Strong π-stacking causes unusually large anisotropic thermal expansion and thermochromism.

π-stacking in ground-state dimers/trimers/tetramers of -butoxyphenyl(naphthalene)diimide (BNDI) exceeds 50 kcal ⋅ mol in strength, drastically surpassing that for the [pyrene] excimer (∼30 kcal ⋅ mol; formal bond order = 1) and similar to other weak-to-moderate classical covalent bonds. Cooperative π-stacking in triclinic (BNDI-T) and monoclinic (BNDI-M) polymorphs effects unusually large linear thermal expansion coefficients (α , α , α , β) of (452, -16.8, -154, 273) × 10 ⋅ K and (70.

Cupriphication of gold to sensitize d-d metal-metal bonds and near-unity phosphorescence quantum yields.

Outer-shell s/p orbital mixing with d orbitals and symmetry reduction upon cupriphication of cyclic trinuclear trigonal-planar gold(I) complexes are found to sensitize ground-state Cu(I)-Au(I) covalent bonds and near-unity phosphorescence quantum yields. Heterobimetallic AuCu {[Au(μ-C,N-EtIm)Cu(µ-3,5-(CF)Pz)], (4a)}, AuCu {[Au(μ-C,N-BzIm)Cu(µ-3,5-(CF)Pz)], (1) and [Au(μ-C,N-MeIm)Cu(µ-3,5-(CF)Pz)], (3a)}, AuCu {[Au(μ-C,N-MeIm)Cu(µ-3,5-(CF)Pz)], (3b) and [Au(μ-C,N-EtIm)Cu(µ-3,5-(CF)Pz)], (4b)} and stacked Au/Cu {[Au(μ-C,N-BzIm)][Cu(µ-3,5-(CF)Pz)], (2)} form upon reacting Au {[Au(μ-C,N-(N-R)Im)] ((N-R)Im = imidazolate; R = benzyl/methyl/ethyl = BzIm/MeIm/EtIm)} with Cu {[Cu(μ-3,5-(CF)Pz)] (3,5-(CF)Pz = 3,5-bis(trifluoromethyl)pyrazolate)}. The crystal structures of 1 and 3a reveal stair-step infinite chains whereby adjacent dimer-of-trimer units are noncovalently packed via two Au(I)⋯Cu(I) metallophilic interactions, whereas 4a exhibits a hexanuclear cluster structure wherein two monomer-of-trimer units are linked by a genuine d-d polar-covalent bond with ligand-unassisted Cu(I)-Au(I) distances of 2.

The curious case of mesityl azide and its reactivity with bpyNiEt2.

A DFT analysis of the reaction of bpyNiEt2 with ArN3 was performed for para-tolyl-azide (Ar = pTol), 3,5-dimethyl-phenyl-azide (Ar = mXy) and ortho-tolyl-azide (Ar = oTol), and mesityl-azide (MesN3). Of particular interest were the different products obtained for the latter (ethylene, butane, azomesitylene, mesityl-ethylamine, etc.) versus the other reagents, i.

Flavin-catalyzed insertion of oxygen into rhenium-methyl bonds.

Flavins and related molecules catalyze organic Baeyer-Villiger reactions. Combined experimental and DFT studies indicate that these molecules also catalyze the insertion of oxygen into metal-carbon bonds through a Baeyer-Villiger-like transition state.