1,2-Ethanediamine chromium complexes

C H402, Acetic acid palladium complex, 26 208 tungsten complex, 26 224 C2H7PS, Phosphine sulfide, dimethyl-manganese complex, 26 162 C H,N2, 1,2-Ethanediamine chromium complex, resolution of, 26 24, 27... 

N2C2H8, 1,2-Ethanediamine chromium complexes, 24 185, 186 chromium, iridium, and rhodium complexes, 24 251, 283-290 cobalt complex, 25 140 cobalt complexes, 21 19, 21, 120-126 23 64, 165... 

N2C10H, 2,2 -Bipyridine, palladium complex, 22 170 mthenium complex, 21 127 NjCioH, 2,2 -Bipyridine, chromium complexes, 23 180 NiC,oH24, 1,2-Ethanediamine, Al,Al -dimethyl-N,N -bis( 1 -methylethyl), platinum complex, 21 88... 

The complex m-[Cr(en)2F2]I is a useful starting material for the preparation of compounds of the type m-(Cr(en)2FX]I (X = CP, Br, NCS, HjO, and NHs). " The initial preparation of m-[Cr(en)2F2]I involved the reaction of anhydrous 1,2-ethanediamine with CrFj-xHjO that was suspended in a dry diethyl ether solution of hydrogen fluoride. Workup of the crude product from hydroiodic acid gave the desired compound. The present method, which is similar to that reported previously, utilizes the direct reaction of chromium(lll) fluoride-water (1/3.5) with excess dry 1,2-ethanediamine to yield m-[Cr(en)2F2](Cr(en)F4)-xH20, from which the desired cation can be easily isolated. This method avoids the difficulty of preparing easily oxidized Cr(II) compounds and working in an atmosphere of nitrogen. 

The di- i,-hydroxo bridged complexes, the preparations of which are described in Sections D and H, have several chemical and physical properties in common. The dithionates are only sparingly soluble in water, whereas the bromides are quite soluble. The dinuclear structures of the cations, as well as the A,A configuration of the 1,2-ethanediamine compounds have been established by the close similarity of the Guinier X-ray powder diffraction patterns of [(NH3)4Rh(0H)2Rh(NH3)JBr4-4H20 and [(en)2Rh(OH)2Rh(en)2] (8205)2 to those of the well-characterized cobalt(III) and chromium(III) analogs. 

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