Syntheses, structures, and properties of three novel coordination polymers of silver(I) aromatic carboxylates with hexamethylenetetramine exhibiting unique metal-π interaction

Three interesting coordination polymers, [Ag-4(mu (4)-hmt)(mu (4)-hmt)(mu (4)-eta (2)-nda)(2)]. 2H(2)O (1), [Ag-2(mu -hmt)(2)- (mu -bi-eta (2)-bna)]. 2H(2)O . MeCN (2), and [Ag-2(mu (4)-hmt)(eta (2) -hna)(MeCN)](hna).H2O (3) (hmt = hexamethylenetetramine, nda = 2,6-naphthalenedicarboxylate, bna = 2,2'-dihydroxy-1,1'-binaphthalene-3,3'-dicarboxylate, and hna = 1-hydroxy-2-naphthalenecarboxylate), were obtained from the reaction of silver(I) aromatic carboxylates in MeCN solution with hmt in CH2Cl2 solution via the liquid diffusion method. In these complexes, the aromatic carboxylates ligate to the metal atoms via a unique eta (2)-coordination mode involving their aromatic rings, in addition to the normal coordination modes utilizing their carboxylate oxygen atoms. These complexes show interesting electronic properties similar to those reported for the silver(I) complexes of other polycyclic aromatic compounds. Both 1 and 2 exhibit a strong blue photoluminescence at room temperature.