TY - JOUR
T1 - Heterometallic CuII/LnIII polymers active in the catalytic aerobic oxidation of cycloalkenes under solvent-free conditions
AU - Cancino, P.
AU - Santibañez, L.
AU - Fuentealba, P.
AU - Olea, C.
AU - Vega, A.
AU - Spodine, E.
N1 - Funding Information:
The authors acknowledge Proyecto Anillo ACT 1404 and Basal Funding FB0807 (CEDENNA) for financial support. PFC thanks 3170186 postdoctoral grant from CONICYT. Authors also acknowledge the group of Prof. García; Universitat Politécnica de Valencia, Spain, for recording the Raman spectra.
PY - 2018/10/14
Y1 - 2018/10/14
N2 - Heterometallic 3d-4f inorganic polymers were prepared using 3,5 pyridinedicarboxylic acid (H2PDC), {[CuLn2(PDC)2(SO4)2(H2O)6]·H2O}n (Ln: SmIII, CuSmPDC, EuIII, CuEuPDC, GdIII, and CuGdPDC). These catalysts are active in the aerobic oxidation of cycloalkenes under solvent-free conditions, with a conversion for the oxidation of cyclohexene of 71% after one hour of the reaction, and a TOF value of 1438 h-1 for CuSmPDC. On the other hand, the oxidation of cycloheptene and cyclooctene exhibited slightly lower conversions of 52% and 47%, and TOF values of 1053 and 159 h-1 after 1 and 6 hours of the reaction, respectively. The radical mechanism for the oxidation reaction of cyclohexene was assessed by Raman and EPR spectroscopy. The first evidenced the formation of Cu-O2 adducts and the second permitted is to observe the presence of the oxygen centered radical species, which act as initiators of the reaction chain to generate the products. An increase in the temperature of the reaction correlates with the adduct formation, and with the enhancement of the oxidation reaction.
AB - Heterometallic 3d-4f inorganic polymers were prepared using 3,5 pyridinedicarboxylic acid (H2PDC), {[CuLn2(PDC)2(SO4)2(H2O)6]·H2O}n (Ln: SmIII, CuSmPDC, EuIII, CuEuPDC, GdIII, and CuGdPDC). These catalysts are active in the aerobic oxidation of cycloalkenes under solvent-free conditions, with a conversion for the oxidation of cyclohexene of 71% after one hour of the reaction, and a TOF value of 1438 h-1 for CuSmPDC. On the other hand, the oxidation of cycloheptene and cyclooctene exhibited slightly lower conversions of 52% and 47%, and TOF values of 1053 and 159 h-1 after 1 and 6 hours of the reaction, respectively. The radical mechanism for the oxidation reaction of cyclohexene was assessed by Raman and EPR spectroscopy. The first evidenced the formation of Cu-O2 adducts and the second permitted is to observe the presence of the oxygen centered radical species, which act as initiators of the reaction chain to generate the products. An increase in the temperature of the reaction correlates with the adduct formation, and with the enhancement of the oxidation reaction.
UR - http://www.scopus.com/inward/record.url?scp=85054071453&partnerID=8YFLogxK
U2 - 10.1039/c8dt01913d
DO - 10.1039/c8dt01913d
M3 - Article
C2 - 30065994
AN - SCOPUS:85054071453
VL - 47
SP - 13360
EP - 13367
JO - Dalton Transactions
JF - Dalton Transactions
SN - 1477-9226
IS - 38
ER -