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Dr. Suman Patra is a postdoctoral researcher in the Department of Chemistry at Stanford University, working under the mentorship of Prof. Edward I. Solomon. His research focuses on uncovering the mechanistic intricacies of non-coupled binuclear copper (NBC) enzymes, particularly tyramine β-monooxygenase (TBM), which catalyzes oxygen activation and selective C–H bond hydroxylation.His work integrates high-resolution spectroscopy, transient kinetics, and protein biochemistry to probe the formation, structure, and reactivity of short-lived copper-oxygen intermediates. As part of this effort, he performs cell culture and protein purification, enabling the isolation of active, recombinant copper enzymes for detailed spectroscopic and mechanistic studies. Through a multi-spectroscopic approach, primarily UV-Vis, CD, MCD, EXAFS, EPR, resonance Raman, and stopped-flow absorption spectroscopy, he investigates how the geometric and electronic structure of the active sites modulate reactivity and enable O₂ activation without direct Cu–Cu coupling.
Dr. Patra earned his Ph.D. in Chemistry from the Indian Association for the Cultivation of Science (IACS), Kolkata, under the supervision of Prof. Abhishek Dey, where he developed iron porphyrin-based electrocatalysts for the selective reduction of CO₂. His research emphasized mechanistic analysis using electrochemical methods coupled with in situ spectro-electrochemistry to monitor redox transitions and catalytic intermediates under applied potentials. These studies were complemented by density functional theory (DFT) calculations, which he used to model key intermediates, protonation pathways, and redox energetics, thereby providing molecular-level insight into how second-sphere interactions and ligand environments influence catalytic behaviour. His integrative experimental–computational approach provided a detailed understanding of structure-function relationships in multi-electron CO₂ reduction.
The mechanistic perspective and technical skillset developed during his doctoral work, particularly in combining spectroscopy, electrochemistry, and computation, now form the foundation of his postdoctoral research. His current studies extend those same principles to more complex metalloenzyme systems, addressing similar core questions about the role of electronic structure, metal-ligand coordination, and local environment in controlling reactivity. His long-term goal is to bridge synthetic and biological catalysis through a mechanistic lens, contributing to the development of efficient, selective systems for small-molecule activation and sustainable energy transformations.
Dr. Patra received his M.Sc. in Chemistry from the Indian Institute of Technology (IIT) Guwahati after qualifying the national IIT-JAM examination and completed his B.Sc. in Chemistry at St. Xavier’s College, Kolkata. Over the course of his academic training, he has cultivated a multidisciplinary research identity that spans coordination chemistry, spectroscopy, electrochemical catalysis, and theoretical modelling. His scientific vision centres on using spectroscopic and computational insight to guide the rational design of catalysts for environmentally relevant redox chemistry.

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  • Functional Nonheme Diiron(II) Complexes Catalyze the Direct Reduction of Nitrite to Nitric Oxide in Relevance to the Diiron Protein YtfE INORGANIC CHEMISTRY Atta, S., Mandal, A., Patra, S., Majumdar, A. 2025; 64 (15): 7726-7745

    Abstract

    The present work reports the functional modeling chemistry of YtfE, which features a nonheme diiron active site and mediates the direct reduction of NO2- to NO. The model complex, [Fe2(HPTP)Cl2]1+ (1), reduces NO2- to NO in a 100% yield within 12 h and generates [Fe4(HPTP)2(μ-O)3(μ-OH)]3+ (2). Similar to YtfE, the reaction involves stepwise oxidation of two Fe(II) centers and product (NO) inhibition, of which the latter produces [Fe2(HPTP)(NO)2Cl2]1+ (3). Complex 3 could also be synthesized by the reaction of [Fe2(HPTP)(NO)2(ClO4)]2+ (4) and chloride. Complex 1 catalyzes the reduction of NO2- to NO in the presence of PhS-, albeit with a low TON of 5, due to the formation of an insoluble product, [Fe2(HPTP)(μ-SPh)Cl2] (5). Another model complex [Fe2(HPTP)(OPr)]1+ (6), reduced NO2- to NO in an 80% yield after 24 h, generated [Fe2(HPTP)(OPr)(NO)2]1+ (7), and offered a TON of 19. The third model complex, [Fe2(HPTP)(ClO4)2]1+ (8), could reduce NO2- to NO in a 100% yield but only after 48 h. A comparison of these results establishes that easy oxidation of the Fe(II) centers, easy accessibility of the Fe(II) centers for the coordination of NO2-, and easy release of NO from the in situ generated dinitrosyl diiron complex increase the efficiency of the functional model complexes of YtfE.

