Syntheses and Structural Properties of Cyclic Tetrathiadiynes

Abstract

The four-component cyclization of dilithium acetylide with dithiocyanatoalkanes yielded the hitherto unknown tetrathiacyclodiynes 34, 38, 41, and 43 in moderate yields. The use of the trimethylsilyl protecting group allowed a more efficient and flexible stepwise approach with good yields. The resulting tetrathiacyclodiynes 25−44 were investigated by X-

Tethered Dithiacyclopropenones. Syntheses and Structural Properties of Tetrathiacyclopropenonophanes

“…The most salient features are the large torsion angles between the CH 2 −S···S−CH 2 bonds tied to the triple bond which vary between 73° and 85°. Similar values have been observed in 4 . These values are due to the repulsion between the 3p lone pairs of the sulfurs and the π-MOs of the triple bond .…”

“…Similar values have been observed in 4 . These values are due to the repulsion between the 3p lone pairs of the sulfurs and the π-MOs of the triple bond . Also important for the conformations of 5 are small torsion angles (0° to 18°) between the H 2 C−S bonds adjacent to the three-membered ring and the C−C double bond.…”

Tethered Dithiacyclopropenones. Syntheses and Structural Properties of Tetrathiacyclopropenonophanes

“…The most salient features are the large torsion angles between the CH 2 −S···S−CH 2 bonds tied to the triple bond which vary between 73° and 85°. Similar values have been observed in 4 . These values are due to the repulsion between the 3p lone pairs of the sulfurs and the π-MOs of the triple bond .…”

“…Similar values have been observed in 4 . These values are due to the repulsion between the 3p lone pairs of the sulfurs and the π-MOs of the triple bond . Also important for the conformations of 5 are small torsion angles (0° to 18°) between the H 2 C−S bonds adjacent to the three-membered ring and the C−C double bond.…”

From Noncovalent Chalcogen–Chalcogen Interactions to Supramolecular Aggregates: Experiments and Calculations

“…If both alkane bridges have the same odd numbers of CH 2 units, γ is close to 63°, as expected for a chair conformation. In all other cases, γ was found considerably larger, in the range between 75° and 110° . These values are based on the fact that the 3p lone pairs at sulfur or 4p lone pairs at selenium centers interact through the π system of the triple bond and hence prefer a perpendicular position.…”

Cyclic Tetraselenadiynes: Rigid Cycles with Long-Range van der Waals Forces between Chalcogen Centers

“…These structures arise by stacking the almost planar rigid rings on top of each other. Checking the corresponding sulfur systems again we found isomorphous structures. , In Figure a, we show as an example the packing of 5 ( 5.5 ). Common to all these rings is a rectangular structure.…”

Tethered Dithiacyclopropenones. Syntheses and Structural Properties of Tetrathiacyclopropenonophanes

“…The most salient features are the large torsion angles between the CH 2 −S···S−CH 2 bonds tied to the triple bond which vary between 73° and 85°. Similar values have been observed in 4 . These values are due to the repulsion between the 3p lone pairs of the sulfurs and the π-MOs of the triple bond .…”

“…Similar values have been observed in 4 . These values are due to the repulsion between the 3p lone pairs of the sulfurs and the π-MOs of the triple bond . Also important for the conformations of 5 are small torsion angles (0° to 18°) between the H 2 C−S bonds adjacent to the three-membered ring and the C−C double bond.…”

From Noncovalent Chalcogen–Chalcogen Interactions to Supramolecular Aggregates: Experiments and Calculations

“…If both alkane bridges have the same odd numbers of CH 2 units, γ is close to 63°, as expected for a chair conformation. In all other cases, γ was found considerably larger, in the range between 75° and 110° . These values are based on the fact that the 3p lone pairs at sulfur or 4p lone pairs at selenium centers interact through the π system of the triple bond and hence prefer a perpendicular position.…”

Cyclic Tetraselenadiynes: Rigid Cycles with Long-Range van der Waals Forces between Chalcogen Centers

“…These structures arise by stacking the almost planar rigid rings on top of each other. Checking the corresponding sulfur systems again we found isomorphous structures. , In Figure a, we show as an example the packing of 5 ( 5.5 ). Common to all these rings is a rectangular structure.…”

Tethered Dithiacyclopropenones. Syntheses and Structural Properties of Tetrathiacyclopropenonophanes

“…The most salient features are the large torsion angles between the CH 2 −S···S−CH 2 bonds tied to the triple bond which vary between 73° and 85°. Similar values have been observed in 4 . These values are due to the repulsion between the 3p lone pairs of the sulfurs and the π-MOs of the triple bond .…”

“…Similar values have been observed in 4 . These values are due to the repulsion between the 3p lone pairs of the sulfurs and the π-MOs of the triple bond . Also important for the conformations of 5 are small torsion angles (0° to 18°) between the H 2 C−S bonds adjacent to the three-membered ring and the C−C double bond.…”

From Noncovalent Chalcogen–Chalcogen Interactions to Supramolecular Aggregates: Experiments and Calculations

“…If both alkane bridges have the same odd numbers of CH 2 units, γ is close to 63°, as expected for a chair conformation. In all other cases, γ was found considerably larger, in the range between 75° and 110° . These values are based on the fact that the 3p lone pairs at sulfur or 4p lone pairs at selenium centers interact through the π system of the triple bond and hence prefer a perpendicular position.…”

Cyclic Tetraselenadiynes: Rigid Cycles with Long-Range van der Waals Forces between Chalcogen Centers

“…These structures arise by stacking the almost planar rigid rings on top of each other. Checking the corresponding sulfur systems again we found isomorphous structures. , In Figure a, we show as an example the packing of 5 ( 5.5 ). Common to all these rings is a rectangular structure.…”