Heterobimetallic nitrido porphyrin complexes with the [(L)(por)M-N-M'(L)Cl] formula {por = 5,10,15,20-tetraphenylporphyrin (TPP) or 5,10,15,20-tetra(p-tolyl)porphyrin (TTP) dianion; L = [Co(η-CH){P(O)(OEt)}]; M = Fe, Ru, or Os; M' = Ru or Os; L = HO or pyridine} have been synthesized, and their electrochemistry has been studied. Treatment of trans-[Fe(TPP)(py)] (py = pyridine) with Ru(VI) nitride [Ru(L)(N)Cl] (1) afforded Fe/Ru μ-nitrido complex [(py)(TPP)Fe(μ-N)Ru(L)Cl] (2). Similarly, Fe/Os analogue [(py)(TPP)Fe(μ-N)Os(L)Cl] (3) was obtained from trans-[Fe(TPP)(py)] and [Os(L)(N)Cl]. However, no reaction was found between trans-[Fe(TPP)(py)] and [Re(L)(N)Cl(PPh)]. Treatment of trans-[M(TPP)(CO)(EtOH)] with 1 afforded μ-nitrido complexes [(HO)(TPP)M(μ-N)Ru(L)Cl] [M = Ru (4a) or Os (5)]. TTP analogue [(HO)(TTP)Ru(μ-N)Ru(L)Cl] (4b) was prepared similarly from trans-[Ru(TTP)(CO)(EtOH)] and 1. Reaction of [(HO)(por)M(μ-N)M(L)Cl] with pyridine gave adducts [(py)(por)M(μ-N)Ru(L)Cl] [por = TTP, and M = Ru (6); por = TPP, and M = Os (7)]. The diamagnetism and short (por)M-N(nitride) distances in 2 [Fe-N, 1.683(3) Å] and 4b [Ru-N, 1.743(3) Å] are indicative of the M═N═M' bonding description. The cyclic voltammograms of the Fe/Ru (2) and Ru/Ru (4b) complexes in CHCl displayed oxidation couples at approximately +0.29 and +0.35 V versus Fc (Fc = ferrocene) that are tentatively ascribed to the oxidation of the {LRu} and {Ru(TTP)} moieties, respectively, whereas the Fe/Os (3) and Os/Ru (5) complexes exhibited Os-centered oxidation at approximately -0.06 and +0.05 V versus Fc, respectively. The crystal structures of 2 and 4b have been determined.

A series of composite CaO-Ca 3 Al 2 O 6 mixed oxides were investigated as potential catalysts for biodiesel synthesis from waste fish oil. Different Ca/Al ratios, in the range of 1.5 to 6 were studied, alongside pure CaO. The catalysts were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and CO 2-Temperature Program Desorption (TPD). The catalytic activity of the materials was studied for the transesterification reaction of cod liver oil with methanol at 65 °C, with 1:12 oil to methanol molar ratio and 10 wt% of catalyst. Over 97% conversion of the triglycerides to methyl esters was achieved for the 6Ca/Al catalyst after 2 h reaction time. This was similar to the performance of CaO. However, 6Ca/Al catalyst was reused successfully for seven consecutive tests, in contrast to CaO that was reused for only five tests, before it deactivated. Therefore, by incorporating the Ca 3 Al 2 O 6 , it was possible to enhance the stability of the catalytically active species and improve the lifetime of the catalyst. Post-test catalyst characterisation showed the formation of an intermediate phase (calcium diglyceroxide) that enhanced the catalyst's performance and tolerance to air exposure and humidity. Finally, the catalyst deactivation, after seven cycles, took place due to the formation of Ca(OH) 2 and CaCO 3 species.

Iridium porphyrin complexes containing μ-nitrido, hydroxo, hydrosulfido, and alkynyl ligands have been synthesized and structurally characterized, and their oxidation has been studied.