Search results for "organometallic"
showing 10 items of 370 documents
Cinoxacin complexes with divalent metal ions. Spectroscopic characterization. Crystal structure of a new dinuclear Cd(II) complex having two chelate-…
1998
Several cinoxacin (HCx) complexes with divalent metal ions have been prepared and characterized by spectroscopic techniques. The crystal structure of [Cd 2 (Cx) 4 (H 2 O) 2 ] · 10H 2 O has been determined by X-ray diffraction. The complex is triclinic, space group with unit-cell dimensions: a =10.412(2), b =11.119(2), c =13.143(6)A, α=76.78(4)°, β =74.59(3)°, γ =77.12(3)°, V =1406.0(8) A 3 . In this complex each cadmium atom is heptacoordinated; the metal environment is formed by two O keto and two O carbox atoms from two different cinoxacinate monoanions, two carboxylate oxygen atoms from a third cinoxacinate ligand and by one water oxygen atom on the seventh position. Two of the cinoxacin…
Relaxed but highly compact diansa metallacyclophanes.
2011
A series of monoansa [μ-1,1′-PR-3,3′-Co(1,2-C2B9H10)2]− and diansa [8,8′-μ-(1″,2″-benzene)-μ-1,1′-PR-3,3′-Co(1,2-C2B9H9)2]− (R = Ph, tBu) cobaltabisdicarbollidephanes have been synthesized, characterized and studied by NMR, MALDI-TOF-MS, UV-visible spectroscopy, cyclic voltammetry, and DFT calculations. Single crystal X-ray diffraction revealed a highly relaxed structure characterized by the title angle α of 3.8° ([7]−), this being the smallest angle α for a metallacyclophane. In such compounds, the metal-to-phosphorus distance is less than the sum of their van der Waals radii. The availability of a phosphorus lone pair causes an electron delocalization through the metal, as shown by the ab…
Structural and magnetic characterization of a 1D chain of [Co(II)2(mu-aqua)(mu-carboxylate)2] strung cores.
2009
A novel 1D chain built up from stringing of [Co2(μ-OH 2)(μ-O2CC(CH3)3)2] units with the bridging 2,2′-bipyrimidine ligand has been synthesized and structurally characterized. The chains are well isolated from each other by the bulky tert-butyl groups of the carboxlyates and show an alternating zigzag configuration for the Co(II) metallic centres. DC magnetic measurements show anti-ferromagnetic coupling, Jca.-3 cm-1 between adjacent Co(II) ions along the chain. Noticeably, good data fitting was obtained by means of simple models that neglect any kind of first order orbital contribution to the spin ground state, which is normally observed in Co(II) complexes. These results were further confi…
Comparison of Protective Effects against Reactive Oxygen Species of Mononuclear and Dinuclear Cu(II) Complexes with N-Substituted Benzothiazolesulfon…
2005
Copper(II) complexes of N-benzothiazolesulfonamides (HL1=N-2-(4-methylphenylsulfamoyl)-6-nitro-benzothiazole, HL2=N-2-(phenylsulfamoyl)-6-chloro-benzothiazole, and HL3=N-2-(4-methylphenylsulfamoyl)-6-chloro-benzothiazole) with ammonia have been synthesized and characterized. The crystal structures of the [Cu(L1)2(NH3)2].2MeOH, [Cu(L2)2(NH3)2], and [Cu(L3)2(NH3)2] compounds have been determined. Compounds and present a distorted square planar geometry. In both compounds the metal ion is coordinated by two benzothiazole N atoms from two sulfonamidate anions and two NH3 molecules. Complex is distorted square-pyramidal. The Cu(II) ion is linked to the benzothiazole N and sulfonamidate O atoms o…
Face-to-face held Pacman type porphyrin-fullerene dyads: design, synthesis, charge transfer interactions and photophysical studies
2008
Pacman-type face-to-face zinc-porphyrin-fullerene dyads have been newly synthesized and studied. Owing to the close proximity of the donor and acceptor entities, strong pi-pi intramolecular interactions between the porphyrin and fullerene entities resulted in modulating the spectral and electrochemical properties of the dyads. New absorption and emission bands that correspond to the charge-transfer interactions were observed in the near-IR region. Time-resolved transient absorption studies revealed efficient photoinduced electron transfer from the singlet excited porphyrin to the fullerene entity. The rate constants for photoinduced electron transfer are analyzed in terms of the Marcus theo…
Aminobisphenolate supported tungsten disulphido and dithiolene complexes
2015
Dioxotungsten(vi) complexes with tetradentate amino bisphenolates were converted into the corresponding Cs-symmetric amino bisphenolate disulphido complexes by a reaction with either Lawesson's reagent or P2S5. Further reaction with diethyl acetylenedicarboxylate leads to the formation of diamagnetic tungsten(iv) dithiolene compounds. The syntheses, crystal structures, spectroscopic and electrochemical characterization of such disulphido and dithiolene complexes are presented.
