Chloro, bromo, and iodo complexes

There are many fluorocomplexes of aluminum. The general formula for the fluoroaluminates is M I, I, a I- based upon A1F6 octohedra. which may share comers to give other ratios of A1 F than 1 6. Chloroaluminates of the type M lAlClj] are obtainable from fused melts. Aluminum ions form chloro-, bromo-, and iodo-complexes containing tetrahedral IALX41 ions. However, in sodium aluminum fluoride NaAlF4, the aluminum atoms are in the centers of octohedra of fluorine atoms in which the fluorine atoms are shared with neighboring aluminum atoms. 

For convenience we group chloro, bromo and iodo complexes together no iluoroammines have yet been reported. 

A wide variety of anionic actinide halide complexes are well known and typically are isolated with alkali or alkahne-earth metal ions. The tendency and stability of the anionic complexes follow the trend F Cl > Br I. The trivalent fluorides and chlorides typically form complexes of the form AnX4 and AnXe ". Plutonium has also been shown to give the following complexes PuCb ", Pu2Cl7, and PuClg . The anionic tetravalent actinide fluorides represent a broad class of complexes, for example, M AnFj, (x = 1, y = 5 x = 2, y = 6 V = 3, y = 7 x = 4, y = 8). Tetravalent actinide chloro, bromo and iodo complexes can be isolated from aqueous solutions in the form of octahedral AnCle " ions. 

Bromo and iodo complexes also known. Chloro, bromo and iodo complexes also known. Bromo and iodo complexes known, also with arsine and stibine ligands. Methoxo and fluoio complexes also known. ... 

The formations of chloro, bromo and iodo complexes have been studied. Recently, electrochemical methods have been used to measure equilibrium constants for the formation of chloro (0.086), bromo (1.1 x 10 ) and iodo (1.1 x 10 ) complexes of diromium(III). ... 

Although chlorination, bromination and iodination of thiophenes by polyhalide salts require forcing conditions with the addition of zinc chloride [52], halogenation of acridine and acridone has been recorded to yield both 3-halo and 3,7-dihalo derivatives under relatively mild reaction conditions [53], However, whereas chloro-, bromo- and iodo-compounds are readily obtained from acridone, acridine only forms the bromo derivatives, as it produces stable complexes with the dichloroiodate and tetrachloroiodate salts [53]. 

The Pt + Pt intervalence transitions of such chain complexes occur in the regions 25,000-18,200 cm 1, 23,600-14,300 cm 1 and 20,600-7,500 cm 1 for chloro-, bromo-, and iodo-bridged complexes, respectively, the trend Cl > Br > I being the reverse of that of the conductivity of the complexes. The transition wavenumbers may be determined either by Kramers-Kronig analysis of specular reflectance measurements or from plots of the excitation profiles of Raman bands enhanced at or near resonance with the Pt I-PtIV intervalence band. The maxima have been found to be related to the Pt —PtIV chain distance, the smaller the latter the less being the intervalence transition energy (3). 

The chemistry of osmium fluorides and fluoro complexes differs sufficiently from that of the chloro, bromo and iodo species to warrant separate treatment here. The early review of Canterford and Colton is still useful for the general halide chemistry of the element.736... 

The enthalpies of these exothermic reactions have been determined for chloro, bromo and iodo species.86 Other complexes that have been obtained from the cyclooctadiene complex include [RhCl(PF3)2]2,36 [RhCl P(OMe)3 2]2 and [RhCl PF2(OPr) 2]2.76... 

Bis(3-diphenylphosphinopropyl)phenylphosphine (99) forms chloro, bromo and iodo rhodium(I) complexes (equations 253 and 254). The bromo complex can be obtained by addition of a large excess of LiBr to [RhCl(cod)]2 prior to addition of the neutral ligand.1051 The iodo complex has also been prepared from [RhI(CgH12)]2.1051,1052 The halo complexes (100) have been shown to be square planar by X-ray crystallography.1051... 

As seen from Fig. 5-11, although the three halobenzenes (points nos. 8, 10, and 11) have similar values of fir, when used as solvents they lead to different reaction rates, lodobenzene (no. 8), with the lowest value, gives the largest rate. This observation strongly suggests that the polarizability of the solvent is an important factor in stabilizing the dipolar activated complex of this reaction. This was confirmed by Reinheimer el al. [57], who studied some Menschutkin reactions in benzene and its chloro, bromo, and iodo derivatives. They showed that the rate of the reaction increases with increasing polarizability of the solvent. 

For example, complexes with very strong EPD ligands, such as Ng ", NCS ", CN, or F may exist even in solvents of high DN such as HMPA or DMSO. In solvents of weak or medium EPD properties, complex formation is essentially quantitative. On the other hand, bromo and iodo complexes usually exist only in weak EPD solvents, such as NM, PDC, or AN, and are completely ionized in solvents such as DMF, DMSO, or HMPA. The stabilities of chloro complexes are somewhat higher in the respective solvents. According to Table VII the chloride ion has an EPD strength similar to that of DMF or DMSO. Consequently chloro complexes in these solvents (compare Table IV) are ionized to some extent, sometimes with autocomplex formation. 

Di-/i-chloro-bis[(t -pentamethylcyclopentadienyl)chlororuthenium(III)], [Cp RuCl2]2 (1) is the general entry into Cp (t -C5Me5) Ru sandwich and half-sandwich chemistry and has been used in numerous transformations since its introduction in 1984. It is easily prepared according to Eq. 1. Analogous bromo and iodo complexes are obtained by halide exchange with NaX in MeOH." ... 

In the second series of materials, 93 [18], all the compounds with X=Cl, Br and I were mesomorphic, showing enantiotropic Colh mesophases from room temperature to 70-80 °C for the chloro-compounds, and 45 and 56 °C respectively for the bromo- and iodo-complexes. Here again, the ligands themselves were not mesomorphic. An intracolumnar distance of 4 A was... 

However, syntheses for carbonyl halide complexes of tungsten, e.g., Tp WX(CO)3 and Tp WX(CO)2, now available " and a comprehensive account of the properties of these compounds has appeared. As expected, compounds of this type are valuable starting materials for low-valence organometallic and high-valence coordination compounds (upon oxidative decarbonylation). The acetonitrile-K A, C complexes, Tp WX(MeCN)(CO), reported by Thomas et al., are also valuable precursors for a variety of organometallic complexes the iodide is the most readily accessible derivative of this type. ° We report here syntheses for NEt4[Tp W(CO)3], the chloro, bromo, and iodo members... 

Senn and Ziegler find the dissociative pathway to be the preferred one in their calculations in THF solution of the oxidative addition of chloro-, bromo- and iodobenzene to Pd(P-P) complexes, where P-P is a chelating diphosphine ligand of the type l,2-bis(dimethylphosphino)ethane or (P)-2,2 -bis(dimethylphosphino)-1,1 -biphenyl. The barriers from the prereaction complex are in fact quite low 31, 12 and 5 kJ/mol for the chloro, bromo and iodo species, respectively. For methyl-(lS,5R)-5-chlorocyclohex-3-ene-l-carboxylate in presence of neutral palladium, Espinet and Echavarren observed retention of configuration in apolar solvent (benzene) and inversion in polar solvent (acetonitrile) [13]. 

N-halosucdnimides (chloro-, bromo-, and iodo-) are useful reagents for oxidations in organic chemistry and for the oxidative halogenation of metal complexes. For example, the reaction of the rhenium hydride, trans-(H,Br)-[Re(Bt)(FO(CO)(PMe Cp l with N-hromosucdnimide in THF at 0 C... 

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