Tin-porphyrin-assisted formation of coordination frameworks

• Synthesis and characterization of three new metal organic frameworks.
• 3D coordination polymers based on Cadmium and Manganese metal ions.
• Solvent driven structural transformation.
• The influence of the tin(IV)-porphyrins on the formation of the coordination networks.
• A mechanism proposal for the role of the porphyrin in the reaction mixture.

Novel 3D networks synthesized by two different methods are reported in this article. Structure 1 {[CdL2]·(solvent)}n consists of CdII-single metallic nodes held together by coordinated isonicotinate ligands (L) to form a 3D chiral framework (P41212). The resulting structure exhibits threefold-interpenetrated dia coordination networks. After a few weeks the crystals were re-measured to form 1a {[Cd(L)2(H2O)]·DMF}n with two interpenetrated dia nets which is thermodynamically more stable. On the other hand, the addition of the tin(IV)-porphyrin to the same reaction mixture led to the formation of 3D pseudo-isostructures, based on oxo-centered CdII and MnII/III cluster nodes, 2 {[Cd3(OH)L4(H2O)3](ClO4)}n and 3 {[Mn3(O)L4(DMF)3](ClO4)}n. These structures represent topologically bcg nets. Possible synthetic mechanism was proposed to emphasize the role of the tin(IV)-porphyrin that led to the construction of oxo-centered trinuclear clusters in 2 and 3.

The formation of new 3D coordination frameworks with metal ions and isonicotinic acid is affected by the presence of the tin(IV)-porphyrin mediator.Figure optionsDownload as PowerPoint slide