Syntheses, Structures and Reactivity of the Complex [(2,9-(tBu)2-phen)Cu(O2CAryl)] and [(2,9-(tBu)2-phen)Cu(Aryl)] : Experimental and Theoretical Investigation on the CO2 Extrusion or Insertion in these Complexes

The molecule 2,9-tBu2phen (phen* (1)) and the copper(I) complexes [(phen*)Cu(O2CR)] (R = o-F-C5H4 (2), p-F-C5H4 (3), C6F5 (4), o-NO2-C5H4 (5), p-NO2-C5H4 (6), CF3 (7)) have been synthesized and isolated by treatment of a mixture of [Cu(OtBu)] and phen* with the corresponding acid. They are rare examples of carboxylate complexes of copper(I). The aryl/alkyl counterparts [(phen*)Cu-R] (R = C6F5 (8), o-NO2-C6H4 (9),CF3 (11)) have also been isolated by distinct ways. The crystal structures of complexes 1-9 and 11, and of [(phen*)CuF(HF)] (10) and the phenanthroline compound [(phen)Cu(C6F5)] (8’) are presented and discussed. Decarboxylation reaction of the [(phen*)Cu(O2CR)] complexes (R =C6F5 (8), o-NO2-C6H4 (9),CF3 (11)) has been attempted and was successful only with R = C6F5 in specific solvents such as quinoline or DMA. In contrast, carboxylation of the alkyl and aryl [(phen*)Cu-R] complexes did not proceed. DFT calculations have been used to rationalize the results.