Search

In order to test the possible presence of the intramolecular interactions O → M in the group 14 elements and its consequences on the geometry, the 2-methoxybenzyl chlorine was reacted with magnesium and subsequently with the group 14 chlorides, Ph3MCl, to produce the organometallic compounds (2-CH3OC6H4)CH2MPh3 [M = Si (1), Ge (2) and Pb (3)]. The compounds were fully characterized by elemental analysis, infrared spectroscopy, mass spectrometry (FAB+), and multinuclear (1H, 13C, 29Si, 207Pb) NMR spectroscopy. The compounds 1 and 2 also were investigated by single crystal X-ray diffraction analysis, they are isostructural with a triclinic crystal system and P-1 space group, exhibiting a distorted tetrahedral environment. The possible intramolecular O → M distances in 1 and 2 are 3.810 A and 3.802 A respectively, and represent more than the 100% of the sum of the appropriate Van der Waal’s radii. By comparison, in the previously reported tin analogous compound, that is not part of this work, the intramolecular distance O → Sn is ∼80% of the sum of the Van der Waal’s radii. The molecular structures of the four organometallic complexes were fully studied within the Density Functional Theory formalism.

Eighteen mononuclear diorganotin(IV) complexes derived from tridentate Schiff bases and R2SnO (IV) oxides (R = Me, n-Bu, Ph) were synthetized by multicomponent reactions in moderate yields. Complexes were characterized by common spectroscopic techniques such as FT-IR, UV–vis, mass spectrometry and NMR (1H, 13C and 119Sn) spectroscopy analysis. Nine complexes were characterized by single crystal X-ray diffraction analysis (1c, 1d, 1g, 1k, 1n, 1o, 1p, 1q and 1r). 119Sn NMR spectra showed signals at δ = 135–145, 175–185 and 319–323 ppm for Me, n-Bu and Ph derivatives respectively, indicating the pentacoordination of the tin atoms. In solid state, for compounds 1c, 1d, and 1g a distorted octahedral geometry for tin atoms was observed owing the presence of intermolecular Sn⋯O interactions, while for compounds 1k, 1n-1r, the pentacoordinate environment for tin atoms is observed. At supramolecular level the presence of O H⋯O, C H⋯O, C H⋯X (X = Cl, Br), C H⋯π and π⋯π interactions allow the formation of 1D and 2D polymeric chains.

The synthesis and characterization of six new O-cholesteryl-dithiophosphonates containing thio-metalloheterocycles of As(III) and Sb(III); (CH2S)2As[S2P(cholesteryl)(4-MeOC6H5)] (2), (CH2S)2Sb[S2P(cholesteryl)(4-MeOC6H5)] (3), O(CH2CH2S)2As[S2P(cholesteryl)(4-MeOC6H5)] (4), O(CH2CH2S)2Sb[S2P(cholesteryl)(4-MeOC6H5)] (5), S(CH2CH2S)2As [S2P(cholesteryl)(4-MeOC6H5)] (6), and S(CH2CH2S)2Sb[S2P(cholesteryl)(4-MeOC6H5)] (7) are reported. 2–7 have been prepared from the reaction between the triethylammonium salt of O-3β-cholest-5-en-3-yl (4-methoxyphenyl) dithiophosphonate (1) and five and eight membered chloro-metalloheterocycles of As(III) and Sb(III). The obtained compounds have been characterized by elemental analyses, IR and NMR (1H, 13C, and 31P) spectroscopy. The 31P NMR data suggest that the dithiophosphonate ligand presents, in solution, a bidentate coordination. The structures of 3 and 4 were determined by X-ray single crystal analysis, that correspond to the first examples of such determinations in Group 15 dithiophosphonates, showing an anisobidentate coordination mode of the dithiophosphonate moiety. Sb(III) and As(III) in compounds 3 and 4 present tetracoordination and pentacoordination, respectively. The pentacoordination in 4 is achieved through a 1,5 transannular As⋯O interaction. Antibacterial assays were performed and the activity was correlated with the electronic distribution and molecular shape, employing their geometrical structures, Mulliken partial charges, dipole moments and Molecular Electrostatic Potential maps from DFT calculations.