Nickel(II) and cobalt(II) chelates with products of condensation of 1,8-diaminonaphthalene and salycylaldehyde

Six Ni(II) and Co(II) chelates were synthesized from different reagents (Ni(II), Co(II) chlorides and 1,8-diaminonaphthalene or the products of a single or double condensation of the latter with salicylaldehyde) and identified and characterized by elemental analysis, powder X-ray diffraction, thermogravimetry, and conductivity methods. The ligand coordination mode and the spatial structure of the complexes were established from the magnetochemistry and spectroscopy (IR, diffuse reflection) data. The dimeric structure of one of the complexes formed due to the chloride bridges was confirmed by EXAFS method.     

Copper(II) complexes with condensation products of aminonaphthalene and benzoin derivatives

New copper(II) complexes with the products of condensation of benzoin with monopotassium 1-amino-8-hydroxy-2,4-naphthalenedisulfonate and 1,8-diaminonaphthalene (complexes I and II, respectively) have been synthesized. The compounds are identified and characterized by elemental analysis; X-ray powder diffraction; thermogravimetry, and electric conductivity data; magnetic susceptibility measurements; and IR, EPR, diffuse reflectance; EXAFS spectroscopy. The geometry and stability of the stereo isomers of complex I are theoretically studied with the use of the molecular mechanics method and semiempirical quantum-chemical calculations. The compositions of the inner spheres of complexes I and II and their coordination polyhedra—a distorted planar square (I) and a distorted octahedron (II)—are determined using different physicochemical methods.     

Nickel(II) complexes with 4-aminobenzophenone

The following nickel(II) complexes with 4-aminobenzophenone (L) have been prepared and investigated: NiBr₂L_0.67, Ni(NO₃)₂L, NiX₂L₂(X = Cl(H₂O), NO₃), NiCl₂L₃, NiX₂L₄(X = Br, I, BF₄, ClO₄(2H₂O)), NiX₂L₆(X = BF₄, NO₃) and Ni(ClO₄)₂L₈. In the NiCl₂L₂.H₂O, Ni(NO₃)₂L, Ni(NO₃)₂L₂ and Ni(NO₃)₂L₆ complexes the ligand is H₂N-coordinated. In the other complexes the coordination occurs through the carbonylic oxygen atom. Some νNiX(X = Cl, Br, I, ONO₂) and νNiN bands and the νNiOH₂ band of the NiCl₂L₂.H₂O complex were assigned.     

Nickel(II) complexes with dicyanamide and tetramines

Four new pseudohalide complexes of the type [NiL{N(CN)₂}₂] (L = N(CH₂CH₂NH₂)₃, TAA; triethylenetetramine, TTA) and [NiL{N(CN)₂}]ClO₄ have been prepared and characterized by spectroscopic and magnetic methods. The X-ray crystal structures of [Ni(TAA){N(CN)₂}₂] and [Ni(TTA){N(CN)₂}₂] have been determined, and analyses show that in both complexes the Ni ion posseses distorted octahedral geometry. The temperature dependence of the magnetic susceptibility of [Ni(TTA){N(CN)₂}](ClO₄) was measured, but no antiferromagnetic interaction was detected.     

Spectral and electrochemical investigations on some condensation products of copper(II)-amino acid complexes

Summary Condensation products of several copper(II) amino acid complexes with formaldehyde or acetaldehyde have been prepared together with ethene-bridged copper(II) amino acid complexes. Structures were deduced from analytical and spectral data. Electronic spectral, e.s.r. and electrochemical behaviour at neutral and various low pH conditions were examined. Spectra of the unbridged complexes indicate the formation of [CuL]⁺ type species at pHca. 5, whereas the bridged complexes are stable at pH 3. The electrochemical behaviour of each complex is identical except for the doubly bridged complex. These results are explained in terms of a three-step electrode mechanism. The data show that the planarity of the complexes increases from unbridged, to bridged, to doubly bridged structures.     

