## 4 Additions to the Ribose Structure
### The Attachment of Adenine to Ribose  
Adenine (Figure 5) is one of the important building blocks of ATP or adenosine triphosphate. We use here ATP as a small-scale example of adenine bonding. If we accept that the C(5) position of the ribose is the one first occupied by the PO\({}_{4}\) group it is tempting to assign the opposite position \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Row** & **Assignment** & **Ribose** & **Phosphate** & **R.C.** & \(\Delta\) **\%\({}_{\infty}\)** & **Reference** \\ \hline
1 & PO\({}_{4}\)\({}^{3}\)–HPO\({}_{4}\)\({}^{2}\)- asymmetric stretching & - & 1044 & 1.991 & 4.5 & [14] \\ \hline
2 & PO\({}_{4}\)\({}^{3}\)- asymmetric stretching & - & 1046 & 1.988 & 6.0 & [15] \\ \hline
3 & vC-O + v(C–C),etc. & 1044 \({}^{*}\) & - & 1.982 & 9.0 & [19] \\ \hline
4 & \(\delta\)(O-C-H) & 1035 & - & 2.009 & 4.5 & [20] \\ \hline
5 & Not assigned & 1041 & - & 1.997 & 1.5 & [21] \\ \hline  & Mean value & 1040 & 1045 & - & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Vibrational data for phosphates and ribose. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Assignment** & **Glucose** & **Phosphate** & **References** \\ \hline PO\({}_{4}\)\({}^{3}\)–/HPO\({}_{4}\)\({}^{2}\)- asymmetric stretching & - & 1044 & [14] \\ \hline PO\({}_{4}\)\({}^{3}\)–asymmetric stretching. & - & 1046 & [15] \\ \hline C-O-H & 1047 & - & [16] \\ \hline v CO + v CC & 1050 & - & [17] \\ \hline CO (79\%) + CC (19\%) PED & 1047 & - & [18] \\ \hline Mean value & 1048 & 1045 & - \\ \hline \hline \end{tabular}
\end{table} 
Table 5: IR data (cm\({}^{-1}\)) for glucose C(6)O-H and solid-state phosphates [4]. The quoted assignments are from respective authors. of the ribose molecule, C(1), for anchoring the adenine molecule. This view is supported by well known structure data, Figure 11. We will use ATP as a model example for describing the bonding of nucleobases, all with an N-H group, towards the C(1) position of ribose. As the picture of ATP shows (Figure 11), the connection between the adenine N(9)-H and the ribose C(1)-OH keeps the different groups together. How does this extremely important bond come about? It is known that the C-O + C-C vibration is found at about 1040 cm\({}^{-1}\) (table 6, in [19; 20; 21]). But what is known about vibrations of the N(9)-H group that might be in close resonance with the vibrations of the C(1)-OH moiety? To follow the treatment discussed above we plot a series of FTIR data [22] as shown in Table 7.  
Table 7 shows a series of FTIR data on anhydrous adenine. From the data given in Table 7, we can safely assume that Row 5 represents a condition where the 'extra terms' give the least disturbance when calculating the vibration frequency of \(\delta\)(N9-H). We, therefore, set forth to find a correction that will give us a 'true' value of this parameter, and thereby understand the transfer of energy from catalyst to the intended reactant. As above (Table 7; Row 5) we can state that (1.521-1.500)/1.5 = 14 o/oo. Hence, to reach an expected, somewhat smaller, value of the resonance condition, one has to increase the denominator with a term that we call \(\Delta\)\". \(\Delta\)\" = 0.014 \(\times\) 1367 cm\({}^{-1}\) = 19 cm\({}^{-1}\). Thus, the true value of \(\delta\) (N9-H) = 1367 + 19 = 1386 cm\({}^{-1}\). We can now check the calculations by forming the expression for resonance condition, R.C. = 2079/1386 = 1.500 = 3:2. This gives full support to our treatment. If we express the value of a vibrational quantum in cm\({}^{-1}\) units, this means that two catalyst quanta = 2 \(\times\) 2079 cm\({}^{-1}\) = 4158 cm\({}^{-1}\), and three reactant quanta = 3 \(\times\) 1386 cm\({}^{-1}\) = 4158 cm\({}^{-1}\). Thus, two vibrational quanta from the catalyst are donated and three quanta are accepted by the reactant for the reaction to go.