Homo- and heteronuclear complexes of a new,vicinal dioxime ligand

A new symmetrical vicinal dioxime, N,N′-bis-{4-[[(2-hydroxyphenyl)methylene]hydrazinecarbonyl]phenyl}diaminoglyoxime (LH₄), was prepared by reacting anti-dichloroglyoxime with salicylaldehyde 4-aminobenzoylhydrazone. The reaction of ligand with Ni²⁺ salts gave mono-and homopentanuclear complexes, [Ni(LH₃)₂] and [Ni₅(LH)₂X₂]. Furthermore, heteropentanuclear complexes of dioxime ligand, [Cu₄Ni(LH)₂X₄], were prepared by the reaction of [Ni(LH₃)₂)] with Cu²⁺ salt and a monodentate ligand (X = SCN⁻, CN⁻, or N ₃ ⁻ ). The structures of both the new symmetrical vicinal dioxime and its complexes were identified by elemental analyses, IR, ¹H NMR, UV-VIS spectra, and magnetic susceptibility. The elemental analyses and spectral data indicate that the hydrazone side of ligand acts as a O,N,O′ tridentate and the fourth position is occupied with monodentate anion such as SCN⁻, CN⁻, N ₃ ⁻ .     

Homo and heteronuclear complexes of dioxime ligands

The mononuclear fragments [Cu(HDopn)(OH)2]+ and [Cu(HPopn)(OH)2]+, [H2Dopn=3,3-(trimethylene- dinitrilo)-dibutan-2–one dioximate and H2Popn, = 3, 3-(phenylenedinitrilo)-dibutan-2–one dioximate] were used to prepare four binuclear complexes [(OH2)Cu (Dopn)Cu(ditn)]2+, [(OH2)Cu(Dopn)Ni(ditn)(H2O)]2+ (ditn=diethylenetriamine) and [(OH2)Cu(Popn)Cu(L) (H2O)]2+ (L=2,2-bipyridine or 1,10–phenanthroline). Two trinuclear complexes, [{Cu(Popn)(OH2)}2M (H2O)n]2+ (when M=CuII, n=1; M=ZnII, n= 2), have been synthesised and characterised by elemental analyses, f.a.b. mass, i.r., electronic, e.s.r. spectroscopy and variable temperature (5–300K) magnetic susceptibility measurements. A strong antiferromagnetic interaction (J=–545cm–1 to –700cm–1) has been found for the binuclear copper(II) complexes. The X-band e.s.r. spectra of these complexes at 300K and for trinuclear complexes at 120K indicate square-pyramidal geometry for the copper centres with a (dx2–y2)1 ground state. The binuclear complex of copper(II)–nickel(II) centres with antiferromagnetic interaction (J=–107 cm–1) is described, and moderately strong zero-field splitting within the quartet state leads to Kramers doublet, as indicated by X-band e.s.r. spectra of this complex. The trinuclear copper(II) complex with an antiferromagnetic interaction (J= –350cm–1) is also described. The heterometallic trinuclear copper(II)–zinc(II)–copper(II) system shows a very weak interaction (J–1cm–1).     

Uranyl complexes with 1,2-cycloheptanedione dioxime

Uranyl compounds with 1,2-cycloheptanedione dioxime (heptoxime) have been studied. Partial isomerization of the ligand takes place upon the formation of aqua complexes. The coordination modes of heptoxime in uranyl complexes were established by X-ray crystallography on [(UO₂)₂(C₇H₁₀N₂O₂)₂{(CH₃)₂SO}₃] single crystals: cis-(E,E)tetradentate chelating bridging and cis-(E,Z)pentadentate chelating bridging.     

Imido-bridged homo- and heterobimetallic complexes

Transamination reactions of primary amines with group 4 and 5 amido precursors M(NMe(2))(4) have been studied to prepare homo- and heterobimetallic complexes [(Me(2)N)(2)M(1)(μ-NR(1))(μ-NR(2))M(2)(NMe(2))(2)(NHMe(2))(x)] (x = 0, 1) with two identical or distinct bridging imido ligands.     

