Search results for "Isostructural"
showing 10 items of 158 documents
Structural, magnetic and electronic characterization of an isostructural series of dinuclear complexes of 3d metal ions bridged by tpbd
2013
Abstract Dinuclear complexes of the type [{M(H2O)(phen)}2(μ-tpbd)](ClO4)4 with N,N,N′,N′-Tetrakis-(2-pyridylmethyl)-benzene-1,4-diamine (tpbd) as bridging ligand and M = Mn(II) (1), Fe(II) (2), Co(II) (3), Ni(II) (4), Cu(II) (5), Zn(II) (6) were synthesized, structurally analyzed and their magnetic as well as their electrochemical properties are determined. A ligand-centered one-electron oxidation leads to radical complexes for which the lifetimes are strongly dependent on the coordinated metal ion as followed from time-resolved UV–Vis absorption spectroscopy. In addition to the six homometallic dinuclear complexes, one analog heterometallic Mn(II)/Ni(II) compound (7) of the same constituti…
Hydroxo Hydrido Complexes of Iron and Cobalt (Sn−Fe−Sn, Sn−Co−Sn): Probing Agostic Sn⋅⋅⋅H−M Interactions in Solution and in the Solid State
2000
Bis(toluene)iron 9 reacts with Lappert's stannylene [Sn[CH(SiMe3)2]2] (4) to form the paramagnetic bis-stannylene complex [[(eta6-toluene)Fe-Sn-[CH(SiMe3)2]2]2] (10). Compound 10 reacts with H2O to form the hydroxo hydrido complex [(eta6-C7H8)(mu-OH)(H)-Fe-[Sn[CH(SiMe3)2]2]2] (12) in high yield; its solid-state structure has been elucidated by X-ray and neutron diffraction analysis. In agreement with the 1H NMR results, 12 contains a hydridic ligand whose exact coordination geometry could be determined by neutron diffraction. The 1H and 119Sn NMR analysis of 12 suggested a multicenter Sn/Sn/H/Fe bonding interaction in solution, based on significantly large values of J(Sn,H,Fe) = 640+/-30 Hz…
[Mnii2(bpym)(H2O)8]4+ and [Miv(CN)8]4– (M = Mo and W) as building blocks in designing bpym- and cyanide-bridged bimetallic three-dimensional networks…
2002
One-pot reaction between the dinuclear [MnII2(bpym)(H2O)8]4+ complex and the mononuclear [MIV(CN)8]4− unit (M = Mo and W; bpym = 2,2′-bipyrimidine) in aqueous solution yields the novel heterobimetallic complexes of formula {(μ-bpym)[Mn(H2O)]2-(μ-NC)6M(CN)2} with M = Mo (1) and W (2). 1 and 2 are isostructural three-dimensional compounds where the manganese atoms are bridged by bisbidentate bpym and hexakismonodentate octacyanometalate units. Variable-temperature magnetic susceptibility data of 1 and 2 show the occurrence of a significant antiferromagnetic coupling between the high spin manganese(II) ions through bridging bpym (Jca. −1.1 cm−1, the exchange Hamiltonian being defined as H = −J…
Photoluminescent and Slow Magnetic Relaxation Studies on Lanthanide(III)-2,5-pyrazinedicarboxylate Frameworks
2017
In the series described in this work, the hydrothermal synthesis led to oxidation of the 5-methyl-pyrazinecarboxylate anion to the 2,5-pyrazinedicarboxylate dianion (2,5-pzdc) allowing the preparation of three-dimensional (3D) lanthanide(III) organic frameworks of formula {[Ln2(2,5-pzdc)3(H2O)4]·6H2O}n [Ln = Ce (1), Pr (2), Nd (3), and Eu (4)] and {[Er2(2,5-pzdc)3(H2O)4]·5H2O}n (5). Single-crystal X-ray diffraction on 1–5 reveals that they crystallize in the triclinic system, P1 space group with the series 1–4 being isostructural. The crystal structure of the five compounds are 3D with the lanthanide(III) ions linked through 2,5-pzdc2– dianions acting as two- and fourfold connectors, buildi…
Isostructural potassium and thallium salts of sterically crowded triazenes: a structural and computational study.
