2, 3-butanedione dihydrazone

The template condensation of 2,3-butanedione dihydrazone with aldehydes or ketones affords a variety of octaazabis(a-diimine) macrocyclic complexes of nickel(II), according to the Scheme 48.2655 NH deprotonation with py or Et3N of the aforementioned cationic complexes leads to neutral NiL species. 

CLATHROCHELATES FORMED BY THE REACTION OF TRIS(2,3-BUTANEDIONE DIHYDRAZONE)-METAL COMPLEXES WITH FORMALDEHYDE [5,6,14,15,20,21-HEXAMETHYL-1,3,4,7,8,10,... 

Butanedione dihydrazone was synthesized by a modification of the procedure described by Busch and Bailar.6 A solution of hydrazine hydrate, 27 g... 

Tris(2,3-butanedione dihydrazone)metal bis(tetrafluoroborate) complexes, [M(C4H10N4)3] [BF4]2, are prepared by dissolving 2.00 g (0.0175 mole) of 2,3-butanedione dihydrazone in 100 mL of hot absolute ethanol and adding a solution of 2.15 g (0.00586 mole) of the appropriate metal(II) tetrafluoro-borate hexahydrate salt (or 41% aqueous solution in the case of commercially available Fe(BF4)2) in 30 mL of absolute ethanol. After the solution is cooled, the product is filtered on a Buchner funnel, washed with absolute ethanol, and dried in vacuo. Yields range from 70 to 95%. All these complexes, except those of iron(II), slowly decompose when stored under ordinary conditions (i.e., at room temperature, bottled in air) and should be used within a week of preparation. 

The clathrochelate complexes, [M(ClgH30Ni2)] [BF4]2, are prepared by adding 5.0 g of 37% aqueous formaldehyde solution to a suspension of 5 g of the appropriate tris(2,3-butanedione dihydrazone)metal bis(tetrafluoroborate) complex in acetonitrile. The condensation reaction is catalyzed by the addition of 0.5 mL of concentrated tetrafluoroboric acid. An immediate darkening of the solutions is observed as the condensation reaction proceeds. The iron (II)-containing solution becomes a very intense purple the nickel(II) solution becomes very dark olive-brown. Precipitation of the clathrochelates requires the addition of approximately 30% by volume of diethyl ether and refrigeration. The products are filtered from the solution, washed with methanol, and air dried. The iron(II) complex is somewhat more soluble in acetonitrile than the other complexes, and increased yields can be obtained by the dropwise addition... 

For example, by template condensation of 2,3-butanedione dihydrazone with formaldehyde, a series of nickel(II), cobalt(II) and copper(II) complexes with the neutral macrocyclic ligand L36 were obtained (Eq. 2.1) [1-4]. 

It is possible to carry out 2,3-butanedione dihydrazone interaction with acetaldehyde, propionaldehyde, acetone or cyclohexanone on the nickel (II) matrix, forming macrocycles similar to L36 [2]. 

Attempts to synthesise manganese(II) and zinc(II) octaazamacrocyclic compounds had no success. Complexes of these metals with 2,3-butanedione dihydrazone react with formaldehyde, but in this case products containing the acyclic tetradentate ligand L37 are isolated [2]. 

Crystal structures have been studied on two monomeric model compounds glyoxal dihydrazone (GDH) [9] and 2,3-butanedione dihydrazone (BDDH) [7]. The geometric parameters for these two materials are given in Table 16.1. GDH crystallizes in the monoclinic space group P2i/a and has cell parameters a = 7.744 A, b = 4.m A, c = 8.063 A, and ) = 115.66° while... 

The condensation of butanedione-2,3-dihydrazone with formaldehyde on a metal ion (Fe-, Co-" and Ni +) matrix (Scheme 74), performed by Goedken and Peng, led to the formation of clathrochelate [M(thz)](BFi)2 complexes. Direct reaction between the three components proved to be efficient only with iron(II) ion [183]. Therefore, nickel, cobalt, and iron(II) tris-dihydrazonates were preliminarily synthesized. It was noted that even when the reaction was carried out under nitrogen and cobalt(II) tris-dihydrazonate was used as the starting material, only cobalt(III) clathrochelate could be isolated from the reaction mixture. Its reduction with anhydrous hydrazine yielded cobalt(II) clathrochelate [95, 183]. 

Table 16.1 Bond lengths and bond angles for glyoxal dihydrazone (GDH) and 2,3-butanedione dihydr one (BDDH). The atomic numbering is shown below.

Monoxime, 2-benzothiazolylhydrazone see 2,3-Butanedione (2-benzothiazolyl)hydrazone, B-00588 Dioxime see Dimethylglyoxime, D-00862 Dihydrazone [3457-52-1]. 2,3-Butanedione dihvdrazone, 9CI C4H10N4 M 114.150... 

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