Isolation of a pentadentate ligand and stepwise synthesis, structures, and magnetic properties of a new family of homo- and heterotrinuclear complexes

A neutral pentadentate ligand, di(pyrazolecarbimido)amine (Hdcadpz), and its adduct with HClO4, [H2dcadpz]+[ClO4]-, were for the first time isolated from our previously reported [Cu3(dcadpz)2(Hpz)2(ClO4)2](ClO4)2.H2O by the use of (NH4)2S to remove the CuII ions and characterized by IR, EA, UV, NMR, MS, and X-ray crystallography. Reactions of copper(II) or nickel(II) nitrate with Hdcadpz in a 1:2 molar ratio generated two mononuclear precursors of [Cu(dcadpz)2] (1) and [Ni(dcadpz)2].2/3DMF (2). Furthermore, three new linear homo- and heterotrinuclear complexes of the same motif [M{M'(dcadpz)2}M] (M=CoII, NiII, M'=CuII, NiII), [{Co(pdm)}2{Cu(dcadpz)2}](NO3)4 (3), [{Ni(pdm)}2{Cu(dcadpz)2}](NO3)4 (4), and [{Ni(MeOH)(H2O)2}2{Ni(dcadpz)2}](NO3)4 (5), were synthesized from these two precursors (pdm=2,6-pyridinedimethanol) and characterized by X-ray crystallography. Magnetic studies show that the central Cu(dcadpz)2 motif is antiferromagnetically coupled with both the terminal Co(II) atoms via the dcadpz- ligand in 3 with a J value of -5.27 cm(-1) and ferromagnetically coupled with both the terminal Ni(II) atoms in 4 with a J value of 2.50 cm(-1), while 5 behaves only as a Curie paramagnet between 2 and 300 K due to the diamagnetic character of the central square-planar Ni(II) atom.     

A new (E,E)-dioxime and its mono and heterotrinuclear complexes containing an 18-membered dithiatetraazamacrocycle

The novel (E,E)-dioxime, 5,6:ll,12:17,18-tribenzo-2,3-bis(hydroxyimino)-7,16-dithia-9, 14-dioxo-l,4,10,13-tetraazacyclooctadecane (H₂L) has been synthesized by reacting (E,E)-dichloroglyoxime (2) with 2,3:8,9:14,15-tribenzo-4,13-di-thia-6,11-dioxa-l,7,10,16-tetraazahexzadecane (3), prepared by the reaction of N,N-bis(chloroacetyl)-1, 2-phenylene-diamine (1) with 2-aminothiophenol. Mononuclear complexes (4, 5) of this ligand have been synthesized by reacting the vic-dioxime (H₂L) with K₂PtCl₄ and NiCl₂ · 6H₂O, respectively. Heterotrinuclear complexes (6)and(7) have been prepared by the reaction of (4) and (5) mononuclear complexes with [Cu(MeCN)₄]PF₆. The structures of the vic-dioxime and its mono and trinuclear complexes were identified by elemental analysis, ¹H- and ¹³C-n.m.r, i.r. and m.s. data.     

Ferromagnetic heterotrinuclear Cu-Ni complexes of a compartmental chiral Schiff base

