Combined experimental and theoretical studies of dithiocarbamate complexes of yttrium, lanthanum and bismuth

Sammanfattning: Metal-dithiocarbamate complexes find wide-ranging applications in nanomaterial and metal separation science, and have potential use as chemotherapeutic, pesticides, and as additives to lubricants. A highly versatile dialkyldithiocarbamate (R2NCS2 –) ligand can form stable complexes with all the transition elements and also the majority of main group, lanthanide and actinide elements. Here we present structural investigations of the molecular and electronic structures of dialkyldithiocarbamate complexes with yttrium(III), lanthanum(III), and bismuth(III) of molecular formula [Y{S2CN(C2H5)2}3PHEN], [La{S2CN(C2H5)2}3PHEN], and [Bi2{S2CN-n(C4H9)2}6] (where PHEN=1,10-Phenanthroline) . The experimental solid-state 13C and 15N cross polarization magic-angle-spinning (CP-MAS) NMR results are reported for all these three complexes. We also report new single-crystal X-ray structures of heteroleptic yttrium, lanthanum, and homoleptic bismuth dialkyldithiocarbamate complexes. The comparative analysis of powder XRD patterns and solid-state 13C and 15N CP-MAS spectra of polycrystalline yttrium(III) and lanthanum(III) diethyldithiocarbamato-phenanthroline complexes shows the presence of significant structural differences. The diethyldithiocarbamatophenanthroline complex of yttrium has a very similar structural type to a previously reported Xray diffraction structure for [Nd{S2CN(C2H5)2}3PHEN] whereas, the crystal structure of [La{S2CN(C2H5)2}3PHEN] is considerably more complex. Our NMR and single-crystal X-ray diffraction results suggested polymorphism for bismuth di-n-butyldithiocarbamate complex. Finally, the experimental NMR results are complemented by chemical shifts obtained using quantum chemical methods and verified the spectral assignments. Overall, our work demonstrates how different experimental and theoretical methods can be combined that can afford insights into the solid-state structure and bonding environments of metal complexes.