Hydrazide complexes

Methods of Synthesis of Hydrazide Complexes 133.7.2.1 Hydrazido(2 ) complexes... 

The aldehyde or ketone can now desorb, leading to the initial copper(I) hydrazide complex 13 which re-enters the catalytic cycle. The replacement of DEAD-H2 12 by DEAD 19 can be easily understood when considering this catalytic cycle. Indeed, several entries to the main catalytic cycle are possible, either via the hydrazino copper species 13 or via the direct formation of the ternary loaded complex 18 from the azo-derivative 19, Phen CuCl 3 and the alcohol 1. The key-role played by the hydrazine or azo compounds can also be readily appreciated when considering the proposed mechanistic rationale. The hydrazide, not only helps in reducing the copper(II) salt to the copper(I) state but, by virtue of its easy passage into the azo derivative, it also acts as a hydrogen acceptor, allowing the efficient oxidation of the alcohol into the carbonyl compound. 

Complexes formed between thiourea (Htu) and vanadyl with the putative formulation [VO(OMe)(tu)2] (29) and the porphyrin complex 30 exhibit activity against HlV-1. 29 additionally is a spermicide. Preparations containing the macrocycle 31 and vanadyl in a 1 1 ratio and the hydrazide complex 32 are examples of in vitro inhibitory effects against tuberculosis mycobacteria. 

Dinitrogen complexes of molybdenum and tungsten with mono-, di - and tii - tertiary phosphine co -ligands are electrosynthesised from molecular nitrogen andMo or precursors vw cleavage of halide or thiolate bonds and from Mo or oxide, imide or hydrazide complexes by... 

Another pathway takes place upon cyclization of hydrazides of benzene carboxylic acids in the presence of CuCl in an inert atmosphere in DMF. However, only the cyclization of hydrazide 76 (R = H) in conditions of copper catalysis makes it possible to isolate compound 77 (yield 20%). Other hydrazides of acetylenylbenzoic acids react to give a complex mixture of products (Scheme 132) (85IZV1367 85MI2). 

Complexes (65) and (66) result from the reaction of IrCl3 with inah and PPh3 (inah = isonicotinic acid hydrazide).92 Reaction of Troger s base (tb) (67) with IrCl3 yields dark violet tb 2IrCl3 (6S).93 (68) was not catalytically active towards the hydrosilylation of alkynes. 

A series of mixed-ligand thiosalicylato complexes of the type PtL(PPh3)Y2] (Y2 = thiosalicylate L = pyridine, 4-methylpyridine, picolinic acid hydrazide, imidazole) have been prepared by the reaction of [PtCl2(COD)] with PPh3, thiosalicylic acid, and A-donor ligand in MeOH solution.375 The X-ray structure of the pyridine derivative (162) was determined, the first example of where a platinum atom is coordinated to a N, O, P, and S donor atom set. 

Several heavy metal complexes of the hydrazide (ML2.2H20) exploded around... 

Solution studies of the complexes outlined in Table 3 are in general agreement that they remain aggregated in solution, with the most common form being dimers.325 Solution studies of 300 in arene solvent indicate that at least two independent aggregates coexist.322 The most likely scenario from the data available is that a dimer-hexamer equilibrium is present in solution. Gas-phase studies of the hydrazides have proved to be problematic due to decomposition of the complexes on volatilization. 

A small number of mixed anion complexes containing lithiated hydrazides have also been identified. 

These include complexes containing both mono- and dilithiated hydrazides, as well as products resulting from the fragmentation of the N-N backbone. 

Figure 22 Structures of the hexameric sodium hydrazide 317 and the mixed mono- and dianionic complex 318. Hydrogen atoms have been omitted for clarity.

Aldehyde-containing macromolecules will react spontaneously with hydrazide compounds to form hydrazone linkages. The hydrazone bond is a form of Schiff base that is more stable than the Schiff base formed from the interaction of an aldehyde and an amine. The hydrazone, however, may be reduced and further stabilized by the same reductants utilized for reductive amination purposes (Chapter 3, Section 4.8). The addition of sodium cyanoborohydride to a hydrazide-aldehyde reaction drives the equilibrium toward formation of a stable covalent complex. Mallia (1992) found that adipic acid dihydrazide derivatization of periodate-oxidized dextran (containing multiple formyl functionalities) proceeds with much greater yield when sodium cyanoborohydride is present. 

---