Search results for "AGN"
showing 10 items of 28126 documents
Cooperative H-bonds, π⋯π and anion⋯π interactions as driving forces in the construction of novel Cu(II) bis(imidazol-2-yl) supramolecular 3D framewor…
2019
Abstract Two new Cu(II) complexes with bis(2-imidazolyl) based ligands, with the formula [Cu(BIM)2(SCN)2]·2H2O (BIM = bis(2-imidazol-2-yl)methane) and [Cu(HBIMAM)2(OH2)2](BF4)4·2H2O (BIMAM = bis(2-imidazol-2-yl)methylaminomethane) have been synthesized and characterized. Both compounds contain mononuclear entities as molecular building blocks (MBBs); neutral [Cu(BIM)2(SCN)2] in compound 1 and cationic [Cu(HBIMAM)2(OH2)2]4+ in compound 2. The coordination around the metal atoms shows a tetragonally-elongated octahedral geometry (CuN4S2 and CuN4O2 chromophores). The Q-band EPR spectra of both compounds are indicative of an essentially d x 2 - y 2 ground state for copper(II) ions. The analysis…
Synthesis, Structural and Spectroscopic Characterization of Cr III , Fe III , Co III , Ni II and Cu II Complexes with an Asymmetric 1,3,4‐Thiadiazole…
2016
The reaction of the new asymmetric 1,3,4-thiadiazole-based ligand 2-[(5-ethylthio-1,3,4-thiadiazol-2-yl)hydrazonomethyl]phenol (H1ETHP) with various third-row transition metal salts resulted in the formation of six new mononuclear complexes [Cr(ETHP)2]ClO4 (1), [Fe(ETHP)2][FeCl4] (2), [Co(ETHP)(ETHP–H)] (3), [Ni(ETHP)(H1ETHP)]Cl (4), [Ni(ETHP)(H1ETHP)](ClO4) (5), [Ni(ETHP)(H1ETHP)]Br (6), and one tetranuclear complex [Cu2Cl3(ETHP)(H1ETHP)]2 (7). H1ETHP and all complexes have been analyzed by single crystal X-ray diffraction. Structural analysis of 1–6 reveals complexes of the [ML2]n+-type (n = 0,1), in which the mono anionic ligand ETHP coordinates in a tridentate NNO fashion via its imine,…
Triorganotin( iv ) cation-promoted dimethyl carbonate synthesis from CO 2 and methanol: solution and solid-state characterization of an unexpected di…
2018
Two novel C,N-chelated organotin(IV) complexes bearing weakly coordinating carborane moieties were prepared by the reaction of the corresponding C,N-chelated organotin(IV) chloride (i.e. LCNR2SnCl, R = n-Bu (1) and Ph (2); LCN = 2-(N,N-dimethylaminomethyl)phenyl)) with monocarba-closo-dodecaborate silver salt (AgCB11H12; Ag·3). Both products of the metathesis, [LCN(n-Bu)2Sn]+[CB11H12]− (4) and [LCNPh2Sn]+ [CB11H12]− (5), respectively, were characterized by both multinuclear NMR spectroscopy and elemental analysis. The instability of 4 and 5 towards water is discussed. The solid-state structure of LCN(n-Bu)2SnOH·B(C6F5)3 (4a) as a model compound with a Sn–O(H)⋯B linkage is also reported. The…
Enhancement of the Intermolecular Magnetic Exchange through Halogen···Halogen interactions in Bisadeninium Rhenium(IV) Salts
2017
Two novel ReIV salts of general formula [H2ade]2[ReIVX6]X2·4H2O [H2ade2+ = 9H-adenine-1,7-diium; X = Cl(1) and Br(2)] have been synthesized and magneto-structurally characterized. 1 and 2 are isostructural salts that crystallize in the orthorhombic system with space group Fdd2. Both compounds are made up of discrete mononuclear [ReIVX6]2- and X- anions and doubly protonated adenine cations. The six-coordinate rhenium(IV) ion is bonded to six halide ligands [X = Cl (1) and Br (2)] in an octahedral geometry. Short intermolecular ReIV−X···X−ReIV interactions, as well as ReIV−X···H−N(H2ade) and ReIV−X···H−Ow hydrogen bonds, are present in the crystal lattice of 1 and 2. Magnetic suscep-tibility…
Synthesis, Crystal Structure and Magnetic Properties of Heteropolynuclear Re IV M II Complexes Based on the Robust [ReCl 5 (pyzCOO)] 2– Unit (pyzCOO …
2016
The syntheses, crystal structures and magnetic properties of four rhenium(IV) compounds of formulae NBu4[ReCl5(pyzCOOH)]·H2O (1), [ReCl5(µ-pyzCOO)M(dmphen)2]·2CH3CN [M = Ni (2) and Co (3)] and {[ReCl5(µ3-pyzCOO)]2Mn2(dmphen)3}n (4) (NBu4 = tetra-n-butylammonium cation, pyzCOOH = 2-pyrazinecarboxylic acid, dmphen = 2,9-dimethyl-1,10-phenanthroline) are reported herein. Compound 1 was obtained by the reaction of NBu4[ReCl5(dmf)] (dmf = dimethylformamide) with pyzCOOH in acetone, whereas the other complexes were obtained by the reaction of 1 with M(ClO4)2·6H2O [M = Ni (2), Co (3), Mn (4)] and dmphen in acetonitrile. Complex 1 is a mononuclear compound, 2 and 3 are neutral heterodinuclear compl…
