Search results for "Isostructural"
showing 10 items of 158 documents
Slow relaxation of magnetization in a {Fe6Dy} complex deriving from a family of highly symmetric metallacryptands
2019
The synthesis and characterization of a new family of isostructural {Fe6Ln} complexes, (pipH)3{Fe6Ln(shiH)3(shi)6}·1.5 pip·xH2O (Ln = Gd (1), Dy (2), Tb (3) and Y (4), pip = piperidine, and shi3− = salicylhydroxamic acid) is reported. The resulting compounds possess an exceptionally unique structure of a metallacrown-like motif while the overall complexes feature more the structure of metallacryptates. Magnetic studies are reported and reveal that the {Fe6Dy} analogue belongs to the single-molecule magnet (SMM) family.
Synthesis, crystal structures and magnetic properties of cyanide- and phenolate-bridged [MIIINiII]2tetranuclear complexes (M = Fe and Cr)
2005
The binuclear complex NiII2L(H2O)2(ClO4)2 (1) and the neutral tetranuclear bimetallic compounds [{MIII(phen)(CN)4}2{NiII2L(H2O)2}]·2CH3CN with M = Fe (2) and Cr (3) [H2L = 11,23-dimethyl-3,7,15,19-tetraazatricyclo[19.3.1.19,13]hexacosa-2,7,9,11,13(26),14,19,21(25),22,24-decaene-25,26-diol] have been synthesized and the structures of 2 and 3 determined by single crystal X-ray diffraction. 2 and 3 are isostructural compounds whose structure is made up of centrosymmetric binuclear cations [Ni2(L)(H2O)2]2+ and two peripheral [M(phen)(CN)4]− anions [M = Fe (2) and Cr (3)] acting as monodentate ligands towards the nickel atoms through one of their four cyanide nitrogen atoms. The environment of t…
A rare isostructural series of 3d–4f cyanido-bridged heterometallic squares obtained by assembling [FeIII{HB(pz)3}(CN)3]− and LnIII ions: synthesis, …
2021
A new series of cyanido-bridged {FeIIILnIII}2 neutral molecular squares of general formula [Fe{HB(pz)3}(CN)(μ-CN)2Ln(NO3)2(pyim)(Ph3PO)]2·2CH3CN [Ln = Ce (1), Pr (2), Nd (3), Gd (4), Tb (5), Dy (6) and Er (7); {HB(pz)3}− = hydrotris(pyrazolyl)borate, pyim = 2-(1H-imidazol-2-yl)pyridine and Ph3PO = triphenylphosphine oxide] were obtained by reacting the low-spin [Fe{HB(pz)3}(CN)3]− species with the preformed [LnIII(pyim)(NO3)2(pyim)(Ph3PO)]+ complex anions (generated in situ by mixing the nitrate salt of each Ln(III) ion with pyim and Ph3PO molecules). Single-crystal X-ray diffraction studies show that 1–7 are isostructural compounds that crystallize in the triclinic P space group. Their cry…
The First P ‐Stereogenic 1D Coordination Polymers with the Metal Centers in the Backbone
2011
The enantiomeric ligands (R,R)- and (S,S)-bis(o-anisylphenylphosphanyl)methane (R,R-22 and S,S-22) and (R,R)- and (S,S)-bis(phenyl-m-xylylphosphanyl)methane (R,R-23 and S,S-23; dppm*), were treated with [Cu(NCCH3)4](BF4) and AgBF4 to produce the binuclear complexes [Cu2(dppm*)2(NCCH3)4](BF4)2 or [Ag2(dppm*)2](BF4)2, respectively. Then, these complexes were used as building blocks to prepare the first P-chirogenic 1D coordination polymers {[M2(dppm*)2(dmb)2](BF4)2}n [dppm* = (R,R)-22, (S,S)-22, (R,R)-23, (S,S)-23, M = Cu, Ag, dmb = 1,8-diisocyano-p-menthane] where M is part of the backbone of the polymer chain. The isostructural nature of these new polymers with the achiral parent polymers, …
Oxalate-Based Soluble 2D Magnets: The Series [K(18-crown-6)]3[MII3(H2O)4{MIII(ox)3}3] (MIII = Cr, Fe; MII = Mn, Fe, Ni, Co, Cu; ox = C2O42−; 18-crown…
2008
The synthesis and magnetic properties of the oxalate-based molecular soluble magnets with general formula [K(18-crown-6)] 3[M (II) 3(H 2O) 4{M (III)(ox) 3} 3] (M (III) = Cr, Fe; M (II) = Mn, Fe, Ni, Co, Cu; ox = C 2O 4 (2-)) are here described. All the reported compounds are isostructural and built up by 2D bimetallic networks formed by alternating M (III) and M (II) ions connected through oxalate anions. Whereas the Cr (III)M (II) derivatives behave as ferromagnets with critical temperatures up to 8 K, the Fe (III)M (II) present ferri- or weak ferromagnetic ordering up to 26 K.
