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Research

Research in the AG Tambornino treads the ground between inorganic molecular and solid-state chemistry. Our focus lies on reactive species comprising pseudohalogen ions. We are interested in the syntheses and stabilisation of the at times highly reactive species as well as their reactivities.

• Inhalt ausklappen Inhalt einklappen Reactive Carbonyl and Thiocarbonyl Pseudohalides

  In the Tambornino Group, we are interested in small, highly reactive carbonyl- and thiocarbonyl-based molecules that occupy a particularly rich region of molecular chemistry. These compounds stand at the intersection of main-group chemistry, pseudohalide chemistry, and reactive synthesis. Although many of them have been known in name for decades, their actual chemistry has often remained incomplete: synthetic procedures were inconvenient/not reproducible, structural information was limited, and their reactivity was described only in isolated cases. We revisit these systems with modern experimental and computational tools in order to establish them as well-defined chemical entities.

  A central theme of this work is the study of carbonyl and oxalyl pseudohalides such as carbonyl diisothiocyanate,[1] oxalyl diisothiocyanate,[1] thiocarbonyl dithiocyanate,[2] and oxalyl dicyanide.[3] In these projects, we combine preparative chemistry with single-crystal and powder diffraction, NMR spectroscopy, vibrational spectroscopy, and quantum-chemical calculations. This allows us to address questions that are fundamental in nature but often decisive in practice: which conformations are preferred, how weak intermolecular interactions influence the solid-state structure, how stability changes across related series, and how electronic structure is reflected in experimental observables.

  Beyond characterization, we use these compounds as model systems for understanding reactivity at a more general level. Closely related molecules can display strikingly different behavior, for example kinetic versus thermodynamic product formation, double addition versus ring closure,[4,5] or conformational relaxation under photochemical conditions.[6,7] We are interested in the underlying reasons for these differences. By studying reactive carbonyl and thiocarbonyl synthons in a systematic way, we aim to uncover broader principles that connect molecular structure, bonding, and chemical transformation.

  [1] J. Pfeiffer, C. Trost, A. Pachkovska, F. Tambornino, Inorg. Chem. 2021, 60, 10722-10728.
  [2] J. Pfeiffer, H. Günther, P. Fuzon, F. Weigend, F. Tambornino, Chem. Eur. J. 2024, 30, e202401508.
  [3] S. Ringelband, T. Cohen, F. Tambornino, Inorg. Chem. 2026, ASAP, doi:10.1021/acs.inorgchem.5c05620.
  [4] J. Pfeiffer, C. Trost, F. Tambornino, J. Molecular. Chem. 2024, 1308, 138079.
  [5] J. Pfeiffer, M. Möbs, S. Reith, M. Tallu, F. Tambornino, J. Molecular. Chem. 2024, 1309, 138198.
  [6] J. Pfeiffer, J. P. Wagner, F. Tambornino, Eur. J. Inorg. Chem. 2023, 26, e202300290.
  [7] E. Gougoula, J. Pfeiffer, M. Schnell, F. Tambornino, Phys. Chem. Chem. Phys. 2024, 26, 25678.

• Inhalt ausklappen Inhalt einklappen Heavy Pseudohalides and Chalcogenocyanate Chemistry

  We study the chemistry of heavy pseudohalides, with a particular focus on selenocyanates and tellurocyanates. In contrast to cyanates and thiocyanates, which are firmly established in textbook chemistry, their heavier congeners remain comparatively underexplored. This makes them especially attractive from a fundamental perspective. They allow us to examine where simple analogies to lighter systems remain valid, where they begin to fail, and how bonding, stability, and coordination behavior evolve across a homologous series.

  Our work in this area ranges from simple salts to more complex molecular and coordination compounds. We investigate alkali-metal,[1,2] ammonium,[3] and tetraalkylammonium selenocyanates,[4] as well as compounds such as lead chalcogenocyanate,[5] Cu[SeCN],[6] and isolated tellurocyanate salts.[7] Across these systems, we seek to establish reliable synthetic access, definitive structural information, and a coherent picture of how heavy pseudohalide anions behave in different chemical environments. In doing so, we aim to build the structural foundation that is still missing for much of this chemistry.

