Crystal structure of N-(1,3-benzothiazol-2-yl)-4-iodobenzene-1-sulfonohydrazide: the unexpected importance of I N-H center dot center dot center dot pi and I center dot center dot center dot pi interactions on the supramolecular arrangement

The 2-hydrazinyl-1,3-benzothiazole derivatives are precursors for synthesis of several compounds of technological interest, including the Bt-NH-N=CHR1 (R-1=alkyl, aryl, heteroaryl), derivatives. Usually when Bt-NH-NH2 is allowed to react with a benzenesulfonyl chloride the substitution is observed in the terminal nitrogen of the arenehydrazine unit, but when 4-iodophenyl sulfonyl chloride (4-IC6H4SO2Cl) was used, the product isolated was the title compound as confirmed by Rx-analysis. Determination of the crystal structure revealed that the definition of the arrangement was driven by N-H center dot center dot center dot pi, C-I center dot center dot center dot pi and S2-O21 center dot center dot center dot pi interactions instead of the classic O center dot center dot center dot H-N hydrogen bonds. The interactions were confirmed by HS analysis. Interaction energy calculations showed that the pi interactions-based motifs play an important role in the supramolecular arrangement, contributing about 60% to the total energy of the lattice. DFT calculations showed that the energy of the C-I center dot center dot center dot pi dimer is complemented with contributions of pi center dot center dot center dot pi stacking and N-H center dot center dot center dot pi interaction between the primary amine and the thiazole aromatic ring.