Complexes of Azaphospholes: Synthesis and Structure of Pentacarbonyl-(η1)-2-phosphaindolizine)chromium(0), -molybdenum(0), and -tungsten(0)

✍ Scribed by Neelima Gupta; Chandra B. Jain; Joachim Heinicke; Raj K. Bansal; Peter G. Jones

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 306 KB
• Volume: 1998
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/(sici)1099-0682(199808)1998:8<1079::aid-ejic1079>3.0.co;2-u

✦ Synopsis

The complex chemical behaviour of 2-phosphaindolizines 1 strong upfield signal (δ 31 P = 6.1) was observed with a coordination shift of ∆δ = -161.7, which is typical for π-(1,3-azaphospholo[1,5-a]pyridines) towards metal carbonyl compounds was studied. (η 1 -2-Phosphaindolizine)M(CO) 5 coordination. Prolonged reaction or work-up led, however, to dismutation yielding 1g and the fac-L 3 Mo(CO) 3 complex 6g. complexes 2-4 (M = Cr, Mo, W) were formed from 1 and [(THF)M(CO) 5 ], the cis-L 2 Cr(CO) 4 complex 5f from 1f and X-ray structure analysis of 2a indicates an increased 10πdelocalization compared with 1a and a changed tetracarbonyl(norbornadiene) chromium(0). The reaction of 2-phosphaindolizines 1e, 1f, or 1g with tricarbonyl(cyclo-conformation of the acyl substituent. The influence of substituents and metals on the 31 P and 13 C complexation heptatriene)molybdenum(0) or tricarbonyl(mesitylene)tungsten(0) yielded σ-complexes of the types L 2 M(CO) 4 or chemical shifts and coupling constants is discussed. L 3 M(CO) 3 rather than isolable π-complexes. In one case a