Water mediated self assembly of 5-(2-benzoimidazole-1-yl-ethoxy)-3-methyl- 1-phenyl-1H-pyrazole-4-carboxylic acid methyl ester through CAH O and OAH N interactions

Abstract

Single crystal X-ray structure analysis of 5-(2-benzoimidazole-1-yl-ethoxy)-3-methyl-1-phenyl-1H-pyrazole- 4 carboxylic acid methyl ester (2).0.5H2O provided experimental proof for H O@C, CAH OAH and HAO N interactions. The embedded water molecule bridges between molecules 2 via non-covalent interactions. Thus this molecule behaves as a preorganized host molecule for water, presenting a minimum ring-size molecular environment for water binding. Single crystal X-ray structure analysis of 5-(2-benzoimidazole-1-yl-ethoxy)-3-methyl-1-phenyl-1H-pyrazole-4-carboxylic acid methyl esterhemihydrate provided experimental proof for six hydrogen bonds by one molecule of water. The embedded water molecule bridges six molecules by two types of hydrogen bonding. Theoretical calculations showed that the conformation of the bicyclic hetero-ring alters only slightly due to the presence of the water molecule. Thus this organic molecule behaves as a very interesting preorganized host molecule for water, presenting maximum binding environment for water binding.