Copper(I) complexes of neutral,deprotonated and protonated 4,6-dimethylpyrimidine-2 (1H)-thione

Summary The following copper(I) complexes of 4,6-dimethylpyrimidine-2(1H)-thione (HL), its protonated cation (H₂L⁺) and deprotonated anion (L^–) have been prepared: CuL, Cu(HL)X (X = Cl, Br or I), Cu(HL)₂X (X = C1 or Br), Cu₂(HL)₃Br₂, Cu(H₂L)X₂ (X = Cl or Br), Cu₃(HL)₂LA₂ (A = ClO₄ or BF₄ ). The i.r. spectra show that in all the HL and L^– complexes and in the Cu(H₂L)Br₂ complex, the ligands are S, N coordinated to the metal ion, while in Cu(H₂L)Cl₂ only the thiocarbonylic sulphur is coordinated, probably bridging two copper(I) atoms. Thev(CuN) (288–317 cm^–1 ) andv(CuS) (191–225 cm^–1 ) have uniform frequency values in all the complexes. The halide ions are, in all their complexes, wholly or in part coordinated giving twov(CuX) bands which may indicate an asymmetrical Cu-X Cu halide bridging bond.Author to whom all correspondence should be directed.     

Copper(I) complexes of rhodanine

Summary Some new crystalline copper(I) complexes of rhodanine (HL) have been prepared and studied by i.r. and conductometric methods. The neutral ligand is bonded to the metal atom through the thiocarbonylic sulphur atom. The Cu(HL)₂OH · 0.5 H₂O complex has a dimeric tetrahedral hydroxyl-bridged structure as have the isostructural halides Cu(HL)₂X (X = Cl, Br and I) for which the halide-bridged stretching bands have been identified. The Cu(HL)₃A (A = ClO₄, BF₄, 0.5 SO₄ and CF₃CO₂) complexes have monomeric distorted tetrahedral structures with the anion bonded to the metal.     

Novel Copper(I) Clusters with 2‐(Diphenylphosphanyl)anilide Ligands. Synthesis and Crystal Structures of [Cu6X2(NHR)4] (X = Cl,Br, I; R = C6H4‐2‐PPh2)

Treatment of copper(I) halides CuX (X = Cl, Br, I) with lithium 2‐(diphenylphosphanyl)anilide [Li(HL)] in THF led to the formation of hexanuclear copper(I) complexes [Cu₆X₂(HL)₄] [X = Cl ( 1 ), Br ( 2 ), I ( 3 )]. In compounds 1 – 3 , the copper atoms are in a distorted octahedral arrangement and the amide ligands adopt a μ₃‐κP,κ²N bridging mode. Additionally there are two μ₂‐bridging halide ligands. Each of the [Cu₆X₂(HL)₄] clusters comprises two copper atoms, which are surrounded by two amide nitrogen atoms in an almost linear coordination [Cu–N: 186.2(3)–188.0(3) pm] and four copper atoms, which are connected to an amide N atom, a P atom, and a halogen atom in a distorted trigonal planar fashion [Cu–N: 199.6(3)–202.3(3) pm)].     

Cobalt(II) Complexes of 4,6-Dimethylpyrimidine-2(1H)-one

Some cobalt(II) complexes of 4,6-dimethylpyrimidine-2(1H)-one (HL) have been prepared and studied by infrared and electronic spectra and by magneto-chemical and conductometric measurements. The ligand is coordinated through the unprotonated ring-nitrogen atom and in one case also through the carbonylic oxygen atom. The “blue” complexes [CoX₂ · 2HL] (X₂ = Cl₂, ClBr, Br₂, (NCS)₂) and [CoX₂ · 2HL] · 2HL (X = Cl, Br) have a distorted C_2v [CoX₂N₂] coordination; the thiocyanate ion is N-bonded to the metal. The “green” complexes CoX₂ · 2HL (X = Cl(4H₂O), Br) have a square-pyramidal [CoX₂N₂O] coordination. The “pink” CoX₂ · 4HL · nH₂O (X = ClO₄, n = 2; X = BF₄, n = 8; X = F₃Ac, n = 4) and “cream” CoX₂ · 4HL · 6 H₂O (X = I, ClO₄) complexes have an octahedral coordination; only the F₃Ac^? ion is coordinated. The “cyclamen” CoAcL · 2HL · 2 H₂O and Co₃Ac₄L₂ · 2HL · 2H₂O complexes have a polynuclear constitution; the Ac^? ion behaves as bidentate ligand.     

