About

Elena Jakubikova is an Associate Head for Teaching and a Professor in the Department of Chemistry at NC State University. Her educational background includes a Ph.D. in Chemistry from Colorado State University obtained in 2010, an M.S. in Mathematics from Colorado State University in 2007, a Magister (M.S.) in Physics from Comenius University in Slovakia in 2000, and a postdoctoral position at Los Alamos National Laboratory in 2010. Her primary area of expertise involves computational studies of ground and excited state properties of inorganic compounds, with a focus on understanding light-induced processes such as excited-state electron transfer and nonradiative decay in first-row transition metal complexes. Her research aims to deepen the understanding of these processes, contributing to the fields of inorganic and physical chemistry.

Selected publications

• No Room for Nitrate: Insights into Nitrite Reduction by a Surface‐Conjugated Electrocatalyst

  ChemCatChem · 2026-05-01

  articleOpen accessSenior authorCorresponding

  ABSTRACT The rise in the concentration of anthropogenic nitrogen oxyanions, such as nitrates and nitrites, necessitates the design of efficient nitrate and nitrite reducing electrocatalysts. Herein, we report a detailed computational mechanistic study on a cobalt‐based graphite‐conjugated electrocatalyst GCC‐[Co(DIM)Br 2 ] + (GCC‐Co‐DIM) and its ability to reduce nitrate and nitrite in water. We observed that unlike the molecular CoDIM electrocatalyst, which is active for both nitrate and nitrite reduction, the conjugated congener only reduces nitrite. This is due to a high kinetic barrier associated with the intramolecular electron transfer from the electrocatalyst into the bound nitrate. Our results, however, predict a facile nitrite to NH 3 reduction by the GCC‐Co‐DIM electrocatalyst that proceeds via the amino proton assisted mechanism. Other nitrite reduction pathways (such as ligand‐mediated and hydroxyl transfer) were ruled out due to higher kinetic barriers. The highly exergonic nature of the nitrite to NH 3 potential energy surface suggests a selective reduction to ammonia. This is consistent with our experimentally determined Faradaic efficiencies. In agreement with DFT analysis of the mechanisms, in situ X‐ray spectroscopy has shown that while under catalytic conditions the cobalt ions in both catalysts are reduced to Co(II), the observed reactive intermediates have different structures. Overall, the insights provided by this study can serve as a guide for the design of better electrocatalysts.

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• Tuning the ²LMCT Deactivation of Cyclometalated Iron Carbene Complexes with Electronic Substituent Effects

  Chemistry - A European Journal · 2025-07-25 · 4 citations

  articleOpen accessCorresponding

  Abstract Fe III complexes based on the [Fe III (ImP) 2 ] + motif (ImP = bis(2,6‐bis(3‐methylimidazol‐2‐ylidene‐1‐yl)phenylene)), where the ligand contains both carbene and cyclometalated moieties, are a promising class of photoactive materials made from this abundant metal. In this work, it is shown that bromo or furanyl substituents attached to the cyclometalating moiety of the ImP ligands stabilize the 2 LMCT excited state to very different extent resulting in opposing effects on the 2 LMCT lifetime. For [Fe III (ImPBr) 2 ] + , the lifetime (255 ps) of its moderately stabilized 2 LMCT state (1.85 eV) is slightly increased compared to the parent complex (1.90 eV, 240 ps) pointing to an increased barrier for deactivation via the 4 MC state and enabling applications as photoredox catalyst. In contrast, the 2 LMCT energy of [Fe III (ImPFur) 2 ] + is lowered substantially to a value of 1.63 eV due to the extended π‐system of the ligands and the reduced energy gap favors internal conversion directly to the ground state resulting in a considerably reduced 2 LMCT lifetime of 59 ps. These findings have general implications for design of ligand modifications aiming at extended LMCT lifetimes and/or modified ground and excited state potentials.

  PublisherOA PDFDOI

• Illuminating the mechanistic impacts of an Fe-quaterpyridine functionalized crystalline poly(triazine imide) semiconductor for photocatalytic CO ₂ reduction

  Inorganic Chemistry Frontiers · 2025-01-01 · 2 citations

  articleOpen access

  Attachment of a Fe-quaterpyridine catalyst to carbon nitride produces a photocatalyst that selectively reduces CO 2 to CO in water.

