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2‐tert‐Butyl‐1H‐1,3‐benzazaphosphole (1a) reacts with tBuLi without addition to the P=C bond to form a lithium benzazaphospholide that affords the η1‐(benzazaphospholide‐P)tungsten(II) complex 2 upon reaction with [CpW(CO)3Cl]. It is sensitive to alcoholysis and to air oxidation yielding 1a and the P‐oxo‐benzazaphospholide complex 3, respectively. The (1,3‐benzazaphosphole)pentacarbonyltungsten complex 4, obtained from 1b and [W(CO)5(THF)], reacts preferentially with tBuLi by lithiation of the NH function and is attacked by [CpW(CO)3Cl] at phosphorus to give the mixed valence bimetallic tungsten(II)‐tungsten(0) benzazaphospholide complex 5. A side product, (3‐tert‐butyl‐2‐methyl‐1,3‐benzazaphosphole)pentacarbonyltungsten (6), is attributed to side‐reaction where tBuLi adds to the P=C bond in 4. The composition of the products was determined from X‐ray structure analysis of 3 and spectroscopic data.

1H-1,3-Benzazaphospholes react with M(CO) 5 (THF) (M ϭ Cr, Mo, W) to give thermally and relatively air stable η 1 -(1H-1,3-Benzazaphosphole-P)M(CO) 5 complexes. The 1 H-and 13 C-NMR-data are in accordance with the preservation of the phosphaaromatic π-system of the ligand. The strong upfield 31 P coordination shift, particularly of the Mo and W complexes, forms a contrast to the downfield-shifts of phosphine-M(CO) 5 complexes and classifies benzazaphospholes as weak donor but efficient acceptor ligands. Nickelocene reacts as organometallic species with metalation of the NH-function. The resulting ambident 1,3-benzazaphospholide anions prefer a µ 2 -coordination of the η 5 -CpNi- Metallierte 1,3-Azaphosphole: η 1 -(1H-1,3-Benzazaphosphol-P)M(CO) 5 und µ 2 -[(1,3-Benzazaphospholid-P)(cyclopentadienid)nickel] KomplexeInhaltsübersicht.1H-1,3-Benzazaphosphole reagieren mit M(CO) 5 (THF) (M ϭ Cr, Mo, W) zu thermisch und zumindest kurzzeitig luftstabilen η 1 -(1H-1,3-Benzazaphosphol-P)M(CO) 5 -Komplexen. Die 1 H-und 13 C-NMR-Daten sind mit dem Erhalt des phosphaaromatischen π-Systems im Liganden im Einklang. Die starke 31 P-Koordinationsverschiebung zu hohem Feld, vor allem der Mo-und W-Komplexe, steht im Gegensatz zur Koordinationsverschiebung zu tiefem Feld, beobachtet bei Phosphin-M(CO) 5 Komplexen, und verweist auf schwache Donator-, aber gute Akzeptoreigenschaften der Liganden. Nickelocen reagiert als Übergangsmetallorganyl unter Metallierung der NH-Funktion.

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Organic chemistryOrganic chemistry Z 0200 Lithium-1,3-benzazaphospholides: Structure and Reactivity -[6 refs.]. -(HEINICKE, J.; PEULECKE, N.; SURANA, A.; SINGH, S.; GUPTA, N.; STEINHAUSER, K.; BANSAL, R. K.; SPANNENBERG, A.; Phosphorus, Sulfur Silicon Relat.

The 2‐phosphaindolizines 1 react with hydrogen sulfide and elemental sulfur to give the new zwitterionic heterocyclic systems 2 of the N‐pyridiniomethyl dithiophosphinate type. In contrast, no reaction is observed with sulfur alone. MeI methylates 2e,f at sulfur. The analogous pyridiniodiselenophosphinate 5 results from the reaction of 1a with 1,3,2,4‐diselenadiphosphetane‐2,4‐diselenide, 4a, in the absence of an additional base. As a further product, the perselenophosphinic anhydride 6 is identified. In the presence of triethylamine, 1a reacts with each of the diselenides 4a–c to give the new triethylammonium diselenophosphinates 7a–c, respectively. This reaction can be extended to 1‐aza‐2‐phosphaindolizine, 8, which yields with each of 4a,b and NEt3 the diselenophosphinates 9a,b, respectively. The anhydride 6 and the diselenophosphinates 7 and 9 result from an electrophilic substitution at the phosphaindolizine ring. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:445–452, 1998