Cobalt(II) perchlorate,tetrafluoroborate, nitrate and sulphate complexes with 4,6-dimethylpyrimidine-2(1H)-thione

Contrary to earlier reports in which no adducts of Co(II) metal ion with 4,6-dimethylpyrimidine-2(1H)-thione(HL) could be isolated starting from Co(ClO₄)₂ · 6H₂O, we now report bis- and tris-ligand Co(II) complexes of the type [Co(HL)₂(H₂O)₂]X₂ · H₂O (X = ClO₄, BF₄), [Co(HL)₂NO₃]NO₃, [Co(HL)₂SO₄] · 0.5H₂O and [Co(HL)₃]X₂ · 0.5H₂O (X = ClO₄, BF₄). They have been synthesized by refluxing 2:1 and 3:1 mixtures of HL and CoX₂ · nH₂O in ethanol-triethyl orthoformate. We also describe new Co(HL)₂X₂ · nH₂O complexes in which for X₂ = ClBr, ClI and BrI, n = 2; for X₂ = I₂, n = 1 and for X₂ = (SCN)₂, n = 0. Structural characterization of the complex species is made from electronic and vibrational spectra, magnetic susceptibility measurements in the solid state and conductivity measurements in DMF solution. The magnetic and electronic spectral data together with ligand-field parameters suggest a pseudo-octahedral environment for all the Co(II) complexes, with the exception of Co(HL)₂SO₄ · 0.5H₂O in which the Co(II) ion appears to be pentacoordinated. The IR spectra are consistent with a coordination involving N,S-chelation of the ligand through the non-protonated ring nitrogen atom and the exocyclic sulphur atom.     

Complexes of cobalt(II), nickel(II) and copper(II) with 4-amino-3,5-dimethylisoxazole

Summary Complexes of the type M(4-ADI)_nX₂ · mH₂O (where 4-ADI = 4-amino-3,5-dimethylisoxazole; n = 1–4; X = Cl, Br, I, SCN, ClO₄; m = 1–4) have been studied by i.r. and electronic spectroscopy, magnetic and conductivity measurements. The ligand behaves as a monodentate -NH₂ bonded species in monomeric complexes, but as a bridging ligand-NH₂ and -N(ring) bonded species in polymeric complexes. All the compounds have an octahedral stereochemistry, except Co(4-ADI)₂X₂ (X = Cl, Br, I) complexes, which are tetrahedral.     

Thorium(IV) complexes with tetradentate Schiff base ligands

Summary Some thorium(IV) complexes were synthesized with the tetradentate Schiff base ligands (N₂O₂ donor set) obtained by the condensation of ethylenediamine with salicylaldehyde (H₂salen) or acetylacetone (H₂ acacen). In all cases the neutral Schiff bases and not their anions are coordinated to the central thorium(IV) atom. The complexes have the general formula: ThL₂Xa (L = H₂ salen; X = Cl, Br, 1, NCS and L = lie acacen; X = Cl, 1, NCS, ClO₄) or ThLX₄ (L = H₂ salen; X = NO₃, ClO₄ and L = H₂ acacen; X = Br, NO₃). The stoichiometry and coordination number of the complexes was determined on the basis of elemental analysis, conductivity measurements, i.r. spectra and t.g.a./d.t.a. data. The coordination number of the complexes is either 12 or 8 for the bisor monocomplexes respectively.     

