About

A. S. Borovik is a Distinguished Professor at the University of California, Irvine, within the Department of Chemistry. His research interests encompass Chemical Biology, Inorganic and Organometallic Chemistry, as well as Organic and Synthetic Chemistry. He is actively involved in advancing knowledge in these fields through his faculty position, contributing to the academic and scientific community at UC Irvine.

Research topics

• Chemistry
• Organic chemistry
• Stereochemistry
• Nanotechnology
• Computational chemistry
• Combinatorial chemistry
• Crystallography
• Photochemistry
• Thermodynamics
• Biochemistry

Selected publications

• Forged in O2: Transition metal ions and the rise of aerobic life

  Journal of Inorganic Biochemistry · 2025-11-08

  reviewSenior authorCorresponding
  PublisherDOI

• Proton-Induced Switching of Paramagnetism: Reversible Conversion between a Low and High Spin Co^III Center within a Heterobimetallic Core

  Journal of the American Chemical Society · 2025-01-15 · 6 citations

  articleOpen accessSenior authorCorresponding

  The development of molecular species with switchable magnetic properties has been a long-standing challenge in chemistry. One approach involves binding an analyte, such as protons, to a compound to trigger a change in magnetism. Transition metal complexes have been targeted for this type of magnetic modulation because they can undergo changes in their spin states. However, heterobimetallic complexes have had limited utility because of a lack of ligands that create differentiated structures around each metal center that are often necessary to regulate the electronic and magnetic properties. To circumvent this problem, we have used a tripodal ligand with phosphinic amido groups to prepare a complex with a discrete [CoIII(μ-OH)FeIII] core and an overall system spin of ST = 5/2. Deprotonation readily produces a species with a unique [CoIII(μ-O)FeIII] core and an ST = 1/2 system spin. X-ray diffraction studies, electron paramagnetic resonance spectroscopy, and Mössbauer spectroscopy pinpoint the hexacoordinate CoIII center as the cause of this spin change: the typical SCo = 0 spin state of the CoIII center in the [CoIII(μ-OH)FeIII] complex switches to a rare SCo = 2 spin state in the [CoIII(μ-O)FeIII] analogue; this change turns on antiferromagnetic coupling between the two metal centers. Computational studies link an increase in π bonding within the Co–oxido unit to the change in the CoIII spin state. The conversion is reversible and provides a blueprint for using oxido/hydroxido ligands within a heterobimetallic core to regulate the spin state of a metal site and thus modulate the paramagnetism of a system.

  PublisherOA PDFDOI

• Steric and Electronic Modulation of Iron Complexes via Chalcogen Atom Substitution in the Secondary Coordination Sphere

  Zeitschrift für anorganische und allgemeine Chemie · 2025-12-09

  articleSenior authorCorresponding

  The secondary coordination sphere surrounding metal centers has been shown to have a regulatory effect on the structure and function of metal complexes. In this study, we report the preparation of Fe complexes supported by a new tripodal ligand N , N ′, N ″‐[nitrilotris(ethane‐2,1‐diyl)]tris( P , P ‐diphenylthiophosphinic amido) ([psat] 3– ) that features thiophosphinic (PS) amido groups. This ligand was designed to evaluate the effect of chalcogen substitution on the coordination chemistry of iron complexes when compared to analogous species that have been previously reported with the phosphinic (PO) amido ligand system, N , N ′, N ″‐[nitrilotris(ethane‐2,1‐diyl)]tris( P , P ‐diphenylphosphinic amido) ([poat] 3– ). Although this variation had minimal impact on the structural and electronic properties of Fe(II) centers, their oxidative chemistry was found to be different, which isattributed to change in the chalcogen atoms within the secondary coordination sphere.

