Zinc dimethyldithiocarbamate is a

coordination complex A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ' ...

of zinc with dimethyldithiocarbamate. It is a pale yellow solid that is used as a

fungicide Fungicides are pesticides used to kill parasitic fungi or their spores. Fungi can cause serious damage in agriculture, resulting in losses of yield and quality. Fungicides are used both in agriculture and to fight fungal infections in animals, ...

, the

sulfur vulcanization Sulfur vulcanization is a chemical process for converting natural rubber or related polymers into materials of varying hardness, elasticity, and mechanical durability by heating them with sulfur or sulfur-containing compounds. Sulfur forms cros ...

of rubber, and other industrial applications.

Applications

Known as ziram in agriculture, it was introduced in the United States in 1960 as a broad-spectrum fungicide. It was used to address scab on apples and pears, leaf curl in peaches, and

anthracnose A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore can have major economic implications for agriculture and horticultur ...

and

blight Blight is a specific symptom affecting plants in response to infection by a pathogenic organism. Description Blight is a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs. A ...

in tomatoes. In 1981, additional uses for ziram were approved, including the prevention of leaf blight and scab on almonds, shot-hole in apricots, brown rot and leaf spot in cherries, and scab and anthracnose in pecans. Ziram also began to be used on residential ornaments as a bird and mammal repellent. As a protectant fungicide, it is active on the plant’s surface where it forms a

chemical A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combin ...

barrier between the plant and a fungus. A protectant fungicide is not absorbed into the plant and must be applied prior to infection. Ziram can either be directly sprayed on to a plant’s leaf or it can be used as a soil and seed treatment. The top five crops ziram is used on are:

almonds The almond (''Prunus amygdalus'', syn. ''Prunus dulcis'') is a species of tree from the genus ''Prunus''. Along with the peach, it is classified in the subgenus ''Amygdalus'', distinguished from the other subgenera by corrugations on the sh ...

peaches The peach (''Prunus persica'') is a deciduous tree first domesticated and cultivated in China. It bears edible juicy fruits with various characteristics, most called peaches and the glossy-skinned, non-fuzzy varieties called nectarines. Peac ...

, nectarines,

pear Pears are fruits produced and consumed around the world, growing on a tree and harvested in late summer into mid-autumn. The pear tree and shrub are a species of genus ''Pyrus'' , in the Family (biology), family Rosaceae, bearing the Pome, po ...

s, and table and

raisin A raisin is a Dried fruit, dried grape. Raisins are produced in many regions of the world and may be eaten raw or used in cooking, baking, and brewing. In the United Kingdom, Republic of Ireland, Ireland, New Zealand, Australia and South Afri ...

grapes. Alternatively, ziram is used as an additive ingredient in industrial

adhesive Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advantage ...

caulking Caulk (also known as caulking and calking) is a material used to seal joints or seams against leakage in various structures and piping. The oldest form of caulk consisted of fibrous materials driven into the wedge-shaped seams between board ...

, and paint. It also serves as a

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

and

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

repellent on outdoor ornamental items.

Chemistry

The compound is a prototypical zinc dithiocarbamate, a broad class of

es with the formulae Zn(R₂NCS₂)₂, where R can be varied. Such compounds are produced by treating zinc and

dithiocarbamate In organic chemistry, a dithiocarbamate is a chemical compound with the general formula . It contains the functional group with the Chemical structure, structure . It is the analog of a carbamate in which both oxygen atoms are replaced by sulfur ...

(R₂NCS₂⁻), as illustrated with dimethyldithiocarbamate: :2 (CH₃)₂NCS₂⁻ + Zn²⁺ → Zn((CH₃)₂NCS₂)₂ Annually, approximately 1.9 million pounds of the active ziram ingredient are used. Ziram is often sold in powder or granule form. Zinc bis(diethyldithiocarbamate) complexes degrade thermally to give

zinc sulfide Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various i ...

Structure

Compounds of the type Zn(S₂CNR₂)₂ are dimeric, i.e. their proper formula is n(S₂CNR₂)₂sub>2. Each Zn center is in a distorted pentacoordinate site, with four Zn–S bonds of 2.3 Å length and one Zn–S interaction is over 2.8 Å in length. Mono-zinc derivatives are obtained by adding strong

ligand In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...

s (L) such as amines, which give adducts Zn(S₂CNR₂)₂L.

Ecological effects

The U.S. Environmental Protection Agency has concluded that ziram poses a low toxicity risk to mammals, a moderate risk to birds, and a high risk to aquatic species. After reviewing studies that investigated the effect of ziram on aquatic organisms, the Pesticide Action Network Pesticide Database concluded that its LC₅₀dose (amount of pesticide that is lethal to 50% of the test organisms within the stated study time) for

amphibians Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

places it in the "highly toxic" category.

References

External links

* http://pmep.cce.cornell.edu/profiles/extoxnet/pyrethrins-ziram/ziram-ext.html * {{Monoamine neurotoxins Fungicides bis

zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It 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 tabl ...