    View details for DOI 10.1021/acs.inorgchem.5c00753

    View details for Web of Science ID 001460205900001

    View details for PubMedID 40180608

  • Electrostatic versus Hydrogen Bonding Control of Selectivity in CO<sub>2</sub> Reduction by Iron Porphyrins ACS CATALYSIS Ghosh, S., Patra, S., Bisoi, A., Ghosh, S., Maurya, N., Das, A., Singh, P., Dey, A. 2025; 15 (5): 3595-3610

    View details for DOI 10.1021/acscatal.5c00170

    View details for Web of Science ID 001421785300001

  • Synthesis of ethane from CO<sub>2</sub> by a methyl transferase-inspired molecular catalyst PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Patra, S., Dinda, S., Ghosh, S., Roy, T., Dey, A. 2025; 122 (2): e2417764122

    Abstract

    Molecular catalysts with a single metal center are reported to reduce CO2 to a wide range of valuable single-carbon products like CO, HCOOH, CH3OH, etc. However, these catalysts cannot reduce CO2 to two carbon products like ethane or ethylene and the ability to form C-C from CO2 remains mostly limited to heterogeneous material-based catalysts. We report a set of simple iron porphyrins with pendant thiol group can catalyze the reduction of CO2 to ethane (C2H6) with H2O as the proton source with a Faradaic yield >40% the rest being CO. The mechanism involves a CO2-derived methyl group transfer to the pendant thiol akin to the proposal forwarded for methyl transferases and a follow-up C-C bond formation of the thioether thus formed and a Fe(II)-CH3 species generated by the reduction of a second molecule of CO2. The availability of a "parking space" in the molecular framework for the first reduced C1 product from CO2 reduction allows C-C bond formation resulting in a unique case where a component of natural gas can be generated from direct electrochemical reduction of CO2.

    View details for DOI 10.1073/pnas.2417764122

    View details for Web of Science ID 001413574500001

    View details for PubMedID 39772746

    View details for PubMedCentralID PMC11745356

  • Hydrogen Oxidation by Bioinspired Models of [FeFe]-Hydrogenase ACS ORGANIC & INORGANIC AU Nayek, A., Poria, R., Ahmed, M., Patra, S., Dey, S., Dey, A. 2024; 5 (2): 105-116

    Abstract

    Synthetic azadithiolate-bridged diiron clusters serve as structural analogues of the active site of [FeFe]-hydrogenases. Recently, an o-alkyl substitution of aniline-based azadithiolate bridge allowed these synthetic models to both oxidize H2 and reduce H+, i.e., bidirectional catalysis. Hydrogen oxidation by synthetic analogues of hydrogenases is rare, and even rarer is the ability of diiron hexacarbonyls to oxidize H2. A series of synthetic azadithiolate-bridged biomimetic diiron hexacarbonyl complexes are synthesized where the substitution in the para position of the ortho-methyl aniline in the azadithiolate bridge is systematically varied between electron-withdrawing and electron-donating groups to understand factors that control H2 oxidation by diiron hexacarbonyl analogues of [FeFe]-hydrogenases. The results show that the substituents in the para position of the ortho-ethyl aniline affect the electronic structure of the azadithiolate bridge as well as that of the diiron cluster. The electron-withdrawing -NO2 substituent results in faster H2 oxidation relative to that of a -OCH3 substituent.

    View details for DOI 10.1021/acsorginorgau.4c00073

    View details for Web of Science ID 001369503200001

    View details for PubMedID 40190389

    View details for PubMedCentralID PMC11969278

  • Reduction of Nitrite in an Iron(II)-Nitrito Compound by Thiols and Selenol Produces Dinitrosyl Iron Complexes via an {FeNO}<SUP>7</SUP> Intermediate INORGANIC CHEMISTRY Karmakar, S., Patra, S., Halder, R., Karmakar, S., Majumdar, A. 2024; 63 (49): 23202-23220

    Abstract

    Reaction of an Fe(II) complex, [Fe(6-COO--tpa)]1+ (1), with PhE- and NO2- produced [Fe(6-COO--tpa)(EPh)] (E = S, 2a; Se, 3) and [Fe(6-COO--tpa)(κ2-O,O'-NO2)] (4), respectively (6-COOH-tpa is bis(2-pyridylmethyl)(6-carboxyl-2-pyridylmethyl)amine). Treatment of 4 with 2 equiv of PhEH (E = S, Se) produced NO in ∼40% yields, respectively, along with 1 and the DNICs, [Fe(EPh)2(NO)2]1- (E = S, Se). Treatment of 4 with excess PhEH produced NO in similar yields, while 4 was converted to the same DNICs and 2a/3 (instead of 1). The DNICs have been proposed to be generated via the reaction of PhE- with an in situ generated, unstable {FeNO}7 intermediate, [Fe(6-COO--tpa)(NO)]1+ (6), which has also been synthesized separately. Compound 6 reacts with PhS- to generate [Fe(SPh)2(NO)2]1-, thus supporting the proposed reaction pathway. Finally, while the treatment of two unique compounds, featuring inbuilt proton sources, [Fe(6-COO--tpa)(S-C6H4-p-COOH)] (7) and [Fe(6-COO--tpa)(S-C6H4-o-OH)] (8), with 0.5 and 1 equiv of NO2- could produce NO only in 8-26% yields, treatment of 4 with HS-C6H4-p-COOH and HS-C6H4-o-OH produced NO in much higher yields (65-77%). The combined results delineated the importance of coordination of NO2- for the proton-assisted reduction of NO2- to generate NO.

