In organic chemistry, a dithiocarbamate is a functional group with the general formula and structure . It is the analog of a carbamate in which both oxygen atoms are replaced by sulfur atoms (when only 1 oxygen is replaced the result is thiocarbamate).
A common example is sodium diethyldithiocarbamate. Dithiocarbamates and their derivatives are widely used in the vulcanization of rubber.
Many primary and secondary amines react with carbon disulfide and sodium hydroxide to form dithiocarbamate salts:
R2NH + CS2 + NaOH → R2NCS2−Na+ + H2O
Ammonia reacts with CS2 similarly:
2 NH3 + CS2 → H2NCS2−NH4+
Dithiocarbamate salts are pale colored solids that are soluble in water and polar organic solvents.
Dithiocarbamates are readily S-alkylated. Thus, methyl dimethyldithiocarbamate can be prepared by methylation of the dithiocarbamate:
(CH3)2NCS2Na + (CH3O)2SO2 → (CH3)2NC(S)SCH3 + Na[CH3OSO3]
Oxidation of dithiocarbamates gives the thiuram disulfide:
2 R2NCS2− → [R2NC(S)S]2 + 2e−
Thiuram disulfides react with Grignard reagents to give esters of dithiocarbamic acid:
[R2NC(S)S]2 + R'MgX → R2NC(S)SR' + R2NCS2MgX
Dithiocarbamates react with transition metal salts to give a wide variety of transition metal dithiocarbamate complexes.
Dithiocarbamates are described by invoking resonance structures that emphasize the pi-donor properties of the amine group. This bonding arrangement is indicated by a short C–N distance and the coplanarity of the NCS2 core as well as the atoms attached to N.
Because of the pi-donation from nitrogen, dithiocarbamates are more basic than structurally related anions such as dithiocarboxylates and xanthates. Consequently, they tend to bind as bidentate ligands. Another consequence of the C–N multiple bonding is that rotation about that bond is subject to a high barrier.
Several transition metal dithiocarbamate complexes are useful in industry. Zinc dithiocarbamates are used to modify the crosslinking of certain polyolefins with sulfur, a process called vulcanization. They are used as ligands for chelating metals.
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In organic chemistry, a dithiocarbamate is a functional group with the general formula and structure . It is the analog of a carbamate in which both oxygen atoms are replaced by sulfur atoms (when only 1 oxygen is replaced the result is thiocarbamate). A common example is sodium diethyldithiocarbamate. Dithiocarbamates and their derivatives are widely used in the vulcanization of rubber.
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes.