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2‐Phosphanylphosphinines as Bridging Ligands for Dinuclear Transition Metal Carbonyls
Author(s) -
Waschbüch Klaus,
Le Floch Pascal,
Ricard Louis,
Mathey François
Publication year - 1997
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19971300706
Subject(s) - chemistry , transition metal , triple bond , metal , molecule , metal carbonyl , crystallography , thermal decomposition , crystal structure , stereochemistry , medicinal chemistry , polymer chemistry , catalysis , double bond , organic chemistry
The 2‐phosphanyl‐4,5‐dimethylphosphinines 1‐5 are powerful bridging ligands able to stabilize metal‐metal single and triple bonds between low‐valent transition metal centres. Their reaction with Mn 2 (CO) 10 in refluxing xylene yields the corresponding Mn 2 (CO) 8 complexes 6 and 7 . Reaction with [Fe 2 Cp 2 (CO) 4 ] under UV irradiation similarly yields the Fe‐Fe‐bridged Fe 2 Cp 2 (CO) 2 complexes 8 and 9 . An additional observation is that the 2‐phosphininyl‐3,4‐dimethylphosphaferrocene 10 is formed upon reaction of the 2‐phospholylphosphinine 5 with [Fe 2 Cp 2 (CO) 4 ] at high temperature under CO pressure. A clean addition occurs at the Mo≡Mo triple bond of [Mo 2 Cp 2 (CO) 4 ] to give the Mo‐Mo single‐bonded complexes 11 ‐ 15 . The thermolysis of these complexes succeeds when the phosphanyl group is a phosphonite P(OEt) 2 ( 13 ) or P(OAr) 2 ( 14 ), affording cleanly the Mo 2 Cp 2 (CO) 4 triple‐bonded complexes 16 and 17 , respectively. The metal‐metal triple bonds of these complexes readily add two molecules of CO to reform 13 and 14 , or one molecule of t Bu‐N≡C to give 18 and 19 . The X‐ray crystal structure analysis of the MO 2 C 2 (CO) 4 complex 13a , with the 2‐P(OEt) 2 ‐ phosphinine, shows a gauche orientation of the two Cp rings and very short P‐Mo bonds of 2.3565(4) and 2.406(2) Å to the phosphinine and P(OEt) 2 groups, respectively.