Nickel(II) and copper(II) acetate react with the trinucleating compartmental Schiff base H(4)L (H(4)L = 6,6'-(E)-3,3'-(ethane-1,2-diyl)bis(1-(2-((E)-3-bromo-5-chloro-2-hydroxybenzylideneamino)ethyl)imidazolidine-3,2-diyl)bis(2-bromo-4-chlorophenol)) to produce the heterotrinuclear complexes [Ni(2)CuL(OAc)(2)]·0.25H(2)O·2.5MeOH (1·0.25H(2)O·2.5MeOH) and [NiCu(2)L(OAc)(2)]·3.25H(2)O·0.5MeOH (2·3.25H(2)O·0.5MeOH) as a function of the Ni(OAc)(2)?:?Cu(OAc)(2) molar ratio. The crystal structures of H(4)L, 1·0.25H(2)O·2.5MeOH and 2·3.25H(2)O·0.5MeOH could be solved. The free ligand presents two stereogenic methine groups on the imidazolidine heterocycles. X-Ray diffraction studies on H(4)L determined that the solved crystal structure corresponds to a racemate formed by the (2R,2'R) and (2S,2'S) enantiomers, without detecting the (2R,2'S) diastereoisomer. The crystal structures of both heterotrinuclear complexes reveal that Ni(II) has a preference for the central ligand pocket, showing that this cavity discriminates between Ni(II) and Cu(II) when both species are present in the reaction medium. These results are validated by DFT calculations. As a consequence of the coordination, 1·0.25H(2)O·2.5MeOH and 2·3.25H(2)O·0.5MeOH are also chiral, but crystallise as racemates. In addition to their asymmetric methine groups, these complexes present four other stereogenic centres: the four coordinated imidazolidine N atoms. The luminescent properties of the ligand and both complexes were analysed, showing that the presence of the metals partially inhibits the emission of the ligand and apparently tunes the position of the secondary fluorescence emission band. The magnetic characterisation of 1·0.25H(2)O·2.5MeOH and 2·3.25H(2)O·0.5MeOH was also performed, showing the ferromagnetic behaviour of both complexes.     

In vitro cytotoxic and apoptotic effect of vic‐dioxime ligand and its metal complexes

In this study, vic‐dioxime ligand, (1E,2E)‐2‐(hydroxyimino)‐N′‐[(1E)‐2‐oxo‐2‐phenylethylidene]ethanehydroximohydrazide (LH₂), and its Cu (II) and Ni (II) transition metal complexes were synthesized and characterized using analytical and spectroscopic techniques. Furthermore, in vitro cytotoxic and apoptotic effects of this vic‐dioxime ligand and its Cu (II) and Ni (II) complexes on Caco‐2 heterogeneous human epithelial colorectal adenocarcinoma cells were evaluated. The effect of the vic‐dioxime ligand and its Ni (II) and Cu (II) complexes in combination with Campto on the cells was also investigated. The cytotoxicity test was carried using the MTT assay, and the apoptotic effect was tested by DNA diffusion assay. Campto was used as a standard anti‐cancer drug, Caco‐2 cancer cells treated with dimethylsulfoxide acted as solvent control, and human peripheral lymphocytes were used as control. The ligand and its complexes exhibit concentration‐dependent cytotoxic and apoptotic behavior. The ligand induces the weakest cytotoxic and apoptotic effects on both Caco‐2 cancer cells and lymphocytes. The Ni (II) complex of ligand induces high cytotoxic and apoptotic effects on both Caco‐2 cancer cells and lymphocytes. The Cu (II) complex of ligand has high cytotoxic and apoptotic effects on Caco‐2, but weak cytotoxic and apoptotic effects on lymphocytes. The cytotoxic and apoptotic effects of the ligand and its Ni (II) and Cu (II) complexes were found to be concentration dependent, i.e. the higher the concentration is the more cytotoxic it will be. The present findings suggest that Cu (II) complex has the potential to act as a promising anti‐cancer compound against Caco‐2 colon cancer cells.     

A novel tetraoxime and its dinuclear and tetranuclear transition metal complexes

A new bis(dioxime) ligand (H₄L) containing the diphenyl ether moiety has been prepared by reacting 3,3,4,4-tetraaminodiphenyl ether (1) with 2,3-butanedione monoxime (2). Dinuclear copper(II) and cobalt(III) complexes of H₄L exhibit a metal–ligand ratio of 2:1 and the ligand coordinates through the 4 nitrogen atoms, as do most bis(dioximes). The [Cu₂(H₂L)](ClO₄)₂ molecule coordinates to the other two copper(II) ions through the deprotonated oximate oxygens to yield a tetranuclear structure, doubly-bridged by the oximate groups in a cis arrangement. The structure of bis(dioxime) and its complexes were identified by elemental analyses, ¹H-, ¹³C-n.m.r, i.r and m.s. spectral data.     

