Novel Carbazole–Formazan Derivatives: Synthesis, Spectroscopic Characterization, DFT Analysis, and Molecular Docking Studies

Serkan Öncüoğlu

doi:10.18596/jotcsa.1834699

Novel Carbazole–Formazan Derivatives: Synthesis, Spectroscopic Characterization, DFT Analysis, and Molecular Docking Studies

Abstract

In this study, three novel chloro-substituted carbazole–formazan derivatives were synthesized through a diazotization–coupling reaction starting from carbazole-based hydrazone intermediates. The structures of the obtained compounds were elucidated using FT-IR, ¹H NMR, ¹³C NMR, and HRMS spectroscopy (for the p-chloro derivative), all of which confirmed the successful formation of the azo–hydrazone tautomeric framework. FT-IR spectra exhibited characteristic N–H, C=N, N=N, and C–N stretching vibrations, while the NMR data clearly reflected the electronic environments of the carbazole scaffold and the substituted formazan moiety. To investigate the electronic and structural features of the synthesized regioisomers, Density Functional Theory (DFT) calculations were performed, including frontier molecular orbital (FMO) analysis, molecular electrostatic potential (MEP) mapping, and global reactivity descriptors. The results revealed that the position of the chloro substituent significantly influences orbital distributions, charge separation, and overall reactivity. The ortho isomer exhibited the lowest HOMO–LUMO energy gap and highest electrophilicity, indicating enhanced reactivity. In contrast, the para isomer displayed the greatest chemical hardness and π-delocalization, suggesting superior electronic stability. Molecular docking simulations were carried out against six clinically relevant microbial enzymes, including TEM-1 β-lactamase, AmpC β-lactamase, PBP2a, PBP5, CYP51B, and CYP51. All derivatives exhibited favorable binding energies, supported by diverse stabilizing interactions, including hydrogen bonding, π–π stacking, and hydrophobic contacts. Among them, the p-chloro derivative demonstrated the strongest binding affinities, consistent with its DFT-derived stability and electron distribution. Overall, the combined spectroscopic, computational, and molecular docking results highlight these carbazole–formazan derivatives as promising scaffolds with potential antimicrobial relevance. The findings provide a robust foundation for future biological evaluation and rational structural optimization.

Keywords

Supporting Institution

This research received no specific grant or financial support from any funding agency, institution, or organization.

Ethical Statement

This research does not involve human participants, animal experiments, or any sensitive data requiring ethical approval. All experimental procedures were conducted in accordance with standard chemical laboratory safety practices. No ethical issues are associated with the synthesis, characterization, computational analyses, or molecular docking studies reported in this manuscript. The author declare that ethical approval was not required for this study.

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Details

Primary Language

English

Subjects

Organic Chemical Synthesis

Journal Section

Research Article

Authors

Serkan Öncüoğlu ^*
0000-0001-7900-5231
Türkiye

Publication Date

March 11, 2026

Submission Date

December 2, 2025

Acceptance Date

February 19, 2026

Published in Issue

Year 2026 Number: 2026-1

DOI

https://doi.org/10.18596/jotcsa.1834699

IZ

https://izlik.org/JA86RP73ES

Cite

RIS / Bibtex

APA

Öncüoğlu, S. (2026). Novel Carbazole–Formazan Derivatives: Synthesis, Spectroscopic Characterization, DFT Analysis, and Molecular Docking Studies. Journal of the Turkish Chemical Society Section A: Chemistry, 2026-1, 1-21. https://doi.org/10.18596/jotcsa.1834699

AMA

1.Öncüoğlu S. Novel Carbazole–Formazan Derivatives: Synthesis, Spectroscopic Characterization, DFT Analysis, and Molecular Docking Studies. JOTCSA. 2026;(2026-1):1-21. doi:10.18596/jotcsa.1834699

Chicago

Öncüoğlu, Serkan. 2026. “Novel Carbazole–Formazan Derivatives: Synthesis, Spectroscopic Characterization, DFT Analysis, and Molecular Docking Studies”. Journal of the Turkish Chemical Society Section A: Chemistry, no. 2026-1: 1-21. https://doi.org/10.18596/jotcsa.1834699.

EndNote

Öncüoğlu S (March 1, 2026) Novel Carbazole–Formazan Derivatives: Synthesis, Spectroscopic Characterization, DFT Analysis, and Molecular Docking Studies. Journal of the Turkish Chemical Society Section A: Chemistry 2026-1 1–21.

IEEE

[1]S. Öncüoğlu, “Novel Carbazole–Formazan Derivatives: Synthesis, Spectroscopic Characterization, DFT Analysis, and Molecular Docking Studies”, JOTCSA, no. 2026-1, pp. 1–21, Mar. 2026, doi: 10.18596/jotcsa.1834699.

ISNAD

Öncüoğlu, Serkan. “Novel Carbazole–Formazan Derivatives: Synthesis, Spectroscopic Characterization, DFT Analysis, and Molecular Docking Studies”. Journal of the Turkish Chemical Society Section A: Chemistry. 2026-1 (March 1, 2026): 1-21. https://doi.org/10.18596/jotcsa.1834699.

JAMA

1.Öncüoğlu S. Novel Carbazole–Formazan Derivatives: Synthesis, Spectroscopic Characterization, DFT Analysis, and Molecular Docking Studies. JOTCSA. 2026;:1–21.

MLA

Öncüoğlu, Serkan. “Novel Carbazole–Formazan Derivatives: Synthesis, Spectroscopic Characterization, DFT Analysis, and Molecular Docking Studies”. Journal of the Turkish Chemical Society Section A: Chemistry, no. 2026-1, Mar. 2026, pp. 1-21, doi:10.18596/jotcsa.1834699.

Vancouver

1.Serkan Öncüoğlu. Novel Carbazole–Formazan Derivatives: Synthesis, Spectroscopic Characterization, DFT Analysis, and Molecular Docking Studies. JOTCSA. 2026 Mar. 1;(2026-1):1-21. doi:10.18596/jotcsa.1834699