Lineare Oligophosphaalkane

On reaction with diironenneacarbonyl the tertiary primary phosphine Ph 2 PCH 2 PH 2 yields the hydrido cluster (μ 2 -H)(μ 2 -PHCH 2 PPh 2 )Fe 3 (CO) 9 ( 4 ). If excess of Fe 2 (CO) 9 is employed in this reaction the PCP-bridged Fe 4 -cluster 5 is formed with loss of hydrogen. At higher temperatures rearrangement of the Fe 3 (Fe)P-skeleton and phosphinidene fragmentation of the PCP backbone of 5 affords the Fe 4 P spiro compound (μ 4 -P)(μ 2 ,η 2 -PPh 2 CH 2 )Fe 4 (CO) 14 ( 6 ) with an edge bridging Ph 2 CH 2 unit. X-ray structural analysis of 6 (space group P 2 1 / n ) reveals a distorted Fe 4 P spiro type arrangement. The iron atoms Fe(1) and Fe(3) and the Ph 2 PCH 2 ligand with a short PC bond (P(1)C(1) 178.6(7) pm) form a distorted almost planar four-membered Fe 2 PC ring system.