    View details for DOI 10.1021/acs.inorgchem.4c03555

    View details for Web of Science ID 001360666200001

    View details for PubMedID 39569438

  • Silver-Containing Metallo Hydrogel as a Nanocatalyst for Hydrogen Evolution ACS APPLIED POLYMER MATERIALS Mondal, T., Patra, S., Mondal, B., Ghosh, P., Hamley, I. W., Banerjee, A. 2024; 6 (18): 11383-11391

    View details for DOI 10.1021/acsapm.4c01965

    View details for Web of Science ID 001315137300001

  • Reactivity of Thiolate and Hydrosulfide with a Mononuclear {FeNO}<SUP>7</SUP> Complex Featuring a Very High N-O Stretching Frequency INORGANIC CHEMISTRY Karmakar, S., Patra, S., Pramanik, K., Adhikary, A., Dey, A., Majumdar, A. 2024; 63 (19): 8537-8555

    Abstract

    Synthesis, characterization, electronic structure, and redox reactions of a mononuclear {FeNO}7 complex with a very high N-O stretching frequency in solution are presented. Nitrosylation of [(LKP)Fe(DMF)]2+ (1) (LKP = tris((1-methyl-4,5-diphenyl-1H-imidazol-2-yl)methyl)amine) produced a five-coordinate {FeNO}7 complex, [(LKP)Fe(NO)]2+ (2). While complex 2 could accommodate an additional water molecule to generate a six-coordinate {FeNO}7 complex, [(LKP)Fe(NO)(H2O)]2+ (3), the coordinated H2O in 3 dissociates to generate 2 in solution. The molecular structure of 2 features a nearly linear Fe-N-O unit with an Fe-N distance of 1.744(4) Å, N-O distance of 1.162(5) Å, and

    View details for DOI 10.1021/acs.inorgchem.3c03274

    View details for Web of Science ID 001227988400001

    View details for PubMedID 38679874

  • Outer-Coordination-Sphere Interaction in a Molecular Iron Catalyst Allows Selective Methane Production from Carbon Monoxide ACS CATALYSIS Patra, S., Bhunia, S., Ghosh, S., Dey, A. 2024; 14 (10): 7299-7307

    View details for DOI 10.1021/acscatal.3c06112

    View details for Web of Science ID 001228451700001

  • Kinetic isotope effect offers selectivity in CO<sub>2</sub> reduction CHEMICAL COMMUNICATIONS Patra, S., Atta, S., Ghosh, S., Majumdar, A., Dey, A. 2024; 60 (36): 4826-4829

    Abstract

    A binuclear Ni complex with N,O donors catalyzes CO2 reduction via its Ni(I) state. The product distribution when H2O is used as a proton source shows similar yields for CO, HCOOH and H2. However, when D2O is used, the product distribution shows a ∼65% selectivity for HCOOH. In situ FTIR indicates that the reaction involves a Ni-COO* and a Ni-CO intermediate. Differences in H/D KIEs on different protonation pathways determine the selectivity of CO2 reduction.

    View details for DOI 10.1039/d3cc06336d

    View details for Web of Science ID 001202417800001

    View details for PubMedID 38618750

  • Facile electrocatalytic proton reduction by a [Fe-Fe]-hydrogenase bio-inspired synthetic model bearing a terminal CN<SUP>-</SUP> ligand CHEMICAL SCIENCE Nayek, A., Dey, S., Patra, S., Rana, A., Serrano, P. N., George, S. J., Cramer, S. P., Dey, S., Dey, A. 2024; 15 (6): 2167-2180

