Search results for "Octahedron"
showing 10 items of 405 documents
Syntheses, crystal structures and magnetic properties of one- and two-dimensional pap-containing copper(II) complexes (pap = pyrazino[2,3- f ][4,7]…
2001
Three polynuclear complexes containing copper(II) and pyrazino[2,3-f][4,7]phenanthroline (pap) as the basic building blocks have been prepared [Cu2(pap)(H2O)2(NO3)3]n[NO3]n1, [Cu4(pap)4Cl7]nCln·15nH2O 2, and [Cu4(pap)4(H2O)4(C4O4)2]n[C4O4]n[NO3]2n·12nH2O 3, and their crystal structures and variable-temperature magnetic susceptibilities determined. Compound 1 is a single stranded zigzag chain where pap and nitrate alternate as bridges between the copper atoms. The copper coordination geometry is to a first approximation distorted square pyramidal, but with an additional semi-coordinated oxygen from non-bridging nitrate groups. The bridging nitrate coordinates in the apical position to both c…
Towards oxalate-bridged iron(ii), cobalt(ii), nickel(ii) and zinc(ii) complexes through oxotris(oxalato)niobate(v): an open air non-oxidizing synthet…
2018
Four compounds with the formula [M2(dmphen)4(μ-C2O4)](ClO4)2·2dmso [M = Fe (1), Co (2) and Zn (4); dmphen = 2,9-dimethyl-1,10-phenanthroline] and [Ni2(dmphen)4(μ-C2O4)]3[NbO(C2O4)3]2·16H2O (3) have been synthesized using the tris(oxalato)oxoniobate(V) complex anion as the oxalate source, and their structures have been determined by single crystal X-ray diffraction. X-ray quality crystals of highly insoluble oxalate-bridged species were obtained by taking advantage of the slow release of oxalate by the tris(oxalato)oxoniobate(V) complex anion. The structures of 1–4 all contain oxalate-bridged dimetal(II) units with didentate dmphen molecules acting as end-cap ligands; electroneutrality is ac…
Syntheses, crystal structures and magnetic properties of chromato-, sulfato-, and oxalato-bridged dinuclear copper(II) complexes
2000
Abstract Four dinuclear copper(II) complexes of formula [Cu2(bpca)2(H2O)3(CrO4)]·H2O (1), [Cu2(bpca)2(H2O)3(SO4)]·H2O (2), [Cu2(bpca)2(H2O)2(C2O4)]·2H2O (3), and [Cu2(bpca)2(C2O4)] (4) [bpca=bis(2-pyridylcarbonyl)amide anion] have been synthesized and their magnetic behavior has been investigated as a function of temperature. The structures of 1–3 have been determined by single-crystal X-ray diffraction, whereas the structure of 4 was already known. The structures of this family of complexes are made up of neutral chromateO1,O1′ (1), sulfateO1,O1′ (2) and oxalateO1,O2:O1′,O2′-bridged (3 and 4) dinuclear copper(II) units. The two copper atoms within the dinuclear unit of the isomorphous c…
Playing with different metalloligands [NiL] and Hg to [NiL] ratios to tune the nuclearity of Ni(II)–Hg(II) complexes: Formation of di-, tri-, hexa- a…
2015
Abstract Five new hetero-metallic nickel(II)–mercury(II) complexes, [(NiL1)HgCl2] (1), [(NiL1)2HgCl2] (3), [(NiL1)2Hg(N3)2] (4), [{(NiL2)2Hg(N3)(μ1,1-N3)}2] (5) and [{(NiL2)2Hg(N3)(μ1,1-N3)HgCl2}2{Hg(N3)(μ1,1-N3)}] (6) have been synthesized by reacting metalloligands [NiL1] or [NiL2] (where H2L1 is N,N′-bis(salicylidene)-1,2-ethylenediamine and H2L2 is N,N′-bis(salicylidene)-1,3-propanediamine) with HgX2 (X− = Cl− or N3−) at different molar ratios. All five complexes have been characterised by X-ray single-crystal structural, elemental and spectroscopic analyses. In complex 1, the Hg(II) ion is coordinated to two phenoxido oxygen atoms of one [NiL1] moiety and two terminal chloride ions to …
Oxalate, squarate and croconate complexes with bis(2-pyrimidylcarbonyl)amidatecopper(II): synthesis, crystal structures and magnetic properties
2005
Abstract The preparation and magnetic properties of three copper(II) compounds of formulae [Cu2(bpcam)2(H2O)2(C2O4)] (1), [Cu2(bpcam)2(H2O)4(C4O4)] · 10 H2O (2) and Cu2(bpcam)2(C5O5)(H2O)3 (3) [bpcam = bis(2-pyrimidyl)amidate, C 2 O 4 2 - = dianion of oxalic acid , C 4 O 4 2 - = dianion of 3 , 4 - dihydroxycyclobut - 3 - ene - 1 , 2 - dione and C 5 O 5 2 - = dianion of 4 , 5 - dihydroxycyclopent - 4 - ene - 1 , 2 , 3 - trione ] are reported. The structures of two of them (1 and 2) have been solved by single crystal X-ray diffraction and consists of centrosymmetric discrete copper(II) dinuclear units bridged by bis-bidentate oxalate (1) and bis-monodentate squarate (2), with the bpcam group …