Three-Component Entanglements Consisting of Three Crescent-Shaped Bidentate Ligands Coordinated to an Octahedral Metal Centre
2007
3,3'-biisoquinoline ligands (biiq) L, bearing aromatic substituents on their 8 and 8' positions, have been used to generate interwoven systems consisting of three crescent-shaped ligands disposed around an octahedral metal centre. Mono-ligand complexes of the type [ReL(CO)3py]+ (py: pyridine) have also been prepared, leading to sterically non-hindering complexes in spite of the endotopic nature of the chelate used. The three-component entanglements have been prepared by using either FeII or RuII as gathering metal centre. The synthetic procedure is simple and efficient, affording fully characterised complexes as their PF6 or SbCl6 salts. X-ray crystallography clearly shows that the crescent…
Dilution-Triggered SMM Behavior under Zero Field in a Luminescent Zn2Dy2 Tetranuclear Complex Incorporating Carbonato-Bridging Ligands Derived from A…
2013
The synthesis, structure, magnetic, and luminescence properties of the Zn2Dy2 tetranuclear complex of formula {(mu(3)-CO3)2[Zn(mu-L)Dy(NO3)}(2)}center dot 4CH(3)OH (1), where H2L is the compartmental ligand N,N',N"-trimethyl-N,N"-bis(2-hydroxy-3-methoxy-5-methylbenzyl)diethylenetriamine, are reported. The carbonate anions that bridge two Zn(mu-L)Dy units come from the atmospheric CO2 fixation in a basic medium. Fast quantum tunneling relaxation of the magnetization (QTM) is very effective in this compound, so that single-molecule magnet (SMM) behavior is only observed in the presence of an applied dc field of 1000 Oe, which is able to partly suppress the QTM relaxation process. At variance,…
Imidazolate bridged Cu(II)-Cu(II) and Cu(II)-Zn(II) complexes of a terpyridinophane azamacrocycle: a solution and solid state study.
2007
The dinuclear Cu2+ and Zn2+ as well as the mixed Cu2+-Zn2+ complexes of a 5,5''-pentaazaterpyridinophane ligand (L) are able to incorporate imidazolate (Im-) as a bridging ligand. The crystal structure of [Cu(2)L(Im)(Br)(H2O)](CF(3)SO(3))(2).3H2O (1) shows one copper coordinated by the three pyridine nitrogens of the terpyridine unit, one nitrogen of the imidazolate bridge (Im-) and one bromide anion occupying the axial position of a distorted square pyramid. The second copper atom is coordinated by the remaining imidazolate nitrogen, the three secondary nitrogens at the centre of the polyamine bridge and one water molecule that occupies the axial position. Magnetic measurements have been p…
Cyclic [2]Pseudorotaxane Tetramers Consisting of Two Rigid Rods Threaded through Two Bis-Macrocycles: Copper(I)-Templated Synthesis and X-ray Structu…
2008
Variously substituted coordinating rigid rods have been synthesized which incorporate a central 4,7-phenanthroline nucleus attached to two 2-pyridyl groups via its 3 and 8 positions, so as to yield bis-bidentate chelates, the two-coordinating axes of the chelates being parallel to one another. Regardless of the nature of the substituents borne by the rods, the copper(I)-induced threading reaction of two such rods through the rings of two bis-macrocycles affords in a quantitative yield the 4-copper(I) threaded assembly. The [2]pseudorotaxane tetramers thus obtained have been fully characterized in solution and, for one of them, an X-ray structure could be obtained, confirming the threaded na…