Copper(I) complexes of nitrogen-sulphur ligands. 1-Phenyl-4,6-dimethylpyrimidine-2-thione and its protonated form as ligands in copper(I) complexes. Chemical,spectroscopic, conductivity and polarographic studies

Summary 1-Phenyl-4,6-dimethylpyrimidine-2-thione (L) and its protonated cation 1-phenyl-4,6-dimethyl pyrimidinium-2-thione , have been employed to prepare the following copper(I) complexes: CuXL (X=Cl, Br, I, ClO₄ or BF₄), (CuX)₃L₂ (X=Cl, Br, I or SCN), (CuX)₂L₅ (X= ClO₄ or BF₄) and the zwitterionic species CuXY(LH) X=Y=Cl, Br or I; X=Br; Y=Cl; X=I; Y=Br). Chemical analysis, conductivity, and near-and far-i.r. spectroscopic data are presented and the chemical relationships between them discussed in terms of postulated dinuclear or polynuclear species for the complexes. Metalligand vibrations suggest that the neutral ligand is N, S-bidentate in its copper(I) complexes as well as S-coordinat for the cation in the zwitterionic compounds. Diagnostic i.r. bands frequencies of counterions and (Cu–X) modes indicate the coordinating character of Cl^–, Br^–, I^–, SCN^– and of ClO ₄ ^– , BF ₄ ^– (in CuXL) anions. For the chloro-complexes CuClL and (CuCl)₃L₂, salt-like species of the [CuL₂][CuCl₂] and [{Cu₂L₂Cl}_n] [CuCl₂]_n type respectively, are proposed. The polarographic data for the perchlorate complexes have shown that in dimethylformamide (DMF) solution, the prevailing species are CuClO₄L, CuClO₄L₂ and (CuClO₄)₂L₅; their overall stability constants were determined.     

Thorium(IV) and zirconium(IV) complexes of oxygen donor ligands,Part 6. thorium(IV) complexes of 2,6-lutidine-N-oxide and tetramethylene sulphoxide

Summary The synthesis and physical properties of crystalline thorium(IV) complexes, Th(ClO₄)₄ · 6 LNO, ThX₄ · 2 LNO (X = Br or SCN), ThX₄ · 4 LNO (X = NO₃ or I) andTh(ClO₄)₄ · 10 TMSO, Th(NO₃)₄ · 6 TMSO, ThX₄ · 4 TMSO (X = Cl or Br), ThI₄ · 6 TMSO and Th(NCS)₄ · 2 TMSO (where LNO = 2,6-lutidine-N-oxide and TMSO = tetramethylene sulphoxide) are reported together with their i.r. spectra, molar conductivities, molecular weights, t. g. a. and d. t. a. data. In all the complexes, LNO and TMSO are bonded to thorium(IV) through oxygen. The coordination number of thorium(IV) in these complexes varies from six to ten depending upon the nature of the anions.Presented at the XVI Annual Convention of Chemists, Andhra University, Waltair, A. P. India, December 27–31, 1978.     

Substitutions of organopalladium(II) species with benzimidazole derivatives

The [Pd(cod)(cotl)]ClO₄ complex (cod = cycloocta-1,5-diene; cotl = cyclooctenyl, C₁₈H₁₃ ^–) undergoes substitutions with new Schiff base ligands containing benzimidazole L [L = 2-(2-N-n-propylidenephenyl)benzimidazole (L¹); 2-(2-N-i-propylidenephenyl)benzimidazole (L²); 2-(2-N-n-butylidenephenyl)benzimidazole (L³); 2-(2-N-i-butylidenephenyl)benzimidazole (L⁴)]. Facile displacement of cod by L occurs to produce complexes of the type [Pd(cotl)L]ClO₄· nMe₂CO (n= 0; L = L¹, L² or L³; n= 2, L = L⁴). Dihalobridge complexes of the type [Pd(cotl)X]₂(X = Cl or Br) undergo halogen-bridge cleavage with L¹–L⁴ to give mononuclear complexes of the type Pd(cotl)LX · nH₂O (n= 2, X = Cl, L = L¹; n= 0, X = Br, L = L¹; n= 0, X = Cl, L = L²; n= 0, X = Cl or Br, L = L³; n= 0, X = Cl, L = L⁴; n= 2, X = Br, L = L⁴) and a binuclear complex [Pd(cotl)Br]₂L². The complexes were characterised by physical properties, i.r., ¹H- and ¹³C-n.m.r. spectral techniques and by mass spectra. Probable structures have been proposed.     

