| 释义 |
chelate, a. (and n.)|ˈkiːleɪt|
[f. chela1 + -ate2.]
1. Zool. Having chelæ or prehensile claws.
1826Kirby & Sp. Entomol. (1828) IV. xlvii. 397 Mandibles chelate. 1836–9Todd Cycl. Anat. II. 910 The chelate organs of Crustacea and Arachnida. 1880Huxley Cray-Fish 22.
2. Chem. Applied to a group (ligand) that loops round a central metal ion to be attached at two or more points, and also to the co-ordination compound so formed. Hence as n., a chelate compound.
1920Morgan & Drew in Jrnl. Chem. Soc. CXVII. 1457 The adjective ‘chelate’, derived from the great claw or ‘chela’ (‘chely’) of the lobster and other crustaceans, is suggested for these caliper-like groups which function as two associating units and fasten on to the central metallic atom so as to produce heterocyclic rings. Among the compounds which..function as chelate groups are ethylenediamine, [etc.]. 1935Nature 26 Jan. 147/2 Abnormally large differences in solubility and volatility between isomers of some disubstituted benzene derivatives have been explained..as arising from the presence of chelate rings in the anomalous compounds. 1955Sci. News Let. 15 Oct. 248/2 These compounds, known as chelates. 1957Sci. News XLIV. 19 The so-called ‘chelate’ groups which are able to attach themselves at more than one position around the metal atom. 1965Phillips & Williams Inorg. Chem. I. vii. 252 A chelate ligand such as ethylenediamine, which is able to occupy two coordinate positions around the copper (II) ion and thus displace two water molecules per ligand attached.
Hence ˈchelate v. trans., to combine with (a substance) to form a chelate ring; so cheˈlated ppl. a.; cheˈlating vbl. n. and ppl. a.; cheˈlation, the process producing a chelate compound; cheˈlator, a substance producing a chelate compound.
1922Morgan & Moss in Jrnl. Chem. Soc. CXXI. 2862 A partly chelated lake was obtained by adding slowly a solution of..dinitrosoresorcinol. Ibid. 2865 The partially chelated compound. 1932Jrnl. Chem. Soc. 952 (title) Chemical evidence of chelation in the sodium salts of o-hydroxybenzaldehydes. 1946Nature 16 Nov. 708/1 The correspondence between the six-membered rings chelating the metal in both systems is apparent. 1953Jrnl. Brit. Interplan. Soc. XII. 162 It is difficult to keep all needed minerals in solution. For this purpose a chelating agent such as ethylene diamine tetracetic acid is commonly used. 1955Sci. Amer. Aug. 39/1 The powerful chelating agent known as EDTA has a high affinity for plutonium and the rare earths. 1958New Scientist 2 Oct. 941/1 Other lichen derivatives will come into increasing use as chelators in industrial chemistry. 1959Sci. News LII. 9 The attachment of two or more co-ordinate links from the same complexing molecule (ligand) to a single metal atom is usually known as chelation. 1961Lancet 16 Sept. 637/2 Clinical studies on the use of chelating agents in the treatment of various cardiovascular diseases. Ibid. 638/2 We suggest that E.D.T.A. chelated the zinc of this exogenous hormone.
▸ chelation therapy n. therapy in which a chelating agent is used to lower abnormally high levels of a metal in the body, used to treat iron overload (as in haematological disorders), metabolic disorders such as Wilson's disease, and heavy metal poisoning, and also as a complementary therapy (of unproven efficacy) for other conditions.
1960H. Peters in M. Seven & L. Johnson Metal-Binding in Med. xxiii. 190/2 Elevation of urinary zinc levels from 2 to 36 times normal before *chelation therapy..seemed to parallel symptoms more closely. 1982Arch. Dis. Childhood 12 929 The desferrioxamine test was useful..in assessing response to chelation therapy thus enabling such treatment to be started early to prevent harm from iron overload. 2000Record (Kitchener-Waterloo, Ontario) (Nexis) 5 Apr. a10 The U.S. federal trade commission ruled in 1988 that chelation therapy's claims of effectiveness for atherosclerosis are unsubstantiated. 2004Current Med. Chem. 11 2161 Deferiprone..is effective and inexpensive to synthesise thus increasing the prospects of making it available to most thalassaemia patients in third world countries who are not currently receiving any form of chelation therapy. |