Synthesis and structural characterization of dialkyldithiocarbamato complexes of niobium

The reaction of alkyne-containing niobium(III) complexes [NbCl3(dme)(RC&z.tbd6;CR′)] (dme 4;= 4;1,2-dimethoxyethane) with the appropriate Na(S2CNR″2) reagents, in a 1∶3 molar ratio, afforded the corresponding dialkyldithiocarbamato complexes [Nb(RC&z.tbd6;CR′)(S2CNR″2)3] (R 4;= 4;R′ 4;= 4;Ph, R″ 4;= 4;Me 1; R 4;= 4;R′ 4;= 4;Ph, R″ 4;= 4;Et 2; R 4;= 4;R′ 4;= 4;R″ 4;= 4;Me 3; R 4;= 4;R′ 4;= 4;Me, R″ 4;= 4;Et 4; R 4;= 4;R′ 4;= 4;Et, R″ 4;= 4;Me 5; R 4;= 4;R′ 4;= 4;R″ 4;= 4;Et 6; R 4;= 4;R′ 4;= 4;SiMe3, R″ 4;= 4;Me 7; R 4;= 4;R′ 4;= 4;SiMe3, R″ 4;= 4;Et 8; R 4;= 4;Ph, R′ 4;= 4;Me, R″ 4;= 4;Me 9). The same complexes were also prepared from the reaction of the appropriate [NbCl3(bpzm)(RC&z.tbd6;CR′)] [bpzm 4;= 4;bis(pyrazol-1-yl)methane] complexes with the corresponding sodium dialkyldithiocarbamates. All complexes were spectroscopically characterized and the dynamic behaviour of some of them was studied by variable-temperature NMR techniques. The molecular structure of complex 9 was also established.