Table 4. The energy E (a.u.) of aldo-pentose sugars and intramolecular H-bond lengths (A…H-D) in Å for their conjugate bases obtained at the B3LYP/6-311++G (d,p) Table 4. The energy E (a.u.) of aldo-pentose sugars and intramolecular H-bond lengths (A…H-D) in Å for their conjugate bases obtained at the B3LYP/6-311++G (d,p) Table 4. The energy E (a.u.) of aldo-pentose sugars and intramolecular H-bond lengths (A…H-D) in Å for their conjugate bases obtained at the B3LYP/6-311++G (d,p) Table 4. The energy E (a.u.) of aldo-pentose sugars and intramolecular H-bond lengths (A…H-D) in Å for their conjugate bases obtained at the B3LYP/6-311++G (d,p) Table 4. The energy E (a.u.) of aldo-pentose sugars and intramolecular H-bond lengths (A…H-D) in Å for their conjugate bases obtained at the B3LYP/6-311++G (d,p) Table 4. The energy E (a.u.) of aldo-pentose sugars and intramolecular H-bond lengths (A…H-D) in Å for their conjugate bases obtained at the B3LYP/6-311++G (d,p) Table 4. The energy E (a.u.) of aldo-pentose sugars and intramolecular H-bond lengths (A…H-D) in Å for their conjugate bases obtained at the B3LYP/6-311++G (d,p)
Aldo-pentose
E (a.u.) in neutral
H-bonds in conjugate bases
deprotonation sites
deprotonation sites
deprotonation sites
deprotonation sites
C1-HO1 C2-HO2 C3-HO3 C4-HO4
D-xylose -572.6601 O2….HO3-O3 2.13
O3….HO2-O2 2.10
O4….HO3-O3 2.02
L-lyxose -572.659 O1….HO2-O2 1.75
O2….HO3-O3 2.12
O2…HO1-O1 1.78
O2…HO3-O3 1.84
O2…HO1-O1 2.08
O3…HO2-O2 1.80
O4…HO3-O3 1.98
aD-ribose -572.6605 O2….HO3-O3 2.16
O3….HO4-O4 2.15
O2….HO3-O3 1.82
O3….HO4-O4 2.12
O3….HO2-O2 1.85
O3….HO4-O4 1.84
O4…HO2-O2 1.64
O4…HO3-O3 2.06
L-arabinose -572.6594 O3….HO4-O4 2.15
O3….HO1-O1 1.53
O3….HO4-O4 1.92
O4….HO3-O3 1.66
O3….HO1-O1 1.87
a For D-ribose, in its neutral strucuture, the only H-bond is O4….HO2-O2 (2.17 Å). a For D-ribose, in its neutral strucuture, the only H-bond is O4….HO2-O2 (2.17 Å). a For D-ribose, in its neutral strucuture, the only H-bond is O4….HO2-O2 (2.17 Å). a For D-ribose, in its neutral strucuture, the only H-bond is O4….HO2-O2 (2.17 Å). a For D-ribose, in its neutral strucuture, the only H-bond is O4….HO2-O2 (2.17 Å). a For D-ribose, in its neutral strucuture, the only H-bond is O4….HO2-O2 (2.17 Å). a For D-ribose, in its neutral strucuture, the only H-bond is O4….HO2-O2 (2.17 Å).