2008
Because of their similar cationic radii, potassium and thallium(I) compounds are usually regarded as closely related. Homologous molecular species containing either K(+) or Tl(+) are very rare, however. We have synthesized potassium and thallium salts MN3RR' derived from the biphenyl- or terphenyl-substituted triazenes Tph2N3H (1a), Dmp(Mph)N3H (1b), Dmp(Tph)N3H (1c), and (Me4Ter)2N3H (1d) (Dmp=2,6-Mes 2C6H3 with Mes=2,4,6-Me3C6H2; Me4Ter=2,6-(3,5-Me2C6H3)2C6H3; Mph=2-MesC6H4; Tph=2-TripC6H4 with Trip=2,4,6-(i)Pr3C6H2). The potassium complexes 2a- d were obtained in almost quantitative yield from the reaction of 1a- d with potassium metal in n-heptane. Metalation of 1a- d with TlOEt afforde…
A Rational Design for Imidazolate-Bridged Linear Trinuclear Compounds from Mononuclear Copper(II) Complexes with 2-[((Imidazol-2-ylmethylidene)amino)…
2001
Two mononuclear copper(II) complexes with the unsymmetrical tridentate ligand 2-[((imidazol-2-ylmethylidene)amino)ethyl]pyridine (HL), [Cu(HL)(H2O)](ClO4)2.2H2O (1) and [Cu(HL)Cl2] (2), have been prepared and characterized. The X-ray analysis of 2 revealed that the copper(II) ion assumes a pentacoordinated square pyramidal geometry with an N3Cl2 donor set. When 1 and 2 are treated with an equimolecular amount of potassium hydroxide, the deprotonation of the imidazole moiety promotes a self-assembled process, by coordination of the imidazolate nitrogen atom to a Cu(II) center of an adjacent unit, leading to the polynuclear complexes [[Cu(L)(H2O)](ClO4)]n (3) and [[Cu(L)Cl].2H2O]n (4). Variab…
The crystal and molecular structures of hexaquocobalt(II) diisonicotinate N-oxide and its isostructural nickel(II) homologue
1981
Abstract In this experiment the crystal and molecular structures of hexaaquocobalt(II)diisonicotinate N-oxide were determined from three-dimensional X-ray diffraction dat. The crystals belong to the monoclinic space group P2 1 /c. The cell parameters are a = 7.74(2), b = 9.826(2), c = 11.474(2) A , β = 91.08(2)°, V = 873.2(3) A 3 for the Co-complex, and a = 7.765(2), b = 9.725(6), c = 11.363 A , β = 91.20(3)°, V = 857.9(7) A 3 for the Ni-complex. Both structures were refined to a final R-value of 0.045. The X-ray structure analysis showed that there are metal(II)hexaquo cations and isonicotinate N-oxide anions formulated as Co(H 2 O) 6 2+ 2L − and Ni(H 2− O) 6 2+ 2L − in the structures. The…
Layered Molecule-Based Magnets Formed by Decamethylmetallocenium Cations and Two-Dimensional Bimetallic Complexes [MIIRuIII(ox)3]−(MII=;Mn, Fe, Co, C…
2001
Abstract A new series of hybrid organometallic-inorganic layered magnets with formula [Z III Cp * 2 ] [M II Ru III (ox) 3 ] ( Z III =Co and Fe; M II =Mn, Fe, Co, Cu, and Zn; ox=oxalate: Cp * =pentamethylcyclopentadienyl) has been prepared. All of these compounds are isostructural to the previously reported [ Z III Cp * 2 ] [ M II M III (ox) 3 ] ( M III =Cr, Fe) series and crystallize in the monoclinic space group C 2/ m , as found by powder X-ray diffraction analysis. They are novel examples of magnetic materials formed by bimetallic oxalate-based extended layers separated by layers of organometallic cations. The magnetic properties of all these compounds have been investigated (ac and dc m…
Synthesis, structure and conductivity of Ag2ZnSiO4, Ag2ZnGeO4 and Ag2BeSiO4
1995
Abstract The compounds Ag2MM′O4 with MM′ = ZnSi, ZnGe and BeSi have been synthesised by reacting the corresponding Na compounds with molten AgNO3. The crystal structures of Ag2ZnSiO4 and Ag2ZnGeO4 have been refined from Cu K α1 powder diffractometer data by the Rietveld technique to RF = 3.3 and 7.1%, respectively. They are isostructural with monoclinic Na2ZnSiO4. The powder pattern of Ag2BeSiO4 indicates that it is isostructural with orthorhombic Na2BeSiO4. The conductivity of the compounds has been determined using ac impedance measurements. Ag2ZnSiO4 and Ag2BeSiO4 are ionic conductors, with conductivities that are very similar to those of their corresponding isostructural Na compounds. A…
Molecule-Based Magnets Formed by Bimetallic Three-Dimensional Oxalate Networks and Chiral Tris(bipyridyl) Complex Cations. The Series [ZII(bpy)3][ClO…
2000
The synthesis, structure, and physical properties of the series of molecular magnets formulated as [ZII(bpy)3][ClO4][MIICrIII(ox)3] (ZII = Ru, Fe, Co, and Ni; MII = Mn, Fe, Co, Ni, Cu, and Zn; ox = oxalate dianion) are presented. All the compounds are isostructural to the [Ru(bpy)3][ClO4][MnCr(ox)3] member whose structure (cubic space group P4(1)32 with a = 15.506(2) A, Z = 4) consists of a three-dimensional bimetallic network formed by alternating MII and CrIII ions connected by oxalate anions. The identical chirality (lambda in the solved crystal) of all the metallic centers determines the 3D chiral structure adopted by these compounds. The anionic 3D sublattice leaves some holes where th…