Ligational behaviour of two biologically active N−S donors towards cobalt(III), iron(III), iron(II) and rhodium(III)

Summary The chelating behaviour of two biologically active ligands, pyridine-2-carboxaldehyde(4-phenyl) thiosemicarbazone(L₁H) and pyridine-2-carboxaldehyde thiosemicarbazone(LH), towards Fe^III, Co^III, Fe^II and Rh^III has been investigated. The ligands act as tridentate N–N–S donors, resulting in the formation of bis-chelate complexes of the type M^III(A)₂X·nH₂O (A=L₁ or L; X=Cl, ClO₄; M=Co^III, Rh^III, Fe^III), Fe^II(L₁H)₂SO₄·2H₂O and Fe^II(L₁)₂·H₂O. Biological activity of the ligands and the metal complexes in the form ofin vitro antibacterial activities towardsE. coli has been evaluated and the possible reasons for enhancement of the activity of ligands on coordination to metal ion is discussed.     

New hydroxylated metabolites of 4-monochlorobiphenyl in whole poplar plants

Background

The importance of the isatinic quinolyl hydrazones arises from incorporating the quinoline ring with the indole ring. Quinoline ring has therapeutic and biological activities whereas, the indole ring occurs in Jasmine flowers and Orange blossoms. As a ligand, the isatin moiety is potentially ambidentate and can coordinate the metal ions either through its lactam or lactim forms. In a previous study, the ligational behavior of a phenolic quinolyl hydrazone towards copper(II)- ions has been studied. As continuation of our interest, the present study is planned to check the ligational behavior of an isatinic quinolyl hydrazone.

Results

New homo- and heteroleptic copper(II)- complexes were obtained from the reaction of an isatinic quinolyl hydrazone (HL) with several copper(II)- salts viz. Clˉ, Brˉ, NO₃ˉ, ClO₄ ^-, SO₄ ^2- and AcO^-. The obtained complexes have O_h, T_d and D_4h- symmetry and fulfill the strong coordinating ability of Clˉ, Brˉ, NO₃ˉ and SO₄ ^2- anions. Depending on the type of the anion, the ligand coordinates the copper(II)- ions either through its lactam (NO₃ˉ and ClO₄ ^-) or lactim (the others) forms.

Conclusion

The effect of anion for the same metal ion is obvious from either the geometry of the isolated complexes (O_h, T_d and D_4h) or the various modes of bonding. Also, the obtained complexes fulfill the strong coordinating ability of Clˉ, Brˉ, NO₃ˉ and SO₄ ^2- anions in consistency with the donor ability of the anions. In case of copper(II)- acetate, a unique homoleptic complex (5) was obtained in which the AcO^- anion acts as a base enough to quantitatively deprotonate the hydrazone. The isatinic hydrazone uses its lactim form in most complexes.     

