Lanthanum- Oligopyrrole Complexes (neutral, III) for biogas capture applications by DFT

The structures and interactions of systems formed by the MPBCP (meta-Phenylene-Bridged Cyclic Oligopyrrole) functionalized with lanthanum atom were studied for investigating the abilities of MPBCP, [La-MPBCP]+3 and La-MPBCP to absorb biogas (CO2, N2, H2 and CH4) using density functional theory. The Eads calculated values for biogas molecules on [La-MPBCP]+3 and La-MPBCP showed that these gas molecules have favorable interactions with the lanthanum atom coordinated on the MPBCP. CO2 molecule shows strong interactions, with Eads values of -28.63 and -15.95 kcal/mol. In the case of H2 molecule, the Eads is lower with values of -7.51 and -5.28. It is easy to observe the CO2 molecule on the [La-MPBCP]+3 system has four times higher energy value than adsorption energy for the H2 molecule. The natural bond orbital analysis reveals that gas molecules are electron donator in the systems and the acceptor orbitals belong to lanthanum atom. Computational studies suggest that CO2, N2, CH4 and H2 molecules on [La-MPBCP]+3 and La-MPBCP present physisorption. Our findings divulge promising potential of the [La-MPBCP]+3 as an adsorber/separator CO2/H2.

Syntheses, Characterization, Thermal, and Antimicrobial Studies of Lanthanum(III) Tolyl/Benzyldithiocarbonates

Lanthanum(III) tris(O-tolyl/benzyldithiocarbonates), [La(ROCS2)] (R =o-,m-,p-CH3C6H4and C6H5CH2), were isolated as yellow solid by the reaction of LaCl3·7H2O with sodium salt of tolyl/benzyldithiocarbonates, ROCS2Na (R =o-,m-,p-CH3C6H4and C6H5CH2), in methanol under anhydrous conditions in 1 : 3 molar ratio. These complexes have formed adducts with nitrogen and phosphorus donor molecules by straightforward reaction of these complexes with donor ligands, which have the composition of the type [La(ROCS2)3·nL] (where n = 2, L = NC5H5or P(C6H5)3and n = 1, L = N2C12H8or N2C10H8). Elemental analyses, mass, IR, TGA, and heteronuclear NMR (1H,13C and31P) spectroscopic studies indicated bidentate mode of bonding by dithiocarbonate ligands leading to hexacoordinated and octacoordinated geometry around the lanthanum atom. Antimicrobial (antifungal and antibacterial) activity of the free ligands and some of the complexes have also been investigated which exhibited significantly more activity for the complexes than the free ligands.