    Abstract

    An azadithiolate bridged CN- bound pentacarbonyl bis-iron complex, mimicking the active site of [Fe-Fe] H2ase is synthesized. The geometric and electronic structure of this complex is elucidated using a combination of EXAFS analysis, infrared and Mössbauer spectroscopy and DFT calculations. The electrochemical investigations show that complex 1 effectively reduces H+ to H2 between pH 0-3 at diffusion-controlled rates (1011 M-1 s-1) i.e. 108 s-1 at pH 3 with an overpotential of 140 mV. Electrochemical analysis and DFT calculations suggests that a CN- ligand increases the pKa of the cluster enabling hydrogen production from its Fe(i)-Fe(0) state at pHs much higher and overpotential much lower than its precursor bis-iron hexacarbonyl model which is active in its Fe(0)-Fe(0) state. The formation of a terminal Fe-H species, evidenced by spectroelectrochemistry in organic solvent, via a rate determining proton coupled electron transfer step and protonation of the adjacent azadithiolate, lowers the kinetic barrier leading to diffusion controlled rates of H2 evolution. The stereo-electronic factors enhance its catalytic rate by 3 order of magnitude relative to a bis-iron hexacarbonyl precursor at the same pH and potential.

    View details for DOI 10.1039/d3sc05397k

    View details for Web of Science ID 001139642300001

    View details for PubMedID 38332837

    View details for PubMedCentralID PMC10848691

  • Electrocatalytic production of hydrogen using nickel complexes with tridentate N3 ligands CATALYSIS TODAY Patra, S., Das, A., Bhunia, S., Rajeev, A., Sankaralingam, M. 2023; 423

    View details for DOI 10.1016/j.cattod.2022.12.003

    View details for Web of Science ID 001063382600001

  • Silver nanostructure-modified graphite electrode for in-operando SERRS investigation of iron porphyrins during high-potential electrocatalysis JOURNAL OF CHEMICAL PHYSICS Chattopadhyay, S., Samanta, S., Sarkar, A., Bhattacharya, A., Patra, S., Dey, A. 2023; 158 (4): 044201

    Abstract

    In-operando spectroscopic observation of the intermediates formed during various electrocatalytic oxidation and reduction reactions is crucial to propose the mechanism of the corresponding reaction. Surface-enhanced resonance Raman spectroscopy coupled to rotating disk electrochemistry (SERRS-RDE), developed about a decade ago, proved to be an excellent spectroscopic tool to investigate the mechanism of heterogeneous oxygen reduction reaction (ORR) catalyzed by synthetic iron porphyrin complexes under steady-state conditions in water. The information about the formation of the intermediates accumulated during the course of the reaction at the electrode interface helped to develop better ORR catalysts with second sphere residues in the porphyrin rings. To date, the application of this SERRS-RDE setup is limited to ORR only because the thiol self-assembled monolayer (SAM)-modified Ag electrode, used as the working electrode in these experiments, suffers from stability issues at more cathodic and anodic potential, where H2O oxidation, CO2 reduction, and H+ reduction reactions occur. The current investigation shows the development of a second-generation SERRS-RDE setup consisting of an Ag nanostructure (AgNS)-modified graphite electrode as the working electrode. These electrodes show higher stability (compared to the conventional thiol SAM-modified Ag electrode) upon exposure to very high cathodic and anodic potential with a good signal-to-noise ratio in the Raman spectra. The behavior of this modified electrode toward ORR is found to be the same as the SAM-modified Ag electrode, and the same ORR intermediates are observed during electrochemical ORR. At higher cathodic potential, the signatures of Fe(0) porphyrin, an important intermediate in H+ and CO2 reduction reactions, was observed at the electrode-water interface.

    View details for DOI 10.1063/5.0136333

    View details for Web of Science ID 000923569100005

    View details for PubMedID 36725507

  • Bioinorganic Chemistry on Electrodes: Methods to Functional Modeling JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Nayek, A., Ahmed, M., Samanta, S., Dinda, S., Patra, S., Dey, S., Dey, A. 2022; 144 (19): 8402-8429

    Abstract

    One of the major goals of bioinorganic chemistry has been to mimic the function of elegant metalloenzymes. Such functional modeling has been difficult to attain in solution, in particular, for reactions that require multiple protons and multiple electrons (nH+/ne-). Using a combination of heterogeneous electrochemistry, electrode and molecule design one may control both electron transfer (ET) and proton transfer (PT) of these nH+/ne- reactions. Such control can allow functional modeling of hydrogenases (H+ + e- → 1/2 H2), cytochrome c oxidase (O2 + 4 e- + 4 H+ → 2 H2O), monooxygenases (RR'CH2 + O2 + 2 e- + 2 H+ → RR'CHOH + H2O) and dioxygenases (S + O2 → SO2; S = organic substrate) in aqueous medium and at room temperatures. In addition, these heterogeneous constructs allow probing unnatural bioinspired reactions and estimation of the inner- and outer-sphere reorganization energy of small molecules and proteins.

    View details for DOI 10.1021/jacs.2c01842

    View details for Web of Science ID 000804699500002

    View details for PubMedID 35503922

https://orcid.org/0000-0003-4572-614X