Crystal structure, DFT, vibrational properties, Hirshfeld surface and antitumor activity studies of 1-Octyl-1 <i>H</i> -Indole derivatives

Indole derivatives, recognized as privileged scaffolds in medicinal chemistry, were utilized to design ten novel compounds synthesized from 4-bromobenzenesulfonyl chloride and 5-bromoindole via a five-step route. Structural confirmation was achieved by nuclear magnetic resonance (
1
H NMR,
1
3
C NMR), infrared (IR), and mass spectrometry (MS). Remarkably, single-crystal X-ray diffraction (XRD) of compound
7a
, supported by density functional theory (DFT) calculations, confirmed a highly consistent molecular conformation. Subsequent molecular electrostatic potential (MEP) and frontier molecular orbital (FMO) studies identified key electronic features, while Hirshfeld analysis decoded intermolecular packing forces. Molecular docking against protein target PDB: 4A2N indicated stable binding modes and significant affinity. Importantly,
7a
and its analogues exhibited potent antiproliferative effects against the human breast cancer cell line MCF-7 (Michigan Cancer Foundation-7) and the human promyelocytic leukemia cell line HL-60, underscoring their potential as promising anticancer leads for further development.