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Complexes of Azaphospholes: Synthesis and Structure of Pentacarbonyl‐(η 1 )‐2‐phosphaindolizine)chromium(0), ‐molybdenum(0), and ‐tungsten(0)
Author(s) -
Gupta Neelima,
Jain Chandra B.,
Heinicke Joachim,
Bansal Raj K.,
Jones Peter G.
Publication year - 1998
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199808)1998:8<1079::aid-ejic1079>3.0.co;2-u
Subject(s) - chemistry , norbornadiene , molybdenum , chromium , tungsten , substituent , cycloheptatriene , metal , cyclooctatetraene , medicinal chemistry , mesitylene , inorganic chemistry , molecule , photochemistry , organic chemistry , catalysis
The complex chemical behaviour of 2‐phosphaindolizines 1 (1,3‐azaphospholo[1,5‐ a ]pyridines) towards metal carbonyl compounds was studied. (η 1 ‐2‐Phosphaindolizine)M(CO) 5 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 tetracarbonyl(norbornadiene) chromium(0). The reaction of 2‐phosphaindolizines 1e , 1f , or 1g with tricarbonyl(cycloheptatriene)molybdenum(0) or tricarbonyl(mesitylene)tungsten(0) yielded σ‐complexes of the types L 2 M(CO) 4 or L 3 M(CO) 3 rather than isolable π‐complexes. In one case a strong upfield signal (δ 31 P = 6.1) was observed with a coordination shift of Δδ = –161.7, which is typical for π‐coordination. Prolonged reaction or work‐up led, however, to dismutation yielding 1g and the fac ‐L 3 Mo(CO) 3 complex 6g . X‐ray structure analysis of 2a indicates an increased 10π‐delocalization compared with 1a and a changed conformation of the acyl substituent. The influence of substituents and metals on the 31 P and 13 C complexation chemical shifts and coupling constants is discussed.