5'-deoxyadenosine (LH) complexes with divalent 3d metal perchlorates were prepared by refluxing mixtures of LH and salt in triethylorthoformate-ethylacetate. With one exception (M =Co), adducts of the types M(LH),(C104),.3EtOH (M = Mn, Fe, Ni, Zn) and Cu(LH),(ClO4),.2EtOH were obtained. Ethanol is introduced to the system by hydrolysis of triethylorthoformate during the dehydration of the metal salts. Co(I1) perchlorate yielded a complex involving both neutral LH and monoanionic L-ligands, i.e., Co,(LH)L,(C104),.4EtOH. An analogous Cu(I1) complex, Cu,(LH)L,(C104),.Et0H.3H,0, was also obtained by refluxing substantially more dilute suspensions of LH and Cu salt, relative to the standard preparative method employed. The new complexes were characrerized as dimers or linear polymers, involving bridging bidentate Nl,N7-bound LH ligands between adjacent metal ions and coordination number six. The new adducts also involve terminal N7-bound LH and EtOH ligands and ionic perchlorate, and the Co and Cu complexes a chelating N6,N7-bound L-(monodeprotonation of the exocyclic NH, group) per metal ion and terminal -0C10, and ROH (R=Et or H) ligands.