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• Mechanistic Insights into Visible-Light-Induced ATRA Reactions Powered by the Symbiotic Relationship between Cu(II)/Cu(I) Phenanthroline Complexes

  ACS Catalysis · 2025-08-26

  article

  As photoredox catalysis continues to yield promising chemical transformations, there is an increased need to understand how specific photocatalysts function to improve reaction efficiencies while expanding their scope. Copper-phenanthroline-based photocatalysts such as CuII(dap)Cl2 (dap = 2,9-di(p-anisyl)-1,10-phenanthroline) and [CuI(dap)2]Cl were both found to be equally capable of olefin activation through electrophilic atom transfer radical addition (ATRA) reactions. Although these molecular catalysts have proven successful, many intermediates suggested in the proposed catalytic cycles have never been detected. One undetermined aspect in this chemistry is related to how one equivalent of CuII(dap)Cl2 generates half of an equivalent of [CuI(dap)2]+ during the photocatalytic sequence. To this end, we initially used more synthetically accessible model systems, namely, [CuI(dpp)2]Cl and CuII(dpp)Cl2 (dpp = 2,9-diphenyl-1,10-phenanthroline), to glean detailed mechanistic insights into this unusual symbiotic relationship. We directly detected several intermediates involved in the ATRA photocatalytic cycle using these model chromophores in conjunction with electronic spectroscopy, infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry, electronic structure calculations, EPR spin-trap experiments, and 1H NMR spectroscopy. We found that the unique ligand lability and coordinating properties of acetonitrile enable both the in situ oxidation of [CuI(dpp)2]+ by tosyl chloride into CuII(dpp)Cl2 and the visible-light-induced homolysis of the CuII–Cl bond, which initiates the conversion to the CuI species [CuI(dpp)2][CuICl2]. The combined findings from the present study of the catalytic cycle demonstrate that the symbiotic relationship between CuII(dpp)Cl2 and [CuI(dpp)2]+, as well as between CuII(dap)Cl2 and [CuI(dap)2]+, is the critical factor enabling the ATRA photoreaction by departing from either photocatalyst.

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• Fullerene Promotes CO₂ Reduction to Methanol by a Cobalt(II) Phthalocyanine Electrocatalyst

  Inorganic Chemistry · 2025-06-11 · 6 citations

  articleSenior authorCorresponding

  Heterogenization of molecular electrocatalysts offers an attractive way to improve the catalytic selectivity and efficiency of CO2 conversion to liquid fuels. Herein, we employ density functional theory to compare the mechanism of CO2RR by a cobalt(II) tetra(amino)phthalocyanine (Co(II)Pc(NH2)4) electrocatalyst with and without the presence of fullerene support. Our DFT calculations suggest that the CO2 reduction mechanism is initiated by a metal-based electron reduction followed by subsequent CO2 nucleophilic addition, electron transfer, proton transfer, water dissociation, and proton-coupled electron transfer steps that lead to CO and methanol formation. We show that graphitic interactions between the Co(II)Pc(NH2)4 electrocatalyst and C60 support selectively improve the CO2RR to methanol at mild potentials. The undesirable hydrogen evolution reaction (HER) was also investigated for both electrocatalysts and proceeds via the protonation of the cobalt metal center over the nitrogen atom in the inner ring. The competition between the HER and the CO2RR was improved in favor of CO and methanol formation using the Co(II)Pc(NH2)4@C60 electrocatalyst. Overall, our results suggest C60 as a promising graphitic support for molecular electrocatalysts integration for CO2 catalysis.

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• A Rhenium <i>Bis</i>- tetramethylphenanthroline Catalyst for CO₂ Reduction to Formate

