Thermochemistry of Cu(II) and Ni(II) complexes with N,N-di-n-butyl-N′-thenoylthiourea and N,N-di-iso-butyl-N′-thenoylthiourea

Two substituted N-acylthioureas and the respective Ni(II) and Cu(II) complexes were synthesized, namely: N,N-di-n-butyl-N′-thenoylthiourea (Hnbtu); N,N-di-iso-butyl-N′-thenoylthiourea (Hibtu); bis[N,N-di-n-butyl-N′-thenoylthioureato]nickel(II), [Ni(nbtu)₂]; bis[N,N-di-n-butyl-N′-thenoylthioureato]copper(II), [Cu(nbtu)₂]; bis[N,N-di-iso-butyl-N′-thenoylthioureato]nickel(II), [Ni(ibtu)₂]; bis[N,N-di-iso-butyl-N′-thenoylthioureato]copper(II), [Cu(ibtu)₂]. The standard (p^° = 0.1 MPa) molar enthalpies of formation and sublimation of the two N-acylthioureas were measured, at T = 298.15 K, by rotating-bomb combustion calorimetry and Calvet microcalorimetry, respectively. The standard (p^° = 0.1 MPa) molar enthalpies of formation of the Ni(II) and Cu(II) complexes were determined, at T = 298.15 K, by high precision solution–reaction calorimetry. From the results obtained, the enthalpies of hypothetical metal–ligand and metal–metal exchange reactions, in the gaseous phase, were derived, thus allowing a discussion of the gaseous phase energetic difference between the complexation of Ni(II) and Cu(II) to 1,3-ligand systems with (S,O) ligator atoms.     

4,4′-Bipyridine complexes of molybdenum(II) and tungsten(II)

Treatment of [MI₂(CO)₃(NCMe)₂] with two equivalents of 4,4-bipyridine (4,4-bipy) in CH₂Cl₂ at room temperature gave the MeCN displaced products, [MI₂(CO)₃(4,4-bipy-N)₂] (1) and (2). Equimolar amounts of [MI₂(CO)₃(NCMe)₂] and L (L = PPh₃, AsPh₃ or SbPh₃) react to give [MI₂(CO)₃(NCMe)L], which when reacted in situ with 4,4-bipy yield the new complexes, [MI₂(CO)₃(4,4-bipy-N)L] (3)–(8). Reaction of equimolar quantities of [WI₂(CO)(NCMe)( ²-RC₂R)₂] (R = Me or Ph) and 4,4-bipy gave the new bis(alkyne) complexes, [WI₂(CO)(4,4-bipy-N)( ²-RC₂R)₂] (9) and (10). Treatment of [MI₂(CO)₃(NCMe)₂] with two equivalents of (9) or (10) in CH₂Cl₂ at room temperature affords the bimetallic complexes, [MI₂(CO)₃{WI₂(CO)(4,4-bipy-N,N)( ²-RC₂R)₂}₂] (11)–(14). Equimolar quantities of [MI₂(CO)₃(NCMe)(PPh₃)] (prepared in situ) and (9) or (10), react to give the 4,4-bipy-bridged complexes, [MI₂(CO)₃{WI₂(CO)(4,4-bipy-N,N)( ²-RC₂R)₂}(PPh₃)] (15)–(18). All the new complexes, (1)–(18) were characterised by elemental analysis (C, H and N), i.r. and ¹H-n.m.r. spectroscopy.     

Photochemical Behavior of Platinum(II) and Palladium(II) Complexes of 4,4′-Dimethyl-2,2′-Bipyridine

