Synthesis, spectroscopic characterization and in vitro antimicrobial activity of diorganotin(IV) dichloride adducts with 1,2,4triazolo-1,5-apyrimidine and 5,7-dimethyl-1,2,4triazolo-1,5,apyrimidine.

摘要

The heterocyclic ligands [1,2,4]triazolo-[1,5-a]pyrimidine (tp) and 5,7-dimethyl-[1,2,4]triazolo-[1,5-a]pyrimidine (dmtp), react withuddiorganotin dichlorides giving the addition compounds Me2SnCl2(tp)2, Et2udSnCl2(tp)2, Me2udSnCl2(dmtp)2, Et2udSnCl2(dmtp)2,udBu2SnCl2(dmtp), Ph2SnCl2(dmtp). The organotin:ligand stoichiometry goes from 1:2 to 1:1 by increasing the steric hindrance of theudorganic groups bound to tin. The compounds have been characterized by means of infrared, 119Sn Mo¨ssbauer and 1H AND 13CudNMR spectroscopy.udThe ligands presumably coordinate to tin classically through the nitrogen atom at the position 3. The 1:1 complexes adopt trigonaludbipyramidal structures, with the organic groups on the equatorial plane and the ligand in the apical position. All-trans octahedral structuresudare inferred for the 1:2 complexes, except for Et2SnCl2(tp)2, characterized by a skew-trapezoidal structure.ud119Sn Mo¨ssbauer measurements, at room temperature, in concomitance with DFT calculations, performed on isomeric structures ofudR2SnCl2(tp)2 (R = Me, Et), allowed us to conclude that the all-trans octahedral coordination induces self-assembly in the solid state,udpossibly accomplished through p–p stacking interactions among the planar ligands coordinated to the organotin(IV) compound, whileudthe skew-trapezoidal structure attributed to Et2SnCl2(tp)2, induces the formation of monomeric adducts in the solid state.udIn vitro antimicrobial tests showed that [n-Bu2SnCl2(dmtp)] has interesting properties as anti Gram-positive and antibiofilm agent.