P.A. Vigato

The activation of small molecules by dinuclear complexes of copper and other metals

Revue synthetique concernant la reactivite de complexes avec des coordinats divers (macrocycles, bases de Schiff, heterocycles azotes), vis a vis de O 2 , CO 2 H 2 O 2 etc... Synthese bibliographique

Actinide nitrate complexes

ELT. U. V. W. X. Y. Introduction Modes of coordination of the nitrate group Actinide(II1) nitrates and complexes Actinide(IV) nitrates and complexes (i)Nitrates (ii) Nitrato complexes Actinide(V) nitrates and complexes (i)Nitrates (ii) Nitrato complexes Actinide(V1) nitrates and complexes. (i)Nitratesandnitratehydrates (ii) Nitrato complexes Actinide(IV) nitrate complexes with ligands containing nitrogen donors ..... Actinide(V1) nitrate complexes tiith ligands containing nitrogen donors ..... Actinide(V1) nitrate complexes with ethers Actinide( IV) nitrate complexes with crown ethers Actinide(V1) nitrate complexes with crown ethers Actinide(IV) and actinide(V1) nitrate complexes with cryptates Actinide(IV) nitrate complexes with urea Actinide(V1) nitrate complexes with urea Actinide(V1) nitrate complexes with carbamates Actinide(IV) nitrate complexes with amides Actinide(V1) nitrate complexes with amides Actinide(IV) nitrate complexes with amine N-oxides Actinide(V1) nitrate complexes with amine N-oxides Actinide(IV) nitrate complexes with phosphine and amine oxides _ . _ . _ _ _ . Actinide(V1) nitrate complexes with phosphine and amine oxides ......... Actinide(IV) nitrate complexes with sulphoxides Actinide(VI) nitrate complexes with sulphoxides Conclusions Addendum 184 184 192 193 193 198 202 202 204 204 204 212 216 217 219 219 220 223 224 224 227 229 233 233 234 236 246 251 256 257 258 References . .._ _._____.._ _ _ _._ _ _ _ _.___._____ _ _.._ _ _.__.__._ 259

Lanthanide complexes with compartmental schiff bases

Abstract Lanthanide complexes have been prepared with acyclic and cyclic compartmental Schiff bases (H2L) obtained by condensation of 2,6-diformyl-4-chlorophenol and the polyamines NH2(CH2)2X(CH2)2NH2 (X = NH, S). They can be formulated as Ln(L)NO3· nH2O or Ln(H2L)(NO3)3·nH2O (Ln3+ = La, Nd, Sm, Gd, Tb, Dy, Ho, Er, Yb; n = 0–5) and have been obtained by step-by-step reactions, which allow a more appropriate control of the reaction procedure. Template syntheses often produce not well defined complexes. The Schiff bases act as neutral of dinegative chelating ligands according to the experimental conditions employed. When they coordinate as neutral ligands, one ionic and two bidentate nitrate groups are present in the complexes. A ring contraction, through an interanl cyclization, has been observed in the macrocyclic complexes when X = NH (H2Lc). The crystal structure of [Tb(H2Lc)(NO3)2]NO3 was determined by X-ray crystallography. The compound is monoclinic, space group C2/c, with a = 23.668(5), b = 14.328(7), c = 19.482(5) A and β = 91.82(5)°; Dc = 1.70 g cm−3 for Z = 8. The structure was refined to R = 0.078. The terbium ion is nona-coordinated in the usual coordination geometry of a distorted tricapped trigonal prism. Two nitrato groups are chelate in approximately bisphenoidal position, the third nitrate being ionic. The organic macrocycle is coordinated through two oxygen and three nitrogen atoms. Selected bond distance are: TbO(nitrate) 2.46 A (mean), TbO(ligand) 2.25 A (mean), TbN(ligand) 2.54 A (mean).

Macrocyclic and macroacyclic compartmental Schiff bases: synthesis, characterization, X-ray structure and interaction with metal ions

