A study of cobalt (II) complexes involved in marine biogeochemical processes: Co(II)-1,10-Phenanthroline and Co(II)-1,10-Phenanthroline-L-a-Phosphatidylcholine

Bačinić, Anđela; Frka, Sanja; Mlakar, Marina (2022) A study of cobalt (II) complexes involved in marine biogeochemical processes: Co(II)-1,10-Phenanthroline and Co(II)-1,10-Phenanthroline-L-a-Phosphatidylcholine. Bioelectrochemistry, 144 . ISSN 1567-5394

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Abstract

The cell membrane is structured so that the surface layer is composed of lipid molecules with selective permeability for micronutrients and organic ligands. Binding of Co (II) to natural lipid phosphatidylcholine (PC) has been studied to identify a possible mechanism of Co (II) entry through the cell membrane of the biota in detail, by voltammetry followed by checking the system at the air-water boundary, by Langmuir method. Binding of cobalt (II) ions to the PC molecules was enabled by the Co(II)-1,10-Phenanthroline (Phen) complex formation as an intermediate. Co(II)-Phen-PC complex reduction was recorded in the pH range from 5 to 9.5. The reduction was identified as a two-electron irreversible reaction at about -1.5 V, with the reactant adsorption followed dissociation (EC mechanism). The Co(II)-Phen-PC complex electrode surface concentration (Γ) was calculated to be (1.45 ± 0.12) x 10-10 mol cm-2. Conditional stability constants KCo(II)Phen2PC = 23.02 ± 0.26 and log KCo(II)Phen2PC2 = 29.31 ± 0.17 (Ic = 0.55) were calculated by CLE/ACSV method. Pressure-area (π-A) isotherms obtained at water-air interface by Langmuir monolayer technique indicated penetration of Co(II)-Phen into the PC monolayer, supporting electrochemical results. The equilibrium constants of the Co (II)-PC system (1:1) at the air-water interface was calculated to be K1 = 2.4 x 10-2 m3 mol-1, while for Co(II)-Phen-PC K2 = 4.86 x 1010 m2 mol-1.

Item Type:	Article
Uncontrolled Keywords:	Cobalt (II) ; 1,10-Phenanthroline; Phosphatidylcholine; Voltammetry; Langmuir trough
Subjects:	NATURAL SCIENCES NATURAL SCIENCES > Interdisciplinary Natural Sciences NATURAL SCIENCES > Interdisciplinary Natural Sciences > Marine Science NATURAL SCIENCES > Interdisciplinary Natural Sciences > Environmental Science INTERDISCIPLINARY FIELDS OF ART
Divisions:	Division for Marine and Enviromental Research
Projects:	Project title Project leader Project code Project type Biokemijski odgovori površinskog sloja oligotrofnog područja Jadranskog mora na atmosfersko taloženje-BiREADI Sanja Frka Milosavljević IP-2018-01-3105 HRZZ
Depositing User:	Sanja Frka Milosavljević
Date Deposited:	07 Feb 2024 09:23
URI:	http://fulir.irb.hr/id/eprint/8521
DOI:	10.1016/j.bioelechem.2021.108009

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