Theoretical Study of an Isolable Compound with a Short Silicon-Silicon Triple Bond, (tBu3Si)2MeSiSi≡SiSiMe(SitBu3)2

Tin Analogues of Alkynes. Multiply Bonded Structures vs Singly Bonded Structures

“…The optimized Sn−Sn distance and Sn−Sn−C trans-bent angle (θ) are 2.677 Å and 126.5°, respectively. These (as well as the arrangement of the aryl rings) agree very well with the X-ray crystal data of Sn−Sn = 2.668 Å and θ = 125.2°, unlike our previous calculations at a lower level,2d suggesting that the present calculations are reliable. The core skeleton is almost planar, as indicated by the dihedral C−Sn−Sn−C angle (ω) of 179.7° .…”

Tin Analogues of Alkynes. Multiply Bonded Structures vs Singly Bonded Structures

“…The optimized Sn−Sn distance and Sn−Sn−C trans-bent angle (θ) are 2.677 Å and 126.5°, respectively. These (as well as the arrangement of the aryl rings) agree very well with the X-ray crystal data of Sn−Sn = 2.668 Å and θ = 125.2°, unlike our previous calculations at a lower level,2d suggesting that the present calculations are reliable. The core skeleton is almost planar, as indicated by the dihedral C−Sn−Sn−C angle (ω) of 179.7° .…”

Why Do the Heavy-Atom Analogues of Acetylene E2H2 (E = Si−Pb) Exhibit Unusual Structures?

“…Figure shows the optimized geometries of structures A − E of E 2 H 2 and the relative energies of the isomers with respect to the global energy minimum A calculated at the BP86/QZ4P level. The geometries and relative energies are in agreement with previous theoretical calculations at DFT and ab initio levels. − ,, We want to point out that only structures A , B , C , and D1 are predicted as minima on the PES, while D2 is a transition state. It has been shown before that the bulky substituents in R*PbPbR* are the reason that structure type D2 becomes an energy minimum .…”

A Stable Compound Containing a Silicon-Silicon Triple Bond

“…According to theoretical investigations, substitution by electropositive silyl groups leads to a less trans-bent disilyne structure (25). The structure of 2 presented here is close to that predicted by a recent density functional (DFT) calculation on ( t Bu 3 Si) 2 MeSiSiϵSiSiMe(Si t Bu 3 ) 2 , where t Bu is tert-butyl (26).…”

Tin Analogues of Alkynes. Multiply Bonded Structures vs Singly Bonded Structures

“…The optimized Sn−Sn distance and Sn−Sn−C trans-bent angle (θ) are 2.677 Å and 126.5°, respectively. These (as well as the arrangement of the aryl rings) agree very well with the X-ray crystal data of Sn−Sn = 2.668 Å and θ = 125.2°, unlike our previous calculations at a lower level,2d suggesting that the present calculations are reliable. The core skeleton is almost planar, as indicated by the dihedral C−Sn−Sn−C angle (ω) of 179.7° .…”

Why Do the Heavy-Atom Analogues of Acetylene E2H2 (E = Si−Pb) Exhibit Unusual Structures?

“…Figure shows the optimized geometries of structures A − E of E 2 H 2 and the relative energies of the isomers with respect to the global energy minimum A calculated at the BP86/QZ4P level. The geometries and relative energies are in agreement with previous theoretical calculations at DFT and ab initio levels. − ,, We want to point out that only structures A , B , C , and D1 are predicted as minima on the PES, while D2 is a transition state. It has been shown before that the bulky substituents in R*PbPbR* are the reason that structure type D2 becomes an energy minimum .…”

A Stable Compound Containing a Silicon-Silicon Triple Bond

“…According to theoretical investigations, substitution by electropositive silyl groups leads to a less trans-bent disilyne structure (25). The structure of 2 presented here is close to that predicted by a recent density functional (DFT) calculation on ( t Bu 3 Si) 2 MeSiSiϵSiSiMe(Si t Bu 3 ) 2 , where t Bu is tert-butyl (26).…”

Tin Analogues of Alkynes. Multiply Bonded Structures vs Singly Bonded Structures

“…The optimized Sn−Sn distance and Sn−Sn−C trans-bent angle (θ) are 2.677 Å and 126.5°, respectively. These (as well as the arrangement of the aryl rings) agree very well with the X-ray crystal data of Sn−Sn = 2.668 Å and θ = 125.2°, unlike our previous calculations at a lower level,2d suggesting that the present calculations are reliable. The core skeleton is almost planar, as indicated by the dihedral C−Sn−Sn−C angle (ω) of 179.7° .…”

Why Do the Heavy-Atom Analogues of Acetylene E2H2 (E = Si−Pb) Exhibit Unusual Structures?

“…Figure shows the optimized geometries of structures A − E of E 2 H 2 and the relative energies of the isomers with respect to the global energy minimum A calculated at the BP86/QZ4P level. The geometries and relative energies are in agreement with previous theoretical calculations at DFT and ab initio levels. − ,, We want to point out that only structures A , B , C , and D1 are predicted as minima on the PES, while D2 is a transition state. It has been shown before that the bulky substituents in R*PbPbR* are the reason that structure type D2 becomes an energy minimum .…”

A Stable Compound Containing a Silicon-Silicon Triple Bond

“…According to theoretical investigations, substitution by electropositive silyl groups leads to a less trans-bent disilyne structure (25). The structure of 2 presented here is close to that predicted by a recent density functional (DFT) calculation on ( t Bu 3 Si) 2 MeSiSiϵSiSiMe(Si t Bu 3 ) 2 , where t Bu is tert-butyl (26).…”