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We report the ability to trap the dimer Au2(μ-dppe)2I2 (dppe is 1,2- bis(diphenylphosphino)ethane) with different separations between the three-coordinate gold ions in crystalline solvates. All of these solvates ((Au2(μ-dppe)2I2·4(CH2Cl2) (1), Au2(μ- dppe)2I2·2(CH2Cl2) (2), the polymorphs α-Au2(μ-dppe)2I2·2(HC(O)NMe2) (3) and β- Au2(μ-dppe)2I2·2(HC(O)NMe2) (4), and Au2(μ-dppe)2I2·4(CHCl3) (5)) along with polymeric {Au(μ-dppe)I}n·n(CHCl3) (6)) originated from the same reaction, only the solvent system used for crystallization differed. In the different solvates of Au2(μ-dppe)2I2, the Au···Au separation varied from 3.192(1) to 3.7866(3) Å. Computational studies undertaken to understand the flexible nature of these dimers indicated that the structural differences were primarily a result of crystal packing effects with aurophillic interactions having a minimal effect. 

The relationshipE_pvs. ΔG_H− correlates the applied potential (E_p) needed to drive organohydride formation with the strength of the hydride donor that is formed: hydride transfer catalysis - as in enzymes like LarA - will be more energy efficient ifE_pis shifted anodically using kinetic effect.

 

Thermal Sn–C cleavage in the diarylstannylene Sn(Ar^iPr4)₂(Ar^iPr4= C₆H₃-2,6-(C₆H₃-2,6-iPr₂)₂) was used to generate ˙Sn(Ar^iPr4) and ˙Ar^iPr4radicals for alkyne arylstannylation.

 

N-alkylation andN-metallation of pyridine are explored herein to understand how metal-ligand complexes can model NAD⁺redox chemistry.

 

Six salts ([Au2(μ-dppe)2](BF4)2·CHCl3, [Au2(μ- dppe)2](BF4)2·1,2-Cl2C2H4, [Au2(μ-dppe)2](PF6)2·CHCl3, [Au2(μ-dppe)2](PF6)2, [Au2(μ-dppe)2](SbF6)2, and [Au2(μ- dppe)2](OTf)2·2CHCl3), (dppe is bis(diphenylphosphine)ethane) containing the dication, [Au2(μ-dppe)2]2+, have been prepared and structurally characterized by single-crystal X-ray crystallography. Unlike the three-coordinate dppe-bridged dimers, Au2X2(μ-dppe)2 (X = Br, I), which show considerable variation in the distance between the gold(I) ions over the range 3.0995(10) to 3.8479(3) Å in various solvates, the structure of the helical dication, [Au2(μ- dppe)2], in the new salts is remarkably consistent with the Au···Au separation falling in the narrow range 2.8787(9) to 2.9593(5) Å. In the solid state, the six crystals display a green luminescence both at room temperature and at 77 K, which has been assigned as phosphorescence. However, solutions of the dication are not luminescent. Salts containing the analogous dication [Au2(μ-dppp)2](PF6)2 (dppp is bis(diphenylphosphine)propane) have been prepared to determine whether the longer bridging ligand might also twist into a helical shape. These salts include [Au2(μ- dppp)2](OTf)2 (OTf is triflate) and three crystalline forms of [Au2(μ-dppp)2](PF6)2: the solvate [Au2(μ-dppp)2](PF6)2·(CHCl3) and two polymorphs of the unsolvated salt. None of these crystals are luminescent, but all contain a similar dication, [Au2(μ- dppp)2]2+, that contains two nearly parallel, linear P−Au−P groups and a long separation between the gold ions that varies from 5.3409(4) to 5.6613(6)Å. 

Spontaneous Ge₆O₈cluster formation under ambient conditions using dispersion enhanced aryloxo ligands.

 

Half a century since the photocatalytic disproportionation of Lappert's dialkyl stannylene SnR 2 , R = CH(SiMe 3 ) 2 (1) gave the persistent trivalent radical [·SnR 3 ], the characterization of the corresponding Sn(I) product, ·SnR is now described. It was isolated as the hexastannaprismane Sn 6 R 6 (2), from the reduction of 1 by the Mg(I)-reagent, Mg(BDI Dip ) 2 , (BDI = (DipNCMe) 2 CH, Dip + 2,6-diisopropylphenyl). 

Substrates engineered to undergo a 1,4-C–H insertion to yield benzocyclobutenes resulted in a novel elimination reaction to yieldortho-quinone dimethide (o-QDM) products that undergo Diels–Alder or hetero-Diels–Alder cycloadditions.