Several mixed-ligand complexes of formula [MX 2 (MBPY)] {where M is Pd(II) or Pt(II); X is Cl m , I m , N 3 m or NO 2 m and MBPY is 4,4'-dimethyl-2,2'-bipyridine} have been prepared. The UV-Vis spectra of these complexes were found to show a low-lying MLCT band and on irradiation at the MLCT band these complexes sensitize the oxidation of 2,2,6,6-tetramethyl-4-piperidinol (XH) in N , N -dimethylformamide (DMF) to 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinoloxy free radical (XO). This photo-oxidation reaction involves singlet molecular oxygen ( 1 O 2 ) as an intermediate and its presence was confirmed by quenching studies using bis(diethyldithiocarbamato)nickel(II) [Ni(DDTC) 2 ], a well-known 1 O 2 quencher. The ability of the complexes to photosensitize the above photo-oxidation reaction follows the order: [Pt ( N 3 ) 2 ( MBPY ) ] ( 2 ) ～ [Pt ( NO 2 ) 2 ( MBPY ) ] ( 3 ) > [PtCl 2 ( MBPY ) ] ( 4 ) > [PtI 2 ( MBPY ) ] ( 1 ) > [Pd ( NO 2 ) 2 ( MBPY ) ] ( 7 ) ～ [Pd ( N 3 ) 2 ( MBPY ) ] ( 6 ) > [PdCl 2 ( MBPY ) ] ( 8 ) > [PdI 2 ( MBPY ) ] ( 5 ), which reflects the nature of the metal ion and the nature of the ligands present in the complexes.     

Copper(II) and palladium(II) complexes of N,N′-bis(2-hydroxyethyl)stilbenediamine

A new 1,2-diamine ligand, N,N-bis(2-hydroxyethyl)stilbenediamine (L), has been prepared by reduction of the condensation product of benzaldehyde with 2-aminoethanol with Al amalgam. Mononuclear complexes of the [CuL(H₂O)]X₂ type where X=Cl^– or AcO^– with Cu^II and PdLCl₂ with palladium(II) have been prepared and characterized by elemental analysis and i.r., u.v.–vis. or ¹H-n.m.r. spectroscopy.     

Synthesis,characterization, and interaction with DNA of Cu(II) and Zn(II) complexes with 2,2′-bipyridyl-6,6′-dicarboxylic acid

Two transition metal complexes, [Cu₂(bpdc)₂H₂O]·2H₂O (1) and Zn(bpdc)(H₂O)₂ (2) (H₂bpdc?=?2,2′-bipyridine-6,6′-dicarboxylic acid), were synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Complex 1 is dinuclear with two five-coordinate cupric ions and 2 is mononuclear with one six-coordinate zinc. Interactions of 1 and 2 with DNA have been investigated using UV–Vis absorption spectra. The cleavage reaction on DNA has been monitored by agarose gel electrophoresis.     

Palladium(II) and Platinum(II) Complexes of N-Phenyl- and N-Ethyl-N′-pyrimidin-2-ylthiourea

Palladium(II) and platinum(II) complexes of N-ethyl-N′-pyrimidin-2-ylthiourea(HL¹) and N-phenyl-N′-pyrimidin-2-ylthiourea (HL²) have been prepared, and the complexes [M(HL)Cl₂], [Pt(L)₂], [Pd(HL¹)₂]Cl₂, and [Pd(L²)₂] (where M = Pd^II or Pt^II) were characterized. The spectroscopic data are consistent with coordination of thioureas as neutral or monoanionic ligands to Pd^II and Pt^II through S and a pyrimidine-N. The IR spectra show shifts of CS and pyrimidine ring stretch bands to lower and higher frequencies, respectively. The ¹H NMR spectra differentiate between H(4′) and H(6′) resonances and indicate downfield shifts for all protons of pyrimidine [H(4′), H(5′), and H(6′)], two resonances for two N?H protons for complexes containing the neutral ligand (HL), and only one N?H proton chemical shift for complexes containing the monoanion (L). ¹³C NMR chemical shifts of pyrimidine carbons are correlated with the type of bonding between Pd^II or Pt^II and pyrimidine-N. The magnetic susceptibilities suggest a diamagnetic planar structure for all complexes.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Tin,palladium and platinum derivatives of 1,1′-bis(diphenylphosphine)ferrocene. Crystal and molecular structures of 1,1′- bis-(diphenylphosphine)ferrocenedichloropalladium(II) and of 1,1′-bis(diphenylphosphine)ferrocenedichloroplatinum(II)