  Energy & Fuels · 2025-06-18 · 2 citations

  articleCorresponding

  Catalytic CO2 reduction reactions featuring high selectivity toward formate are relatively rare. In some homogeneous molecular CO2-reducing electrocatalysis, using triethylamine (TEA) and isopropanol (IPA) as additives improves catalytic performance in producing formate. In this work, we investigate whether the rhenium(I) bis-diimine dicarbonyl complexes, cis-[Re(N^N)2(CO)2]+, where N^N is 2,2’-bipyridine ([1]+) or 3,4,7,8-tetramethyl-1,10-phenanthroline ([2]+), are capable of electrocatalytically reducing CO2 to formate in acetonitrile containing TEA and IPA. Catalyst [1]+ was ineffective at CO2 reduction, yielding formate quantities comparable to those produced in experiments without the catalyst. Catalyst [2]+, however, is a promising electrocatalyst for the CO2 reduction reaction in the presence of TEA and IPA, with formate being produced in millimolar concentrations (10.5 mM), as detected by 1H NMR spectroscopy after 6 h electrolysis (formate Faradaic efficiency = 11%, with the major balance going to H2). Upon more detailed examination, [2]+ exhibited a turnover frequency (TOF) of 12 s–1 for formate, comparable to other leading molecular catalysts that competently execute this reduction. Combinations of spectroscopy, electrochemistry, and theory were used to better understand the mechanism of CO2 reduction by [2]+. Fourier transform infrared spectroelectrochemical (FTIR-SEC) data provided no evidence for CO ligand dissociation or substitution upon one- and two-electron reduction of [2]+, suggesting that a mechanism distinct from one that is metal-hydride-based is operative in catalysis. Computational studies guide mechanistic investigations toward the proposed formation of a hydrophenanthroline-based intermediate responsible for hydride transfer to CO2 and electrocatalytic formate production from [2]+.

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• Iron <i>N</i>-Heterocyclic Carbene Photoactive Complexes with Rigid Phenylethynyl Substituents as Ligand π-System Extensions

  Inorganic Chemistry · 2025-06-09

  articleOpen accessCorresponding

  MLCT energies and lifetimes.

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• Kinetic trapping for the production of a long-lived ³ MLCT excited state in Fe( <scp>ii</scp> ) complexes

  Chemical Communications · 2025-01-01 · 1 citations

  articleCorresponding

  The formation of long-lived metal-to-ligand charge-transfer (MLCT) excited states in iron complexes has been challenging, but is critical for the development of affordable sensitizers for solar energy conversion. Iron complexes with extended aromatic ligands were prepared and their excited state properties are consistent with an MLCT state.

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• Photophysical Characterization and Excited State Dynamics of Decamethylruthenocenium

  The Journal of Physical Chemistry A · 2025-02-04 · 1 citations

  article

  Understanding the landscape of molecular photocatalysis is vital to enable efficient conversion of feedstock molecules to targeted products and inhibit off-cycle reactivity. In this study, the light-promoted reactivity of [RuCp*2]+ was explored via electronic structure, photophysical, and photostability studies and the reactivity of [RuCp*2]+ within a photocatalytic hydrogen evolution cycle was assessed. TD-DFT calculations support the assignment of a low-energy ligand-to-metal charge transfer transition (LMCT) centered at 500 nm, where an electron from a ligand-based orbital delocalized across both Cp* ligands is promoted to a dx2–y2-based β-LUMO orbital. Upon irradiating the LMCT absorption feature, ultrafast transient absorption spectroscopy measurements show that an initial excited state (τ1 = 1.3 ± 0.1 ps) is populated, which undergoes fast relaxation to a longer-lived state (τ2 = 12.0 ± 0.9 ps), either via internal conversion or vibrational relaxation. Despite the short-lived nature of these excited states, bulk photolysis of [RuCp*2]+ demonstrates that photochemical conversion to decomposition products is possible upon prolonged illumination. Collectively, these studies reveal that [RuCp*2]+ undergoes light-driven decomposition, highlighting the necessity to construct molecular photocatalytic systems resistant to off-cycle reactivity in both the ground and excited states.

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• Modulating Excited State Lifetimes in Cu(I) Complexes: The Role of Surface Binding Motifs

  ACS Applied Energy Materials · 2025-06-18 · 3 citations

  articleCorresponding

  Many transition metal coordination complexes are known to undergo a structural change in response to a stimulus, like light, which can have a debilitating impact on properties of interest (e.g., quantum yield, stability, reactivity, etc.). This is particularly true for Cu(I) coordination complexes that suffer from short, excited-state lifetimes due to D2d to D2 distortion and solvent coordination. Here, we investigate the impact of strategic surface binding and the role of the surface binding motif on the excited state lifetime of Cu(I) complexes with carboxylate-functionalized N-phenylpyridin-2-ylmethanimine ligands. Relative to the solution, the excited state lifetime for the ZrO2-bound complexes increases 7-fold when either one ligand is bound or both ligands are bound through a flexible linker but 17-fold when both ligands are rigidly bound to the surface. With support from theoretical calculations, we attribute the dramatic increase in lifetime for the latter to the rigid binding strategy inhibiting the planarizing distortion and possible quenching via solvent coordination. These results lend further support to the idea that molecular immobilization via strategic surface binding is an effective strategy for inhibiting undesired molecular distortion.

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Labs

• Elena Jakubikova LabPI