Mixed-Anion Cu(II) Complexes with 3-(pyridin-2-yl)pyrazole (L), Syntheses and X-ray Crystal Structure of [Cu(L)2 Br]ClO4 (L=3-(pyridin-2-yl)pyrazole)

Reaction of the ligand 3-(pyridin-2-yl)pyrazole (L) with Cu(ClO₄)₂ and CuX₂ (X=Cl, Br, I) gives complexes with stoichiometry [Cu(L)₂X]ClO₄ (X = Cl, Br, I). The new complexes were characterized by elemental analyses and infrared and electronic spectroscopy. The crystal structure of the [Cu(L)₂Br]ClO₄ was determined by X-ray crystallography. The cation complex (i.e. [Cu(L)₂Br]P) contains copper(II) with a distorted trigonal bipyramid geometry with a Br^― ligand occupying an equatorial site. The penta-coordinated metal atom is bonded to two pyridinic nitrogens, two pyrazolic nitrogens, and one bromide anion. The pyrazolic H atoms are hydrogen bonded to Br atoms, resulting in infinite hydrogen-bonded chains running in the b direction. There are π‐π stacking interactions (charge-transfer arrays) between the parallel aromatic rings belonging to adjacent chains that may help to form hydrogen bonding in the coordination geometry around Cu (II).     

Chemical and antifungal properties of the copper(II) complexes of 2-formylpyridine4 N-methyl-,4 N-dimethyl,4 N-diethyl and4 N-dipropylthiosemicarbazones

Summary Two series of copper(II) complexes. [Cu(HL)X₂] and [Cu(L)Cl], where HL is a 2-formylpyridine⁴ N-substituted thiosemicarbazone, L is an anion formed by loss of the²N hydrogen and X=Cl or Br, have been prepared and spectrally characterised. Their growth inhibition ofAspergillus niger andPaecilomyces variotii has been measured and compared with analogous complexes formed from 2-acetylpyridine thiosemicarbazones.     

Zum Einfluß der Ringgröße auf die Struktur von Metallchelaten. IV. Palladium(II)- und Platin(II)-Komplexe pyridylsubstituierter Dialkylsulfide und -amine

The Influence of Ring Size on the Structure of Metal Chelates with Tridentate Ligands. IV. Palladium(II) and Platinum(II) Complexes of Pyridyl Substituted Dialkyl Sulfides and Amines [β-(Pyridyl-2)-ethyl]-[(pyridyl-2)-methyl]-amine(2,3-py₂tri) forms planar palladium(II) complexes [Pd(2,3-py₂tri)X]X (X = Cl, Br) occupying trans-positions as a tridentate ligand. An analogous behaviour is observed with bis[β-(pyridyl-2)-ethyl]-sulfide(3,3-py₂Stri) in the chelate compounds [Me^II(3,3-py₂Stri)X]X (Me^II = Pd, Pt; X = Cl, Br, J, SCN). On the other hand the rigid ligand bis[(pyridyl-2)-methyl]-sulfide(2,2-py₂Stri) is only bidentate in the complexes Me^II(2,2-py₂Stri)X₂ (Me^II = Pd, Pt; X = Cl, Br, J, SCN), one pyridine group does not interact with the central atom. The reasons are the angular relations within the thioether group of 2,2-py₂Stri which allow a tridentate coordination in a facial conformation (octahedral and trigonal-bipyramidal nickel(II) and copper(II) complexes), but not in a meridional one (planar palladium(II) and platinum(II) complexes). In Pt(2,2-py₂Stri)(SCN)(NCS) one thiocyanato ligand is linked by sulfur, the other one by nitrogen.     

Polymetallic complexes: Part V. ONNO tetradentateN,N′-bis(acetoacetanilide)-1, 3-diaminopropane complexes of cobalt(II), copper(II) and zinc(II)

Summary Ten complexes of composition [Co₂L₂X₄] (X=Cl, Br, NO₃ or ClO₄); [Cu₂L₂(NO₃)₄]; [Zn₂L₂X₄ (X=Cl, SCN or ClO₄); [CuCl₂L] and [ZnBr₂L] have been synthesized, where L is the ONNO tetradentate ligand,N,N-bis(acetoacetanilide)-1,3-diaminopropane. The complexes have been characterised by elemental analysis, conductance, magnetic susceptibility, molecular weight and i.r., and electronic spectral measurements.Author to whom all correspondence should be directed.     

