21907-47-1Relevant articles and documents
Synthesis, and crystal and molecular structures of the triflato and trifluoroacetato complexes of zinc, Zn(O3SCF3)2(DME)2 and [Zn(O2CCF3)2(DME)]n
Dell'Amico, Daniela Belli,Boschi, Daniele,Calderazzo, Fausto,Labella, Luca,Marchetti, Fabio
, p. 149 - 154 (2002)
Anhydrous Zn(O3SCF3)2 and Zn(O2CCX3)2, X=F, Cl, Br were obtained in substantially quantitative yields from ZnO (or ZnEt2 in the case of the bromide derivative) and a mixture of the corresponding acid and anhydride in heptane as medium. The reactions are rapid and moderately exothermic. Recrystallization of the triflate and trifluoroacetate complexes from dimethoxyethane (DME) produced single crystals of Zn(O3SCF3)2(DME)2 (1) and [Zn(O2CCF3)2(DME)]n (2) suitable for X-ray diffraction studies. In both compounds zinc is hexacoordinated with a pseudo-octahedral geometry. Compound 1 is constituted by mononuclear molecules with terminal monodentate O3SCF3 ligands in trans position. A polynuclear chain structure was found for 2 with zinc atoms joined alternatively by triple and single carboxylato bridges, and with bidentate terminal DME.
Formation of ionic liquids of divalent metal complexes comprising N?alkylethylenediamines and the solvation of the nickel(II) complexes
Yasuda, Haruka,Nakayama, Chisayo,Iida, Masayasu
, p. 169 - 177 (2018/08/21)
A series of divalent N?alkylethylenediamine (alkyl?en) metal(II) (alkyl = hexyl, 2?ethylhexyl, octyl, dodecyl; metal = Ni, Cu, and Zn) complexes was prepared and their phase behavior was studied using differential scanning calorimetry. This kind of metal complexes is very useful for systematically investigating the relationship between phase behavior and molecular structures. It was found that several of the zinc(II) and nickel(II) complexes form room-temperature ionic liquids (RTILs), despite the divalent cation. Although the solid-to-liquid transition temperatures of metal(II) complex-based ILs are typically higher than those of the more common monovalent ionic liquids (ILs), they are dependent on the nature and combination of the metal(II) ions, alkyl chains, and counter anions. The zinc(II) complexes coupled with weakly coordinating bis(fluorosulfonyl)amide (FSA) or bis(trifluoromethanesulfonyl)amide (Tf2N) anions have significantly lower melting points, which is attributable to the longer distance between the zinc(II) ions and the counter anions upon the formation of tetrahedral bis(alkyl?en)zinc(II) complexes as compared to the corresponding distances in NO3 and trifluoroacetate (TFA) complexes. The correlation of melting points with the molecular structures of the zinc(II) complexes is similar to that for the silver(I) alkyl?en complexes. The tris(alkyl?en)nickel(II) complexes coupled with Tf2N counter ions do not readily solidify and have glass transition temperatures below 0 °C, whereas the corresponding bis complexes have much higher melting points despite the counter-ions residing in the outer-spheres of the nickel(II) ions. The interactions of NO3, TFA, FSA, and Tf2N anions with the nickel(II) ions of the bis(alkyl?en) complexes and their solvation behaviors were also studied in organic solvents using visible absorption spectroscopy based on the structures of the neat states. The characteristic solvation behaviors of the nickel(II) complexes were rationalized in terms of the counter anions and solvents.
Series of dicyanamide-interlaced assembly of zinc-schiff-base complexes: Crystal structure and photophysical and thermal studies
Maiti, Monami,Sadhukhan, Dipali,Thakurta, Santarupa,Roy, Syamantak,Pilet, Guillaume,Butcher, Ray J.,Nonat, Aline,Charbonniere, Loic J.,Mitra, Samiran
, p. 12176 - 12187 (2013/01/15)
Four new dicyanamide (dca) bridged multinuclear ZnII-Schiff-base complexes, {[Zn2L1(μ1,5-dca)dca] ·CH3OH}2 (1), [Zn2L2(μ 1,5-dca)dca]n (2), [Zn3L3 2(μ1,5-dca)2]n (3), and [(ZnL4)2Zn(μ1,5-dca)dca]n (4), have been synthesized using four different Schiff bases L1H 2 = N,N/-bis(3-methoxysalicylidenimino)-1,3- diaminopentane, L2H2 = N,N'-bis(5-bromo-3- methoxysalicylidenimino)-1,3-diaminopropane, L3H2 = N,N'-bis(5-bromosalicylidenimino)-1,3-diaminopropane, and L4H 2 = N,N'-bis(5-chlorosalicylidenimino)-1,3-diaminopropane and NaN(CN)2 in order to extend the metal-ligand assembly. The directional properties of linear end-to-end bridging dca ligands have resulted in different metal ion connectivities leading to unique variety of templates in each of the complexes. All the ligands and complexes have been characterized by microanalytical and spectroscopic techniques. The structures of the complexes have been conclusively determined by single crystal X-ray diffraction studies. Thermogravimetric analyses have been performed to investigate the thermal stability of the metal-organic frameworks. Finally, the photoluminescence properties of the complexes as well as their respective ligands have been investigated with a comparative approach.
(II), Copper(II), and Nickel(II) Complexes of Bis(tripodal) Diamide Ligands - Reversible Switching of the Amide Coordination Mode upon Deprotonation
Hahn, F.Ekkehardt,Schroeder, Henning,Pape, Tania,Hupka, Florian
, p. 909 - 917 (2010/06/18)
A series of dinuclear Zn(II), Cu(II) and Ni(II) complexes of two new bis-tripodal ligands with aromatic (H2-4a) and aliphatic (H 2-4b) diamide spacers has been synthesized and structurally characterized. Each of the two tripodal entities of the neutral dinucleating ligands coordinates to one metal ion via three amine functions and a carbonyl oxygen atom of the amide groups. Either trifluoroacetate counterions or solvent molecules complete the trigonal-bipyramidal (Zn, Sa), square-pyramidal (Cu, 6a and 6b), and octahedral (Ni, 7a and 7b) coordination environment at the metal centers. Complexes 5a, 6a, and 7a with the phenylene-bridged diamide ligand are readily deprotonated by potassium tert-butoxide effecting a rearrangement of the dinuclear complexes. In the resulting zinc and copper complexes 8 and 9, one of the metal centers is coordinated by three amine functions of a tripodal subunit and the two amidate nitrogen atoms of the deprotonated ligand 4a2- while the coordination geometry of the second metal atom remains unchanged. The analogous nickel compound crystallizes as neutral tetranuclear complex (10) 2 with intermolecular coordination of two amide carbonyl oxygen atoms to the nickel atoms of an adjacent dinuclear complex. The resulting coordination mode with binding of all four donor functions of the diamide spacer to three discrete metal centers is to date unprecedented for ortho-phenylene-bridged acetamides. The rearrangement upon deprotonation has been shown to be fully reversible and the starting complexes can be retrieved upon protonation of the two amidate functions. Synthesis of the trinuclear zinc complex 11 with coordination of the two amidate nitrogen atoms to a third metal center was achieved via deprotonation of (H6-4a)-(CF 3CO2)4 by three equivalents of diethylzinc. In protic solvents 11 rapidly rearranges to give the entropically favored dinuclear complex 8 with elimination of one equivalent of zinc trifluoroacetate.
