One-size adjustable-gap cluster anions: systematic approach to multinary, water-soluble chalcogenidometalate compounds

Reactions of defined mixtures of ternary salts K 4(H 2O) 4]SnSe 4] and K 4(H 2O) 0.5]SnTe 4] with transition-metal ions M = Zn (2+) or Mn (2+) provide an easy approach to penternary salts of quaternary cluster anions M 4Sn 4Se 17- x Te x ] (10-), with x corresponding to the Se/Te ratio of the reactant mixture. In this way, it is possible to generate both protic solutions and single crystals with finely adjustable electronic excitation energies E g; the fact that the E g values cover the whole visible part of the electromagnetic spectrum as a function of the parameter x spotlights these cluster compounds with respect to diverse photocatalytic applications.