Crystal structure studies, Hirshfeld surface analysis and DFT calculations of novel 1-[5-(4-methoxy-phenyl)-[1,3,4]oxadiazol-2-yl]-piperazine derivatives

159Crystal structures, density functional theory (DFT) geometry optimization and molecular Hirshfeld surface calculations of two novel 1-[5-(4-methoxy-phenyl)-[1,3,4]oxadiazol-2-yl]- piperazine derivatives: 1-(4-tert-butyl-benzenesulfonyl)-4-[5-(4-methoxy-phenyl)-[1,3,4]oxadiazol-2-yl]-piperazine, (I): C23H28N4O4S and 1-[5-(4-methoxyphenyl)-[1,3,4]oxadiazol-2-yl]-4-[(4-bromo)benzene sulfonyl]-piperazine, (II): C19H19N4O4 S Br.