A potentially tridentate hemilabile ligand, PPh2-C6H4-PPh(O)-C6H4-PPh2 (P(3)O), has been used for the construction of a family of bimetallic complexes [MM'(P(3)O)2](2+) (M = M' = Cu (1), Ag (2), Au (3); M = Au, M' = Cu (4)) and their mononuclear halide congeners M(P(3)O)Hal (M = Cu (5-7), Ag (8-10)). Compounds 1-10 have been characterized in the solid state by single-crystal X-ray diffraction analysis to reveal a variable coordination mode of the phosphine-oxide group of the P(3)O ligand depending on the preferable number of coordination vacancies on the metal center. According to the theoretical studies, the interaction of the hard donor P[double bond, length as m-dash]O moiety with d(10) ions becomes less effective in the order Cu > Ag > Au. 1-10 exhibit room temperature luminescence in the solid state, and the intensity and energy of emission are mostly determined by the nature of metal atoms. The photophysical characteristics of the monometallic species were compared with those of the related compounds M(P(3))Hal (11-16) with the non-oxidized ligand P(3). It was found that in the case of the copper complexes 5-7 the P(3)O hybrid ligand introduces effective non-radiative pathways of the excited state relaxation leading to poor emission, while for the silver luminophores the P[double bond, length as m-dash]O group leads mainly to the modulation of luminescence wavelength.
The reliance of communities on River Ankobra as the source of drinking water makes the assessment of its quality very imperative to human health and environmental management. The objective of this work was to investigate the concentration of heavy metal in the Ankobra River sediments at the Prestea Huni-Valley District using pollution indices. Sediments were collected randomly from the bottom of the Ankobra River at four different communities namely: Awodua, Heman, Ankobra and Tarkwa Breman. The presence of a set of heavy metals Fe, Mn, Cd, Pb, Zn, Cu, and Hg in the sediments was determined using Atomic Absorption Spectroscopy (AAS). The results showed that the concentration of Fe, As, and Hg did not differ significantly (p > 0.05) amongst the four communities but significant variation in the levels of Cu, Mn, Cd, Pb, and Zn was found (p < 0.05) amongst the sampling areas. The geo-accumulation index revealed that the communities were not polluted with Cu, Mn, Fe, Pb and Zn. However, all communities except Tarkwa Breman were found to have exceptionally high levels of Cd. The contamination factor results were consistent with the I-geo results. The pollution load index (PLI) showed that the four communities were not polluted with heavy metals. Strong statistical positive relationship were found between Mn and Cu; Cd and Cu; Pb and Mn; Hg and Mn; Zn and Cu; Zn and Mn; Zn and Pb; Zn and Hg whilst As and Fe showed strong negative correlation.
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