Search

Three different classes of ferrocenyl-containing β-keto compounds Fc-CO-CH2-CO-R were synthesised to obtain two β-diketones with R = CH3, 3, and R = Fc (ferrocenyl = FeII(C5H5)(C5H4)), 4, a β-ketoester, 5, with R = OEt and a β-ketoamide, 6, with R = NH2. The β-diketones exhibited keto ⇌ enol tautomerization with the enol form Fc-CO-CH=C(OH)-R as the dominant isomer. Both the β-ketoester and β-ketoamide primarily existed in the keto form. FTIR and 1H NMR measurements could distinguish between keto and enol isomers. Dilute CHCl3 solutions of 3 and 4 exhibited FTIR ѵC=O keto vibrations between 1627 and 1712 cm−1 and ѵC=O enol vibrations between 1590 and 1660 cm−1. X-ray photoelectron spectroscopic (XPS) measurements showed keto isomer Fe 2p3/2 photoelectron lines at smaller binding energies than enol isomers. Significantly lower calculated molecular energies of the keto form of the β-ketoester 5 and β-ketoamide 6 utilising the Gaussian09 suite of programs at the B3LYP (uB3LYP for open-shell species), confirmed that 5 and 6 almost exclusively exists in the keto conformation. Cyclic voltammetry also distinguished between keto and enol isomers, and it was found that the electrochemical reversible ferrocenyl formal oxidation potential, E°ꞌ, of keto isomers of compounds can be estimated with the equation E°ꞌketo = 170.99χR–57.57 where χR is the group electronegativities of R in FcCOCH2COR. This result complements earlier research that enables calculation of the ferrocenyl formal oxidation potentials of enol isomers of β-diketones. Computational studies further showed that the HOMO orbitals of 3–6 is exclusively on the Fe centre and computed Mulliken spin densities on the dxy orbital of the oxidised iron species approached 1 e−.

The data presented in this paper is related to the research article entitled “Synthesis, Spectroscopy, Electrochemistry and DFT of Electron-Rich Ferrocenylsubphthalocyanines” [1] where electrochemical redox data and cyclic voltammograms at only a scan rate of 0.10 V s−1 of four ferrocenylsubphthalocyanine dyads Fc(CH2)nCO2BSubPc(H)12 (n = 0, 1 or 3) and FcCO(CH2)2CO2BSubPc(H)12, are presented. This data article provides extensive electrochemical redox data and cyclic voltammograms at various scan rates from 0.05 up to 5.00 V s−1 to illustrate the effect of the different scan rates on the electrochemical behaviour of the four ferrocenylsubphthalocyanine dyads.

A novel subphthalocyanine (HO)BSubPc(C12H25)6(H)6, 3, with a hydroxy group in the axial position and alkyl ligands (C12H25) on the non-peripheral positions as well as two other subphthalocyanines, ClBSubPc(H)12, 2, and ClBSubPc(F)12, 1, have been synthesized and characterized. The redox properties of subphthalocyanines 1–3 was investigated using cyclic voltammetry (CV), both in dichloromethane (at 25 °C) and dichloroethane (at 60 °C) as solvent and compared to previous studies. The electrochemical experimental conditions used made it possible for the first time to experimentally observe electrochemically quasi reversible oxidation for subphthalocyanines. It was found that the novel subphthalocyanine 3 exhibits the lowest macrocycle-based oxidation potential reported for SubPcs till date. The results obtained were further validated by DFT calculations on subphthalocyanines 1–3 as well as related subphthalocyanines from literature. Linear relationships between the redox potentials (oxidation and reduction vs Fc+/Fc) of these subphthalocyanines and various solvent phase B3LYP calculated energies were obtained.

Tris-(8-hydroxyquinolinato)aluminium (Alq3) was used as both the emission and electron transporting layer in organic light emitting diodes. One way to tune the emissive color of Alq3 is to introduce substituents onto the hydroxyquinoline ligands. These substituents will have an effect on the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital. In this study, Alq3 powders were synthesized with –CH3 substituted at position 5 and 7 (tris-(5,7-dimethyl-8-hydroxyquinolinato)aluminium) and –Cl at position 5 (tris-(5-chloro-8-hydroxyquinolinato) aluminium). Optical absorption and cyclic voltammetry measurements were performed on the samples. The optical band gap was determined from these measurements. The band gap did not vary with more than 0.2 eV from the theoretical value of Alq3.

National Research Foundation, South Africa, (DIB, Grant number 76226; JCS, Grant number 81829), and by the Spanish MICINN and CAM (IF, Grants CTQ2010-20714-CO2-01/BQU, Consolider-Ingenio 2010, CSD2007-00006, S2009/PPQ-1634).

The interaction of Fe(III) and Cu(II) with Aspergillus awamori-derived recombinant human lactoferrin was studied by means of UV–Vis and electron paramagnetic resonance spectroscopy. Results are interpreted as to indicate that non-specific metal binding occurs after a 2:1 stoichiometric metal uptake at the two specific binding sites of lactoferrin has taken place. Like wild-type lactoferrin from human milk, the expressed protein also coordinates the metal at the two specific binding sites to two deprotonated tyrosil and one histidine side chain, one aspartate and a bidentate sinergistic anion, here carbonate. Results of the cobalt(III), manganese(III), cerium(III) and cerium(IV) lactoferrin complexes are also presented and differences induced by the medium (Tris–HCl, phosphate and Hepes buffers) are explained.