Bromo-complexes

In contradistinction to this, weak ferromagnetism has been observed in a number of chloro and bromo complexes of the type M2[CrX4] (M = a variety of protonated amines and alkali metal cations, X = Cl, Br), which are analogous to previously known copper(II) complexes (p. 1192). They have magnetic moments at room temperature in the region of 6BM (compared... 

The products obtained from the Pt(PR3)2X2-CNCH3 reactions were dependent on the nature of the platinum species. Five-coordinate adducts, [Pt(PR3)2(CNCH3)2X]X, were isolated for the iodo and bromo complexes (R=Ph), although the latter was unstable and slowly lost isocyanide. The observation of five-coordination here is somewhat unusual, but since this report, it was also observed in a different situation (85), mentioned above. The more common observation was the isolation of four-coordinate species, implying the low stability of most five-coordinate complexes. Data on these reactions are summarized below [Eqs. (33, 34)]. 

No j3-bromo- or iodoalkyl complexes have yet been isolated. The reaction of vicinal dibromides or diiodides with [Co (CN)j] , [Co(CN)5H], or a Co(I)-DMG complex merely gives the olefin 32, 75,105,109,161), though kinetic evidence was obtained for the intermediate formation of the j8-bromo complex in the reaction of [Co"(CN)5] with a,j8-dibromopropionate and a,/3-dibromosuccinate (75). It is interesting that the pentacyanide produced is the bromo or iodo, and not the aquo, complex 32, 75), which suggests that the decomposition may involve a cis rather than a trans elimination of Co—X. The /3-chloroethyl complex can be prepared by tbe reaction of [Co(CN)5H]3- with CICH2CH2I 105). 

To date, the only reported cobalt(II) complexes involve 2-acetylpyridine N-oxide JV-dimethylthiosemicarbazone, 34 [189]. [Co(39-H)A] (A = Cl, Br) have magnetic moments suggestive of flattened tetrahedra, but calculations based on Tj symmetry yield values of Dq of about 330 cm and B values of 743 and 707 cm for the chloro and bromo complexes, respectively. 

Ruthenium alkyls were also formed via chlorine-alkyl interchange. An enhancement of the activity of RhCl(PPh3)3 by AlBr3 was simply due to formation of the more active bromo complex, while enhancement by addition of Al(i-Bu)3 was attributed to formation of HRh(PPh3)3 (see Section II,B,1). 

Solutions of [ReXg] complexes (X = Cl, Br) are phosphorescent at room temperature, with emission maxima of 1,340 nm (chloro complex) and 1,380 nm (bromo complex) at life times between 40ns and 80ns. The phosphorescences are assigned to the transi-... 

The cw-l,2-bis(diphenylphosphino)ethene complexes [Fe(Ph2PCH=CHPPh2)2X2], X = C1 or Br, undergo pressure-induced spin-state transitions at about 8kbar for the chloro complex, about 60 kbar for the bromo complex. The difference is ascribed to the difference in ligand field strengths and lattice cooperativity. ... 

Bromine combines with rubidium and cesium bromides forming solid poly-bromo complexes that can be crystallized from aqueous solutions. The complexes are soluble in liquid bromine. 

Bromoanions, irivalent uranium, 34 98-99 Bromo complexes, osmium, 37 297-299 Bromocuprates(I), 37 39 Bromocyclophosphazene alkyl and aryl derivatives, 21 43 synthesis, 21 43, 44... 

Bromofluorobenzene, formation by nuclear activation, 5 191-192 Bromofluorophosphine, 13 378-380 Bromopiotactinates, see Protactinium, bromo complexes of... 

R. B. Jordan, having learned about the work of Pearson and Moore, has become interested in the issues and has searched for the formation of (NHs CoBr1"2 when (NH3)5CoX03+2 reacts in the presence of Br ". His observations suggest that the bromo complex does appear initially, but on calculating the competition ratio finds it to be less by a factor of about 2 than that reported by Haim and myself. Jordan has done only a single experiment on this. The subject is obviously worth going into in some detail, but at this point I am neither prepared to say that Jordan s result supports the conclusions which Dr. Haim and I reached, nor that it does not. 

The stage is therefore set for the competition experiment in which the bromo complex is put in and all the various ligands which react rapidly with this complex at their characteristic second-order rates, and a little hydroxide to see if any aquo complex is generated during the reaction. The results are best demonstrated in the system, Pt(dien)Br+, plus iodide, plus hydroxide. This works nicely because hydroxide is the thermodynamic product thus hydroxide will finally prevail. 

Chromium metal may be oxidized by Cl2, Br2 or I2 in ethanenitrile solution to give the octahedral complexes [CrCl3(MeCN)3]-MeCN, CrBr3(MeCN)3 and [CrI2(MeCN)4]I although the nitrile content of the bromo complex is somewhat variable.658 The chloro complex loses the uncoordinated nitrile when heated at 80 °C under vacuum. Some properties of these complexes are listed in Table 72. Reaction of CrCl3 with propanenitrile and acrylonitrile affords the dark purple complexes CrCl3(nitrile)3.6M... 

The Mo04+ core structure is found in MoVI chemistry in a relatively small number of authenticated structures and in a few suggested examples shown in Table 3. The simplest set of complexes which potentially contains the Mo04+ core is MoOX4(X = F, Cl, Br). While a square pyramidal structure seems probable for the chloro and bromo complexes,232 the fluoro complex is polymeric in the solid state and in solution as well.233-235... 

For Bu 3P complexes of the type Bu3PAgX, where X = Cl", Br , I, CN", SCN", OAc- and NOJ, XH and 31PNMR and IR spectra as well as conductance measurements showed that the complexes were non-ionic. Molecular weight measurements in 1,2-dichloroethane or chloroform, suggested that for X = C1", OAc" or NOJ the species were monomeric, whereas the bromo complex was a dimer.182... 

Raman measurements on concentrated aqueous solutions of cadmium halides show the presence of chloro complexes of tetrahedral and octahedral symmetry, but the formation of only tetrahedral bromo complexes.978 A combination of solution and solid state 113CdNMR spectroscopic results have allowed the compilation of 113Cd chemical shifts for the complexes [CdX]+, [CdX2], [CdX3] and [CdXJ2-, for X = Cl, Br or I.979... 

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