Complexes perchlorates

The perchlorate ion, CIO , is considered to be noncoordinating ia the presence of water. When water is rigorously excluded, anhydrous complexes such as Ni(CH2CN) (C10 2> where n is 2, 4, or 6, can be prepared. Perchlorate complexes of Ni, Co, Cu, and Sn have been reported. In each case, however, an organic group such as CH CN, CH, or pyridyl is involved (73—76). 

The mixture of diastereomers has been separated into its two principal components by Izatt, Haymore, Bradshaw and Christensen who had previously identified the two principal diastereomers as the cis-syn-cis and cis-anti-cis isomers. Their previous separation technique involved a protracted chromatography on alumina but the new method relied upon the difference in water solubility between the lead perchlorate and hydroniur perchlorate complexes. The lead perchlorate complex is essentially insoluble in aqueous solution and precipitates from it. Using this method, one may obtain 39% of the high-melting polymorph (mp 83—84°) and 44% of the low-melting compound (mp 62—63°). Note that the former also exists in a second crystalline form, mp 69—70°. 

The similarity between the cryptands and the first of these molecules is obvious. Compound 7 7 is a urethane equivalent of [2.2.2]-cryptand. The synthesis of 7 7 was accomplished using a diacyl halide and l,10-diaza-18-crown-6 (shown in Eq. 8.13). Since amidic nitrogen inverts less rapidly than a tertiary amine nitrogen, Vogtle and his coworkers who prepared 7 7, analyzed the proton and carbon magnetic resonance spectra to discern differences in conformational preferences. Compound 7 7 was found to form a lithium perchlorate complex. 

Figure 17.22 The structures of monodeniate perchlorate complexes (see text).

Among the J ,J -DBFOX/Ph-transition(II) metal complex catalysts examined in nitrone cydoadditions, the anhydrous J ,J -DBFOX/Ph complex catalyst prepared from Ni(C104)2 or Fe(C104)2 provided equally excellent results. For example, in the presence of 10 mol% of the anhydrous nickel(II) complex catalyst R,R-DBFOX/Ph-Ni(C104)2, which was prepared in-situ from J ,J -DBFOX/Ph ligand, NiBr2, and 2 equimolar amounts of AgC104 in dichloromethane, the reaction of 3-crotonoyl-2-oxazolidinone with N-benzylidenemethylamine N-oxide at room temperature produced the 3,4-trans-isoxazolidine (63% yield) in near perfect endo selectivity (endo/exo=99 l) and enantioselectivity in favor for the 3S,4J ,5S enantiomer (>99% ee for the endo isomer. Scheme 7.21). The copper(II) perchlorate complex showed no catalytic activity, however, whereas the ytterbium(III) triflate complex led to the formation of racemic cycloadducts. 

Methylamine Cupric Perchlorate Complex. (MeNH2)4Cu(Cl04)2, C4H2od2C uN408, mw 386.72, N 14.49%. It is prepd by the interaction of methylamine and Cu(II)perchlorate and is obtd as blue crysts which expld in 30secs at 247°... 

Thermal analysis has proved useful in determining the number of sulfoxide moieties which are lattice-held in a given complex. For example, the thorium and zirconyl perchlorate complexes of Me2SO undergo thermal degradation (Eqs. (2) and (3)]. 

Complexes of picolinamide with lanthanide perchlorates, nitrates, and isothiocyanates have been isolated by Condorelli et al. (59). All these complexes show changes in the stoichiometry on going from La(III) to Lu(III). The ligand acts as bi-dentate with the oxygen of the amide group as well as the heterocyclic nitrogen coordinating to the metal (Structure I). While the anions in the perchlorate complexes are not coordinated to lanthanide ions, those in the nitrate and isothiocyanate complexes are coordinated. 

A number of methyl substituted PyO have been tried as ligands for coordination with the lanthanides. Depending on the position of the substituent, these ligands impart different degrees of steric strain for the formation of complexes. Since substituents in the 4 or 3 position do not introduce substantial steric hindrance to coordination, Harrison and Watson (160) could synthesize octakis-4-MePyO complexes. Subsequently, Koppikar and Soundararajan (161) could also synthesize octakis-3-MePyO complexes with lanthanide perchlorates. Complexes of 4-MePyO (162, 163) and 3-MePyO (164, 165) with lanthanide iodides and bromides also have a L M of 8 1. 

The equilibrium constant (A exch for extraction, exc/tange) for this reaction increases in the order CIO4 < NO3 < Cl" < HSO4 < F". From Chapter 3 it follows that the formation constants for the metal complex ML " nsnally increases in the same order. Therefore, in order to extract a metal perchlorate complex, very high CIO4 concentrations are reqnired the perchlorate complex is easily replaced by anions higher in the seqnence. 

The trans- [chloro(isocyanide)bis(triethylphosphine)platinum(Il)] perchlorate complexes used below were prepared by the method of Church and Mays.6... 

Comparison of Structures between Nickel(I) and Nickel(II) Perchlorate Complexes... 

Caution. Perchlorate complexes are extremely hazardous. Use of the salts of [Au(PMe2Ph)]+ with other weakly coordinating anions such as [PF6], or [CF3S03] is advised. 

According to Friederich and Vervoorst (Ref 11, p 49) the chlorate and perchlorate complexes decomp with explosive violence, when heated, and the reactions proceed as follows ... 

Although tellurium tetrachloride has been reported55 to form a 1 2 complex with acetamide, there appears to be little other information available on the complex. Similarly, the reported tributyl phosphate complex of polonium tetrachloride56 has received little attention. The formation of a polonium(IV) perchlorate complex with tributyl phosphate has been suggested57 in the solvent extraction of polonium from perchloric acid. 

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