  PublisherDOI

• Synthesis, characterization and reactivity of a Mn(III)–hydroxido complex as a biomimetic model for lipoxygenase

  Journal of Inorganic Biochemistry · 2024-06-12 · 4 citations

  articleOpen accessSenior authorCorresponding
  PublisherOA PDFDOI

• VERTICALLY ALIGNED CARBON NANOTUBES GROWN ON HAFNIUM OXIDE: STRUCTURE AND PROPERTIES

  Автометрия · 2024-08-30

  article

  Методом каталитического химического осаждения из газовой фазы впервые выращены массивы вертикально ориентированных углеродных нанотрубок (ВОУНТ) на поверхности Si/HfO2/Fe высотой от 25 до 100 мкм и удельным сопротивлением от 1,5 до 4 Ом · см. Рост ВОУНТ на оксиде гафния наблюдается в интервале температур 625-725 ° C, а при T ≥ 750 ° C не реализуется. При этом температурная зависимость скорости роста ВОУНТ характеризуется величиной ~1,5 эВ. С использованием высокоразрешающей сканирующей электронной микроскопии и спектроскопии комбинационного рассеяния света показано доминирующее присутствие в массиве нанотрубок с диаметрами от 1 до 10 нм. Обнаружено, что нанокристаллизация HfO2 при отжиге подложек затрудняет СЭМ-анализ каталитических частиц Fe, размер которых на поверхности исходного аморфного HfO2 составляет 2-5 нм. Using the catalytic chemical vapor deposition method, VACNT arrays with a height of 25 to 100 μm and a resistivity of 1.5 to 4 Ohm ⋅ cm have been grown for the first time on a Si/HfO2/Fe surface. The growth of VACNTs on hafnium oxide is observed in the temperature range T = 625-725°C, but is not realized at T ≥ 750 °C. In this case, the temperature dependence of the VACNT growth rate is characterized by a value of ~1.5 eV. Using high-resolution scanning electron microscopy and Raman spectroscopy, the dominant presence of nanotubes with diameters from 1 to 10 nm in the array is shown. It is found that nanocrystallization of HfO2 during annealing of substrates complicates the SEM analysis of catalytic Fe particles whose size on the surface of the initial amorphous HfO2 is 2-5 nm.

  PublisherDOI

• Selective oxidation of active site aromatic residues in engineered Cu proteins

  Chemical Science · 2024-11-18 · 5 citations

  articleOpen accessSenior authorCorresponding

  site in particulate methane monooxygenases (pMMOs) and the second sphere aromatic residues in lytic polysaccharide monooxygenases (LPMOs), implicated in the protection against oxidative damage. However, these features are subjects of continued debate. Our work utilizes biotin-streptavidin (Sav) technology to develop artificial metalloproteins (ArMs) that mimic the active sites of natural copper metalloenzymes. By engineering ArMs with aromatic residues within their secondary coordination spheres, we systematically investigate the influence of these residues on Cu reactivity and oxidant activation. We demonstrate that the placement and orientation of tyrosine relative to the Cu cofactor critically affect the oxidation outcomes upon exposure to hydrogen peroxide. A key finding is the interplay between the coordination of an active site asparagine and the incorporation of aromatic residues proximal to the artificial Cu cofactor, which are the only variants where oxidation of an engineered residues is observed. These findings underscore the importance of the secondary coordination sphere in modulating Cu center reactivity, suggest a role for amide coordination in C-H bond activation by pMMOs, and potential inactivation pathways in natural copper enzymes like LPMOs.

  PublisherDOI

• Structure and Properties of Vertically Oriented Carbon Nanotubes Grown on the Hafnium Oxide Surface

  Optoelectronics Instrumentation and Data Processing · 2024-08-01

  article

  Arrays of vertically oriented carbon nanotubes (VOCNTs) with a height from 25 to 100 $$\mu$$ m and a specific resistance from 1.5 to 4 $$\Omega$$ cm have been grown by catalytic chemical vapor deposition on the Si/HfO $${}_{2}$$ /Fe surface for the first time. The growth of VOCNTs on hafnium oxide is observed within a temperature range of $$625{-}725$$ °C and does not occur at $$T\geq 750$$ °C. At the same time, the temperature dependence of the VOCNT growth rate is characterized by a value of $$\sim$$ 1.5 eV. Using high-resolution scanning electron microscopy and Raman spectroscopy, the predominance of nanotubes with diameters from 1 to 10 nm in the array is shown. It has been revealed that HfO $${}_{2}$$ nanocrystallization during the annealing of substrates complicates the SEM analysis of catalytic Fe particles, whose size on the surface of initial amorphous HfO $${}_{2}$$ is $$2{-}5$$ nm.

