Bis 4-methylamino-3-penten-2-onato cobalt II

50 mole) of 4-methylamino-3-penten-2-one is added to the solution, and the nitrogen stream is continued for about 10 minutes. At this point a magnetic stirring bar is placed in the flask, the nitrogen source is connected to the sidearm of the flask, and a 20-cm. glass chimney with standard-taper joints is attached to the flask. Tetraethylammonium tetrabromocobaltate(II)  

028 mole) is added through the chimney under a stream of nitrogen admitted through the sidearm. The chimney is closed off at the top, and a slight positive pressure of nitrogen is maintained in the flask. 

The product which crystallizes from the cold n-heptane solutions is collected, using the apparatus and techniques just described. The products from the three extractions are combined, and two additional recrystallizations are performed by the indicated procedure. Traces of solvent are removed from the final product by drying it on the filter at room temperature by means of evacuation through E with C and F closed. The 

Bis (4-methylamino-3-penten-2-onato) cobalt (II) forms orange crystals which melt at 169-171° and which are stable in air for several hours. The complex is soluble in most organic solvents, but its solutions are susceptible to rapid oxidation by air. Traces of moisture in solution may hydrolyze the complex. Room-temperature magnetic moments of the crystalline solid (4.22 B.M.) and of the complex in toluene solution (4.36 B.M.), together with ligand field spectra, demonstrate a tetrahedral stereochemistry in both phases.  

The preparation of tetraethylammonium tetrachlorovanadate-(III) has recently been given. The procedure which follows 

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