TY - JOUR
T1 - Exploration of Pynaphthyridine and Binaphthyridine Manganese(I) Tricarbonyl Complexes
T2 - Influence on Carbon Dioxide Reduction Electrocatalysis
AU - Cohen, Kailyn Y.
AU - Simonyan, Hovnan
AU - Ortiz, Mason
AU - Solomon, Benjamin F.
AU - Simkins, Luke
AU - Dominey, Raymond N.
AU - Goldman, Emma W.
AU - Bocarsly, Andrew B.
N1 - Publisher Copyright:
© 2024 American Chemical Society.
PY - 2024/7/22
Y1 - 2024/7/22
N2 - For CO2 electrocatalysts of the form fac-[Mn(diimine)(CO)3Br], we previously reported that expanding the π-system of the chelating ligand from 2,2′-bipyridine (bpy) to 2-(2-pyridyl)quinoline (pq) to 2,2′-biquinoline (bqn) introduced a shift in the mechanism for CO2 reduction to CO. Here, we have synthesized pynaphthyridine and binaphthyridine ligands which incorporate extra nitrogen atoms that can act as H-bond acceptors. Though these ligands redshift the MLCT bands, which has previously been associated with a decrease in electrocatalytic performance for CO2 reduction, MnBr(1,8-pynap) in acetonitrile (MeCN) displays a smaller overpotential for CO2 reduction than MnBr(pq). This effect was not observed in N,N-dimethylformamide (DMF), suggesting that H-bonding plays a major role in increasing the catalytic activity. While MnBr(1,8-bn) also had a higher Faradaic efficiency for CO formation than MnBr(bqn), it was not more effective than MnBr(1,8-pynap) in DMF. To demonstrate the importance of the nitrogen ring positions, MnBr(1,6-pynap) was also synthesized, where the aryl nitrogen is facing away from the Mn center. The MnBr(1,6-pynap) was a poor electrocatalyst for CO2 reduction, suggesting that the nonligated N atom in the 1,8-complexes stabilizes the Mn-C(O)OH intermediate.
AB - For CO2 electrocatalysts of the form fac-[Mn(diimine)(CO)3Br], we previously reported that expanding the π-system of the chelating ligand from 2,2′-bipyridine (bpy) to 2-(2-pyridyl)quinoline (pq) to 2,2′-biquinoline (bqn) introduced a shift in the mechanism for CO2 reduction to CO. Here, we have synthesized pynaphthyridine and binaphthyridine ligands which incorporate extra nitrogen atoms that can act as H-bond acceptors. Though these ligands redshift the MLCT bands, which has previously been associated with a decrease in electrocatalytic performance for CO2 reduction, MnBr(1,8-pynap) in acetonitrile (MeCN) displays a smaller overpotential for CO2 reduction than MnBr(pq). This effect was not observed in N,N-dimethylformamide (DMF), suggesting that H-bonding plays a major role in increasing the catalytic activity. While MnBr(1,8-bn) also had a higher Faradaic efficiency for CO formation than MnBr(bqn), it was not more effective than MnBr(1,8-pynap) in DMF. To demonstrate the importance of the nitrogen ring positions, MnBr(1,6-pynap) was also synthesized, where the aryl nitrogen is facing away from the Mn center. The MnBr(1,6-pynap) was a poor electrocatalyst for CO2 reduction, suggesting that the nonligated N atom in the 1,8-complexes stabilizes the Mn-C(O)OH intermediate.
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U2 - 10.1021/acs.organomet.4c00008
DO - 10.1021/acs.organomet.4c00008
M3 - Article
AN - SCOPUS:85198582750
SN - 0276-7333
VL - 43
SP - 1517
EP - 1527
JO - Organometallics
JF - Organometallics
IS - 14
ER -