  PublisherDOI

• Accessing a synthetic Fe^IIIMn^IV core to model biological heterobimetallic active sites

  Chemical Science · 2023-12-27 · 7 citations

  articleOpen accessSenior author

  Characterization of a synthetic mimic for an enzymatic Fe III Mn IV intermediate and its reactivity with phenolic substrates.

  PublisherOA PDFDOI

• Modulation of the Bonding between Copper and a Redox-Active Ligand by Hydrogen Bonds and Its Effect on Electronic Coupling and Spin States

  Journal of the American Chemical Society · 2023-12-27 · 13 citations

  articleOpen accessSenior authorCorresponding

  The exchange coupling of electron spins can strongly influence the properties of chemical species. The regulation of this type of electronic coupling has been explored within complexes that have multiple metal ions but to a lesser extent in complexes that pair a redox-active ligand with a single metal ion. To bridge this gap, we investigated the interplay among the structural and magnetic properties of mononuclear Cu complexes and exchange coupling between a Cu center and a redox-active ligand over three oxidation states. The computational analysis of the structural properties established a relationship between the complexes’ magnetic properties and a bonding interaction involving a dx2–y2 orbital of the Cu ion and π orbital of the redox-active ligand that are close in energy. The additional bonding interaction affects the geometry around the Cu center and was found to be influenced by intramolecular H-bonds introduced by the external ligands. The ability to synthetically tune the d−π interactions using H-bonds illustrates a new type of control over the structural and magnetic properties of metal complexes.

  PublisherOA PDFDOI

• Selective C–H Bond Cleavage with a High-Spin FeIV–Oxido Complex

  Molecules · 2023-06-14 · 4 citations

  articleOpen accessSenior authorCorresponding

  Non-heme Fe monooxygenases activate C–H bonds using intermediates with high-spin FeIV–oxido centers. To mimic these sites, a new tripodal ligand [pop]3− was prepared that contains three phosphoryl amido groups that are capable of stabilizing metal centers in high oxidation states. The ligand was used to generate [FeIVpop(O)]−, a new FeIV–oxido complex with an S = 2 spin ground state. Spectroscopic measurements, which included low-temperature absorption and electron paramagnetic resonance spectroscopy, supported the assignment of a high-spin FeIV center. The complex showed reactivity with benzyl alcohol as the external substrate but not with related compounds (e.g., ethyl benzene and benzyl methyl ether), suggesting the possibility that hydrogen bonding interaction(s) between the substrate and [FeIVpop(O)]− was necessary for reactivity. These results exemplify the potential role of the secondary coordination sphere in metal-mediated processes.

  PublisherOA PDFDOI

Recent grants

• Confining Metal Complexes within Protein Hosts: Models for Metalloprotein Active Sites

  NIH · $2.4M · 2017–2026

• HYDROGEN BONDING CAVITY MOTIFS ABOUT METAL IONS

  NIH · $4.1M · 1994–2015

• NIH Grant R29GM050781

  NIH · $503k · 1999

• The Chemistry of the Later 3d Metals with Terminal Chalcogenido, Imido, and Amido Ligands

  NSF · $287k · 2006–2009

• NIH Grant R01GM058680

  NIH · $663k · 2004

Frequent coauthors

• Michael P. Hendrich

  128 shared

• Joseph W. Ziller

  University of California, Irvine

  122 shared

• Arnold L. Rheingold

  University of California, San Diego

  74 shared

• Victor G. Young

  54 shared

• Rajeev Gupta

  University of Delhi

  46 shared

• Glenn P. A. Yap

  Indiana University Bloomington

  45 shared

• Ethan A. Hill

  University of California, Irvine

  31 shared

• B.S. Hammes

  31 shared

Education

• Ph.D., Chemistry

  University of North Carolina

  1986