Syntheses and properties of 2-D and 3-D Pb–Ag heterometallic iodides decorated with ethylene polyamines at the Pb(ii) center†
Abstract
Hybrid organic–inorganic Pb–Ag heterometallic iodides [(en)2(PbAgI3)]2n·nH2O (1), [(pda)2(PbAgI3)]n (2), [(tmeda)(PbAgI3)]n (3), [(trien)(PbAgI3)]n (4), [(tepa)(PbAg2I4)]n (5), and [{(dien)3(CO3)}2(Pb6Ag8I15)]nIn (6) were prepared by the reactions of PbI2, AgI (or Ag2CO3) and KI with different polyamines in N,N′-dimethylformamide (DMF) solution. In 1–4, two AgI4 tetrahedra share a common edge to form the bimeric Ag2I6 unit. It coordinates to the Pb(II) ion of [PbL2]2+ or [PbL′]2+ (L = en, pda; L′ = tmeda, trien) via iodine atoms to form hybrid organic–inorganic heterometallic iodides 1, 2, 3 and 4, respectively. Compounds 1, 3, and 4 contain 2-D layered backbones of [PbAgI3]n, whereas 2 contains a backbone of [PbAgI3]n with a 3-D structure. Steric hindrance and denticity of the ethylene polyamines influence the coordination modes and connection strength between the iodoargentate aggregates and Pb(II) ions. In 5, the AgI4 units are joined via sharing common edges to form a 1-D polymeric [Ag2I4]n2n− anion. It is connected with [Pb(tepa)]2+via iodine atoms to form a 3-D network of [(tepa)(PbAg2I4)]n. In 6, the CO32− ion binds three [Pb(dien)]2+ units to form the novel trinuclear [{Pb(dien)}3(μ3-CO3)]4+ complex ion. Eight AgI4 tetrahedra are connected via sharing common edges to give a novel Ag8I15 cluster with C3 symmetry. The Ag8I15 cluster and the [{Pb(dien)}3(CO3)]4+ unit are connected to form a novel layered heterometallic iodometallate cation [{(dien)3(CO3)}2(Pb6Ag8I15)]nn+via sharing iodine atoms. Compounds 1–6 represent a new type of hybrid organic–inorganic heterometallic iodide containing coordinative organic components. Optical absorption spectra show a blue shift of the absorption edges for 1–6 compared with those of the bulk PbI2 and AgI solids.