[M(NMesBMes2)2] (M = Cr, Ni) : Stable, Distorted, Two-Coordinate d4 and d8 Complexes

✍ Scribed by Ruth A. Bartlett; Hong Chen; Prof. Philip P. Power

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 262 KB
• Volume: 28
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.198903161

✦ Synopsis

Since one of the PtBu2 groups in 4 is trans to the others, only three signals, rather than four, are observed in the "P NMR spectrum. 6=67 (IP), 47 (2P). The signal at 6= -163 (3P. high field shift typical for three-membered ring compounds) consists of two overlapping signal patterns for the three exocyclic P atoms. MS: m/z 528.2631 (M"), 471.1945 (M" -rBu). 5 crystallizes from the reaction mixture at -20°C.

(M"), 559.2389 (M" -PrBu), 533.1407 (MQ-3tBu). Compounds 4 and 5 are known from the decomposition of rBu2P-P(SiMe,)-P(SiMe3), [C.

Fritz, T. Vaahs, Z. Anorg. Allg. Chem. 553 (1987) 851. They are formed at 65°C (15 h) with preferred cleavage of P(SiMe,), [side product, rBuP(SiMe,),] suggesting the intermediacy of 6.

[lo] For the trapping reactions, 1 was dissolved in 2,3-dimethyl-1,3-butadiene or cyclohexene. 2 was then added at 0°C and the solution stirred at 20°C for 5 d. In each case, a clear orange solution formed which gradually became cloudy as LiBr precipitated. Quantities for 7 and 8 : 0.5 g (1.21 mmol) 1, 0.22 g (1.21 mmol) 2, 10 mL 2,3-dimethyl-l,3-butadiene; for 9: 1.0 g (2.42 mmol) 1,0.44 g (2.42 mmol) 2, 15 mL cyclohexene. "P NMR (spectrum of the reaction solution): 7: 6=45.3 (PA), -48.7 (P"), JIB.= -277, JAB= -329, JAw=65, I . / A A ~~ 1 HZ. 8 : 6=34.5 (d: PI), -189.0 (d, P2); J 1 2 = -233 Hz. 9 : 6=65.5 (d, P'), -225.0 (d, Pi), "P NMR: 6 = 6 3 (Pluhn), -43 (Prlng). ' J p p = -329 Hz. MS: m / ~ 708.3562 Ji2= -220 Hz.

The formation of 7 can be compared with the reaction of rBuP=P-SiMe, [from rBuCIP-P(SiMe,),] with 2.3-dimethyl-1.3-butadiene [ti. Fritz, H. Fleischer, Z. Anorg. Allg. Chem.. in press] as well as the reactions of fBu2P-P=PrBu [from tBu2P-P(SiMe3)-PCltBu] and tBu,P-P=P-SiMe, [from rBu,P-P(CI)-P(SiMe3),] with cyclopentadiene [ti.