A new class of macrocyclic complexes formed via nickel-promoted macrocyclisation of dioxime with dinitrile

o-Phthalonitrile couples with chelating dioxime on nickel(II), with formation of a dinuclear nickel(II) macrocyclic complex--the first representative of a new class of imine-appended macrocycles.     

A new unsymmetrical vic-dioxime bearing salicylaldehyde 4-aminobenzoylhydrazone and its homo-and heterotrinuclear complexes with copper(II) and nickel(II) ions

A new vic-dioxime, N-{4-[[(2-hydroxyphenyl)methylene]hydrazinecarbonyl]phenyl}aminoglyoxime (H₃L), was prepared by the reaction of anti-chloroglyoxime with salicylaldehyde 4-aminobenzoylhydrazone. The reaction of H₃L with Cu(II) salts and an appropriate simple ligand gave only homotrinuclear complexes [Cu₃(HL)₂X₂], whereas the reaction of H₃L with Ni(II) salts gave mono-and homotrinuclear complexes [Ni(H₂L)₂ and Ni₃(HL)₂X₂]. Also, heterotrinuclear complexes of H₃L were prepared by the reaction of Ni(H₂L)₂ with Cu(II) salt and an appropriate simple ligand, [NiCu₂(HL)₂X₂], X = Cl⁻, NO ₃ ⁻ , SCN⁻, CN⁻, and N ₃ ⁻ . The new vic-dioxime and its complexes were identified by elemental analyses, IR, ¹H NMR, UV-VIS, magnetic susceptibility, and mass spectral data. The elemental analyses and spectral data indicated that the hydrazone side of H₃L acted as monobasic tridentate and the fourth position was occupied by simple ligands, such as Cl⁻, NO ₃ ⁻ , SCN⁻, CN⁻, and N ₃ ⁻ . The text was submitted by the author in English.     

New heterotrinuclear complexes containing copper(II) and a group IV metal

Summary Heterotrinuclear complexes of the type [Cu₂(TETA)₂Cl₄M] (M = Si, Ge, Sn, Ti and Zr; TETA = triethylene tetramine) have been prepared by direct reaction of [Cu[TETA)]Cl₂ with MCl₄ in a 21 ratio in MeOH. The compounds have been characterized by elemental analyses, e.s.r., electronic and i.r. spectra, magnetic susceptibility and conductivity measurements. The results indicate that [Cu(TETA)]Cl₂ is square planar and ionic, while its heterotrinuclear complexes, [Cu₂(TETA)₂Cl₄M], are covalent with an octahedral environment around the copper(II) ion.     

Luminescent heterotrinuclear complexes with Pt(diimine)(dithiolate) and metal diphosphine as components

