SummaryThe electron affinities (EAs) of a training set of 19 metal-salen compounds were calculated using density functional theory. Concurrently, the experimental reduction potentials for the training set were measured using cyclic voltammetry. The EAs and reduction potentials were found to be linearly correlated by metal. The reduction potentials of a test set of 14 different metal-salens were then measured and compared to the predicted reduction potentials based upon the training set correlation. The method was found to work well, with a mean unsigned error of 99 mV for the entire test set. This method could be used to predict the reduction potentials of a variety of metal-salen compounds, an important class of coordination compounds used in synthetic organic electrochemistry as electrocatalysts.

Steric Effects and Aurophilic Interactions in Crystals of Au 2 (μ-1,2-bis(diphenylphosphino)ethane)X 2 and Au 2 (μ-1,2-bis(dicyclohexylphosphino)ethane)X 2 (X = Cl, Br, I), Polyhedron (2016), doi: http://dx. Abstract Crystalsin the isostructural series Au 2 (µ-dppe)X 2 (dppe is 1,2-bis(diphenylphosphino)ethane, X = Cl, Br, I) form centrosymmetric, dimeric structures with two short Au … Au contacts between the component molecules. We found no evidence for a second polymorph for any member of the Au 2 (µ-dppe)X 2 series, although two polymorphs were observed previously for the related Au 2 (Ph 2 As(CH 2 ) 2 AsPh 2 )X 2 series. Crystals of Au 2 (µ-dcpe)X 2 (where dcpe is 1,2-bis(dicyclohexylphosphino)ethane) show structures that differ appreciably from those of Au 2 (µ-dppe)X 2 . The bulky cyclohexyl substituents appear to be playing a major role eliminating the formation of polymeric or dimeric structures. Au 2 (µ-dcpe)Cl 2 has a monomeric structure without aurophilic interactions. In contrast, Au 2 (µ-dcpe)Br 2 and Au 2 (µ-dcpe)I 2 have similar structures with intramolecular aurophilic interactions. Au 2 (µ-dcpe)I 2 displays a form of aggregation-induced emission. It displays a red-pink luminescence in crystalline form but is non-emissive in solution.3

The colorless, two-coordinate gold(i) complex, [(H2O)3Na][Au(SCSN3)2], has been synthesized through the [2 + 3] cyclic reaction of carbon disulfide and sodium azide in the presence of the labile complex (tht)AuCl. Metathesis of [(H2O)3Na][Au(SCSN3)2], with tetra(phenyl)arsonium chloride produced colorless needles of (Ph4As)[Au(SCSN3)2]. The structure of [(H2O)3Na][Au(SCSN3)2] involves linear gold coordination by two exocyclic sulfur atoms of the 1,2,3,4-thiatriazole-5-thiolate anions. These two-coordinate anions self-associate to form extended, zig-zag chains that are connected by aurophilic bonding with Au∙∙∙Au distances of 3.2653(3) Å and 3.3090(3) Å. Remarkably, the individual S-Au-S units that are connected though aurophilic interactions are eclipsed. The structure of (Ph4As)[Au(SCSN3)2] also contains linear, two-coordinate gold ions with bonding to the 1,2,3,4-thiatriazole-5-thiolate anionic ligands through the exocyclic sulfur atoms. However, in this salt, the anions self-associate through AuAu bonds (Au∙∙∙Au distance of 3.2007(3) Å) to form simple dimers, which also have an eclipsed arrangement of the ligands. Electronic structure calculations strongly suggest that the staggered geometry for the [(Au(SCSN3))2](+) dimer is energetically favored relative to the eclipsed geometry. However, attractive π-stacking interactions appear to promote the observed eclipsed arrangement of the ligands.

The mono‐ and di‐chloroform solvates of [Au2(μ‐1,2‐bis(diphenylarsino)ethane)2](AsF6)2 undergo single‐crystal‐to‐single‐crystal transformations that result in gain (over 12 hours) or slow loss (over five years) of only one chloroform molecule. The change in solvation results in changes in the structure and luminescence of the digold cation. The cation consists of a pair of slightly bent As‐Au‐As units that are connected through the two bridging dpae ligands and by aurophilic interactions with Au⋅⋅⋅Au contacts of 3.05152(15) Å in the disolvate or 2.9570(5) Å in the monosolvate.

No abstract