Summary Ten derivatives of 1,1-bis(diphenylphosphine)ferrocene (BDPF) are described in this paper. The first three, [BDPF·SnCl₄] (1), [BDPF·MeSnCl₃] (2) and [BDPF·PhSnCl₃] (3), present the two phosphorus atoms of the ligand directly bonded to a Sn centre. Two others, [BDPF-PdCl₂ (4) and [BDPF·PtCl₂] (5), similarly have the ligand BDPF acting as a bidentate species towards a transition metal. The crystal and molecular structures of (4) and (5) are presented here. Two other BDPF complexes were obtained with Pd and Pt, with the transition metals in the zerovalent state, namely [Pd(BDPF)₂] (6) and [Pt(BDPF)₂] (7). Finally, three trimetallic complexes are also described; [BDPF·Pd(-Cl)₂SnCl₂] (8), [BDPF· Pt(-Cl)₂SnCl₂] (9) and [BDPF·PdClSnCl₃] (10).     

Synthesis and magnetic properties of copper(II)-cobalt(II) complexes ofN,N′-1,2-propanedisalicylamidatocuprate(II)

Summary The binuclear metal complexes [Cu(sampn)Co(L)₂] (L=bipy, phen), have been prepared by the reaction of sodiumN,N-1,2-propanedisalicylamidatocuprate(II) heptahydrate, Na₂[Cu(sampn)] 7H₂O, with a divalent metalion, and 2,2-bipyridine or 1, 10-phenathroline. The complexes were characterized by variable-temperature magnetic susceptibility measurements; the results indicate that a weak antiferromagnetic spin-exchange interaction operates between the metal ions.     

Investigation of complexes of zinc(II) and cadmium(II)DI-n-butyldithiocarbamates with 2,2′-bipyridyl

A new mixed-ligand complex, Cd(S₂CN(C₄H₉)_{2 2})₂(2,2′-Bipy), was synthesized. A polycrystal X-ray diffraction analysis was performed (DRON-3M and DRON-UM1 diffractometers, CuK_α radiation, Ni filter) and the crystal structure was determined [Enraf-Nonius CAD-4 automatic diffractometer, MoK_α radiation, 2440 nonzero independent reflections, 153 refined structural parameters, R is 0.11 for I>2σ(I)]. Crystal data for C₂₈H₄₄CdN₄S₄ : a = 28.716(4), b = 6.848(6), c = 17.188(2) Å, space group Pcca, V-3380.2(7) ų, Z = 4, M = 679.42, dcaU.= 1.335 g/cm3. The structure consists of monomeric molecules in which the cadmium atom has a distorted octahedral environment. The polycrystal diffraction analysis revealed that the complex is isostructural with the defined complex Zn(S₂CN(C₄Hg)₂)₂(2,2′-Bipy). A crystal-chemical search on metal dialkyldithiocarbamates in the Cambridge Structural Database was accomplished and isostructural pairs of Zn and Cd metal complexes were found.     

Complexes of N-aroyl-N′-thiobenzohydrazide with cobalt(II), nickel(II) and zinc(II)

Summary New potential tetradentate ligands, N-benzoyl-N-thiobenzohydrazide (H₂BTBH) and N-salicyl-N-thiobenzohydrazide (H₂SBTH) have been prepared and characterized. Their complexes with Co^II, Ni^II and Zn^II have been prepared and characterized on the basis of elemental analyses, magnetic susceptibility measurements, and u.v.-vis., i.r. and ¹H-n.m.r. spectral studies. The bonding and stereochemistries of the complexes are discussed. H₂BTBH, H₂SBTH and the complexes have been screened towards a number of bacteria.     

Coordination reactions of 3,3′-bis(dipyrrolylmethene) with Co(II), Cu(II), and Zn(II) acetylacetonates, valinates, and dipyrrolylmethenates

Using spectrophotometry we found that ligand exchange in the systems of H₂L-[MX₂]-DMF, where M denotes Co²⁺, Cu²⁺, and Zn²⁺; X means Acac^?, Val^?, dpm^?; Hdpm^? is hexamethyldipyrrolylmethene, H₂L is bis(2,4,7,8,9-pentamethyldipyrrolylmethene-3-yl)methane, proceeds through successive stages of formation of hetero- and homoleptic binuclear complexes. Conventional sensitivity of the spectrophotometric determination of Co²⁺, Cu²⁺, and Zn²⁺ reaches 10^?9 M.     

