From polyoxometalate building blocks to polymers and materials: The silver connection

Molecular growth processes utilizing polyoxometalate-based building blocks with silver connecting units have been used to produce four new materials: 1, [Ag₃(bhepH)₈(W_11.5Na_0.5O ₄₀P)₂]·8H₂O (bhep = N,N′-bis(2- hydroxyethyl)piperazine); 2, [Ag₄(DMSO)₈(Mo ₈O₂₆)]_n; 3, {Ag₃[MnMo ₆O₁₈{(OCH₂)₃CNH₂} ₂(DMSO)₅]·3(DMSO)}_n; 4, {Ag ₃[MnMo₆O₁₈{(OCH₂) ₃CNH₂}₂(DMSO)₆(CH ₃CN)₂]·DMSO}_n. The compounds were characterised using single crystal X-ray crystallography, elemental analysis, IR, TGA, DSC, and compounds 2-4 were imaged on silicon substrates using scanning electron microscopy. Compound 1 represents a 0D dimer connected by silver ions but was also found to form channels facilitated by the hydrogen bonding between the protonated [bhepH]⁺ ligand and the cluster, and complex 2 forms 2D layered networks, whereas both compounds 3 and 4 form 1D networks; these networks are all connected by Ag(i) ions. Thermal studies show that the stabilities of compounds 2-4 are affected by the linking Ag(i) ions and the DMSO ligands and EM studies on compounds 3 and 4 showed the formation of fibres on silicon substrates.