Axially Chiral Spiro Compounds with Heavier Group 14 Elements as Spiro-Centers
Aynura Mammadova1, Clemens Bruhn1, Rudolf Pietschnig1
1Institute for Chemistry and CINSaT, University of Kassel, Heinrich-Plett-Straße 40, Kassel 34132, Germany.
Inorganic Chemistry
|May 2, 2026
Summary
New chiral ligands featuring tert-butyl groups were synthesized and used to create novel axially chiral compounds with Group 14 elements. Researchers explored their structural properties and reactivity, particularly with lead and germanium complexes.
Area of Science:
- Organometallic Chemistry
- Ligand Synthesis
- Chiral Chemistry
Background:
- Development of novel ditopic ligands is crucial for creating new organometallic compounds.
- Axially chiral molecules with Group 14 elements are of interest due to their unique properties and potential applications.
- The synthesis and characterization of ligands with thiol and selenol groups offer versatile coordination possibilities.
Purpose of the Study:
- To prepare homo- and heteroditopic 4-tert-butyl-1,2-benzene-bischalcogenol ligands.
- To synthesize and characterize novel axially chiral compounds incorporating Group 14 elements (Sn, Ge, Pb).
- To investigate the reactivity and aggregation behavior of the synthesized complexes, especially lead derivatives.
Main Methods:
- Functionalization of 4-tert-butylthiophenol to introduce thiol and selenol groups.
- Isolation and structural characterization of lithiated ligand derivatives.
- Synthesis of Group 14 complexes and their characterization using multinuclear NMR spectroscopy, elemental analysis (EA), high-resolution mass spectrometry (HR-MS), and single-crystal X-ray diffraction (SCXRD).
- Exploration of chiral resolution using high-performance liquid chromatography (HPLC) for germanium compounds.
Main Results:
- Successfully synthesized and characterized novel homo- and heteroditopic bis(chalcogenol) ligands.
- Prepared axially chiral complexes of tin, germanium, and lead.
- Observed reduction of Pb(IV) to Pb(II) in lead complexes, leading to aggregation; adducts were formed with donor molecules but did not deaggregate the polymeric structure.
- Stable germanium complexes were synthesized, and attempts at chiral resolution via HPLC were explored.
Conclusions:
- The developed ligands are versatile precursors for synthesizing novel axially chiral organometallic compounds.
- The reactivity of lead complexes differs significantly, showing a tendency towards reduction and aggregation.
- The synthesized germanium compounds represent stable chiral frameworks with potential for further investigation and resolution.
![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
Related Concept Videos
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
5.5K
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
5.5K
02:25Molecules with Multiple Chiral Centers
11.6K
Molecules that possess multiple chiral centers can afford a large number of stereoisomers. For instance, while some molecules like 2-butanol have one chiral center, defined as a tetrahedral carbon atom with four different substituents attached, several molecules like butane-2,3-diol have multiple chiral centers. A simple formula to predict the number of stereoisomers possible for a molecule with n chiral centers is 2n. However, there can be a lower number where some of the stereoisomers are...
11.6K
02:05Prochirality
4.0K
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
4.0K
02:25Chirality
23.4K
Chirality is a term that describes the lack of mirror symmetry in an object. In other words, chiral objects cannot be superposed on their mirror images. For example, our feet are chiral, as the mirror image of the left foot, the right foot, cannot be superposed on the left foot.
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
23.4K
02:33Stereoisomerism of Cyclic Compounds
9.2K
In this lesson, we delve into the role of ring conformation and its stability, which determines the spatial arrangement and, consequently, the molecular symmetry and stereoisomerism of cyclic compounds. 1,2-Dimethylcyclohexane is used as a case study to evaluate the possible number of stereoisomers. Here, given the multiple (n = 2) chiral centers, there are 2n = 4 possible configurations that lack a plane of symmetry, as the ring skeleton exists in a non-planar chair conformation. In addition,...
9.2K
02:21Naming Enantiomers
18.9K
The naming of enantiomers employs the Cahn–Ingold–Prelog rules that involve assigning priorities to different substituent groups at a chiral center. Each enantiomer, being a distinct molecule, is assigned a unique name by the Cahn–Ingold–Prelog (CIP) rules, also called the R–S system. The prefix R- or S- attached to the chiral centers in an enantiomer is dependent on the spatial arrangement of the four substituents on the chiral center. The R–S system...
18.9K