Synthesis,structure and magnetic studies of copper(II)-nickel(II) complexes withN,N′-bis(2-aminopropyl)oxamidocopper(II)

Three novel heterobinuclear complexes have been prepared and identified as [Cu(oxap)Ni(L)₂](ClO₄)₂·ξH₂O, where oxap denotes theN,N′-bis(2-aminopropyl)oxamido dianion and L denotes 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) or 5-nitro-1,10-phenanthroline (NO₂-phen). The crystal structure of [Cu(oxap)Ni(phen)₂]-(ClO₄)₂·2H₂O has been determined. Crystal data: triclinic, space group , a=12.079 (6), b=12.409 (4), c=17.261 (8) ?, α=70.91 (2), β=86.72 (4), γ=89.19 (3)^o. At room temperature, Z=2. The Cu^II is in a square planar environment and the Ni^II is in an octahedral environment. The Cu−Ni distance is 5.292 ?. The temperature dependences of the magnetic susceptibilities of [Cu(oxap)Ni(phen)₂]-(ClO₄)₂·2H₂O and [Cu(oxap)Ni(bipy)₂](ClO₄)₂ have been studied in the 4.2–300 K range, giving the exchange integral J=−92.4 cm⁻¹ for bipy and J=−94.3 cm⁻¹ for phen. These results are commensurate with antiferromagnetic interactions between the adjacent metal ions.     

Manganese(II), nickel(II) and copper(II) complexes of (1,3-bis-aminomethyl) cyclohexane-N,N,N′,N′-tetrakisbenzimidazole

Summary Mn^II, Ni^II and Cu^II complexes of (1,3-bis-aminomethyl)-cyclohexane-N,N,N,N-tetrakisbenzimidazole (CDTB) have been prepared and characterized by spectral techniques. The complexes are monomeric and pseudo-octa-hedral, as evidenced by their e.p.r. spectra and analytical data. Parameters ², ², ² and for Cu^II complexes, and the crystal field splitting parameter (10 Dq) together with the Nephelauxetic ratio (), for Ni^II complexes, are reported.     

Synthesis,characterisation and electrochemical study of 4,4′-bis(salicylideneimino) diphenylethane and its complexes with cobalt(II), copper(II) and cadmium(II)

We have prepared and characterised a new series of metal complexes obtained from 4,4-bis(salicylideneimino)diphenylethane (saldipH₂) and cobalt(II), copper(II) and cadmium(II) chlorides. In every case, the coordinating atoms are N and O. However, each compound has its own structure:[Co(saldip)]·2 H₂O is monomeric and a mononuclear species, [Cu₂(saldip)₂(H₂O)] is a binuclear complex and finally the cadmium complex is formulated as:[(CdCl₂)₂(saldipH₂)]·CdCl₂. An electrochemical study (cyclic voltammetry) indicates that the reduction, as well as the oxidation, of copper in [Cu₂(saldip)₂(H₂O)] proceeds in two steps. For the reduction of the two other complexes, two steps are indicated out: the first is attributed to the reduction of the metal and the second to the reduction of the coordinated ligands.     

Diaminodithioether complexes of nickel(II) and palladium(II): A unique case of dealkylation of S,S′-thioether

Summary Nickel(II) and palladium(II) complexes of the 1,3-di(o-aminophenylthio) propane (H₂L¹) and 1,2-di(o-aminophenylthio)xylene (H₂L²) ligands have been prepared and characterized. The hydrobromide salt of H₂L¹ gave a 12 ligand-metal complex of Pd^II, whereas free H₂L¹ formed the usual 1:1 species. The reaction of Na₂PdCl₄ with H₂L² resulted in S,S-dealkylation of the ligand and formation of a mononuclear complex of the corresponding thiol, i.e. 2-aminobenzenethiol. NiCl₂, NiBr₂ and Ni(ClO₄)₂ did not react directly with H₂L². Ni^II is a fairly hard ion and therefore does not coordinate to the soft thioether moiety in H₂L² in the absence of soft anions which symbiotically motivate Ni^II to act as a soft acceptor. It thus does not react with H₂L² in the presence of hard ions such as Cl^–, Br^- and ClO ₄ ^– , but, the in situ reaction of the constituents produced the tetrahedral Ni^II complex, contrary to earlier reports of similar types of octahedral species.     