Growth, characterization, and high-pressure optical studies of CuWO4
2008
Copper tungstate (CuWO4) crystals grown by the top-seeded solution growth method were characterized by X-ray diffraction, Raman scattering, and optical measurements. CuWO4 has a triclinic structure (P 1¯) with a = 4.709 A, b = 5.845 A, c = 4.884 A, α = 88.3°, β = 92.5°, and γ = 97.2°. It consists of corner-linked CuO6 and WO6 octahedra, the former having a pseudo-tetragonally elongated geometry caused by the Cu2+ Jahn–Teller effect. Fifteen out of the eighteen Raman modes of CuWO4 are reported, discussed, and compared with those of other tungstates. We also determined the indirect band-gap energy of CuWO4 (2.3 eV) and its negative pressure coefficient up to 25 GPa. The pressure evolution of…
Synthesis, characterization and magnetic study of two new octahedral iron(III) complexes with pendant zwitterionic Schiff bases
2016
Two Schiff bases, HL1 [2-((3-(dimethylamino)propylimino)methyl)-5-bromophenol] and HL2 [2-((2-(diethylamino)ethylimino)methyl)-6-methoxyphenol], have been employed to prepare two new octahedral iron(III) complexes, [Fe(HL1)2(N3)2]ClO4·2H2O (1) and [Fe(HL2)2(NCS)2]ClO4·H2O (2). Both complexes are characterized by spectral and elemental analyses. Single crystal X-ray diffraction studies confirm their structures. In both complexes, Schiff bases are trapped in their zwitterionic forms and coordinated to iron(III) only through the imine nitrogen and phenoxo oxygen, i.e., they behave as bi-dentate ligands, keeping the remaining potential donor sites pendant. The measurement of χM vs. T for both c…
Synthesis, structural, and thermal characterization of a new binuclear copper(II) chelate complex bearing an amine-hardener for epoxy resins
2016
A new di(μ-carbonato)bis[aqua(diethylenetriamine)copper(II)] hexahydrate complex, [{Cu(NH(C2H4NH2)2)(H2O)(μ-CO3)}2]⋅6H2O (1), was synthesized by direct interaction of malachite with diethylenetriamine (dien). The crystals of 1 were characterized by X-ray powder diffraction and IR spectra, as well as structurally characterized. Compound 1 consists of [{Cu(dien)(H2O)(μ-CO3)}2] discrete units whose CO32– anions play the role of bridging ligands combining two Cu(II) chelate cores into a centrosymmetric dimer. The elongated octahedral environment of Cu2+ consists of three nitrogens of dien and an oxygen from CO32– at the base of the bipyramid; the two apical positions of such polyhedron are occu…
High temperature ferro-paraelectric phase transition in tris(trimethylammonium) nonachlorodiantimonate(III) (TMACA) studied by X-ray diffraction meth…
2000
Abstract The structure of [NH(CH3)3]3Sb2Cl9, tris(trimethylammonium) nonachlorodiantimonate(III) (TMACA) has been determined at 295 K and 373 K, below and above the high temperature ferro-paraelectric phase transition. In both phases the anionic sublattice of TMACA is built of characteristic two-dimensional (Sb2Cl93−)n polyanionic layers lying in the bc plane. In room temperature, ferroelectric phase (monoclinic, Pc space group) there are three crystallographically non-equivalent trimethylammonium [NH(CH3)3]+ cations. Two of them are located between polyanionic layers and the third one, disordered, inside the cavity formed by six SbCl63− octahedra. In the high temperature paraelectric phase…
Diorganotin(IV) complexes ofD-galacturonic acid: solid-state and solution-phase structural study
2003
Three diorganotin(IV) complexes of D-galacturonic acid (H2GalA; R = Me, n-Bu, Ph), two of which are new derivatives (R = Me, Ph), have been synthesized and their solid-state and solution-phase investigated by IR, Mossbauer, 1H, 13C and 119Sn NMR spectroscopy. The FTIR data suggest that H2GalA, in the dialkyltin derivatives, behaves as a dianionic ligand, coordinating the tin(IV) atom through an ester-type carboxylate and deprotonated alcoholic hydroxo groups, whereas a bridging carboxylate occurs in the diphenyltin(IV) complex. Octahedral and trigonal bipyramidal local geometries on tin(IV) atoms are proposed for dialkyltin(IV)GalA and diphenyltin(IV)GalA complexes respectively on the basis…