Acyclic, potentially hexadentate (H4LAH4LD) or decadentate (H6LE) compartmental Schiff bases have been obtained by reaction in methanol of 2,3-dihydroxybenzaldehyde and 1,2-diaminoethane, 1,2-diamino-2-methylpropane, 1,3-diamino-2,2-dimethylpropane, 1,2-diaminobenzene or tris(2-aminoethyl)amine in a 2:1 or 3:1 molecular ratios as appropriate. The reaction of 2,6-diformyl-4-Z-phenol (ZCl−, CH3−) with 1,2-diaminobenzene in methanol produced the partially reduced macrocycles (H2LF and H2LG). Similarly symmetric tetraimine macrocyclic ligands have been synthesized by cyclo-condensation of the same 2,6-diformyl-4-substituted phenols and 1,5-diamino-3- azapentane (H2LH) or 1,4-bis(3-aminopropyl)piperazine (H2LI). A step by step procedure has been employed for the preparation of the asymmetric macrocycle (H2LL). The ligands are yellow or yellow-orange solids and have been characterized by elemental analyses, IR, 1H NMR spectroscopy and electron impact (EI) or fast atom bombardment (FAB) mass spectrometry. The X-ray crystal structures of H4LC and H2LF have also been solved. Crystals of H4LC, grown from CHCl3, are monoclinic, space group P21/c with a=6.767(4), b=14.106(5), c=18.163(5) A, β=91.05(4)° for Z=4. The molecule is composed of two identical dihydroxybenzaldimine moieties connected by the carbon atom C(9). Three hydroxylic oxygens are protonated while the fourth is negatively charged. An intermolecular hydrogen system, involving the hydroxyl groups, gives rise to the formation of polymer chains parallel to c axis. Crystals of H2LF, grown from CHCl3, are monoclinic, space group P21/a with a=22.481(7), b=8.989(5), c=11.911(5) A, β93.28(5)° for Z=4. The molecule shows some unexpected bond lengths and angles. Two nitrogen atoms of each molecule are iminic, the other two aminic in character. A reduction of two CN bonds occurs during the synthetic procedures with the consequent formation of the partially reduced Schiff base. The coordination properties of the acyclic and cyclic ligands towards d and/or f metal ions have been tested, and the results are discussed in detail.

Mononuclear, homo- and heteropolynuclear complexes with acyclic compartmental Schiff bases

Abstract Acyclic compartmental Schiff bases (H4L) have been synthesized by condensation of 2, 3-dihydroxybenzaldehyde with the diamines NH2RNH2 (R- (CH2)2, H4LA; C(CH3)2CH2, H4LB; CH2C(CH3)2CH2, H4LC; C6H4, H4LD). Mononuclear complexes have been obtained by reaction of these hexadentate ligands with the appropriate metal(II) ions (copper(II), nickel(II), uranyl(VI) or lanthanium(III)) or by template procedure. The d metal ions coordinate into the inner N2O2 compartment, while uranyl(VI) or lanthanium(III) occupy the outer O2O2 site of the ligands. Crystals of Ni(H2LC), grown from a methanol/diethyl ether solution are triclinic, space group P 1 with a=11.040(5), b=13.645(5), c=14.877(6) A; α=71.93(4), β=84.62(5), γ=66.56(5)° for Z=2. The two chemically identical molecules of the nickel complex, present in the asymmetric portion of the cell, contain a methanol or a water molecule, respectively, linked by hydrogen bonds in the O2O2 outer site. The coordination around nickel ions, placed in the N2O2 sites, is not strictly planar, all atoms being tetrahedrally displaced from the mean coordination planes by about 0.047 and 0.093 A (mean) for the two molecules A and B, respectively. The metal ion is displaced by 0.026 and 0.015 A from the same planes. The average bond lengths for NiO and NiN are 1.84 A. In the heteropolynuclear complexes MLn(H2L)(X)3, [MLn(L)(NO3)(S)]2 and MUO2(L)(S), (MCu2+, Ni2+; LnLa, Gd; SH2O, MeOH, dmso), obtained by a step by step procedure, the smaller d ion always occupies the inner N2O2 chamber, while the larger f ion occupies the outer O2O2 chamber. The ligands and the complexes have been characterized by IR, 1H and 13C NMR, X-ray, mass spectrometric and magnetic susceptibility studies. The temperature dependence of the magnetic susceptibility of heterodinuclear and heterotetranuclear complexes containing copper(II) and gadolinium(III) ions, in the temperature range 4.2–300 K, shows a ferromagnetic interaction between the d and f metal ions (JCuGd=1.59(3) and -3.76(4) cm-1 for CuGd(H2LA)(NO3)3 and [CuGd(LA)(NO3)(H2O)]2, respectively.

Mono-, homo- and hetero-dinuclear lanthanide(III) complexes with new acyclic compartmental schiff bases

Abstract A series of homo-dinuclear lanthanide(III) complexes of the type: Ln2(LA)(X)2·.n(H2O) and Ln2(LB)(X)2·.n(H2O) (H4LA and H4LB are the Schiff bases obtained by condensation of 3-formylsalicylic acid and 4-N-dodecyldiethylenetriamine or 1,5-diamino-3-azapentane, respectively; X=NO3−, Cl−; n= 3−8;) has been prepared and characterized. The synthesis of mono- and hetero-dinuclear complexes failed. On the contrary, mono-, homo- and hetero-dinuclear lanthanide(III) complexes, Ln(H4LC(NO3)3·nS, Ln(H4LD)(NO3)3·nS or La(H4LE)(NO3)3·4H2O, Ln2(LC)(NO3)2·nS, Ln2(LD)(NO3)2·nS or La2(LE)(NO3)2·4H2O, Ln1Ln2(LC)(NO3)2·nS or Ln1Ln2(LD)(NO3)2·nS (n=1−3; SH2O, CH3OH), respectively, have been prepared by using the ligands H4LC, H4LD and H4LE, which are the Schiff bases derived by condensation of 2,3-dihydroxybenzaldehyde with 1,5-diamino-3-azapentane, 1,5-diamino-3-thiapentane or 4-N-dodecyldiethylenetriamine, respectively. The metal/metal ratio and the homogeneity of the hetero-dinuclear complexes have been evaluated also by electron microscopy together with X-ray fluorescence microprobe. The physicochemical properties of the prepared complexes have been compared with those of similar macrocyclic complexes. The magnetic behaviour of the complex Gd2(LA)(NO3)2·4H2O has revealed a decrease in the effective magnetic moment from 10.97 μB at room temperature to 7.96 μB at 4.2 K, and an antiferromagnetic coupling constant J=0.211(4) cm−1. A superexchange mechanism through the bridging atoms has been proposed.

