Rotational aspects of non-ionized creatine in the gas phase

On Some Origins of Tautomeric Preferences in Neutral Creatinine in Vacuo: Search for Analogies and Differences in Cyclic Azoles and Azines

“…This lactam compound is spontaneously formed in vertebrates from the acyclic nitrogenous organic acid creatine {C 4 H 9 N 3 O 2 , IUPAC name: 2-[carbamimidoyl(methyl)amino]acetic acid, also called as methylguanidoacetic acid} (Figure 1) [7][8][9][10]. The two biomolecules, acyclic creatine and its cyclic anhydride creatinine, possess different isomeric forms, such as prototropic tautomers, and also conformational and configurational isomers [5,[11][12][13][14]. They play a principal role in the metabolism of proteins [7,9,15].…”

“…This encouraged many chemists and biochemists to undertake various experimental and theoretical studies on their structure and physicochemical, chemical, and biochemical properties (see for example refs [5][6][7][8][9]11,[18][19][20][21][22][23][24][25][26][27][28]). The two derivatives continue attracting the particular attention of researchers even in the 21st century (see for example articles on structural studies [12][13][14][29][30][31][32]). An interesting article was published in 2021 by Léon et al [14], who discussed spectroscopic and computational results for the favored tautomeric forms of creatinine in the solid state, polar solvents, and gas phase.…”