Marrigje M. Conradie

Capturing the spin state diversity of iron(III)-aryl porphyrins: OLYP is better than TPSSh

DFT calculations with a variety of exchange-correlation functionals, including PW91, OLYP, TPSSh, B3LYP and B3LYP*, have been carried out on the low-energy spin states of chloroiron(III) porphyrin and four aryliron(III) porphyrins, viz. Fe(III)(P)Ph (S=1/2), Fe(III)(P)C(6)F(5) (S=5/2), Fe(III)(P)(3,4,5-C(6)F(3)H(2)) (S=1/2), Fe(III)(P)(2,4,6-C(6)F(3)H(2)) (S=5/2), where the expected spin states have been indicated within parentheses. Qualitatively, OLYP reproduces all the expected ground spin states. B3LYP appears to have some difficulty yielding the observed sextet ground states. B3LYP*, TPSSh and PW91 all fail to reproduce the sextet ground states, the latter two by rather large margins of energy. As far as this study is concerned, the overall performance of the functionals appears to be OLYP/OPBE>B3LYP>B3LYP*>>TPSSh>PW91/BLYP/BP86/TPSS.

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 “Novel dichloro(bis{2-[1-(4-methylphenyl)-1H-1,2,3-triazol-4-yl-κN3]pyridine-κN})metal(II) coordination compounds of seven transition metals (Mn, Fe, Co, Ni, Cu, Zn and Cd)” (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-κN3]pyridine-κN})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.

Triphenylstibine-substituted Fischer carbene complexes of tungsten(0): synthesis, structure, DFT and electrochemistry

The synthesis, solid-state structure, and electrochemical behaviour of triphenylstibine-containing Fischer carbene complexes of tungsten(0) of the type [(SbPh3)(CO)4WC(OEt)(Ar)] with Ar = 2-thienyl (1), 2-furyl (2), 2-(N-methyl)pyrrolyl (3) or 2,2′-bithienyl (4) are reported. A density functional theory study of all the possible conformations and isomers of the various moieties in these complexes show that while the 2-furyl group adopts an anti-orientation relative to the ethoxy group, the thienyl and 2-(N-methyl)pyrrolyl adopt a cis-orientation. The preferred orientation of the aryl groups was confirmed by the solid-state structures. An electrochemical study of the complexes reveals that the decreasing order of the metal-centred oxidation and the carbene–carbon reduction of the [(SbPh3)(CO)4WC(OEt)(Ar)] complexes is: Ar = C4H3S > C4H3O > C4H3NMe. The electrochemical study further reveals substitution of a CO group in [(CO)5WC(OEt)(Ar)] with SbPh3, leads to a lowering of the metal-centred oxidation and the carbene–carbon reduction potential of ca. 0.27 and 0.13 V, respectively.

Jahn–Teller distortion in 2-pyridyl-(1,2,3)-triazole-containing copper(II) compounds

The syntheses, characterization and experimental solid state X-ray structures of five low-spin paramagnetic 2-pyridyl-(1,2,3)-triazole-copper compounds, [Cu(Ln)2Cl2], are presented in this study, for the following five Ln ligands: L1 = 2-(1-(p-tolyl)-1H-(1,2,3-triazol-4-yl)pyridine), L2 = 2-(1-(4-chlorophenyl)-1H-(1,2,3-triazol-4-yl)pyridine), L3 = 4-(4-(pyridin-2-yl)-1H-(1,2,3-triazol-4-yl)benzonitril), L4 = 2-(1-phenyl-1H-(1,2,3-triazol-4-yl)pyridine) and L5 = 2-(1-(4-(trifluoromethyl)phenyl)-1H-(1,2,3-triazol-4-yl)pyridine). These five [Cu(Ln)2Cl2] complexes each contain two bidentate 2-pyridyl-(1,2,3)-triazole (Ln) and two chloride ions as ligands, with the Cu–N(pyridine) bonds, Cu–N(triazole) and Cu–Cl bonds trans to each other. All five [Cu(Ln)2Cl2] compounds display elongation Jahn–Teller distortion, either along opposite Cu–N(triazole) bonds, or along opposite Cu–Cl bonds, as indicated by their obtained solid state crystal structures. Quantum chemistry calculations, using density functional theory, indicated however that elongation Jahn–Teller distortion is in fact possible along any two opposite bonds in these octahedral compounds with the elongation distortion along the opposite Cu–N(triazole) bonds being the most stable structure.

An experimental and DFT study of the packing and structure of dithenoylmethane monocarbonylphosphine Rhodium(I) complex [Rh((C4H3S)COCHCO(C4H3S))(CO)(PPh3)]

[Rh((C4H3S)COCHCO(C4H3S))(CO)(PPh3)] crystals stack in one dimensional linear chains in the solid state, with slightly slipped π-stacking of the thienyl groups of one molecule and the β-diketonato backbone of a neighbouring molecule. The observed stacking is possible due to the near planar orientation of the two aromatic thienyl groups and the β-diketonato backbone. The experimentally observed stacking and close intermolecular contacts are in agreement with theoretical QTAIM calculated intermolecular bond paths and intermolecular hydrogen bonds between neighbouring molecules. NBO calculations revealed donor - acceptor NBO interactions between the lone pair on rhodium of one molecule and (i) the empty antibonding orbital on C-H of the nearest thienyl group of a neighbouring molecule, as well as with the (ii) the empty antibonding orbital on two carbons of the nearest thienyl group to rhodium on the neighbouring molecule.

DFT and CV data of 4-phenyl-substituted Dichloro(bis{2-[1-(phenyl)-1H-1,2,3-triazol-4-yl-κN3]pyridine-κN})iron(II) coordination compounds

The data presented in this paper are related to the research article entitled “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, R=CH3, OCH3, COOH, F, Cl, CN, H and CF3.” (Conradie et al., 2019) [1]. This paper presents electrochemical and density functional theory data of 4-phenyl-substituted dichloro(bis{2-[1-(4-R-phenyl)-1H-1,2,3-triazol-4-yl-κN3]pyridine-κN})iron(II) compounds, containing differently substituted 2-(1-(4-R-phenyl)-1H-1,2,3-triazol-1-yl)pyridine ligands (L2 – L9) (Tawfiq et al., 2014) [2]. Density functional theory calculated data of five different structural isomers for each compound, consistently show that the title compounds are octahedral and that the isomer with the chloride atoms, the pyridine nitrogens and the triazol nitrogens trans to each other, has the lowest energy. Natural bonding orbital (NBO) data and quantum theory of atoms in molecules (QTAIM) data of dichloro(bis{2-[1-(phenyl)-1H-1,2,3-triazol-4-yl-κN3]pyridine-κN})iron(II) show origin for the preference of the trans isomer.

Electrochemical data of Co(II) complexes containing phenanthroline functionalized ligands

The data presented in this paper are related to the research article entitled “Electrochemical properties of a series of Co(II) complexes, containing substituted phenanthrolines” (Ferreira et al., 2018) [1]. This paper presents detailed electrochemical data of eight octahedral Co(II) complexes containing functionalized phenanthrolines-ligands. The data illustrate the shift in the CoIII/II and CoII/I redox couples due to different substituents on the phenanthrolines. Polypyridine Co(II) and Co(III) complexes exhibit properties as potential mediators in dye-sensitized solar cells (DSSCs) (Gajardo and Loeb, 2011; Yu et al., 2011) [2], [3]. The ability of a compound to act as a redox mediator to be used in DSSC, depends on the redox potential of the compound (Grätzel, 2005) [4]. Accurate data of the CoIII/II redox couple is presented here.