Preparation and crystal, molecular and electronic structure of 1,1,5,5-tetramethylbicyclo[3.3.0]-1,5-diphospha-3,7-dithia-2,4,6,8-tetrazene: a bicyclic PSN system with a sulfur-sulfur bond

Structure of ethyl {(1S,5R,8R)-8-hydroxy-3-oxo-2-oxa-6-azabicyclo[3.3.0]oct-6-yl}acetate hydrobromide

“…484 (1)A (Zak, 1981). Similar folded structures are found for the following: REP(NSN)EPR2, R --Me, d(S-S) = 2.551 (2)A (Burford, Chivers, Codding & Oakley, 1982); R = Ph, d(S-S) = 2.528 (1) A (Burford, Chivers & Richardson, 1983); and Ph3PN(NSN)ENPPh 3, d(S-S) = 2.452 (2)/~, (Bojes, Chivers, Cordes, Maclean & Oakley, 1981). For comparison, d(S-S)in $4N4 is 2.58 A (Sharma & Donohue, 1963;De Lucia & Coppens, 1978.…”

Bond Stretching and Redox Behavior in Coinage Metal Complexes of the Dichalcogenide Dianions [(SPh2P)2CEEC(PPh2S)2]2− (E=S, Se): Diradical Character of the Dinuclear Copper(I) Complex (E=S)

“…For comparison, the weak (C)S−S(C) contacts in 5c are in the same range as those found for transannular S•••S interactions in eightmembered S-N rings, e.g. 2.60 Å in the cage molecule S4N4 [16] and values of 2.43-2.55 Å for the bicyclic compounds 1,5-R4P2N4S2 (R = alkyl, aryl), [17,18] for which diradical character has been suggested. [19] Side-on bonded μ-η 2 ,η 2 -disulfido dinuclear Cu(II)/Cu(II) complexes of the naked S2 ligand exhibit S−S bond distances in the range 2.07-2.17 Å, [20] while the S−S separation in the trigonal bipyramidal trication [(tmedaCu)3S2] 3+ is 2.73 Å.…”

“…A number of bicyclic and cage compounds with weak transannular S•••S contacts in the range 2.40-2.71 Å and corresponding ν(S−S) stretching vibrations of 186-260 cm -1 have been reported. [16][17][18] Although the S-S stretching mode typically gives rise to strong signals in Raman spectra, calculated fundamental vibrations often reveal contributions to the potential energies from bending and torsion modes, and no vibration with 100% ν(S−S) stretching mode is observed, e.g. in S4N4 vibrations at 201 and 218 cm -1 exhibit 58 and 33 % contribution, respectively, from transannular ν(S−S) stretching.…”

The electronic structure of the tetrasulphur tetranitride dication, S4N42+: an abinitio molecular orbital study

“…This rather ties are desired, the ab initio charge distribution is cant stabilization of the latter reflects the energetic best described at the Hiickel level by setting 8s < importance of the well developed found C~N -However, if inf~rmation concerning the corn-in it. The high n-bond energy achieved in the planar position and ordering of the frontier orbitals is structure is more than sufficient to offset the loss of required, as would be the case in the study of cross-ring SS-bonding (25). pericyclic reactions, the ratio a, > a N will provide more meaningful results.…”