Search results for "Denticity"
showing 10 items of 376 documents
The synthesis and structural characterization of some triorganotin(IV) complexes of 2-{[(E)-1-(2-hydroxyaryl)alkylidene]amino}acetic acid. Crystal an…
2002
Abstract Triorganotin(IV) derivatives of 2-{[(E)-1-(2-hydroxyaryl)alkylidene]amino}acetic acid have been synthesized and characterized by 1H, 13C, 119Sn-NMR, 119Sn Mossbauer and IR spectroscopic techniques in combination with elemental analyses. The crystal structures of triphenyltin 2-{[(E)-1-(2-hydroxyphenyl)methylidene]amino}acetate and trimethyltin 2-{[(E)-1-(2-hydroxyphenyl)ethylidene]amino}acetate are reported. The X-ray structures reveal that the complexes adopt a polymeric trans-O2SnC3 trigonal bipyramidal configuration with the R groups in the equatorial positions and the axial locations occupied by a carboxylate oxygen from the ligand and the phenolic oxygen of the ligand on an ad…
Synthesis and reactivity of an 2-azabutadiene-based π-conjugated dithioether: Formation of a N,S-ligated molybdenum chelate complex and C,N,S-pincer …
2005
Abstract Nucleophilic attack of sodium isopropylthiolate on 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene [Cl2C C(H)–N CPh2}] (1) affords the 2-azabutadiene derivative [(i-PrS)2C C(H)–N CPh2] (2). Upon irradiation of Mo(CO)6 in THF in the presence of 2, the chelate complex cis-[(OC)4Mo{(i-PrS)2C C(H)–N CPh2}] (3) is obtained. Coordination on Mo occurs through the imine nitrogen and a thioether group. Polydentate dithioether 2 acts as N,C,S-pincer ligand after orthometallation reaction with Pd(II) or Pt(II). The molecular structures of 2 and (C,N,S)-[(i-PrS)2C C(H)–N C(Ph)C6H4)PtCl] (4b) have been determined by X-ray diffraction studies.
Homoleptic, heteroleptic and mixed-valent thallium and indium complexes of multidentate chalcogen-centred PCP-bridged ligands.
2011
The metathetical reaction of [Li(TMEDA)][HC(PPh(2)Se)(2)] ([Li(TMEDA)]1) with TlOEt in a 1:1 molar ratio afforded a homoleptic Tl(I) complex as an adduct with LiOEt, Tl[HC(PPh(2)Se)(2)]·LiOEt (7), which undergoes selenium-proton exchange upon mild heating (60 °C) to give the mixed-valent Tl(I)/Tl(III) complex {[Tl][Tl{(Se)C(PPh(2)Se)(2)}(2)]}(∞) (8). Treatment of TlOEt with [Li(TMEDA)](2)[(SPh(2)P)(2)CE'E'C(PPh(2)S)(2)] (3b, E' = S; 3c, E' = Se) in a 2:1 molar ratio produced the binuclear Tl(i)/Tl(i) complexes Tl(2)[(SPh(2)P)(2)CE'E'C(PPh(2)S)(2)] (9b, E' = S; 9c, E' = Se), respectively. Selenium-proton exchange also occurred upon addition of [Li(TMEDA)]1 to InCl(3) to yield the heterolepti…
Binuclear Nickel(II) Complexes Based on Bridging Oxalate and Pseudohalides as Peripheral Ligands: Synthesis, Crystal Structure, DFT Calculations and …
2000
Nickel(II) molecular complexes were obtained by water displacement reactions of [{Ni(dien)(H2O)}2(μ-ox)]Cl2 and the corresponding pseudohalide. The three nickel(II) compounds [{Ni(N3)(dien)}2(μ-ox)] (1), [{Ni(NCO)(dien)}2(μ-ox)] · H2O (2) and [{Ni(NCS)(dien)}2(μ-ox)] (3) are almost isostructural. The structure determinations reveal the presence of a binuclear complex with C2h symmetry, where the oxalate ligand is coordinated in a bis(bidentate) fashion to the twofold related nickel atoms. The distorted octahedral environment of each nickel atom is completed by the three nitrogen atoms of the diethylenetriamine ligand in a fac arrangement and one nitrogen atom from a pseudohalide ligand. Mag…
Di- and Tri-organotin(IV) Complexes ofN-Acetyltriglycine andN-Benzoyltriglycine: Synthesis and Spectroscopic Characterization
1996
Di- and tri-organotin(IV) derivatives of N-acetyltriglycine and N-benzoyltriglycine (HA) were obtained by refluxing equimolar mixtures of the ligand and the organotin(IV) oxide or hydroxide in methanol or acetone. According to the spectroscopic data, triorganotin(IV) derivatives adopt a trigonal-bipyramidal structure in which the planar R 3 Sn IV unit is bonded by a monodentate carboxylate group and a donor group, presumably the amide C=O. The reaction of HA with the appropriate diorganotin(IV) compounds gave both dicarboxylates R 2 SnA 2 , with six-coordinated tin, and dimeric tetra-organodistannoxanes {[R 2 SnA] 2 O}2, in which the tin atoms are essentially five-coordinated.