Nickel(II) and cobalt(II) complexes of rhodanine

Summary Nickel(II) and cobalt(II) complexes of rhodanine (Hrd) were prepared from the metal chloride or acetate and the ligand. With an excess of NH3, the octahedral [Ni(NH₃)₆](Rd)₂ and [Co(NH₃)₅Rd]Rd complexes are ob-tained; use of only two NH₃ equivalents per metal ion yields the Ni(Rd)₂ sd HRd · NH₃ and [Co(Rd)₂ ] · 1.5 H₂O complexes, the first with tetragonally distorted hexacoordination and the second with polymeric octahedral coordination. By using two equivalents of NaOH per metal ion, the binuclear [Ni(Rd)₂][Ni(Rd)₂ · (HRd)₂] · 2 H₂O complex is formed having one diamagnetic planar and one high spin octahedral chromophore. Rhodanine is coordinated through the thiocarbonylic sulphur in the neutral form and through the thiocarbonylic sulphur and the deprotanated nitrogen atoms in the rhodanidato anionic form.     

Nickel(II) complexes of methylphosphinediacetic acid

Methylphosphinediacetic acid (H₂G) is coordinated to nickel(II) in two different ways, depending on whether its carboxyl groups are protonated or dissociated. The acid behaves as a monodentate tertiary phosphine in that it yields a series of trans-square planar NiX₂(H₂G)₂ complexes (X = Cl, Br, NCS or CN) which are stable in the solid state and as solutions in polar non-aqueous solvents. In neutral aqueous solution the NiG₂²⁻ complex is the predominant species (logβ₂ = 8.24 at 25°C and I = 0.1) even in excess nickel(II). Solid NiG·4H₂O is the nickel salt of this anion, Ni[NiG₂]·8H₂O. The X-ray structural determination of the barium salt, BaNiG₂·NaClO₄·5H₂O, revealed the uncommon cis-square planar arrangement around nickel with the G₂₋ anions acting as chelating P,O-bidentate to nickel and as O-monodentate to barium. Sodium and perchlorate ions are located between the complex units and, surprisingly, cannot be removed on recrystallization.     

Nickel(II) complexes of ethylenediphosphinetetra-acetic acid

Ethylenediphosphinetetraacetic acid (H₄L) coordinates nickel(II) preferentially as a chelating di(tertiary phosphine). The two complexes identified in non-aqueous solutions are cis-square planar NiBr₂(H₄L) and square-pyramidal [NiBr₂(H₄L)₂Br; both structures are retained in the solid state. The square planar anion NiL₂^6? is the predominant complex in a neutral aqueous solution. A number of its solid salts M₆NiL₂·aq (M = Na, $\text{1}\text{2}$ divalent metal) has the same square planar NiP₄ core. The compound Ni₂L·8H₂O also belongs to this series and should be formulated as Ni₃[NiL₂]·16H₂O: one nickel(II) is located in the NiP₄ core and the remaining three are coordinated by the carboxyl group oxygen atoms and water molecules in a roughly octahedral environment. The results are based on preparative, X-ray powder, magnetic susceptibility, conductometric, UV-VIS, NMR, IR (both normal and ⁶²Ni) and XPS spectral studies.     

Nickel(II) hexamethyleneiminedithiocarbamate complexes with triphenylphosphine or tributylphosphine

A series of square-planar nickel(II) hexamethylenedithiocarbamate complexes with heterogeneous coordination spheres of composition [NiX(hmidtc)Y] · nCHCl₃ [X = Cl, Br, I or NCS; hmi = C₆H₁₂, dtc = S₂CN^–; Y = PPh₃ or PBu₃, n = 0,1] have been synthesized and characterized by elemental analyses, i.r. and u.v.–v.i.s. spectroscopy, magnetochemical and conductivity measurements, and by thermal analysis. X-ray structures of [NiCl(hmidtc)(PPh₃)] · CHCl₃ and [NiBr(hmidtc)(PPh₃)] · CHCl₃ have been determined.     

New POCOP-type pincer complexes of Nickel(II)

The pincer complex [(POCOP)Ni(NCMe)][OSO₂CF₃] (1: POCOP = {2,6-(i-Pr₂PO)₂C₆H₃}) undergoes an acetonitrile substitution reaction in the presence of CN(t-Bu), KCN, and KOCN to give the new complexes [(POCOP)Ni{CN(t-Bu)}][O₃SCF₃] and (POCOP)Ni(X) (X = CN and NCO). The Ni-CN derivative is also obtained from a gradual decomposition of the Ni-CN(t-Bu) derivative, while the aquo derivative [(POCOP)Ni(OH₂)][O₃SCF₃] was obtained from slow hydrolysis of (POCOP)Ni(OSO₂CF₃). All new complexes have been characterized spectroscopically and by X-ray crystallography. IR and solid state structural data indicate that Ni-L/X interactions are dominated by ligand-to-metal σ-donation; presence of little or no π-backbonding is consistent with the electrophilicity of the cationic fragment [(POCOP)Ni]⁺.     

Nickel(II) complexes of anti-2-furancarboxaldoxime

Five different complexes of nickel(II) withanti-2-furancarboxaldoxime (-FDH) have been prepared and characterized by elemental analysis, molecular weights, conductance studies, magnetic moments and infra-red spectral studies. These are [Ni(FDH)₄Cl₂], [Ni(FD)₂(FDH)], [Ni(FD)₂(FDH)₂], [Ni(FD)₂·en], and [Ni(FD)₂]. All the complexes are neutral monomeric, paramagnetic (=3.3–3.7 B) and may be considered octahedral except the complex [Ni(FD)₂], (=2.92 B) which is tetrahedral. In these complexes the ligand functions as a monodentate and/or bidentate, coordinating with furan oxygen and oxime oxygen in the latter case. The ligand has been shown to be present in the ionized, and/or unionized form in these complexes.     

Nickel(II) complexes of β-N-alkylimme arylhydrazones

Summary -N-alkylimine arylhydrazone ligand complexes of nickel(II) have been synthesised by metal template reactions. The azomethine nitrogen and the a-nitrogen of the arylhydrazone coordinate to the metal with square-planar geometry around the nickel(II) ion. Structures have been proposed based on the spectral properties of the complexes.Reprints of this article are not available.     

Nickel(II) and copper(II) complexes of 5-substituted-salicylaldehyde thiosemicarbazones

Binuclear nickel(II) and copper(II) complexes with four 5-methoxysalicylaldehyde N(3)-substituted thiosemicarbazones and nickel(II) complexes of four 5-nitro-salicylaldehyde N(3)-substituted thiosemicarbazones have been prepared and characterized. I.r., electronic, and e.s.r. spectra of the complexes, as well as i.r., electronic, and 1H- and 13C-n.m.r spectra of the thiosemicarbazones, have been obtained. None of these compounds show significant growth inhibitory activity against the fungi Aspergillus niger and Paecilomyces variotii.     

Nickel(II) and Copper(II) complexes of sulphamide and ethylenediamine

Summary The following ethylenediamine(sulphamide)nickel(II) and ethylenediamine(sulphamide)copper(II) complexes were prepared: Ni(en)₃(H₂Su)Cl₂, in which H₂Su is not coordinated; Ni(en)₂(H₂Su)Cl₂ , Ni(en)₂(HSu)Cl · EtOH, Ni(en)₂(HSu)₂,Ni(en)₂(HSu)₂(H₂Su)₂ · EtOH, Cu(en)₂(HSu)₂(H₂Su) · O.5EtOH, in which the sulphamide molecule, H₂Su, or the sulphamidato anion [HSu] are totally or partially coordinated. The comparison of the i.r. spectra of these complexes with those of H₂ Su and NaHSu and with those of the M(en)₂Cl₂ complexes permits the isolation of the sulphamide or sulphamidato (SO₂) and (SN₂) bands which show oxygen-coordination of these ligands to the metal. Some (MO) bands were identified in the far i.r. region.     

Copper(II) complexes based on 2-thenoyltrifluoroacetone aroyl hydrazones: Synthesis,spectroscopy, and X-ray diffraction analysis

Copper(II) complexes CuL ? NH₃ are synthesized by the interaction of ethanol solutions of parasubstituted 2-thenoyltrifluoroacetylmethane aroyl hydrazones (H₂L¹–H₂L⁴) and an aqueous-ammonia solution of copper(II) acetate in an equimolar ratio. The copper(II) complexes are studied by elemental analysis, IR spectroscopy, and EPR spectroscopy. Single crystals of CuL³ ? NH₃ are grown from 1-(2-thenoyl)- 3,3,3-trifluoroacetone para-methylbenzoyl hydrazone and studied using X-ray diffraction analysis (CIF file CCDC 1045841).     