Towards a better understanding of honeycomb alternating magnetic networks.
2015
Two new two-dimensional homometallic compounds {[M2(bpm)(ox)2]n·5nH2O} with M = Co(II) (1) and Zn(II) (2) and the mononuclear nickel(II) complex [Ni(bpm)2(ox)]·2H2O (3) [bpm = 2,2'-bipyrimidine and ox = oxalate] have been prepared and structurally characterized. 1 and 2 are isostructural compounds whose structures are made up of oxalate-bridged M(II) cations cross-linked by bis-bidentate bpm molecules to afford a honeycomb layered network extending in the crystallographic ab plane. The layers are eclipsed along the crystallographic c axis and show graphitic-like interactions between the bpm rings. The three-dimensional supramolecular network deriving from such interactions is characterized …
Ligand substitution in hexahalorhenate(IV) complexes: Synthesis, crystal structures and magnetic properties of NBu4[ReX5(DMF)] (X=Cl and Br)
2006
Abstract The preparation, crystal structures, and magnetic properties of two rhenium(IV) mononuclear compounds of formula NBu 4 [ReX 5 (DMF)] ( NBu 4 + = tetrabutylammonium cation and DMF = N , N - dimethylformamide ) with X = Cl ( 1 ) and Br ( 2 ) are reported. 1 and 2 are isostructural complexes which crystallize in the monoclinic system with the space group P 2 1 / n . The rhenium atom is six-coordinated with five X atoms and a DMF molecule forming a somewhat distorted octahedral surrounding [values of Re–X varying in the ranges 2.317(1)–2.358(1) ( 1 ) and 2.495(1)–2.518(1) A ( 2 )]. Magnetic susceptibility measurements on samples of 1 and 2 in the temperature range 1.9–300 K are interpr…
Synthesis, crystal structure and magnetic properties of two-dimensional malonato-bridged cobalt(ii) and nickel(ii) compounds
2004
Two isostructural malonato-bridged complexes of formula {[M(H2O)2][M(mal)2(H2O)2]}n [M = Co(II) (1), Ni(II) (2); H2mal = malonic acid] have been synthesised and characterized by X-ray diffraction. Their structure consists of corrugated layers of trans-diaquabismalonatemetalate(II) and trans-diaquametal(II) units bridged by carboxylate–malonate groups in the anti–syn conformation. Two crystallographycally independent metal atoms occur in 1 and 2. The malonate anion acts simultaneously as a bidentate and bis-monodentate ligand. Variable-temperature (1.9–295 K) magnetic susceptibility measurements indicate the occurrence of weak antiferro- (1) and ferromagnetic (2) interactions between the cob…
Metal–Organic Frameworks as Playgrounds for Reticulate Single-Molecule Magnets
2019
Achieving an accurate control on the final structure of Metal-Organic Frameworks (MOFs) is mandatory to obtain target physical properties. Here we describe how the combination of a metalloligand design strategy and a post-synthetic method is a versatile and powerful approach to success on this extremely difficult task. In a first stage, a novel oxamato-based tetranuclear cobalt(III) complex with a tetrahedron-shape geometry is used, for the first time, as metalloligand toward cal-cium(II) cations to lead a diamagnetic Ca(II)-Co(III) three-dimensional (3D) MOF (1). In a second stage, in a single-crystal to single-crystal manner the calcium(II) ions are replaced by terbium (III), dysprosium(I…
The crystal structure of neodymium and europium chromate heptahydrate: Synthesis, infrared spectra, and thermal behavior of lanthanoid chromate hepta…
1991
Abstract The crystal structures of Nd2(CrO4)3 · 7H2O and Eu2(CrO4)3 · 7H2O were determined by the conventional single-crystal X-ray diffraction technique. In addition, unit cell dimensions were measured for La2 (CrO4)3 · 7H2O and Sm2(CrO4)3 · 7H2O. All these compounds are isostructural. Crystals are monoclinic, space group P2 1 c . For Nd2(CrO4)3 · 7H2O, a = 8.052(4) A, b = 19.143(4) A, c = 13.326(6) A, β = 128.15(4)°, Z = 4, Dx = 3.14 Mg · m−3, T = 296(1); and for Eu2(CrO4)3 · 7H2O, a = 7.965(3) A, b = 18.985(4) A, c = 13.185(4) A, β = 128.00(2)°, Z = 4, Dx = 3.29 Mg · m−3, T = 296(1). Ln atoms are nine-coordinated so that the coordination polyhedron is a tricapped trigonal prism for Ln1 a…