Structure and electrochemistry of the bridging-ligand mono-substituted diruthenium compound, [Ru2(II,III)(O2CCH3)3(admpym)(Cl)(MeOH)] (Hadmpym=2-amino-4,6-dimethylpyrimidine)

The ligand substitution reaction of Ru2(O2CCH3)4Cl with 2-amino-4,6-dimethylpyrimidine (Hadmpym) under gentle refluxing conditions in methanol led to the formation of a bridging-ligand mono-substituted compound, [Ru2(O2CCH3)3(admpym)(Cl)(MeOH)] (1). Compound 1 crystallized in monoclinic space group P21/n (no. 14) with a=8.3074(8) Å, b=12.3722(8) Å, c=18.913(1) Å, β=95.559(3)°, V=1934.8(3) Å3, and Z=4. Temperature dependence of the magnetic susceptibility of 1 revealed it to be in a spin ground state S=3/2 arising from the electronic configuration of σ2π4δ2(δ*π*)3. Compound 1 undergoes three metal-centered redox reactions in electrochemistry: E1/2 (ox)=+0.72 V (Ia/Ic<1, ΔEp=0.17 V); E1/2 (1,red)=−0.65 V (Ia/Ic≈1, ΔEp=0.10 V); and E1/2 (2,red)=−1.80 V (Ia/Ic≪1, ΔEp=0.16 V). Then, the redox species produced by electrolysis were characterized by spectroscopic studies.