4 research outputs found
(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)Âarenes 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 <sup><i>t</i></sup>BuONa base made this transformation catalytic under mild conditions.
The present (NHC)ÂCu-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 Co<sub>3</sub>(COO)<sub>6</sub> Secondary Building Unit as a 6-Connected Node
The solvothermal reactions of cobaltÂ(II) chloride hexahydrate
and
1,3,5-benzenetribenzoic acid (H<sub>3</sub>BTB) 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><sub>3</sub> symmetric 3-connected organic node and the linear trinuclear cobalt
carboxylate cluster, Co<sub>3</sub>(COO)<sub>6</sub>, as a 6-connected
secondary building unit (SBU). MOF [Co<sub>3</sub>(BTB)<sub>2</sub>(DMA)<sub>4</sub>], <b>1</b>, with a linear trinuclear cobalt
carboxylate cluster, Co<sub>3</sub>(COO)<sub>6</sub>, 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, Co<sub>3</sub>(COO)<sub>6</sub>, 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 (4<sup>3</sup>)<sub>2</sub>(4<sup>3</sup>·12<sup>12</sup>). The 2-D layered framework, <b>1</b>, shows a significant
sorption hysteresis for adsorbates with relatively strong interactions
with the framework, such as N<sub>2</sub> and CO<sub>2</sub>
3,6-Connected Metal–Organic Frameworks Based on Triscarboxylate as a 3-Connected Organic Node and a Linear Trinuclear Co<sub>3</sub>(COO)<sub>6</sub> Secondary Building Unit as a 6-Connected Node
The solvothermal reactions of cobaltÂ(II) chloride hexahydrate
and
1,3,5-benzenetribenzoic acid (H<sub>3</sub>BTB) 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><sub>3</sub> symmetric 3-connected organic node and the linear trinuclear cobalt
carboxylate cluster, Co<sub>3</sub>(COO)<sub>6</sub>, as a 6-connected
secondary building unit (SBU). MOF [Co<sub>3</sub>(BTB)<sub>2</sub>(DMA)<sub>4</sub>], <b>1</b>, with a linear trinuclear cobalt
carboxylate cluster, Co<sub>3</sub>(COO)<sub>6</sub>, 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, Co<sub>3</sub>(COO)<sub>6</sub>, 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 (4<sup>3</sup>)<sub>2</sub>(4<sup>3</sup>·12<sup>12</sup>). The 2-D layered framework, <b>1</b>, shows a significant
sorption hysteresis for adsorbates with relatively strong interactions
with the framework, such as N<sub>2</sub> and CO<sub>2</sub>
Synthesis, Crystal Structures, and Magnetic Properties of Cyanide-Bridged W<sup>V</sup>Mn<sup>III</sup> Anionic Coordination Polymers Containing Divalent Cationic Moieties: Slow Magnetic Relaxations and Spin Crossover Phenomenon
Two trimetallic coordination
complexes were prepared by self-assembly
of [WÂ(CN)<sub>8</sub>]<sup>3–</sup> and the MnÂ(III) Schiff
base followed by the addition of a ZnÂ(II) or FeÂ(II) cationic unit.
The octacyanotungstate connects neighboring MnÂ(III) centers to form
a one-dimensional chain. The anionic chain requires cationic units
of ZnÂ(II) or FeÂ(II) to maintain charge balance in the structure. The
Zn-containing complex shows ferrimagnetic behavior originating from
the antiparallel alignment of WÂ(V) and MnÂ(III) spins within the chain,
which leads to slow magnetic relaxation at low temperatures. For the
FeÂ(II)-containing compound, FeÂ(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