Self-Assembly of Coordination Polymers from Volatile PdII and PbII β-Diketonate Derivatives through Metallophilic Interactions

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Abstract

New dimetallic coordination polymers based on neutral metal β-diketonate derivatives can be obtained by simple cocrystallization from organic solvents. X-ray crystallography studies have been performed for the dimetallic complexes [trans-Pd(ki)2]*[Pb(hfa)2] (1; ki = 2-iminopentan-4-onate, hfa = 1,1,1,5,5,5-hexafluoropentane-2,4-dionate), [cis-Pd(ki)2]*[Pb(hfa)2] (2), and [trans-Pd(tmha)2]*[Pb(hfa)2]2 (3; tmha = 2,2,6,6-tetramethyl-3-iminoheptan-5-onate). The crystals of 1 and 3 are composed of chains of coordination polymers containing alternating molecules of the metal complexes. The crystals of 2 are composed of tetrametallic species. Directed noncovalent metal–metal interactions along with the bridging ligand atoms bind the coordination polymers of these heterometallic coordination compounds. Structural evidence is reported for the formation of PdII···PbII metallophilic interactions in a series of similar compounds. A comparison of the calculated and experimental IR spectra allowed determination of the absorption bands in the region 100–600 cm–1 that correspond to the cooperative vibrations of the metal atoms that result from such interactions. The steric and electronic factors of the chelate ligands can be used to design the architecture of these new coordination polymers.

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