10 research outputs found
Synthesis, characterization, experimental and theoretical structure of novel Dichloro(bis{2-[1-(4-methoxyphenyl)-1H-1,2,3-triazol-4-yl-ÎșN3]pyridine-ÎșN})metal(II) compounds, metal = Mn, Co and Ni
© 2018 Elsevier B.V. The syntheses, characterizations and structures of three novel dichloro(bis{2-[1-(4-methoxyphenyl)-1H-1,2,3-triazol-4-yl-ÎșN 3 ]pyridine-ÎșN})metal(II), [M(L) 2 Cl 2 ], complexes (metal = Mn, Co and Ni) are presented. In the solid state the molecules are arranged in infinite hydrogen-bonded 3D supramolecular structures, further stabilized by weak intermolecular ÏâŠÏ interactions. The DFT results for all the different spin states and isomers of dichloro(bis{2-[1-phenyl-1H-1,2,3-triazol-4-yl-ÎșN 3 ]pyridine-ÎșN})metal(II) complexes, [M(L 1 ) 2 Cl 2 ], support experimental measurements, namely that (i) d 5 [Mn(L 1 ) 2 Cl 2 ] is high spin with S = 5/2; (ii) d 7 [Co(L 1 ) 2 Cl 2 ] has a spin state of S = 3/2, (iii) d 8 [Ni(L 1 ) 2 Cl 2 ] has a spin state of S = 1; and (iv) for all [M(L 1 ) 2 Cl 2 ] and [M(L) 2 Cl 2 ] comple xes, with M = Mn, Co and Ni, the cis-cis-trans and the trans-trans-trans isomers, with the pyridyl groups trans to each other, have the lowest energy
Novel dichloro(bis{2-[1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl-ÎșN3]pyridine-ÎșN})metal(II) coordination compounds of seven transition metals (Mn, Fe, Co, Ni, Cu, Zn and Cd)
© 2018 Elsevier Ltd. The synthesis, characterization, DFT and, in two cases, the structure of seven novel dichloro(bis{2-[1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl-ÎșN3]pyridine-ÎșN})metal(II) coordination compounds ([M(L2)2Cl2]), containing transition metals of groups 7â12, are described. Both experimentally measured magnetic moment and DFT calculations showed that d5Mn(II) (with ”eff= 5.62 B.M., S = 5/2), d6Fe(II) (with ”eff= 5.26 B.M., S = 2), d7Co(II) (with ”eff= 3.98 B.M., S = 3/2), d8Ni(II) (with ”eff= 3.00 B.M., S = 1) and d9Cu(II) (with ”eff= 1.70 B.M., S = Âœ) are all paramagnetic, while d10Zn(II) and Cd(II) are diamagnetic with S = 0. DFT calculations on the possible isomers of these coordination compounds, showed that the cisâcisâtrans and the transâtransâtrans isomers, with the pyridyl groups trans to each other, are the lowest in energy. The transâtransâtrans isomers were experimentally characterized by X-ray crystallography for [Ni(L2)2Cl2] and [Zn(L2)2Cl2]·L2in this study. In the solid state the coordination compounds are connected by intermolecular hydrogen bonds, mainly involving the chloride atoms, to form 3D supramolecular structures. Computational chemistry calculations, using Natural Bonding Orbital calculations, identified these inter-molecular hydrogen bonds, CâHâŻCl, by a donorâacceptor interaction from a filled lone pair NBO on Cl to an empty antibonding NBO on (CâH). The inter-molecular hydrogen bonds were also identified by QTAIM determined bonding paths between Cl and the respective hydrogen. The theoretically calculated computational chemistry results thus give an understanding on a molecular level why in the solid state where inter-molecular forces and packing play a role, the transâtransâtrans isomers are mostly obtained
Chemical and structural data of (1,2,3-triazol-4-yl)pyridine-containing coordination compounds
The data presented in this paper are related to the research article entitled âNovel dichloro(bis{2-[1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl-ÎșN3]pyridine-ÎșN})metal(II) coordination compounds of seven transition metals (Mn, Fe, Co, Ni, Cu, Zn and Cd)â (Conradie et al., 2018) [1]. This paper presents characterization and structural data of the 2-(1-(4-methyl-phenyl)-1H-1,2,3-triazol-1-yl)pyridine ligand (L2) (Tawfiq et al., 2014) [2] as well as seven dichloro(bis{2-[1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl-ÎșN3]pyridine-ÎșN})metal(II) coordination compounds, [M(L2)2Cl2], all containing the same ligand but coordinated to different metal ions. The data illustrate the shift in IR, UV/VIS, and NMR (for diamagnetic complexes) peaks when L is coordinated to the metals, as well as the influence of the different metals on the peak positions. Solid state structural data is presented for M = Ni and Zn, while density functional theory calculated energies, structures and optimized coordinates are provided for the lowest energy cis and trans conformations for L2 as well as [M(L2)2Cl2] with M = Mn, Fe, Co, Ni, Cu, Zn and Cd
Synthesis, characterisation and electrochemistry of eight Fe coordination compounds containing substituted 2-(1-(4-R-phenyl-1H-1,2,3-triazol-4-yl)pyridine ligands, RâŻ=âŻCH3, OCH3, COOH, F, Cl, CN, H and CF3
© 2018 Elsevier B.V. Eight different Dichloro(bis{2-[1-(4-R-phenyl)-1H-1,2,3-triazol-4-yl-ÎșN3]pyridine-ÎșN})iron(II) compounds, 2â9, have been synthesised and characterised, where group R = CH3 (L2), OCH3 (L3), COOH (L4), F (L5), Cl (L6), CN (L7), H (L8) and CF3 (L9). The single crystal X-ray structure was determined for the L3 which was complemented with Density Functional Theory calculations for all complexes. The structure exhibits a distorted octahedral geometry, with the two triazole ligands coordinated to the iron centre positioned in the equatorial plane and the two chloro atoms in the axial positions. The values of the FeII/III redox couple, observed at ca. â0.3 V versus Fc/Fc+ for complexes 2â9, varied over a very small potential range of 0.05 V. The observation that the different R substituents have virtually no effect on the values of the FeII/III redox couple for all eight complexes 2â9, is explained by the character of the highest molecular orbitals of complexes 2â9, which do not show any communication of electron density between the various ligands and the metal Fe. However, the HOMOs of the free ligands L2 â L9, display extended Ï-character over the entire ligand, explaining the sensitivity of the 1H NMR CâH-triazole peak, which is dependent on the electron donating/withdrawing power of the R substituent attached to the 2-[1-(4-R-phenyl)-1H-1,2,3-triazol-4-yl]pyridine ligands