Related Experiment Video
Updated: Aug 4, 2025

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Reactivity of Yellow Arsenic towards Cyclic (Alkyl)(Amino) Carbenes (CAACs)
Maria Haimerl1, Christoph Schwarzmaier1, Christoph Riesinger1
1Institute for Inorganic Chemistry, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
Abstract:
Different cyclic (alkyl)(amino)carbenes (CAACs) were reacted with yellow arsenic. Several products [(CAAC-n)2 (μ,η1:1 -As2 )] (n=1 (1), 4 (2)), [(CAAC-2)3 (μ3 ,η1:1:1 -As4 )] (3) and [(CAAC-3)4 (μ4 ,η1:1:1:1 - As8 )] (6) were isolated due to the differing steric properties of CAAC-1-4. The products contain As2 , As4 or As8 units and represent the first examples of CAACs-substituted products of yellow arsenic. The reactivity of As4 was compared with the reactivities of P4 and the interpnictogen compound AsP3 , which led to a series of phosphorus-containing derivatives such as ([(CAAC-3)3 (μ3 ,η1:1:1 -P4 )] (4) and [(CAAC-3)4 (μ4 ,η1:1:1:1 -P8 )] (7)) and [(CAAC-3)3 (μ3 ,η1:1:1 -AsP3 )] (5). The products were characterized by spectroscopic and crystallographic methods and DFT computations were performed to clarify their formation pathway.
Related Concept Videos
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo,...
Nucleophilic Aromatic Substitution: Elimination–Addition
Relative Reactivity of Carboxylic Acid Derivatives
A key factor in assessing the reactivity of the acid derivatives is the basicity of the substituent or the leaving group. The lower the basicity of the leaving group, the higher the reactivity of the derivative. The basicity of the leaving group follows this order:
Halide ions < Acyloxy ions < Alkoxy ions < Amine ions
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H
Aryldiazonium Salts to Azo Dyes: Diazo Coupling

![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)