Metal complexes of some tetraketones and their schiff bases

Abstract Metal complexes of the tetraketones N-(o-tolyl)-diacetoacetamide (H 2 L a and 1,1′-(2,6-pyridyl)bis-1,3-butanedione (H 2 L b ) are reported. The reaction of H 2 L b with hydroxyalkyl- and hydroxyarylamines to yield Schiff bases (H 4 L) is given and metal complexes of the type, M 2 L, M(H 4 L)X 2 and M 2 (H 2 L)X 2 have been prepared. The properties of the metal complexes are discussed and suggested structures presented.

New acyclic and cyclie Schiff bases derived from 2,6-diformyl-4-chlorophenol and their interaction with uranyl(Vl), copper(II) and nickel(Il) ions

Abstract New acyclic and cyclic Schiff base compartmental ligands have been prepared, by reaction of 4-chloro- 2,6-diformylphenol and polyamines of the type NH 2 (CH 2 ) 2 X(CH 2 ) 2 NH 2 (X = NH, S). These ligands have two similar or dissimilar compartments in dose proximity and can link two metal ions in an identical or different coordination mode. The preparation of mono and binuclear uranyl(VI), nickel(II) and copper(II) complexes is also reported together with their physicochemical properties. For the mononuclear species, with ligands having dissimilar compartments, the site occupancy is also discussed on the basis of IR, UV and magnetic properties. For the homobinuclear copper(II) and nickel(II) complexes an antiferromagnetic interaction between the two paramagnetic centres is suggested.

The preparation and characterisation of metal complexes of a new binucleating ligand having two different coordination sites

Abstract A new ligand, referred to as H 4 aapen, has been prepared; it is the ethylenediamine Schiff base derivative of o -acetoacetylphenol and has one site with two nitrogen and two oxygen atoms (N 2 O 2 ) and a second site with four oxygen atoms (O 2 O 2 ) two central oxygens being common to both sites. A series of mono-nuclear complexes have been prepared from this ligand in order to investigate the coordination selectivity of the two compartments. In Ni(H 2 aapen) the nickel(II) is in the N 2 O 2 site, while in UO 2 (H 2 aapen)(H 2 O) and Li 2 [UO 2 (aapen)(H 2 O)]H 2 O the uranyl ions are in the O 2 O 2 site. Positional isomers can be prepared with copper(II): one having the copper in the O 2 O 2 site and the other with copper in the N 2 O 2 one. The mononuclear complexes were used as ligands to prepare the binuclear complexes MM′(aapen) (M = Ni 2+ , Cu 2+ , UO 2+ 2 ; M′ = Ni 2+ , Cu 2+ ). These complexes were characterized on the basis of the analytical data, mass, ir, uv spectra and magnetic moments at room temperature.

Macrocyclic complexes with lanthanoid salts part 38. Synthesis and luminescence study of homo- and hetero-binuclear complexes of lanthanides with a new cyclic compartmental Schiff base

Homo- and hetero-binuclear lanthanide(III) complexes with the macrocyclic ligand H2L1 derived from the condensation of 4-chloro-2,6-diformylphenol and the polyamine NH2(CH2)2O(CH2)2O(CH2)2NH2 have been synthesized: [Ln2L1(NO3)4]·nH2O (Ln = La, Pr, Sm, Eu, Gd, Tb, or Dy; n= 1 or 2) and [LnxLn′2 –xL1(NO3)4]·nH2O (Ln,Ln′= La,Sm; La,Gd; La,Dy; La,Eu; Dy,Gd; Dy,Eu; Gd,Eu; Gd,Tb; Eu,Tb; or La,Tb; n= 1 or 2). Their possible structure and the interaction between the metal ions are discussed on the basis of spectroscopic, mass spectrometric, and magnetic data together with scanning electron microprobe analyses. Electron microscopy with X-ray fluorescence analysis as well as magnetic susceptibility measurements suggest that the complexes containing two different lanthanide ions may be truly heterobinuclear, with the two metal centres lying at a long distance from each other and not connected by any bridging heteroatoms. Laser-excited luminescence spectra and lifetimes also point to the presence of heterobinuclear species. The yield of the TbIII to EuIII energy transfer was quantified and the intermetallic distance evaluated.