Novel Sterically Hindered Substituted Ferrocenes and Their Transition Metal Complexes

Bis(1‘-organylthiolatoferrocenylene)disulfanes, RS-fc-SS-fc-SR type I ligands (R = Me, tBu), have been synthesized by cleavage of 1,2,3-trithia[3]ferrocenophane with organolithium reagents, RLi. The disulfanes have been successfully cleaved using lithium triethylborohydride and then reacted with dibromo-organyl species (Br-X-Br) to produce a novel series of sterically hindered ligands, RS-fc-S-X-S-fc-SR type II ligands {(1) R = tBu; X = CH2CH2CH2, CH2C5H3NCH2, CH2C10H6CH2; (2) R = Me; X = CH2CH2CH2, CH2C5H3NCH2, CH2C10H6CH2}. Both type I and type II ligands have been structurally characterized, and their coordination chemistry has been investigated by reaction with the late transition metal reagents Cu(MeCN)4PF6 and Pd(cod)Cl2. The resulting Cu(I) and Pd(II) complexes have been fully characterized, showing some unusual reactivity and a preponderance for a bis-bidentate chelating mode.