Reactions of Pt(diimine)(tdt) (tdt =3,4-toluenedithiolate) with [M(2)(dppm)(2)(MeCN)(2)](2+) (M = Cu(I) or Ag(I), dppm = bis(diphenylphosphino)methane) gave heterotrinuclear complexes [PtCu(2)(tdt)(mu-SH)(dppm)(3)](ClO(4)) (1) and [PtCu(2)(diimine)(2)(tdt)(dppm)(2)](ClO(4))(2) (diimine = 2,2'-bpyridine (bpy) 2; 4,4'-dimethyl-2,2'-bipyridine (dmbpy) 3; phenanthroline (phen) 4, 5-bromophenanthroline (Brphen) 5) for M = Cu(I), but [PtAg(2)(tdt)(mu-SH)(dppm)(3)](SbF(6)) (6) and [PtAg(2)(diimine)(tdt)(dppm)(2)](SbF(6))(2) (diimine = bpy 7; dmbpy 8; phen 9; Brphen 10) for M = Ag(I). While the complexes [PtAg(2)(diimine)(tdt)(dppm)(2)](SbF(6))(2) (7-10) result from linkage of Pt(diimine)(tdt) and [M(2)(dppm)(2)(MeCN)(2)](2+) by tdt sulfur donors, formation of [PtCu(2)(diimine)(2)(tdt)(dppm)(2)](ClO(4))(2) (2-5) is related to rupture of metal-ligand bonds in the metal components and recombination between the ligands and the metal atoms by self-assembly. The formation of 1 and 6 is involved not only in dissociation and recombination of the metal components, but also in disruption of C-S bonds in the dithiolate (tdt). The dithiolate tdt adopts a chelating and bridging coordination mode in anti conformation for [PtCu(2)(diimine)(2)(tdt)(dppm)(2)](ClO(4))(2) (2-5), whereas there is the syn conformation for other complexes. Compounds 1 and 6 represent sparse examples of mu-SH-bridged heterotrinuclear Pt(II)M(I)(2) complexes, in which Pt(II)-M(I) centers are bridged by dppm and sulfur donors of tdt, whereas M(I)-M(I) (M = Cu for 1; Ag for 6) centers are linked by dppm and the mu-SH donor. The (31)P NMR spectra show typical platinum satellites (J(Pt-P) = 1450-1570 Hz) for 1-6 and Ag-P coupling for Pt(II)-Ag(I) (J(Ag-P) = 350-450 Hz) complexes 6-10. All of the complexes show intense emission in the solid state and in frozen glasses at 77 K. The complexes [PtAg(2)(diimine)(tdt)(dppm)(2)](SbF(6))(2) (7-10) also afford emission in fluid acetonitrile solutions at room temperature. Solid-state emission lifetimes at room temperature are in the microsecond range. It is revealed that emission energies of the trinuclear heterometallic complexes [PtAg(2)(diimine)(tdt)(dppm)(2)](SbF(6))(2) (7-10) exhibit a remarkable blue shift (0.10-0.35 eV) relative to those of the precursor compounds Pt(diimine)(tdt). The crystal structures of 1, 2, 4, 6, 8, and 9 were determined by X-ray crystallography.     

The synthesis and characterization of a new (E,E)-dioxime and its mono and heterotrinuclear complexes containing dioxadithiadiazamacrobicyclic moieties

A new (E,E)-dioxime (2Z,3Z)-1,4,7,8,15,16-hexahydro-9,14-(ethanothioethanothioethano)quinoxalino[6,7-e] [4,7,1,10]benzodioxadiazacyclododecine-2,3,19,26-tetrone2,3-dioxime (H₂L) has been synthesized by reacting cyanogen-di-N-oxide with 2,3-diamino-6,7,14,15-tetrahydro-8,13-(ethanothioethanothioethano)dibenzo[b,h] [1,4,7,10]dioxadiazacyclodecine-17,24-dione (6). Mononuclear complexes (8, 9) of this ligand have been synthesized by reacting the vic-dioxime (H₂L) with NiCl₂ · 6H_2O and COCl₂ · 6H₂O respectively. The BF ₂ ⁺ capped cobalt(III) complex (10) of the new (E,E) vic-dioxime has been synthesized by using as precursor a hydrogen-bridged mononuclear cobalt(III) complex (9). The heterotrinuclear complex (11) has been prepared by reacting one mononuclear cobalt(III) complex (10) with [Cu(MeCN)₄]PF₆. The new compounds were characterized by a combination of elemental analysis, ¹H- and ¹³C-n.m.r, i.r. and m.s. spectral data.     

Two photoluminescent pentanuclear homo- and hetero-metal complexes based on benzotriazole bridge

Two new discrete Btz-bridged pentanuclear metal complexes, [HDMF][NaHg₄(Btz)₆I₄] (1) and [Zn₅(Btz)₆(L)₃(Ac)]?·?0.5MeOH?·?0.5H₂O (2) (Btz?=?deprotonated benzotriazole, L?=?p-aminobenzoate, HDMF?=?protonated DMF, and Ac?=?acetate), were synthesized using three-layered diffusion and natural evaporation methods, respectively. In 1, the pentanuclear anion [NaHg₄(Btz)₆I₄]^? is composed of a tetrahedral arrangement of four four-coordinate Hg(II) ions centered on the six-coordinate Na(I), and thereby forming a rare Btz-bridged hetero-metal complex. Compound 2 is a neutral pentanuclear homo-metal complex, consisting of a tetrahedral arrangement of four five-coordinate Zn(II) ions centered on the fifth six-coordinate Zn(II). The thermal stabilities and solid-state photoluminescence of the two complexes have been investigated.     

