TY - JOUR
T1 - Hydrogenation and hydrogenolysis of furfural and furfuryl alcohol catalyzed by ruthenium(II) bis(diimine) complexes
AU - Gowda, Anitha S.
AU - Parkin, Sean
AU - Ladipo, Folami T.
PY - 2012/2
Y1 - 2012/2
N2 - The catalytic activity of ruthenium(II) bis(diimine) complexes cis-[Ru(6,6′-Cl 2bpy) 2(OH 2) 2](Z) 2 (1, Z = CF 3SO 3; 2, Z = (3,5-(CF 3) 2C 6H 3) 4B, i.e. BArF) and cis-[Ru(4,4′-Cl 2bpy) 2(OH 2) 2](Z) 2 (3, Z = CF 3SO 3; 4, Z = BArF) for the hydrogenation and/or the hydrogenolysis of furfural (FFR) and furfuryl alcohol (FFA) was investigated. The molecular structures of cis-[Ru(4,4′- Cl 2bpy) 2(CH 3CN) 2](CF 3SO 3) 2 (3′) and dimeric cis-[(Ru(4,4′-Cl 2bpy) 2Cl) 2](BArF) 2 (5) were characterized by X-ray crystallography. The structures are consistent with the anticipated reduction in steric hindrance about the ruthenium centers in comparison with corresponding complexes containing 6,6′-Cl 2bpy ligands. While compounds 1-4 are all active and highly selective catalysts for the hydrogenation of FFR to FFA under modest reaction conditions, 3 and 4 showed decreased activity. This is best explained in terms of reduced Lewis acidity of the Ru 2+ centers and reduced steric hindrance about the metal centers of catalysts 3 and 4. cis-[Ru(6,6′-Cl 2bpy) 2(OH 2) 2](BArF) 2 (2) also displayed high catalytic efficiency for the hydrogenation of FFA to tetrahydrofurfuryl alcohol. Presumably, this is because coordination of C=C bonds of FFA to the ruthenium center is poorly inhibited by non-coordinating BArF counterions. Interestingly, cis-[Ru(6,6′-Cl 2bpy) 2(OH 2) 2](CF 3SO 3) 2 (1) showed some catalytic activity in ethanol for the hydrogenolysis of FFA to 2-methylfuran, albeit with fairly modest selectivity. Nonetheless, these results indicate that ruthenium(II) bis(diimine) complexes need to be further explored as catalysts for the hydrogenolysis of C-O bonds of FFR, FFA, and related compounds.
AB - The catalytic activity of ruthenium(II) bis(diimine) complexes cis-[Ru(6,6′-Cl 2bpy) 2(OH 2) 2](Z) 2 (1, Z = CF 3SO 3; 2, Z = (3,5-(CF 3) 2C 6H 3) 4B, i.e. BArF) and cis-[Ru(4,4′-Cl 2bpy) 2(OH 2) 2](Z) 2 (3, Z = CF 3SO 3; 4, Z = BArF) for the hydrogenation and/or the hydrogenolysis of furfural (FFR) and furfuryl alcohol (FFA) was investigated. The molecular structures of cis-[Ru(4,4′- Cl 2bpy) 2(CH 3CN) 2](CF 3SO 3) 2 (3′) and dimeric cis-[(Ru(4,4′-Cl 2bpy) 2Cl) 2](BArF) 2 (5) were characterized by X-ray crystallography. The structures are consistent with the anticipated reduction in steric hindrance about the ruthenium centers in comparison with corresponding complexes containing 6,6′-Cl 2bpy ligands. While compounds 1-4 are all active and highly selective catalysts for the hydrogenation of FFR to FFA under modest reaction conditions, 3 and 4 showed decreased activity. This is best explained in terms of reduced Lewis acidity of the Ru 2+ centers and reduced steric hindrance about the metal centers of catalysts 3 and 4. cis-[Ru(6,6′-Cl 2bpy) 2(OH 2) 2](BArF) 2 (2) also displayed high catalytic efficiency for the hydrogenation of FFA to tetrahydrofurfuryl alcohol. Presumably, this is because coordination of C=C bonds of FFA to the ruthenium center is poorly inhibited by non-coordinating BArF counterions. Interestingly, cis-[Ru(6,6′-Cl 2bpy) 2(OH 2) 2](CF 3SO 3) 2 (1) showed some catalytic activity in ethanol for the hydrogenolysis of FFA to 2-methylfuran, albeit with fairly modest selectivity. Nonetheless, these results indicate that ruthenium(II) bis(diimine) complexes need to be further explored as catalysts for the hydrogenolysis of C-O bonds of FFR, FFA, and related compounds.
KW - carbon-oxygen bond hydrogenolysis
KW - catalytic hydrogenation
KW - furfuryl alcohol
KW - ruthenium bis(diimine) complexes
KW - tetrahydrofurfuryl alcohol
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U2 - 10.1002/aoc.2819
DO - 10.1002/aoc.2819
M3 - Article
AN - SCOPUS:84856399462
SN - 0268-2605
VL - 26
SP - 86
EP - 93
JO - Applied Organometallic Chemistry
JF - Applied Organometallic Chemistry
IS - 2
ER -