Transition-metal complexes with bidentate ligands spanning trans-position. Part XVI. X-ray structural and 31P-NMR solution studies of 2,11-Bis(diethylphosphinomethyl)benzo[c]phenanthrenesilver(I) perchlorate

The preparation of complexes {AgX(1c)} (X ? Cl, Br, I, NO₃ and ClO₄; 1c = 2,11-bis(diethylphosphinomethyl)benzo[c]phenanthrene) is reported. The ³¹P-NMR spectra of the above complexes were recorded and the ¹J(¹⁰⁷Ag, ³¹P) values are compared with the corresponding data for related complexes. The X-ray crystal structure of [Ag(1c)](ClO₄) was determined. There are two crystallographically independent molecules in the unit cell each containing two-coordinate silver, the O-atoms of the perchlorate anions being outside bonding range from the central atom. The two molecules, however, show different bonding parameters: Thus for ‘molecule 1’ P(1)? Ag(1)? P(2) = 167.6(1)°, Ag(1)? P(1) = 2.389(3) and Ag(1)? P(2) = 2.393(3) Å, while for ‘molecule 2’ P(3)? Ag(2)? P(4) = 164.8(1)°, Ag(2)? P(3) = 2.377(3), and Ag(2)? P(4) = 2.378(3) Å. These differences are probably due to packing forces in the crystal lattice.     

Stereochemical versatility of Cu(II): Cu(II) complexes of benzyl methyl ketone semicarbazone

Copper(II) complexes of the general composition Cu(ligand)₂X₂ (where X = Cl, Br, NO₃, ClO₄, and $\text{1}\text{2}$SO₄) and Cu(ligand)(CH₃COO)₂ have been synthesised with benzymethylketonesemicarbazone. All the complexes prepared have been characterised by elemental analysis, magnetic moment, conductance, IR, electronic and electron spin resonance spectral studies. The complexes Cu(ligand)₂X₂ (X = Cl, Br, NO₃) and Cu(ligand)(CH₃COO)₂ may have tetragonal symmetry while the Cu(ligand)₂X₂ (ClO₄ and $\text{1}\text{2}$SO₄) may be five-coordinate trigonal bipyramidal in structure.     

Zinc(II), Cadmium(II), and Mercury(II) Complexes of 2-Methyl-benzoselenazole

The following zinc(II), cadmium(II) and mercury(II) complexes of 2-methyl-benzoselenazole (L) have been prepared and studied by conductometric and i.r. methods: MLX₂ (M ? Cd, Hg, X ? Cl, Br, I), ML_1.5X₂ (M ? Zn, X ? ClO₄(4 H₂O); M ? Hg, X ? NO₃, ClO₄), ML₂X₂ (M ? Zn, X ? Cl, Br, I, NO₃; M ? Cd, X ? NO₃, ClO₄). The ligand is N-bonded. All the anions are coordinated.     

Direct synthesis,spectral and magnetic properties of trans-aniono(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7-acetato) copper(II) complexes

7-Carboxymethyl-7,16-diaza-18-crown-6 acid hydrates (LH·H₂O) and their copper(II) complexes [CuLX], (X = Cl, Br, NO₃, ClO₄ and CH₃CO₂) were obtained. The earlier X-ray investigation of the [CuLCl] complex, as well as the IR and UV-vis spectral evidence for the complexes revealed the inner chelate structure with the six-coordinated copper(II) ion embedded inside the macrocyclic ligand (deformed octahedral, 4+2, N,N, CO₂⁻,X⁻,O,O-coordination sphere) and the trans arrangement of the CO₂ and X ligands. The spectral data, the conductivity measurements and the chemical properties show the existence of the macrocyclic inclusion cation [CuL]⁺ and the formulation of the complexes as the [(CuL)⁺X⁻] inner salts. The magnetic moments of the complexes amount to 1.76–1.83 BM at room temperature and 1.3–0.92 BM at 4.2 K. These results revealed the monomeric form of the complexes with the occurrence of the intermolecular (through space) magnetic super-exchange interactions of copper(II) paramagnetic centres.