(ETHER-PHOSPHANE)IRON(II) COMPLEXES WITH THE COORDINATION NUMBERS-4, NUMBER-5, AND NUMBER-6

Photolysis of cis,cis,trans-Br2(OC)2Fe(P approximately O)2 (1a, b) [O, P = Ph2PCH2CH2OCH3 (a), Ph2PCH2C4H7O (b)] results in the formation of the iron(II) complexes Br2Fe(P approximately O)2 (2a), [BrFe(P and O)( mu-Br)]2 (4b), and [trans-Br2Fe(P and O)(mu-CO)]2 (5a) with the coordi nation numbers four, five, and six, respectively. 2a crystallizes in t he triclinic space group P1BAR with Z = 2 and has two monodentated O,P functions (P approximately O: eta1-P-coordinated; P and O: eta2-O,P-c oordinated). The dimeric complex 4b with two O and P-chelated ligands crystallizes in the orthorhombic space group Pbca with Z = 4. 2a and 4 b, which react under CO pressure to give the starting complexes 1 a, b , are also accessible from the ether-phosphanes 3a, b and anhydrous Fe Br2.