Polydentate ligands based on closo-decaborate anion for the synthesis of gadolinium(iii) complexes

A reaction of the closo-decaborate anion 1,4-dioxane derivative with polyatomic alcohols (ethyleneglycol, glycerol, triethanolamine) was studied. These reactions include the ring opening of the cyclic substituent and the addition of the alcohol molecule to boron cluster through the alkoxy spacer chain. The products obtained form coordination compounds upon the reaction with gadolinium(iii) salts, playing the role of polydentate ligands. The compounds obtained were studied by IR spectroscopy, NMR spectroscopy, ESI mass spectrometry, elemental and thermographic analysis.     

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.     

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.     

Nucleophilic addition of amino acid esters to nitrilium derivatives of closo-decaborate anion

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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) 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 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.     

Ni(II) complexes with 8-aminoquinoline derivatives

Some Ni(II) complexes with 5,7-dicloro-8-aminoquinoline (dcaq), 5,7-dibromo-8-aminoquinoline(dbaq) and 5,7-diiodo-8-aminoquinoline(diaq) are described. The compounds are of stoichiometry NiL₂X₂(L= dcaq, dbaq, diaq; X= NO^?₃ and L= dbaq; X= Cl^?, Br^?, I^?, NCS^?) and NiLX₂·H₂O(L= dcaq, diaq; X= Cl^?). The electronic spectra and magnetic susceptibility data at room temperature, are consistent with octahedral geometry for the Ni(II) in each compound. I.r. spectra show the presence of ionic and bridging nitrate groups in the compounds NiL₂(NO₃)₂(L= dcaq, dbaq, diaq) and we assign them polymeric structures. Polymeric structures with bridging chloride are proposed for the compounds NiLCl₂·H₂O(L= dcaq, diaq) and monomeric octahedral structures for NiL₂X₂(L= dbaq; X= Cl, Br, I, NCS).     

Nickel(II) complexes of phthalic hydrazide or its anion,and their reaction with oxygen and nitrogen-donor ligands

The reaction of phthalic hydrazide(H₂PH) with Ni(II) salts yields complexes of the type [NiHPH)₂(H₂O)₂]2H₂O(I). Reaction of this complex with acetylacetone(acac) and ethyl-enediamine(en) gives mononuclear complexes of type [NiHPH)(acac)₂(H₂O)]H₂O(II) and [Ni(HPH)₂(en)₃(H₂O)]H₂O(IV) respectively and with monoethanolamine (MEA), aniline(An) and p-phenylenediamine(p-Phda) it gives trinuclear complexes of type [Ni₃(PH)₇(MEA)₄ (H₂O)3H₂O(III), [Ni₃(HPH)₄(An)(H₂O)₇]H₂O(V) and [Ni₃(HPH)₅(p-Phda)(H₂O)₇]H₂O(VI) respectively. The complexes have been characterized on the basis of infrared and electronic spectra and magnetic properties as containing octahedral Ni(II) and anionic hydrazide ligand.Ligand field parameters have been calculated and compared with chromophores containing oxygen and nitrogen donor atoms. Analysis of electronic spectra, calculated Dq values and IR absorptions strongly indicate the presence of NiN₂O₄, NiNO₅, NiO₆ and NiN₃O₃ chromophores.     

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.     

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) 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.     

Sorption of palladium(II) chloride complexes by nitrogen-containing modified shungites

The sorption properties of anion exchangers based on modified shungites with respect to palladium(II) ions from chloride solutions were studied. The effect of sorbent nature, pH of a solution, and process duration on the degree of their recovery was considered.     

Halocuprate(II) complexes with isoxazolium and imidazolium derivatives

Summary We have synthesized and characterized halocuprate(II) complexes with isoxazolium and imidazolium derivatives. The compounds are of three types: a) Cu(LH)X₃ · n H₂O where L=isoxazole (isox), 3,5-diMeisox, or 5-amino-3,4-diMeisox (5-ADI); X=Cl or Br; n=1–2; b) (LH)₂CuCl₄ where L=5-ADI, N-ethylimidazole (N-EtIm) or N-PropIm; c) (3-AMIH)₂Cu₂X₆ where 3-AMI=3-amino-5-methylisox; X= Cl or Br.Complexes (a) seem to be zwitterions with an oxygenbonded ligand and approximately tetrahedral structure; compounds (b) are distorted tetrahedral, nearly square planar; derivatives (c) are polymeric or dimeric with near square planar geometry.