Nickel(II) complexes with nitrogen-containing derivatives of the closo-decaborate anion

The reactions of the salt (Bu₄N)[2-B₁₀H₉O₂C₄H₈] (1) with ammonia and ethylenediamine in ethanol were studied. These reactions afford substituted closo-decaborates with nitrogencontaining groups linked to the cluster through a diethylene glycol spacer. Using this method, we synthesized derivatives of the closo-decaborate anion with the pendant groups -NH₃ ⁺ and -NHCH₂CH₂NH₂; the complexes [Ni(H₂O)(en)(L)] (7) and [Ni(en)(L)]·0.5H₂O (8), where L = [2-B₁₀H₉O(CH₂)₂O(CH₂)₂NH(CH₂)₂NH₂]^2?, were synthesized. The X-ray diffraction study showed that the coordination sphere of the Ni²⁺ ions in complexes 7 and 8 have the same composition (4 N + 2 O). However, the coordination environment differs in the nature of the oxygen atom. Thus the oxygen atom directly bonded to the boron cluster is involved in the coordination of the metal ion in compound 8, whereas a water molecule is involved in the coordination in compound 7.     

Nickel(II) and copper(II) complexes with humic acid anions and their derivatives

Complexation of Ni(II) and Cu(II) in aqueous solutions with anions of humic acids, extracted from naturally oxidized coal, and with their hydroxymethyl derivatives is studied spectrophotometrically and potentiometrically. The complexation stoichiometry and the stability constants of the complexes are determined.     

Heteroarylphosphorus compounds: Nickel(II) and cobalt(II) complexes of thienylphosphines

Complexes of a series of tertiary phosphines bearing 2-thienyl groups with nickel(II) and cobalt(II) halides and thiocyanates have been prepared and their magnetic and spectroscopic properties are presented. The nickel(II) halide and cobalt(II) halide and thiocyanate complexes have a distorted tetrahedral structure, whereas the nickel(II) thiocyanate complexes are square planar. Consideration of the spectroscopic data for the tetrahedral nickel(II) halide complexes of the thienylphosphines indicates that a 2-thienyl substituent is more electron-releasing towards phosphorus than is a phenyl group when the phosphorus is coordinated to the metal, suggesting that in this situation effects of pπ−dπ interactions between the heterocyclic ring system and phosphorus may be significant in influencing the donor properties of the phosphine. Calculation of the Racah parameters for the nickel(II) complexes indicates that the nephelauxetic effects of the thienylphosphines are different from those of triphenylphosphine and that there is a greater degree of covalency in the metal-ligand bond in the case of the thienylphosphines.     

Nickel(II) and copper(II) complexes of 2,5-dimethyl-1,3,4-thiadiazole

Summary Nickel(II) and copper(II) complexes of 2,5-dimethyl-1,3,4-thiadiazole Ni(DTZ)X₂ (X = Cl or Br) and M(DTZ)₂X₂ (M = Ni, X = 1 or N03; M = Cu, X = Cl, Br or NO₃) have been prepared. The i.r. spectra show that in all the complexes the ligand is N,N- or N-bonded to the metal while the sulfur atom does not participate in coordination, and that the halide ions are coordinated forming terminal M-X bonds. The NO ₃ ^- group is coordinated in both the nitrato complexes. Magnetic moments of 3.07–3.29 B.M. for the nickel(II) and 1.86–1.92 B.M. for the copper(II) complexes were observed. The Ni(DTZ)X₂ complexes have a pseudo-tetrahedral [N₂X₂] coordination with N,N-bridging ligand molecules. The Ni(DTZ)₂X₂ and Cu(DTZ)₂X₂ complexes, with predominantly monodentate ligand, involve six-coordinate metal atoms with strong equatorial [N₂X₂] bonds and weaker axial bonds.Author to whom all correspondence should be directed.