To further probe the influence of coordinated metal ions on the electrochemical behavior of azathiaferrocenophane ligands, a series of palladium(II) and copper(II) complexes with both cyclic and acyclic ferrocenophanes has been prepared, spectroscopically characterized and examined by cyclic voltammetry. New complexes of N,N-didecyl-2,8-diaza-5-thia(1,1′) ferrocenophane (1) are HPd(CH3CN)(BF4)3, Pd(PPh3)2(BF4)2 · CH2Cl2, Pd(AsPh3)2 (BF4)2 · 1.5CH2Cl2, Pd(C6O4Cl2) · (HN(C2H5)3)2(BF4)2 · H2O and H2Pd(bpy)(BF4)4. Copper(II) compounds reported include Cu(CH3CO2)2 · 2H2O (2 = 1,5-bis(ferrocenyl)-3-thia-1,5-diaminopentane), Cu(CH3CO2)2 (3 = 1,8-bis(ferrocenyl)-3,6-dithia-1,8 -diaminooctane) and Cu(bas)(CH3CO2)2 (bas = 3-thia-1,5-diaminopentane). The HPd(CH3CN)3+ ca tion (E 1 2(F by tridentate S2N ferrocenophane ligation, leaving one coordination position open to the CH3CN ligand and a protonated aza nitrogen atom uncoordinated. In contrast, 1 ligates PdiI, only through its pair of thioether sulfur atoms in Pd(PPh3)22+ (E 1 2 = 0.58 V) and Pd(AsPh3)22+ (E 1 2 = 0.59 V). The PdII-chloranilate interaction in Pd(C6O4Cl2) · (HN(C2H5)3)2(BF4)2 · H2O is too weak to disrupt ferrocenophane tridentate chelation or to restore the FeIIS bonding previously documented for Pd(C6O4Cl2), which was prepared by another synthetic route. Electronic spectra of Cu(CH3CO2)2 · 2H2O and [3 ]Cu(CH3CO2)2 are consistent with tridentate S2N and tetradentate S2N2 ligat ion of Cu II, respectively, and a finding of E 1 2 = 0.48 V for both complexes is in accord with expectations for the electrostatic influence of a bivalent cation on the FellIII/II couple. Although cyclic voltammetric waves for the CuII,I couple were not observed, the redox reactivity of Cu2+ towards reduction was evaluated through a kinetic study of electron transfer within its mercaptoacetate adduct.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
- Materials Chemistry