About

George Christou is a University Distinguished Professor and Drago Chair at the Department of Chemistry at the University of Florida. His research focuses on the synthetic and physical-inorganic chemistry of transition metals and lanthanides, with applications in coordination chemistry, supramolecular chemistry, and nanoscale magnetic and quantum materials. He was a pioneer in the magnetic phenomenon of single-molecule magnetism, which involves molecules functioning as nanoscale magnets. His group has worked in areas including the supramolecular chemistry of magnetic molecules and their quantum physics properties, such as exchange-biased quantum tunneling of the magnetization vector, quantum superposition, and entanglement states, which are relevant to quantum-based technologies. Additionally, his research involves the 'bottom-up' synthesis of ultra-small nanoparticles of important metal oxides, known as molecular nanoparticles.

Research topics

• Chemistry
• Organic chemistry
• Inorganic chemistry
• Nanotechnology
• Materials science
• Crystallography
• Chemical engineering
• Photochemistry
• Polymer chemistry

Selected publications

• Cybersecurity and cyber defence

  Edward Elgar Publishing eBooks · 2025-05-13

  book-chapter1st authorCorresponding

  Since the EU published its first cybersecurity strategy in 2013, it has evolved rapidly into a purposeful agent in the cyber domain through variegated governance. Dual economic and security logics in the contemporary context have underpinned the EU's approach. Several revisions of its cybersecurity strategy in 2017 and 2020, particularly in the latter, included aspirations to establish resilience, technological sovereignty, and leadership, as well as building operational capacity to prevent, deter, and respond, and to advance the goal of a global and open cyberspace. This chapter charts the EU's journey as an agent in cyber governance and shows how cybersecurity has been shaped by recourse to soft and hard law. Cyber defence, characterized by intergovernmental coordination, shows how multiple crises and an increasingly contested world order have led to a more intensive transgovernmental mode and accelerated the EU's commitment to deepen and enhance its cyber defence policy prerogatives.

  PublisherDOI

• Mixed‐Valence Manganese Carboxylate Clusters, {Mn^III₆Mn^II₄}, {Mn^III₇Mn^II₅Na}, and {Mn^III₇Mn^II₅}, Derived from the Combined Use of Di‐2‐pyridyl Ketone with Selected Aliphatic Diols

  European Journal of Inorganic Chemistry · 2024-01-19 · 2 citations

  articleOpen access

  Abstract Three new polynuclear clusters with the formulae [Mn 10 O 4 (OH)(OMe){(py) 2 C(O) 2 } 2 {(py) 2 C(OMe)(O)} 4 (MeCO 2 ) 6 ](ClO 4 ) 2 ( 1 ), Na[Mn 12 O 2 (OH) 3 (OMe){(py) 2 C(O) 2 } 6 {(py) 2 C(OH)(O)} 2 (MeCO 2 ) 2 (H 2 O) 10 ](ClO 4 ) 8 ( 2 ) and [Mn 12 O 4 (OH) 2 {(py) 2 C(O) 2 } 6 {(py) 2 C(OMe)(O)}(MeCO 2 ) 3 (NO 3 ) 3 (H 2 O)(DMF) 2 ](NO 3 ) 2 ( 3 ) were prepared from the combination of di‐2‐pyridyl ketone, (py) 2 CO, with the aliphatic diols (1,3‐propanediol (pdH 2 ) or 1,4‐butanediol (1,4‐bdH 2 )) in Mn carboxylate chemistry. The reported compounds do not include the aliphatic diols employed in this reaction scheme; however, their use is essential for the formation of 1 – 3 . The crystal structures of 1 – 3 are based on multilayer cores which, to our knowledge, are reported for the first time in Mn cluster chemistry. Direct current ( dc ) magnetic susceptibility studies showed the presence of dominant antiferromagnetic exchange interactions within 1 – 3 . Alternating current ( ac ) magnetic susceptibility studies revealed the presence of out‐of‐phase signals below 3.0 K for 2 and 3 indicating the slow relaxation of the magnetization vector, characteristic of single‐molecule magnets; the U eff value of 2 was found to be 23 K and the preexponential factor τ 0 ~7.6×10 −9 s.

  PublisherOA PDFDOI

• A [Mn₈] Defective Supertetrahedron T3 and Its Dimeric [Mn₁₆] Analogue

  Crystal Growth & Design · 2024-10-09

  articleOpen access

  to stabilize high nuclearity 3d metal clusters based on polynuclear building blocks.

