Second generation O-alkyldithiocarbonates: Easy access to a new class of metalloligands

Abstract

Abstract The second-generation xanthate ligand 4-PyCH 2 OCS 2 Na, consisting of a backbone functionalized O -alkyldithiocarbonate donor set, has been prepared. The reaction of this ligand with either Ph 3 SnCl or (Ph 3 P) 2 CuNO 3 yields the neutral monometallic complexes [4-PyCH 2 OCS 2 SnPh 3 ] and [4-PyCH 2 OCS 2 Cu(PPh 3 ) 2 ], respectively. These compounds were characterized by 1 H NMR and UV–Vis spectroscopies, and in solid state by single crystal X-ray diffraction. The structure of [4-PyCH 2 OCS 2 SnPh 3 ] consists of a mono-dimensional coordination polymer, formed by the monodentate coordination of the O CS 2 − group to the Sn(IV) center, in combination with the coordination of the pyridine group to an adjacent tin atom. In the case of [4-PyCH 2 OCS 2 Cu(PPh 3 ) 2 ], the xanthate ligand coordinates to the Cu(I) center in an isobidentate fashion, leaving the pyridine moiety free. These monometallic complexes act as metalloligands toward the [Rh 2 (OAc) 4 ] dimer, producing the tetrametallic derivatives [Rh 2 (OAc) 4 ]·2[4-PyCH 2 OCS 2 SnPh 3 ] and [Rh 2 (OAc) 4 ]·2[4-PyCH 2 OCS 2 Cu(PPh 3 ) 2 ], respectively. These compounds were investigated in solution phase using 1 H NMR and UV–Vis techniques, and it is proposed that the formation of the first compound proceeds via a two-step process, while the formation of the latter is a one-step process.