Ligand Noninnocence in Cobalt Dipyrrin–Bisphenols: Spectroscopic, Electrochemical, and Theoretical Insights Indicating an Emerging Analogy with Corro…
2019
Three cobalt dipyrrin-bisphenol (DPPCo) complexes with different meso-aryl groups (pentafluorophenyl, phenyl, and mesityl) were synthesized and characterized based on their electrochemistry and spectroscopic properties in nonaqueous media. Each DPPCo undergoes multiple oxidations and reductions with the potentials, reversibility, and number of processes depending on the specific solution conditions, the specific macrocyclic substituents, and the type and number of axially coordinated ligands on the central cobalt ion. Theoretical calculations of the compounds with different coordination numbers are given in the current study in order to elucidate the cobalt-ion oxidation state and the innoc…
Combination of magnetic susceptibility and electron paramagnetic resonance to monitor the 1D to 2D solid state transformation in flexible metal-organ…
2012
Two families of coordination polymers, {[M(btix)(2)(OH(2))(2)]·2NO(3)·2H(2)O}(n) [M = Co (1), Zn (2), Co-Zn (3); btix = 1,4-bis(triazol-1-ylmethyl)benzene] and {[M(btix)(2)(NO(3))(2)]}(n) [M = Co (4), Zn (5), Co-Zn (6)], have been synthesized and characterized. The two conformations of the ligand, syn and anti, lead to one-dimensional (1D) cationic chains or two-dimensional (2D) neutral grids. Extrusion of the water molecules of the 1D compounds results in an irreversible transformation into the 2D compounds, which involves a change in conformation of the btix ligands and a rearrangement in the metal environment with cleavage and reformation of covalent bonds. This structural transformation…
Structure and properties of a novel staircase-like decanuclear [CuII10] cluster supported by carbonate and carboxylate bridges
2018
This article describes a novel staircase-like decanuclear copper(II) cluster [CuII10(cpdp)4(CO3)4(CH3OH)2]·3.33CH3OH·7.83H2O (1) (H3cpdp = N,N′-bis[2-carboxybenzomethyl]-N,N′-bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol) composed of a pair of [CuII5] pentamers. In methanol, the reaction of H3cpdp with Cu(NO3)2·3H2O in the presence of K2CO3 leads to the isolation of complex 1. This complex has been characterized by various analytical techniques including single crystal X-ray crystallography. Structural analysis reveals that the two [CuII5] pentameric units are bridged together exclusively by two μ2:η2:η1 carbonate groups. Complex 1 shows a rare μ3:η2:η1:η1 bridging coordination mode of four b…
Synthesis, reactivity and structural studies of selenide bridged carboranyl compounds.
2006
Reaction of the lithium salt Li[1-R-1,2-closo-C(2)B(10)H(10)] with selenium under mild conditions, followed by hydrolysis gave the diselenide compound (1-Se-2-R-1,2-closo-C(2)B(10)H(10))(2) in contrast to the well-reported mercapto compounds 1-SH-2-R-1,2-closo-C(2)B(10)H(10) obtained using a similar synthetic procedure. Details for the preparation and X-ray structural characterisation of the new compounds (2-Me-1,2-closo-C(2)B(10)H(10))(2)Se, (1-Se-2-R-1,2-closo-C(2)B(10)H(10))(2) (R = Me, Ph, ) are specified. To further explore the mechanism of the dimerization reaction, the complex [Au(1-Se-2-Me-1,2-closo-C(2)B(10)H(10))(PPh(3))] was synthesized, confirming the existence of the intermedia…
Hexanuclear manganese(III) single-molecule magnets based on oxime and azole-type ligands
2019
Abstract Two novel hexanuclear manganese(III) complexes belonging to the Mn6 family of single-molecule magnets (SMMs), of formulae [Mn6(μ3-O)2(H2N-sao)6(bta)2(EtOH)6]·2EtOH·4H2O (1) and [Mn6(μ3-O)2(H2N-sao)6(pta)2(EtOH)6]·4EtOH (2) [H2N-saoH2 = salicylamidoxime, bta = 1,2,3-benzotriazolate anion, pta = 5-phenyl-tetrazolate anion], have been synthesized and characterized structurally and magnetically. Both compounds crystallize in the triclinic system with space group P 1 ¯ (1 and 2). In their crystal packing, adjacent Mn6 complexes are connected through non-coordinating solvent molecules, which are H-bonded to N atoms of azole rings and –NH2 groups of salicylamidoxime ligand. The study of t…