  Methodologically, we combine crystallography, Raman and IR spectroscopy, thermal analysis, isotopic labeling, and quantum-chemical calculations. We are particularly interested in connecting composition and bonding to measurable properties such as vibrational signatures, NMR parameters, polymorphism, and preferred coordination modes. Heavy pseudohalides are therefore not only interesting because they are rare or technically demanding. For us, they serve as a platform for fundamental inorganic and molecular chemistry, one in which periodic trends become tangible and where deviations from simple expectations are often chemically most revealing.

  [1] A. Shlyaykher, M. Ehmann, A. J. Karttunen, F. Tambornino, Chem. Eur. J. 2021, 27(54), 13552-13557.
  [2] A. Shlyaykher, T. Pippinger, T. Schleid, O. Reckeweg, F. Tambornino, Z. Kristallogr. - Cryst. Mater. 2022, 237(1-3), 69-75.
  [3] A. Shlyaykher, F. Tambornino, Inorg. Chem. 2023, 62(30), 11943-11953.
  [4] S. Ringelband, J. Pfeiffer, H. Günther, S. Ivlev, F. Tambornino, Z. Anorg. Allg. Chem. 2026, 652, e202500182.
  [5] A. Shlyaykher, A. Živković, H. Günther, A. L. Barba, N. H. de Leeuw, F. Tambornino, Dalton Trans. 2025, 54, 74-88.
  [6] A. Shlyaykher, F. Tambornino, Z. Crystallogr. 2025, 240(1-2), 39.
  [7] H. Günther, F. Weigend, X. Xie, W. Cao, X.-F. Gao, X.-B. Wang, F. Tambornino, Angew. Chem. Int. Ed. 2025, 64(31), e202507543.

• Inhalt ausklappen Inhalt einklappen Molecular Solids: Structure, Disorder, and Intermolecular Interactions

  In the Tambornino Group, we are interested in what happens when molecules of substances that are liquid at ambient conditions become solids. Many small and reactive compounds are well described as isolated molecules, yet their behavior in condensed phase is often much richer than one might expect. Polymorphism, orientational disorder, phase transitions, and subtle intermolecular interactions can all emerge from seemingly simple building blocks. We study these phenomena because they provide access to an important level of chemical understanding that lies between the individual molecule and the bulk material.

  This line of research includes systems such as phosgene,[1] thiophosgene,[2] methyl chloroformate,[3] and tetramethylammonium selenocyanate.[4] In these compounds, we analyze crystal structures across temperature ranges, identify metastable and high-temperature phases, and examine how weak contacts shape packing and dynamics. Even very small molecules can show surprisingly complex solid-state behavior, and we are particularly interested in understanding the fine energetic balances that govern whether a phase is ordered, disordered, or polymorphic.

  To address these questions, we combine single-crystal and powder diffraction with vibrational spectroscopy, calorimetry, neutron diffraction and scattering together with quantum-chemical calculations. Our aim is not merely to determine crystal structures, but to understand molecular solids as chemically meaningful systems in their own right. In this view, weak interactions, disorder, and dynamics are not peripheral details; they are central features of the chemistry and often the key to understanding how molecular properties are expressed in the condensed phase.

  [1] S. Ringelband, J. Pfeiffer, A. D. Fortes, C. M. Howard, S. F. Parker, A. J. Karttunen, F. Tambornino, Angew. Chem. Int. Ed. 2026, 65, e17323.
  [2] F. Tambornino, S. Ringelband, S. F. Parker, C. M. Howard, A. D. Fortes, Acta Crystallogr. B 2024, 80, 495-503.
  [3] S. Ringelband, F. Tambornino, Acta Crystallogr. E 2025, 81(10), 987.
  [4] S. Ringelband, J. Pfeiffer, H. Günther, S. Ivlev, F. Tambornino, Z. Anorg. Allg. Chem. 2026, 652, e202500182.