Structure, spectroscopic and magnetic properties of a novel 1-D coordination copper(II) polymer containing BIMAM ligand [BIMAM=bis(imidazol-2-yl)meth…
2006
Abstract This paper reports the synthesis and complete characterization (structural, spectroscopic and magnetic) of [Cu(HBIMAM)Cl(C4O4)]n · (H2O)n [BIMAM = bis(imidazol-2-yl)methylaminomethane]. This compound is made of infinite chains – running along c axis – built from [CuCl(HBIMAM)]+ units bridged together by μ-O1,O3-bis(monodentate) squarate anions. Non-covalent interactions (H-bonds and π–π) drive the build-up of an infinite three-dimensional array. The coordination polyhedron about the copper(II) ion is distorted square pyramidal. The EPR spectrum is indicative of a d z 2 - y 2 ground state for the Cu(II) ions with significant contribution of d z 2 . Magnetic susceptibility measuremen…
Charged Bis-Cyclometalated Iridium(III) Complexes with Carbene-Based Ancillary Ligands
2013
Charged cydometalated (CN) iridium(III) complexes with carbene-based ancillary ligands are a promising family of deep-blue phosphorescent compounds. Their emission properties are controlled primarily by the main CN ligands, in contrast to the classical design of charged complexes where NN ancillary ligands with low-energy pi* orbitals, such as 2,2'-bipyridine, are generally used for this purpose. Herein we report two series of charged iridium complexes with various carbene-based ancillary ligands. In the first series the CAN ligand is 2-phenylpyridine, whereas in the second one it is 2-(2,4-difluorophenyl)-pyridine. One biscarbene (:CC:) and four different pyridine carbene (NC:) chelators a…
Metal-organic coordination frameworks based on mixed methylmalonate and 4,4′-bipiridine ligands: synthesis, crystal structure and magnetic properties
2010
Five new complexes of formulae [M2(4,4′-bpy)(Memal)2X2]n [M = Fe(III) (2), Mn(II) (3), Co(II) (4), Ni(II) (5) and Zn(II) (6), and X = Cl−/OH− (2) and H2O (3–6); 4,4′-bpy = 4,4′-bipyridine and Memal = methylmalonate dianion] have been synthesized by following the previously reported procedure for [Cu2(4,4′-bpy)(Memal)2(H2O)2]n (1). Moreover, two new phases of the Cu(II)/Memal/4,4′-bpy system, namely {[Cu(4,4′-bpy)2][Cu(4,4′-bpy)2(Memal)(NO3)(H2O)]}n·nNO3·3.5nH2O (7) and [Cu(4,4′-bpy)2(Memal)(H2O)]n·nH2O (8), were obtained by varying the synthetic conditions. They were all structurally characterized by single crystal X-ray diffraction, and the magnetic properties of 2–5, 7 and 8 were investig…
Dynamic chemical devices: photoinduced electron transfer and its ion-triggered switching in nanomechanical butterfly-type bis(porphyrin)terpyridines.
2005
A series of butterfly-type molecular constructs has been prepared in good yield by using a double Stille coupling synthetic protocol. They are composed of a terpyridine (terpy) scaffold and two wings composed of appended porphyrins that are capable of switching from an extended W geometry to a compact U geometry upon cation coordination of the terpy unit. The porphyrin moieties exist in the constructs either as free bases or they can be sequentially metallated, thus giving rise to wings of different "colours". Stationary and time-resolved emission studies of the HZn, ZnAu and Zn2Au constructs show that the electronic properties are strongly dependent on the geometry. In the extended W confo…
Synthetic, structural and biochemical studies of polynuclear platinum(II) complexes with heterocyclic ligands.
2008
"Non-classical" di- and trinuclear Pt(II) complexes with polydentate nitrogen ligands; ionic [(PtCl(2))(2)(tptz)(2)(mu-PtClNCPh)]Cl (1) [tptz =2,4,6-tris(2-pyridyl)-1,3,5-triazine], [(PtCl(2))(2)(bptz)(2)(mu-Pt)]Cl(2) (2) [bptz = 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine] and neutral [(PtCl(2))(2)(tptz)(2)(mu-PtCl(2))](H(2)O)(4) (3), [(PtCl(2))(2)(mu-tppz)](CHCl(3)) (4) [tppz = 2,3,5,6-tetra(2-pyridyl)pyrazine] complexes, have been prepared and structurally characterized. The neutral tptz and tppz complexes present three and two separate PtCl(2) moieties, respectively, in a cis position, presumably acting in a bifunctional mode towards DNA; the cationic tptz and bptz complexes contain monofuncti…