  PublisherDOI

• CCDC 2282175: Experimental Crystal Structure Determination

  The Cambridge Structural Database · 2023-10-26

  datasetOpen access

  An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  PublisherDOI

• Synthetic Factors Determining the Curvature and Nuclearity of the Giant Mn₇₀ and Mn₈₄ Clusters with a Torus Structure of ∼4 nm Diameter

  Inorganic Chemistry · 2023-04-04 · 12 citations

  articleSenior authorCorresponding

  New members of the Mn70 and Mn84 torus-like cluster family have been prepared from a hybrid comproportionation–alcoholysis reaction of [Mn12O12(O2CR)16(H2O)4] in alcohol in the presence of R′CO2H with NnBuMnO4 or MnII salts as initiators. Reactions using MeCO2H in nPrOH or nBuOH gave [Mn70O60(O2CMe)70(OnPr)20(nPrOH)18.5(H2O)21.5] (3) and [Mn70O60(O2CMe)70(OH)3(OnBu)17(nBuOH)7.5(H2O)32.5] (4), respectively, whereas EtCO2H in nPrOH gave [Mn84O72(O2CEt)84(OnPr)24(nPrOH)16(H2O)32] (5). They consist of alternating near-linear [Mn3(μ3-O)4]+ and distorted-cubane [Mn4(μ3-O)2(μ3-OR)2]6+ units bridged by syn,syn-μ-RCO2– and μ3-O2– groups and overall are [Mn14]5 and [Mn14]6 oligomers, the repeating unit containing two Mn3 and two Mn4 units. 3/4/5 possess external diameters (including organic ligands) of 4.0/4.1/4.6 nm, respectively, and crystallize as supramolecular nanotubes but with different packing arrangements. Considering all Mn70/Mn84 tori now available, we conclude that the Mn70 vs Mn84 nuclearity is determined by the relative bulk of the carboxylates vs the alkoxides, their increasing bulk favoring Mn84 and Mn70, respectively, with carboxylates larger than acetate giving Mn84. Alternating current (ac) magnetic susceptibility studies revealed frequency-dependent χ″M signals below ∼2.4 K, indicating 3–5 to be new members of the giant [Mn14]n torus family of giant single-molecule magnets (SMMs), in which Mn84 and Mn70 are the largest homometallic Mn/O clusters and SMMs to date.

  PublisherDOI

• CCDC 2226086: Experimental Crystal Structure Determination

  The Cambridge Structural Database · 2023-04-09

  datasetOpen accessSenior author

  An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  PublisherDOI

• CCDC 2276660: Experimental Crystal Structure Determination

  The Cambridge Structural Database · 2023-12-12

  datasetOpen accessSenior author

  An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  PublisherDOI

• CCDC 2276685: Experimental Crystal Structure Determination

  The Cambridge Structural Database · 2023-12-12

  datasetOpen accessSenior author

  An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  PublisherDOI

• Search for Toroidal Ground State and Magnetoelectric Effects in Molecular Spin Triangles with Antiferromagnetic Exchange

  The Journal of Physical Chemistry A · 2023-04-24 · 3 citations

  article

  Using first-principles methods and spin models, we investigate the magnetic properties of transition-metal trimers Cr3 and Cu3. We calculate exchange coupling constants and zero-field splitting parameters using density functional theory and, with these parameters, determine the ground spin state as well as thermodynamic properties via spin models. Results for Cr3 indicate uniaxial magnetic anisotropy with a magnetic easy axis aligned along the 3-fold rotational symmetry axis and a mostly isotropic exchange interaction. The Cu3 molecule lacks rotational symmetry and our results show strong antisymmetric interactions for three distinct exchange couplings within the molecule. We are able to reproduce experimental findings on magnetic susceptibility and magnetization of Cr3 with the first-principles spin-Hamiltonian parameters. Our results show no presence of a toroidal ordering of spins for Cr3 and a finite toroidal moment for Cu3 in the ground state. We apply an external electric field up to 0.08 V/Å to each system to reveal the field dependence of exchange coupling as magnetoelectric effects. Finally, we scan the parameter space of a spin Hamiltonian to gain insights into which parameters would lead to a sizable toroidal moment in such systems.

  PublisherDOI

• CCDC 2282176: Experimental Crystal Structure Determination

  The Cambridge Structural Database · 2023-10-26

  datasetOpen access

  An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  PublisherDOI

Recent grants

• Models of the Photosynthetic Oxygen-Evolving Complex

  NSF · $450k · 2014–2018

• Transition Metal Clusters as Single-Molecule Magnets

  NSF · $426k · 2016–2020

• 'Molecular Nanoparticles' of Magnetic Perovskite Manganites and Other Metal Oxides

  NSF · $480k · 2019–2022

• NIH Grant R01GM039083

  NIH · $1.7M · 2001

• Transition Metal Clusters as Single-Molecule Magnets

  NSF · $857k · 2004–2010

Frequent coauthors

• Wolfgang Wernsdorfer

  924 shared

• Khalil A. Abboud

  University of Florida

  592 shared

• David N. Hendrickson

  Broad Institute

  371 shared

• Theocharis C. Stamatatos

  University of Patras

  320 shared

• Euan K. Brechin

  University of Edinburgh

  278 shared

• Anastasios J. Tasiopoulos

  University of Cyprus

  250 shared

• John C. Huffman

  239 shared

• Kirsten Folting

  University of Florida

  200 shared

Awards & honors

• Leadership Mentor Award, National High Magnetic Field Labora…
• ACS Award for Inorganic (2019)
• Nyholm Prize for Inorganic Chemistry, Royal Society of Chemi…
• 2016 Fellow of the American Chemical Society (2016)
• Teacher-Scholar of the Year, University of Florida (2016)