complexes were also screened for in vitro antibacterial activities against some bacteria. The results show that complexes have the effective antibacterial activities. The complexes were employed to prepare ZnO nanoparticles by the combustion synthesis method at 700°C for 8 h. The nanoparticles were characterized, using powder X-ray diffraction analysis (PXRD), scanning electron microscopy and transmission electron microscope. PXRD analysis showed the presence of pure phase in both samples. Furthermore, the crystallite size was approximately 37 and 42 nm for ZnO prepared from complexes I and II, respectively.     

Three- and four-coordinate copper(I) halide complexes of 2-(diphenylphosphano)benzaldehyde: Dimerization induced by thione-S ligation

Reactions of copper(I) halides with 2-(diphenylphosphano)benzaldehyde (PCHO) in 1:2 molar ratio afforded mononuclear complexes of the type [CuX(PCHO)₂], whereas treatment of these compounds with equimolar amounts of pyridine-2-thione or pyrimidine-2-thione gave rise to the formation of mixed-ligand dimers of the formula [CuX(PCHO)(thione)]₂. The molecular structures of [CuCl(PCHO)₂], [CuBr(PCHO)₂] and [CuCl(PCHO)(pymtH)]₂ have been established by single-crystal X-ray diffraction. The two homoleptic complexes feature a trigonal copper(I) centre with the phosphane acting as a monodentate ligand via the P atom. In the structure of the dimeric mixed-ligand complex each of the two metal centres exhibit a distorted tetrahedral environment with the thione-S atoms acting in a doubly bridging mode.     

Novel di-μ-chloro-bis[chloro(4,7-dimethyl-1,10-phenanthroline)cadmium(II)] dimer complex: synthesis, spectral, thermal, and crystal structure studies

A novel di-μ-chloro-bis[chloro(4,7-dimethyl-1,10-phenanthroline)cadmium(II)] dimer complex has been prepared by reacting CdCl₂·2.5H₂O with 4,7-dimethyl-1,10-phenanthroline (dmphen) ligand. The complex was characterized on the basis of elemental analysis, FAB-MS, IR, UV–visible, ¹H, and ¹³C NMR spectroscopy, TG/DTA, and X-ray single-crystal diffraction studies. The Cd(II) ions in [CdCl₂(C₁₄H₁₂N₂)]₂ are coordinated to three Cl atoms with the centrosymmetric dimer bridged through the Cl atoms and two N atoms in a slightly distorted square-pyramidal disposition. Several hydrogen bonds formed between the terminal Cl atoms and H-Me/H-Ph groups may stabilize the structure in the dimer form.     

Synthesis and spectral characterization of zinc(II) and cadmium(II) complexes of acetone-N(4)-phenylsemicarbazone: Crystal structures of acetone-N(4)-phenylsemicarbazone and a cadmium(II) complex

Seven Zn(II) and Cd(II) complexes of ON donor acetone-N(4)-phenylsemicarbazone (HL) have been synthesized and physico-chemically characterized by partial elemental analyses, molar conductance measurements, infrared, electronic and ¹H NMR spectral studies. The semicarbazone binds the metal as a neutral bidentate ligand in all the complexes. The crystal structures of acetone-N(4)-phenylsemicarbazone and [Cd(HL)₂Cl₂] have been determined by X-ray diffraction studies. The coordination geometry around cadmium(II) in the complex [Cd(HL)₂Cl₂] is distorted octahedral.     

Synthesis,spectroscopic characterization,and crystal structures of copper(I) iodide clusters of N-methylthiourea and 1,3-diazinane-2-thione

Two copper(I) iodide complexes, [Cu₄(Metu)₆I₄] (I) and [Cu₈(Diaz)₁₂I₈] (II) (Metu = N-methylthiourea; Diaz = 1,3-diazinane-2-thione), have been prepared and their structures been determined by X-ray crystallography. The crystal structures show that complex I is a tetranuclear, while II is an octanuclear cluster, both having a Cu : S ratio of 2 : 3, characteristic of metallothioneins. In I, each of the four copper atoms is coordinated to three thiourea ligands and one iodide ion in a distorted tetrahedral mode adopting admantane-like structure. In II, four types of core arrangements are observed around copper(I), which include, Cu(μ-S₂)I₂, Cu(μ-S₂)(μ-I)I, Cu(μ-S₃)I, and Cu(μ-S₃)S each having copper(I) tetrahedrally coordinated. The complexes were also characterized by IR and ¹H and ¹³C NMR spectroscopy.