Borate, hydrotris potassium

Complex [(r] (N)-2,1,3-benzothiazole)Os(CH=CHTol-p)(CO)Cl(PPh3)2] with potassium hydrotris(pyrazol-l-yl)borate at the first stage gives the >7 -coordinated [(>7 -Tp)Os(CH=CHTol-p)(CO)Cl(PPh3)2], which eliminates triphenylphosphine on thermolysis and gives the > -coordinated [(> -Tp)Os(CH=CHTol-p)(CO)Cl (PPh3)l [98JCS(D)3501]. 

B. POTASSIUM HYDROTRIS(1 -PYRAZOLYL)BORATE— ALKALI METAL POLY(l-PYRAZOLYL)BORATES... 

Potassium hydrotris(l-pyrazolyl)borate is a white crystalline solid. As prepared, m.p. 185-190°C., it is suitable for the synthesis of transition-metal chelates. Its melting point may be raised to 188-189°C. by recrystallization from anisole but this entails large solubility losses. Its infrared spectrum has a sharp BH peak at 2500 cm.-1. This salt is very soluble in water, alcohols, and polar organic solvents. It is stored best as a solid, and its reactions should be carried out on freshly prepared solutions. 

Potassium hydrotris(l-pyrazolyl)borate, 25.2 g. (0.1 mole), of the solid, as prepared in Sec. B, is stirred in 300 ml. of distilled water, and any insolubles are removed by filtration. To this solution is added, with stirring, 100 ml. of 0.5 M cobalt(II) acetate [or any other Co (II) salt] solution. A yellowish precipitate forms promptly. The mixture is stirred at room temperature for 10 minutes and is filtered after washing with copious amounts of water and then with methanol, the solid is air-dried. It is obtained in 22-23-g. (91-95%) yield and may be purified either by recrystallization from toluene or by chromatography (on acid-washed aluminum oxide packing and eluting with dichloromethane). 

The reaction is carried out in a Schlenk tube, Fig. 1. Acetone (10 mL) is cooled in an ice bath and saturated with carbon monoxide by passing in a brisk stream of the gas for 10 minutes. Potassium hydrotris(pyrazolato)borate (252 mg, 1.0 mmole) and copper(I) chloride (99 mg, 1 mmole) are added to the acetone, and the mixture is stirred for 30 minutes while continuing to pass a slow stream of carbon monoxide. At the end of this period, the white suspension is filtered, using the Schlenk-type apparatus illustrated, Fig. 2, keeping the whole under an atmosphere of CO. The clear colorless filtrate is evaporated to dryness, and the cream-colored residue is extracted with 10 mL light petroleum (boiling range 40-60°, saturated with CO) and filtered. Evaporation of the solvent from the filtrate affords a white powder of Cu(CO)[(pz)3BH] (156 mg, 51%). 

Sand-sodium base. See Sodium-sand base a-Santalene, 42 Sobering process, 118-119 Schiff bases. See Imines 9,10-Secosteroids (calciferols and tachysterols), 31-32, 34, 281-283, 289 Seebach-Frater alkylation, 27. AT-Selectride = potassium hydrotris(l-mcthylpropyl)borate(l —) (KBHBVl), 107 XS-Selectride 1 — potassium tris(l,2-dimethyl-propyl)hydroborate(l —) (KBHSiay), 107 Z-Selectride = lithium hydrotri (l-... 

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