Selective homo- and heterodehydrocouplings of phosphines catalyzed by rhodium phosphido complexes

Reactions of the rhodium complex (dippe)Rh(eta3-CH2Ph) (1, dippe = iPr2PCH2CH2PiPr2) with ArPH2 (Ar = Ph, Mes) proceed via P-H oxidative additions to the phosphido complexes (dippe)Rh(mu-PHAr)2Rh(dippe) (3a, Ar = Ph; 3b, Ar = Mes). The corresponding reaction of Ph2PH occurs similarly, via the intermediate (dippe)Rh(PPh2)PHPh2 (4), to (dippe)Rh(mu-PPh2)2Rh(dippe) (3c). Complexes 3a-c and 4 are catalysts for the catalytic dehydrodimerizations of the corresponding phosphines to diphosphanes. Complex 1 is a more active dehydrocoupling catalyst, and substituent effects suggest that the active catalyst is mononuclear. Efficient dehydrocouplings of 2-EtC6H4PH2, 2-iPrC6H4PH2, and 2,4,6-iPr3C6H2PH2 were also observed. Complex 1 also catalyzes the heterocoupling of Ph2PH with PhSH (to Ph2P-SPh), and stoichiometric reactions in this system allowed isolation of (dippe)Rh(mu-SPh)2Rh(dippe) (6) and (dippe)Rh(SPh)PHR2 (7a, R2PH = MesPH2; 7b, R2PH = Ph2PH).     

Linear heterotrinuclear complexes derived from an alkyl platinum(II) twelve-membered macrocycle

The P,N,P-tridentate ligand 2,6-bis(diphenylphosphino)pyridine, L, was employed to generate a twelve-membered metallomacrocyclic host species cis-Pt(2)Me(4)(mu-L)(2) that encapsulates Tl(I) and Cu(I) guest ions. The ligand was also used to synthesize another two linear heterotrinuclear complexes, [Me(2)Pt(mu-L)(2)Ag(2)(MeCN)(2)](BF(4))(2).MeCN and [(CO)(3)Fe(mu-L)(2)Ag(2)(Et(2)O)](ClO(4))(2), both containing a metal-metal dative bond (Pt-->Ag and Fe-->Ag, respectively) and stabilized by the d(10)-d(10) argentophilic interaction.     

A novel method for preparation of vicinal fluoro-iodo compounds using elemental fluorine

Elemental fluorine reacts with iodine at ?75° and the resulting IF is reacted, without any isolation or purification, with olefins thus producing fluoro-iodo compounds in an excellent regio- and stereospecific mode.     

Synthesis,crystal structures and NIR luminescence of sandwich-like tetradentate salophen phenoxo-bridged heterotrinuclear metal complexes

Six phenoxo-bridged tetradentate salophen heterotrinuclear Zn₂Ln complexes, [Ln(ZnL)₂(NO₃)₃(CH₃OH)₂]·CH₃OH·CH₂Cl₂ [Ln?=?Pr (1), Nd (2)] and [Ln(ZnL)₂(NO₃)₃(CH₃OH)]·CH₃OH·CH₂Cl₂ [Ln?=?Eu (3), Ho (4), Er (5), and Yb (6)], have been isolated from reactions of N,N′-bis(salicylidene)-1,2-(phenylene-diamine) with Ln(NO₃)₃6H₂O and Zn(OAc)₂2H₂O. X-ray diffraction analysis reveals that 1–6 are isomorphic with phenoxo-bridged, sandwich-like {Zn₂Ln} core. Near infrared (NIR) luminescence spectra show that 6 exhibits typical emission of Yb³⁺ upon excitation at the ligand-centered absorption band at 357?nm.