Trifluorophosphine-borane

The known fluorophosphine-borane adducts are listed in Table VIII. Trifluorophosphine-borane can be made directly from diborane and excess trifluorophosphine (255) or by displacement of carbon monoxide from BHa CO (255), which it closely resembles. 

Trifluorophosphine-borane has also been prepared in the gas phase reaction between boroxine and trifluorophosphine, but the method is somewhat hazardous and probably best carried out with small amounts of material 16). Kinetic studies indicate a first-order dependence on the... 

Methylaminodifluorophosphine-borane, MeNHPFg-BHg, and bis-(methylamino)fluorophosphine-borane, (MeNH)2PF BH3, are formed when methylamine reacts with the trifluorophosphine borane adduct 148). The uncoordinated (MeNH)2PF is as yet unknown. 

BeHi2 + B2H4 (PF3)2 -> B5H9 + B3H7 + 2 PF3 of trifluorophosphine-borane, and reaction with diborane (6) gives an almost 100% yield of tetraborane (16). 

Ammonia reacts with trifluorophosphine borane at low temperatures to give the tris amino derivative (9.14). The tris dimethylamino analogue is made from sodium borohydride, carbon dioxide and the appropriate phosphine (7.85). Dimethylamino dimethylphosphine reacts with diborane at -78°C to give an addition compound (9.15), which, on heating, decomposes to give a variety of products. 

The question of the molecular structure of the adducts of tetraborane(8) has now been resolved 144>. The boron-11 nmr spectra of the carbon monoxide and trifluorophosphine adducts have been analyzed 140> in terms of the 2112 topological geometry 141> proposed by Dupont and Schaeffer 142>. The dimethylaminodifluorophosphine adduct of tetra-borane(8) 143> which was prepared by the following reaction is stable at room temperature. 

A novel trifluorophosphine-tris(difluoroboryl)borane complex B4F3 PF3 (m.p. 55°C, b.p. 74°C) is formed by reacting the high-tempera-ture species boron monofluoride with PF3 on a cold surface (316). The crystal structure has recently been determined by X-ray diffraction and is shown in Fig. 7 (74). 

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