Synthesis, spectral characterization, crystal structures, and DFT study of three new La(III) 2-amino-1-cyclopentene-1-carbodithioate complexes

Abstract

• Three lanthanum(III) 2-amino-1-cyclopentene-1-carbodiothioate (ACDA) were obtained. • It is reported the first structural determinations of a rare earth ACDA complexes. • The ACDA is bonded to the lanthanum in a S,S coordination mode. • The DFT calculations for all the ACDA lanthanide complexes is in favor of the S,S mode. The synthesis and characterization of the first three La(III) 2-amino-1-cyclopentene-1-carbodithioate (ACDA) complexes is reported including two ionic complexes, [NEt 3 H][La(ACDA 4 )] ( 1 ), [N( n - Bu) 4 ][La(ACDA 4 ] ( 2 ) and [La(ACDA) 3 )(1,10-phenanthroline)] ( 3 ). The single-crystal X-ray structures of 1 – 3 correspond to the first known structural determination of ACDA rare earth complexes. Compounds 1 – 3 show an S,S coordination mode, and due to hydrogen bonding present in the ligands, secondary interactions were observed. DFT calculations for all the lanthanide series indicate that the ACDA ligand binds in an isobidentate fashion through low covalent M–S bonds, as evidenced by natural population analysis. Furthermore, the S,S coordination mode is overwhelmingly preferred over the N,S coordination, as demonstrated by free energy calculations from the vibrational frequency analysis.