Synthesis of a redox-active molecular switch based on dibenzo[1,2]dithiine

2,2′‐Bipyridine Equipped with a Disulfide/Dithiol Switch for Coupled Two‐Electron and Two‐Proton Transfer

“…The DFT calculated minimum energy structure of 1 (see the Supporting Information for details) shows a S−S bond length of 2.076 Å and tilting of the two pyridine rings with a C‐S‐S‐C torsion angle ϕ =22.3°, which is similar to the experimentally observed values for a S 2 ‐bridged benzidine (2.053 Å, ϕ =29°), A (2.059 Å, ϕ =30.4°) and for B (2.056 Å, ϕ =32°) . The LUMO of 1 has antibonding character with respect to the S−S bond and bonding character with respect to the C−C bond linking the pyridine rings (Figure ).…”

Controlling electron exchange in molecular assemblies

“…This is considered to be a sufficiently large variation to propose constructing a switch for directed electron exchange on the principle of rapid conformational exchange. This raises the question of how to bring about such a large scale conformational change and, in attempting to address this point, our attention has turned to the corresponding dibenzo [1,2]dithiine unit [62]. Here, electrochemical cleavage of the S-S bond gives rise to a major structural change from the near coplanar arrange- ment to an orthogonal conformation (Fig.…”

The Newman–Kwart Rearrangement of O‐Aryl Thiocarbamates: Substantial Reduction in Reaction Temperatures through Palladium Catalysis

“…Thermally induced O Ar !S Ar migration in aryl thiocarbamates (1!2, Scheme 1) [1] is commonly referred to [2] as the Newman-Kwart rearrangement ("NKR") [3] and belongs to a group of rearrangements that generate Ar-S/N compounds from phenols. [4] Of these, only the NKR has been extensively utilized, [1] with applications as broad-ranging as medicinal chemistry, [5] chiral ligand synthesis, [6] supramolecular chemistry, [7] molecular switches, [8] molecular rods, [9] dendrimers, [10] organocatalysts [11] and helicenes. [12] The NKR has also been applied industrially, [1,5] more recently by applying microwave [13, 14a] and flow-reactor technologies.…”

“…The [Pd(tBu 3 P) 2 ] catalyst was tested with a small range of simple aryl thiocarbamates (1 a-h, 100 8C, toluene, Table 1, entries [5][6][7][8][9][10][11]. In all cases rearrangement was catalyzed, allowing NKR at a substantially lower temperature than that required for the standard thermal conditions.…”