Trirhenium Nonachloride

Previous preparations of Re3Cl9 have involved driving the rhenium halides horizontally along bulb trains.1 2 The present procedure is a considerable improvement on these, because it involves decomposition of refluxing rhenium pentachloride in the reaction bulb. Yields are very high and, using the method for the preparation of rhenium pentachloride given in Sec. 11, yields of over 90% from rhenium metal are possible. 

The apparatus (Fig. 1) is flamed dry in a stream of dry nitrogen and transferred with the stopcock closed to a glove bag, previously flushed out with dry nitrogen. Rhenium pentachloride, 5-10 g, is placed in the bulb and the tube is removed from the glove bag and clamped in a vertical position with a moderately fast stream of nitrogen flowing. 

The bulb is heated with a medium Bunsen flame until the rhenium pentachloride melts and is refluxing up the tube.t From time to time heating is stopped and Re3Cl9 formed in the tube is scraped back into the bulb. After about 4 hr, or when no more brown fumes are seen and only solid is observed in the bulb, the apparatus is allowed to cool. The bulb is sealed off and transferred to a glove bag and the dark-red crystalline solid is transferred to ampules. The product can be purified by grinding with a mortar and pestle under nitrogen and pumping off any volatile rhenium halide oxides under vacuum. 

The method affords yields of 95% and above. Anal. Calcd. for Re3Cl9 Cl, 36.4%. Found Cl, 36.3%. 

The product Re3Cl9 is hygroscopic and on exposure to air forms a hydrate. This hydrate is more reactive than the anhydrous material, is soluble in polar solvents, 

---

Triethyldialuminium trichloride, 2556 Trirhenium nonachloride, 4196 Tungsten dichloride, 4119 Tungsten diiodide, 4631... 

The origin of the majority of rhenium—rhenium quadruple bonds can be traced directly to the parent Re2Clg anion. Several routes to the octachloro-dirhenate(III) ionic complex have been compared (42). The method of choice is the reaction of trirhenium nonachloride with molten diethylammonium chloride (12). Yields of up to 65% are attainable when the reaction mixture is extracted with hydrochloric acid and the anion is precipitated as the salt of a large cation (i.e., tetrabutylammonium cation). 

See Oxygen Trirhenium nonachloride See related METAL HALIDES, METAL OXIDES... 

Tripropylborane, 3211 Tripropylindium, 3213 Tripropyllead fulminate, 3357 Tripropylsilyl perchlorate, 3212 Trirhenium nonachloride, 4190... 

Triethyldialuminium trichloride, 2551 Trirhenium nonachloride, 4190 Tungsten dichloride, 4113 Tungsten diiodide, 4626 Tungsten hexachloride, 4187... 

The octachlorodirhenate(III) anion, [Reads]2- has been prepared in several ways, including (a) reduction of perrhenate ion in acid solution with molecular hydrogen at high temperature and pressure 1 (b) reduction of perrhenate ion with hypophos-phorus acid, in a solution of constant boiling hydrochloric acid 1,2 (c) displacement of the carboxylate ligands in Re2-(OOCR)4Cl2 with chloride ion in concentrated hydrochloric acid 1,2 (d) reaction of trirhenium nonachloride in molten diethylammonium chloride.3... 

---