Solution and solid-state NMR studies of thiourea, selenourea, N,N-dimethyl selenourea and their Ag(I) complexes

Silver(I) complexes of thiourea (TU), selenourea (SeU), N,N-dimethyl selenourea (DMSeU) have been prepared. These complexes have been characterized by elemental analysis and NMR (¹H, ¹³C, ⁷⁷Se and ¹⁰⁹Ag) spectroscopy. On complexation, an upfi eld shift in >C=S and >C=Se resonances of thiones and selenones in ¹³C NMR and low-fi eld shifts ⁷⁷Se NMR are consistent withthe sulfur and selenium coordination to metal ion. The principal components of the ⁷⁷Se shielding tensors were determined from solid-state NMR data of Ag-DMSeU complexes. The solid state ¹³C NMR for various 1:1,1:2, 1:3 and 1:4 ratio of Ag(I):TU indicate that TU prefers to bind to Ag(I) only in 1:1 and 1:4 ratios and other are mixture of these two ratios.