The Zn(II)-cyclen-dipeptide ternary systems (where cyclen is abbreviated as L and dipeptide is glycylglycine (HL(1)) or glycyl-(S)-alanine (HL(2))) were investigated by potentiometry applying both ..."out-of-cell" and direct titrations and by (1) H NMR spectroscopy. Especially, the (1)H NMR study was found to be very efficient to estimate speciation in the systems. The results obtained under full equilibria indicated two main species, Zn(L)(HL(1,2))(2+) and Zn(L)(L(1,2))(+), in both the systems. In the Zn(L)(HL(1,2))(2+) complex, presence of carbonyl-carboxylate chelate was confirmed, and in the Zn(L)(L(1,2))(+) species, the peptide coordination is re-organized to carbonyl-amine chelate or only terminal amino group is coordinated. Equilibrium constants describing Zn(L)(2+)-dipeptide interaction are relatively low, log K = 3.4 for Gly-Gly and 4.1 for Gly-(S)-Ala, respectively. Nevertheless, the values are slightly higher than stability constants for interaction of Zn(II) with the dipeptides (i.e. Zn(L(1,2))(+) species) where a chelate formation is expected. It indicates that interaction between Zn(II) ion in Zn(L)(2+) and the dipeptides should be supported by some additional interactions. Potentiometry carried out under non-equilibrum condition showed different species where these additional stabilizing forces play more important role.
Silver(I) pyridinecarboxylates (AgPIC (1), AgNIC (2), Ag(HDIPIC)·0.75H
2
O (3), PIC = picolinate, NIC = nicotinate, HDIPIC = dipicolinate) were prepared by solvothermal syntheses and their ...characterization were completed by elemental, spectral, and thermal analyses. To assign the pyridinecarboxylate coordination mode in the complexes, detailed mid-infrared spectral data and Δ(ν
as
− ν
s
) comparisons were accomplished. In addition, silver(I) pyridinecarboxylate antimicrobial activities and stability by
1
H NMR spectra were determined. Moreover, the spectral, thermal, and antimicrobial properties of silver(I) and previously prepared zinc(II) pyridinecarboxylates were compared and discussed.
Novel layer-pillared metal–organic framework {Zn
2(OH)(AZPY)(BDC)
1.5·H
2O}
n
(AZPY
=
4,4′-azo(bis)pyridine; BDC
=
1,4-benzenedicarboxylate) was prepared and characterized. The compound is formed by ...binuclear secondary building units of the composition Zn
2(OH)(BDC)
0.5
2+, that are interconnected by AZPY and other BDC ligand giving neural (4,4)-grid-like polymeric sheets. Two adjacent sheets are pillared by 1,4-BDC
2− anions forming bilayers, that are further interpenetrated. Wide-angle X-ray scattering experiments demonstrated that the framework structure of the coordination polymer is stable upon the removal of the water molecule by heating and the compound remains crystalline. The packing of the crystal is characteristic by the presence of voids and small structure channels that are propagated along 0
1
1 crystallographic direction. The adsorption studies reveal that prepared compound can adsorb nitrogen and carbon dioxide. The adsorption capacity for CO
2 at 273
K, determined as amount of carbon dioxide adsorbed at
p/
p
0
=
0.9, was 1.04
mmol/g.
Two copper(II) isonicotinate complexes, Cu(INA)2(H2O)4 (1) and {Cu(INA-N-H)2(μ2-H2O)2·2H2O·2NO3}n (2) were prepared using a one-pot synthesis and characterized by single-crystal X-ray diffraction, ...spectral and thermal analysis and magnetic susceptibility. Complex 1 provides Cu–N(pyridyl) coordination mode with ionic carboxylate functionality. A novel complex 2 exhibits a chain-like crystal structure in which the Cu(INA-N-H)2+ ions are bridged by μ2-H2O molecules. The structural, spectral and thermal correlations indicate significant influence of ligand coordination mode and non-covalent interactions to mentioned properties. Magnetic susceptibility data were fitted by Curie–Weiss law with Tc=0.68K for complex 1 and Tc=9.01K for complex 2. Magnetic studies show a very weak interaction between copper(II) centers within the network structure in complex 1 and stronger ferromagnetic coupling between Cu ions caused by the presence of intra-chain Cu–O–Cu interaction in complex 2.
Two copper(II) complexes containing inonicotinate ligand have been successfully synthesized via one-pot synthesis and fully characterized. Moreover, graphical abstract shows molar susceptibility measurements depending on temperature for both prepared compounds. Display omitted
•Two copper(II) isonicotinate complexes were prepared using a one-pot synthesis.•Compounds were characterized by different physicochemical measurements.•Compound 2 exhibits a chain-like structure with unique coordination mode of INA.•Coordination mode influence on spectral, thermal and magnetic properties are presented.
We report on magnetism, transport and spin polarization characteristics of the melt-spun Cu2MnSn alloy prepared by the rapid quenching technique. The as- cast ribbons showed a relatively well ordered ...chemical composition (Cu = 50.4%, Mn = 27.1%, Sn = 22.5%). The structural characterization by using X-ray diffraction shows L21/B2 crystalline structure with the lattice parameter a = 6.196 Å. The magnetic and transport measurements show a metallic behavior with the Curie temperature of 530 K and reveal anisotropic character with the easy magnetization plane parallel with respect to the ribbon plane. As-cast Cu2MnSn ribbons show the spin polarization measured by using Andreev reflection technique within the range 68–75%.
•Single phase Cu2MnSn Heusler alloy with well-defined anisotropy was produced in a single production step.•It exhibit high Curie temperature and well defined anisotropy with the easy plane parallel with the ribbon plane.•The spin polarization reaches values up to 75% due to strong asymmetry in the minority and majority density of state.
The infrared spectra, elemental and thermal (TG/DTG and DTA) analyses of novel Zn(cyclen-κ
4N
1,4,7,10)(HGly-κ
2O,O′)(ClO
4)
2 (
1), and Zn
2(cyclen-κ
4N
1,4,7,10)
2(μ-S-Ala-κ
2N,O)(ClO
4)
3·2H
2O (
...2) complexes (cyclen – 1,4,7,10-tetraazacyclododecane) were recorded and analyzed in the relation to their structural peculiarities. IR spectral data indicate both mono- or bidentate coordination mode of a carboxylate group in the prepared complexes (at pH
≈
9). The results indicate unusual bidentate carboxylate coordination mode (in complex (
1)) toward to Zn
2+–cyclen unit. Therefore the crystal structure determination of the crystalline complex Zn(cyclen-κ
4N
1,4,7,10)(NO
3-κ
2O,O′)(NO
3) was attached in order to support the coordination mode assignment in complex (
1).
Three zinc(II) pyridinecarboxylate complexes, namely Zn(nicot)
2(H
2O)
4, Zn(picol)
2(H
2O)
2·2H
2O and Zn(dipicolH)
2·3H
2O, where nicot = nicotinate, picol = picolinate and dipicolH = ...hydrogenpicolinate were prepared and characterised by the methods of the thermal analysis (TG/DTG, DTA), infrared spectroscopy and elemental analysis. The structure of the complex Zn(nicot)
2(H
2O)
4 was studied by the single crystal XRD. The correlation of the thermal and spectral properties of the complexes with their structures is discussed in the study. The correlation of the spectral data with the structures leads to ambiguous results while the accord and coherence was found between thermal properties and structures of the complexes for both steps of the thermal decomposition (dehydratation and pyrolysis of organic ligand).
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