Synthesis and crystal structure of [Ag-2(mu(4)-hmt)(NO2)(2)](n). A two-dimensional network with square cavities self-assembled by hmt (hmt = Hexamethylenetetramine)

AgNO2 (1 mol) reacts with hexamethylenetetramine (hmt) (1 mol) in MeCN-H2O to yield a two-dimensional coordination polymer [Ag-2(mu (4)-hmt)(NO2)(2)]( n) with square cavities. The Ag2 atom is located in a linear structure coor dination environment with two nitrogen atoms from two hmt molecules respect ively. The Ag1 atom is coordinated in a triangular prism surrounded by two nitrogen atoms from two hmt molecules respectively and four oxygen atoms fr om two NO2- ions respectively. The four nitrogen atoms of each hmt unit are all connected to Ag-I to form a two-dimensional network.