Water-soluble Eu(III) and Tb(III) complexes with N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane-N,N'-diacetic acid (Hbpcd) have been synthesized and characterized in their racemic and enantiopure forms. The ligand has been designed to bind Ln(III) ions, providing a dissymmetric environment able to solicit strong chiroptical features while at the same time leaving a few coordination sites available for engaging further ancillary ligands. Potentiometric studies show that Ln(III) complexes have a relatively good stability and that at pH 7 the [Ln(bpcd)] species is largely dominant. DFT calculations carried out on the (S,S)-[Y(bpcd)(HO)] complexes (the closed-shell equivalents of [Eu(bpcd)(HO)] and [Tb(bpcd)(HO)]) indicate that the two trans-O,O and trans-N,N configurations are equally stable in solution and present two coordinated water molecules. This is in agreement with the hydration number ∼2.6 determined by luminescence lifetime measurements on Tb(III) and Eu(III) complexes. A detailed optical and chiroptical spectroscopic characterization has been carried out and reveals that the complexes display an efficient luminescence in the visible spectral range accompanied by a strong CPL activity. A value for g (around 0.1 on the top of the 546 nm band) for the Tb-based complex has been found. This is one of the highest g values measured up to now for chiral Tb complexes. These results suggest that in principle Tb(bpcd)Cl is suitable to be employed as a CPL bioprobe for relevant analytes in aqueous media.

Extensive calorimetric investigations on the interaction of TiCl 4 with some Lewis bases are presented. Some of the bases were chosen for their industrial relevance in heterogeneous Ziegler-Natta polymerization of propene (ethyl benzoate, L2, diisobutyl phthalate, L3, (2R,3S)-diethyl 2,3-diisopropylsuccinate, L6, (2S,3S)diethyl 2,3-diisopropylsuccinate, L7, and 9,9-bis(methoxymethyl)-9H-fluorene, L13) while other bases were chosen as probe molecules to explore the electronic and steric effects on the complexation energy (ethyl acetate, L1, diethyl phthalate, L4, diethyl succinate, L5, tetrahydrofuran, L8, dimethoxyethane, L9, dimethoxypropane, L10, dimethoxybutane, L11, and 3,3-bis(methoxymethyl)-2,6-dimethylheptane, L12). 1,1,2,2,-Tetrachloroethane was selected as the solvent for its low donating properties, which allows the focus to be on the metal-donor interaction. The calorimetric data are discussed and compared with the efficiency of the derived catalysts. Further understanding is obtained by comparison of the experimental results with theoretical calculations based on density functional theory (DFT). The performance of different computational approaches was validated by comparison of the calculated and experimental complexation energies.

The hydration of cis-[PtCl2(NH3)2] (cisplatin) has been studied by means of classical molecular dynamics simulations using a new interaction potential obtained by fitting about 4000 ab initio interaction energies calculated at the MP2 level. The functional form included several r(-n) terms (n = 4, 6, 8, 12) to achieve an accurate description of the interactions in the different regions around the cisplatin. Bulk solvent effects on the cisplatin-water molecule interactions have been included by means of a continuum model. Radial Distribution Function (RDF) analysis does not provide a clear enough description of the hydration pattern due to the intricate solvent arrangement around the solute. Angle-solved RDFs and spatial distribution functions have been used to provide more detailed pictures of the local hydration structure around the two ligands, chloride and ammine groups, and the axial region. Based on this information, it is shown a more convenient way to compute the running coordination number for the first hydration shell by simultaneously considering angle-solved RDFs centered on the ligand representative atoms of the complex: ammino N, Cl, and Pt atoms. This way, the hydration number is obtained by integrating over an interlocking-sphere volume built by the spheres centered on the cation and the main atoms of each ligand. Compared to previous works dealing with cisplatin hydration, the global hydration number for the first coordination shell is now higher and involves about 27 water molecules. The importance of the structural sampling, the computational level, as well as the functional form adopted for the interaction potential are thoroughly discussed with respect to the previous proposed intermolecular potential.