Microwave assisted synthesis and characterization of N,N′-bis(salicylaldehydo)ethylenediimine complexes of Mn(II), Co(II), Ni(II), and Zn(II)

Microwave chemistry is a green chemical method that improves reaction conditions and product yields while reducing solvent amounts and reaction times. The main aim of this article is to synthesize the tetradentate N₂O₂ ligand [HO(Ar)CH=N–(CH₂)₂–N=CH(Ar)OH] and manganese(II), cobalt(II), nickel(II), and zinc(II) complexes of the type ML by classical and microwave techniques. The resulting Schiff base and its complexes are characterized by ¹H NMR, infrared, elemental analysis, and electronic spectral data. The ligand and its Co(II) and Mn(II) complexes were further identified by X-ray diffraction and mass spectra to confirm the structure. The results suggest that the metal is bonded to the ligand through the phenolic oxygen and the imino nitrogen.     

Synthesis,characterization and nucleolytic property of bis(N,N′-dimethylglycinato)copper(II)

Aquabis(N,N-dimethylglycinato)copper(II) dihydrate, [Cu(dmg)₂(H₂O)]·2H₂O, has been synthesized and characterized by elemental analysis, FT-IR, magnetic data, thermal analysis, solution UV-visible spectroscopy, X-ray crystal structure analysis and electrospray ionization mass spectroscopy. The square pyramidal copper(II) complex crystallizes in the orthorhombic space group P2₁2₁2₁. The complex cleaves circular plasmid DNA (pBR322) in the presence of H₂O₂. The extent of cleavage varies with the concentration range of the complex, the type of buffer used, pH of buffer and the concentration of H₂O₂. Hydroxyl radical scavenger can inhibit the nucleolytic ability of this complex.     

Comparative analysis of physicochemical properties of dinuclear zinc(II) helicates with 2,2′-, 2,3′-, and 3,3′-bis(dipyrromethenes)

The effect of the attachment position of a methylene spacer in 2,2′-, 2,3′-, and 3,3′-bis(dipyrromethene) N₄-ligands (H₂L) on physicochemical properties of their dinuclear homoleptic helicates [Zn₂L₂], such as specific features of their molecular structure, luminescence spectral characteristics, lability in acid solutions, and thermal stability in an argon atmosphere, has been examined. It has been shown that the substitution of the biladiene-type helicand by its 2,3- and especially 3,3′-analogues leads to a considerable enhancement of the chromophoric properties, an increase (up to 30-fold) of the fluorescence quantum yield, and an increase in the stability of corresponding dinuclear helicates [Zn₂L₂].     

Synthesis and characterisation of Co(II), Ni(II), Zn(II) and Cd(II) complexes with 5-bromo-N,N′-bis-(salicylidene)-o-tolidine

New complexes of type [M(HL)(CH₃COO)(OH₂)_m]·nH₂O (where M:Co, m = 2, n = 2; M:Ni, m = 2, n = 1.5; M:Zn, m = 0, n = 2.5 and M:Cd, m = 0, n = 0; H₂L:5-bromo-N,N′-bis-(salicylidene)-o-tolidine) have been synthesized and characterized by microanalytical, IR, UV–Vis-NIR and magnetic data. Electronic spectra of Co(II) and Ni(II) complexes are characteristic for an octahedral stereochemistry. The IR spectra indicate a chelate coordination mode for mono-deprotonated Schiff base and a bidentate one for acetate ion. The thermal transformations are complex according to TG and DTA curves including dehydration, acetate decomposition and oxidative degradation of the Schiff base. The final product of decomposition is the most stable metallic oxide.     

Studies on platinum(II) and palladium(II) complexes of some N,N′-disubstituted thiourea derivatives

Summary A series of new Pt^II and Pd^II complexes of N,N-disubstituted thiourea derivatives of general formulae [MLCl₂]₂, [ML₂Cl₂] and [ML₄]Cl₂ have been prepared and characterised by physicochemical and spectroscopic methods. The reaction of these ligands with [M(DMSO)₂Cl₂], M = Pt, cis- or Pd, trans-, in CHCl₃ and EtOH at ambient temperature or under reflux, is described.