Cobalt bromide, trans

The chloride, [Co en2(H20)2]Cl3 or [Co eii2(H20)2]Cl3.2H20, is prepared from trans-hydroxo-aquo-cobaltic bromide, [Co ena(HaO)... 

BrjCoN4C4H,g, Cobalt(III), dibromobis(l,2-ethanediamine)-, bromide, trans-, 21 120... 

CoBrN407S2C4Hi8 HjO, Cobalt(III), aqua-bromobis(l, 2-ethanediamine)-, dithio-nate, trans-, monohydrate, 21 124 CoBrsNgCgHie, Cobalt(III), dibromobis(l,2-ethanediamine)-, bromide, trans-, 21 120... 

CoBrN403C3Ht6, Cobalt(III), (carbonato)bis-(1,2-ethanediamine)-, bromide, 21 120 CoBrN407S2C4Hi8 H20, Cobalt(III), aqua-bromobis(l, 2-ethanediamine)-, dithionate, trans-, monohydrate, 21 124 CoBr3N4C4Hi , Cobalt(III), dibromobis( 1,2-ethanediamine)-,bromide, trans-, 21 120 CoBr CaHit - H20, Cobalt(IIl), dibromo-bis(l,2-ethanediamine)-, bromide, cis-, monohydrate, 21 121... 

Again, cobalt hydrotricarbonyl probably adds initially. The addition could be either a 1,4-addition or a 1,2-addition in which cobalt initially adds to the second carbon atom of the diene, and then undergoes an allylic rearrangement. The 3-pentenoylcobalt tricarbonyl triphenylphosphine prepared in this manner contains considerably more of the cis isomer than the same compound prepared from trans crotyl bromide and sodium cobalt tetracarbonyl. This, indicates that the hydrocarbonyl prefers cis addition (47). 

Carbonatobis (ethylenediamine)cobalt(III) bromide Tris(cthylenediamine)cobalt(III) chloride Trans-dinitrotetramminecobalt (III) chloride Tris (propylenediamine) cobalt (III) chloride Cis-dinitrotetramminecobalt(III) chloride... 

The X-ray analysis of the complexes (-)5g9-bis[(s,s-trans-l,2-diaminocyclohexane)]-(R,R)-trans-l,2-diaminocyclohexaneo)balt(ni) chloride pentahydrate, (—)s89-(.lel2,ob)-[Co(chxn)3]Cl3 5H20 and (-)5g9-bis[(lR,2R)-l,2-diaminocyclohexane](3,3 -dimethyl-2,2 -bipyTidyl)cobalt(in) bromide diperchlorate monohydrate, (-)58 -[Co(R,R-chxn)2(3,3 -dmbpy)]Br(C104)2 shows that in both cases the molecules... 

Nuclei with spin / > 1 possess an electric quadrupole which can take up different orientations relative to an electric field gradient. These orientations differ in energy, and transitions between them give rise to the nuclear quadrupole resonance (NQR) spectrum. The NQR of ligand atoms such as Cl, Br, and I could, therefore, provide information on the polarity of the metal-ligand bond and the population of the p orbitals (111). The only cobalt(III) complexes that have been studied are trans-[Co-enaXalX HX wHaO, where X = Cl or Br. Hartmann et al. 87) calculated 75-80% ionic character for the Co-Cl bond and also reported data for the bromide complex, from which Kubo and Nakamura (111) calculated a value of 60% ionic character. 

Nitrosylpentaamminecobalt(II) chloride, synthesis 49 cts-Bromoamminebis (ethylenediamine) cobal t (111) bromide, CIS- and trans-aquoamminebis(ethylenediamine)cobalt(IIl) bromide, and cis- and triphenylphosphine)rhodium and chloro-carbonylbis(triphenylarsine)rhodium, synthesis 56 Sodium hexachlororhodate(III) 2-hydrate and potassium hexachlororhodate(III) 1-hydrate, synthesis 57 Ammonium hexachloroiridate(IV), synthesis 58 Resolution of the tris(l,10-phenanthroline)nickel(II) ion, synthesis 59... 

The as-bromoamminebis(ethylenediamine)cobalt(III) bromide crystallizes in purple platelets. The compound has been resolved/ and the kinetics of the reactions of hydroxide ion with the d- and Z-isomers in water have been determined. The red-orange crystals of as-aquoammine-bis(ethylenediamine)cobalt(III) bromide are compact and almost cubic, in contrast to the orange needle-plates of the trans isomer. The crystals of water exchange of the aquoammine complexes have been studied. ... 

A large majority of diacidobis(l, 2-ethanediamine)cobalt(III) complexes can be synthesized from the (carbonato)bis(l, 2-ethanediamine)cobalt(III) ion. This is now readily available in high yield and purity.1 cis- and trans-Dichlorobis(l, 2-ethanediamine)cobalt(III) chlorides are obtained from the carbonato complex with hydrochloric acid using appropriate conditions. These isomeric dichloro salts are widely used starting materials for further syntheses. In this respect, the analogous dibromo complexes can be more convenient starting materials because bromide is substituted from the cobalt center more readily than is chloride ion. The milder conditions minimize the production of cobalt(II), a common side reaction. 

Werner prepared cis- and tazns-dibromobis(l, 2-ethanediamine)cobalt(III) bromide by reacting the carbonato bromide with concentrated hydrobromic acid.2 In the cold, the cis isomer resulted the trans isomer was obtained by heating the mixture. The reaction proceeds via ds-aquabromobis(l, 2-ethanedi-amine)cobalt(III) dibromide which can be isolated by this route. In our hands, the preparations, as originally described, are not reproducible. The reaction times and yields are variable, depending too critically on the conditions for one not intuitively skilled in the art to consistently obtain the desired cis or trans form. However, the syntheses described here for the cis and trans dibromo complexes and based on this reaction are reproducible if one adheres closely to the procedures. 

Other preparative methods have been reported.2,3 ds-Dibromobis(l, 2-ethane-diamine)cobalt(III) bromide is obtained in reasonable yield by evaporating a neutral aqueous solution of the trans isomer to dryness. The reaction between ds-diazidob is( 1,2-ethanediamine)cobalt(III) perchlorate and hydrobromic acid proceeds rapidly and quantitatively at ambient temperature, largely with retention of the cis configuration to yield the dibromo bromide.4,s The diazido starting complex6 7 can be made within 1 hour in greater than 90% yield. 

The conversion of the cfs-bromoamminebis(ethyIenedi-amine)cobalt(III) bromide to the cis- and trans- qno-amminebis(ethylenediamine)cobalt(III) bromide and nitrate salts is a modification of a procedure of Werner. ... 

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