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

Abstract

Unlike the recent proposal by Power and co-workers, theoretical calculations show that Ar′SnSnAr′ (Ar′ ) C 6 H 3 -2,6-(C 6 H 3 -2,6-iPr 2 ) 2 ) has a multiply bonded structure in solution; the same is also true for the related tin analogues of alkynes.

A Combined Charge and Energy Decomposition Scheme for Bond Analysis

“…However, the total bond energy, Δ E tot , increases (in absolute term) when going from the chromium (−31.3 kcal/mol) to the tungsten dimer (−88.7 kcal/mol). Similar conclusions were drawn from the experimental and as well as from the other theoretical investigations. ,− The factor responsible for the trend in Δ E int is the steric repulsion, Δ E steric . This term systematically decreases when chromium atoms are replaced by their group analogues.…”

A Combined Charge and Energy Decomposition Scheme for Bond Analysis

“…However, the total bond energy, Δ E tot , increases (in absolute term) when going from the chromium (−31.3 kcal/mol) to the tungsten dimer (−88.7 kcal/mol). Similar conclusions were drawn from the experimental and as well as from the other theoretical investigations. ,− The factor responsible for the trend in Δ E int is the steric repulsion, Δ E steric . This term systematically decreases when chromium atoms are replaced by their group analogues.…”

Addition of H2 to distannynes under ambient conditions

“…18 However, its reactivity is indistinguishable from that of 1a and 3a. This supports the view that 2a ''relaxes'' to a multiple bonded form which has ground state singlet diradical character in solution and this is consistent with the calculations of Takagi and Nagase 30,31 which predicted that multiple bonded ArSnSnAr is more stable than the strongly bent forms of these molecules (i.e. that of 2a) and that the greater bending in the solid state is a consequence of packing forces.…”

Effects of ligands and spin-polarization on the preferred conformation of distannynes

“…Preliminary calculations were done on the large Ar SnSnAr (Ar = C 6 H 3 -2,6-(C 6 H 2 -2,6-Pr i 2 ) 2 ) system in order to compare with experimental structural data and earlier calculations. These calculations using spin-restricted DFT (full details in ESI) confirmed the earlier findings 15 that this structure does indeed take a multiply bonded structure, consistent with experiment. In particular, the optimized bond length is 2.832 A ˚and the C-Sn-Sn bond angles are 128.2 and 130.7 • .…”

A Combined Charge and Energy Decomposition Scheme for Bond Analysis

“…However, the total bond energy, Δ E tot , increases (in absolute term) when going from the chromium (−31.3 kcal/mol) to the tungsten dimer (−88.7 kcal/mol). Similar conclusions were drawn from the experimental and as well as from the other theoretical investigations. ,− The factor responsible for the trend in Δ E int is the steric repulsion, Δ E steric . This term systematically decreases when chromium atoms are replaced by their group analogues.…”

Addition of H2 to distannynes under ambient conditions

“…18 However, its reactivity is indistinguishable from that of 1a and 3a. This supports the view that 2a ''relaxes'' to a multiple bonded form which has ground state singlet diradical character in solution and this is consistent with the calculations of Takagi and Nagase 30,31 which predicted that multiple bonded ArSnSnAr is more stable than the strongly bent forms of these molecules (i.e. that of 2a) and that the greater bending in the solid state is a consequence of packing forces.…”

Effects of ligands and spin-polarization on the preferred conformation of distannynes

“…Preliminary calculations were done on the large Ar SnSnAr (Ar = C 6 H 3 -2,6-(C 6 H 2 -2,6-Pr i 2 ) 2 ) system in order to compare with experimental structural data and earlier calculations. These calculations using spin-restricted DFT (full details in ESI) confirmed the earlier findings 15 that this structure does indeed take a multiply bonded structure, consistent with experiment. In particular, the optimized bond length is 2.832 A ˚and the C-Sn-Sn bond angles are 128.2 and 130.7 • .…”

A Combined Charge and Energy Decomposition Scheme for Bond Analysis

“…However, the total bond energy, Δ E tot , increases (in absolute term) when going from the chromium (−31.3 kcal/mol) to the tungsten dimer (−88.7 kcal/mol). Similar conclusions were drawn from the experimental and as well as from the other theoretical investigations. ,− The factor responsible for the trend in Δ E int is the steric repulsion, Δ E steric . This term systematically decreases when chromium atoms are replaced by their group analogues.…”

Addition of H2 to distannynes under ambient conditions

“…18 However, its reactivity is indistinguishable from that of 1a and 3a. This supports the view that 2a ''relaxes'' to a multiple bonded form which has ground state singlet diradical character in solution and this is consistent with the calculations of Takagi and Nagase 30,31 which predicted that multiple bonded ArSnSnAr is more stable than the strongly bent forms of these molecules (i.e. that of 2a) and that the greater bending in the solid state is a consequence of packing forces.…”

Effects of ligands and spin-polarization on the preferred conformation of distannynes

“…Preliminary calculations were done on the large Ar SnSnAr (Ar = C 6 H 3 -2,6-(C 6 H 2 -2,6-Pr i 2 ) 2 ) system in order to compare with experimental structural data and earlier calculations. These calculations using spin-restricted DFT (full details in ESI) confirmed the earlier findings 15 that this structure does indeed take a multiply bonded structure, consistent with experiment. In particular, the optimized bond length is 2.832 A ˚and the C-Sn-Sn bond angles are 128.2 and 130.7 • .…”