Organic Chemistry seminars

Omar M. Yaghi examines how reticular chemistry changes the scale and diversity of materials that chemists can design. By joining molecular building blocks into extended structures, researchers have developed large families of metal–organic frameworks and covalent organic frameworks with tunable internal spaces and functions. The lecture asks how artificial intelligence and robotics could accelerate the preparation and exploration of these materials, moving chemical discovery from scarcity toward abundance. Yaghi connects this approach to carbon capture and the collection of water from air, building on design principles for nanoporous frameworks and their applications in gas storage and separation. The discussion extends the metal–organic framework research recognised by the 2025 Nobel Prize in Chemistry into current methods for discovery and environmental applications.

Carbocation-mediated substitution commonly loses stereochemical information and competes with elimination or rearrangement. This seminar describes a strategy using nonclassical carbocations to make SN1 transformations predictable, selecting either inversion or retention. It addresses acyclic products with adjacent stereocentres and controlled regio-, diastereo- and enantioselectivity, then shows how carbon–carbon bond rearrangements can install stereodefined bonds away from the initial cation while tolerating sensitive functional groups.

Two presentations examine selective nitrogen installation in organic molecules. The first studies how changing rhodium nitrene catalysts can direct amination toward different carbon–hydrogen bonds, including normally unreactive sites, beyond the limits of substrate-directed approaches. The second addresses the sustainability problems of scarce metals and conventional nitrene precursors through iron catalysts and hydroxylamine derivatives. Applications include aziridination, alkene difunctionalization within and between molecules, and direct carbon–hydrogen functionalization without an additional external oxidant.

Free N-heterocyclic carbenes are modest reductants, but their reactions with suitable electrophiles can produce exceptionally strong organic electron donors. The seminar explains how electron-rich structures and stabilization after oxidation enable single- and double-electron transfers, and how structural changes tune reduction potentials. It connects mechanistic understanding with radical synthesis and emerging uses in materials, greenhouse-gas chemistry and energy conversion or storage.

The first presentation develops doubly metalated organozinc reagents whose two nucleophilic sites can react sequentially. Examples include silyl- and germylzincation of alkynes, rearrangements producing metalated allenes and enantioselective activation of geminal diorganozincs. The second examines nitrogen extrusion as a driving force for carbanion formation. It surveys synthetic applications and describes decomposition of silylated diazenes to obtain group-one organometallic reagents with tertiary alkyl centres.

This seminar connects molecular chirality with the reactivity of cations and their precursors. Helical structures based on delocalized triarylcarbenium frameworks provide a platform for tuning electronic and chiroptical properties. A second focus is metal-catalysed decomposition of diazocarbonyl compounds, yielding ylides and elaborated heterocycles. The discussion includes tetrahetero-substituted methanes with unusually persistent configurations and relates their resistance to enantiomerization to carbocation chemistry.