(NHC)Cu-Catalyzed Mild C–H Amidation of (Hetero)arenes with Deprotectable Carbamates: Scope and Mechanistic Studies

Primary arylamines are an important unit broadly found in synthetic, biological, and materials science. Herein we describe the development of a (NHC)Cu system that mediates a direct C–H amidation of (hetero)­arenes by using <i>N</i>-chlorocarbamates or their sodio derivatives as the practical amino sources. A facile stoichiometric reaction of reactive copper-aryl intermediates with the amidating reagent led us to isolate key copper arylcarbamate species with the formation of a C–N bond. The use of ^<i>t</i>BuONa base made this transformation catalytic under mild conditions. The present (NHC)­Cu-catalyzed C–H amidation works efficiently and selectively on a large scale over a range of arenes including polyfluorobenzenes, azoles, and quinoline <i>N</i>-oxides. Deprotection of the newly installed carbamate groups such as Boc and Cbz was readily performed to afford the corresponding primary arylamines

3,6-Connected Metal–Organic Frameworks Based on Triscarboxylate as a 3-Connected Organic Node and a Linear Trinuclear Co₃(COO)₆ Secondary Building Unit as a 6-Connected Node

The solvothermal reactions of cobalt­(II) chloride hexahydrate and 1,3,5-benzenetribenzoic acid (H₃BTB) in anhydrous <i>N</i>,<i>N</i>′-dimethylacetamide (DMA) at two different reaction temperatures and reactant concentrations led to two 3,6-connected metal–organic frameworks (MOFs) with different net topologies based on the ligand as a <i>C</i>₃ symmetric 3-connected organic node and the linear trinuclear cobalt carboxylate cluster, Co₃(COO)₆, as a 6-connected secondary building unit (SBU). MOF [Co₃(BTB)₂(DMA)₄], <b>1</b>, with a linear trinuclear cobalt carboxylate cluster, Co₃(COO)₆, and with an inversion point symmetry with “compressed trigonal antiprismatic” 6-connectivity, is a two-dimensional (2-D) layered structure of a 3,6-connected <b>kgd</b> net topology. However, the same linear trinuclear cobalt carboxylate cluster, Co₃(COO)₆, with a 2-fold point symmetry with “compressed trigonal prismatic” 6-connectivity leads to the three-dimensional (3-D) network of <b>2</b>, with an unprecedented 3,6-connected net topology with the point symbol (4³)₂(4³·12¹²). The 2-D layered framework, <b>1</b>, shows a significant sorption hysteresis for adsorbates with relatively strong interactions with the framework, such as N₂ and CO₂

3,6-Connected Metal–Organic Frameworks Based on Triscarboxylate as a 3-Connected Organic Node and a Linear Trinuclear Co₃(COO)₆ Secondary Building Unit as a 6-Connected Node

The solvothermal reactions of cobalt­(II) chloride hexahydrate and 1,3,5-benzenetribenzoic acid (H₃BTB) in anhydrous <i>N</i>,<i>N</i>′-dimethylacetamide (DMA) at two different reaction temperatures and reactant concentrations led to two 3,6-connected metal–organic frameworks (MOFs) with different net topologies based on the ligand as a <i>C</i>₃ symmetric 3-connected organic node and the linear trinuclear cobalt carboxylate cluster, Co₃(COO)₆, as a 6-connected secondary building unit (SBU). MOF [Co₃(BTB)₂(DMA)₄], <b>1</b>, with a linear trinuclear cobalt carboxylate cluster, Co₃(COO)₆, and with an inversion point symmetry with “compressed trigonal antiprismatic” 6-connectivity, is a two-dimensional (2-D) layered structure of a 3,6-connected <b>kgd</b> net topology. However, the same linear trinuclear cobalt carboxylate cluster, Co₃(COO)₆, with a 2-fold point symmetry with “compressed trigonal prismatic” 6-connectivity leads to the three-dimensional (3-D) network of <b>2</b>, with an unprecedented 3,6-connected net topology with the point symbol (4³)₂(4³·12¹²). The 2-D layered framework, <b>1</b>, shows a significant sorption hysteresis for adsorbates with relatively strong interactions with the framework, such as N₂ and CO₂

Synthesis, Crystal Structures, and Magnetic Properties of Cyanide-Bridged W^VMn^III Anionic Coordination Polymers Containing Divalent Cationic Moieties: Slow Magnetic Relaxations and Spin Crossover Phenomenon

Two trimetallic coordination complexes were prepared by self-assembly of [W­(CN)₈]^3– and the Mn­(III) Schiff base followed by the addition of a Zn­(II) or Fe­(II) cationic unit. The octacyanotungstate connects neighboring Mn­(III) centers to form a one-dimensional chain. The anionic chain requires cationic units of Zn­(II) or Fe­(II) to maintain charge balance in the structure. The Zn-containing complex shows ferrimagnetic behavior originating from the antiparallel alignment of W­(V) and Mn­(III) spins within the chain, which leads to slow magnetic relaxation at low temperatures. For the Fe­(II)-containing compound, Fe­(II) moieties are integrated into the ferrimagnetic chains, altering their spin states depending on the temperature. It appears that the coexistence of high- and low-spin states in the low temperature regime is responsible for the slower and faster relaxations of the magnetization