Hydrogen-bonded supramolecular motifs in crystal structures of trimethoprim barbiturate monohydrate (I) and 2-amino-4,6-dimethylpyrimidinium barbiturate trihydrate (II)

Abstract

In the present study, we report the crystal structures of two organic salts, namely 2,4-diamino-5-(3 ,4 ,5 -trimethoxybenzyl)pyrimidinium (TMP) barbiturate monohydrate (TMPBAR) (I), 2-amino-4,6-dimethylpyrimidinium (AMPY) barbiturate trihydrate (AMPYBAR) (II). In both complexes, one ring nitrogen of TMP and AMPY are protonated as a result of proton transfer from the−CH 2 group of barbituric acid. In compound (I), the TMP cation and barbiturate anion are paired through twoN−H···O and one N−H···N hydrogen bonds. This pair further self-organizes through N−H···O hydrogen bonds to generate an array of six hydrogen bonds. These arrays are further cross-linked by N−H···O hydrogen bonds forming a sheet-like structure. The water molecule is also embedded in the sheet via O−H···O and C−H···O hydrogen bonds, forming a rosettelike supramolecular motif. TMP cations are also bridged by alternating water molecules via C−H···O and O−H···N hydrogen bonds. In compound (II), the symmetrical barbiturate anions self-organize on both sides through N−H···O hydrogen bonds generating a supramolecular chain. These chains are cross-linked by the three water molecules. A pair of barbiturate anions and two water molecules constitute an array of four hydrogen bonds (DADA quadruple array). These arrays are cross-linked by another water molecule. 2-Amino-4,6-dimethylpyrimidine cations are paired through P. T. Muthiah ( ) · M. Hemamalini

Synthesis, structural studies and vibrational spectroscopy of Fe2+ and Zn2+ complexes containing 4,4′-bipyridine and barbiturate anion

“…1), due to its ability to associate with complementary molecules via hydrogen bonding interactions, through its three carbonyl oxygen atoms acting as hydrogen bond acceptors and also the two imino groups acting as hydrogen bond donors [13]. Barbituric acid and their derivatives are compounds containing pyrimidine ring which play an important role in many biological systems, being widely pharmacologically used as sedative hypnotic [14][15][16].…”

Hydrogen bonding patterns in salts of derivatives of aminopyrimidine and thiobarbituric acid

“…However, there are a few variations in the architecture which are brought about by O-HÁ Á ÁS hydrogen bonds, the number of water molecules involved in the water-water interaction and the size of molecular ring motifs formed by the molecular recognition. In the case of TMPÁBA (Muthiah et al, 2007), the replacement of oxygen by sulfur and the presence of additional water molecules greatly alter the supramolecular pattern by altering the spatial arrangement of TBA toward TMP and thereby reducing the availability of hydrogen-bond donors and acceptors for the formation of multiple hydrogen bonds as in the reported TMPÁBA. Also there are some aromatic stacking differences between TMPÁBA and TMPÁTBA (III).…”

Interplay of thermochemistry and Structural Chemistry, the journal (volume 18, 2007) and the discipline

“…The next article, by Multhiah et al [84], studies the conformation and hydrogen bonding patterns present in the crystal structures of TMP-barbiturate monohydrate (TMP = 2,4-diamino-5-(3 0 ,4 0 ,5 0 -trimethoxybenzyl)pyrimidinium) and AMPY-barbiturate trihydrate (AMPY = 2-amino-4,6-dimethylpyrimidinium). We find it surprising that although barbituric acid and its derivatives have long been known to the medical, scientific, and general citizenry communities, there have been very few thermochemical investigations involving these species [85,86].…”