2,6-bis(diphenylphosphino)pyridine-bridged hetero-polynuclear complexes consolidated by Fe→M (M = Ag, Hg) dative bonding

The bridging phosphine ligand 2,6-bis(diphenylphosphino)pyddine (L) was used to synthesize a new, neutral organometallic ligand {Fe(CO)(4)}(2)(mu -L) 1, which exhibits eclipsed and staggered conformations in two crystalline forms. This Fe,N,Fe-tridentate ligand reacts with silver perchlorate to form the hetero-trinuclear complex {Fe(CO)(4)}(2)Ag(mu -L)(ClO4) 2, in which the central silver(l) atom bridges a pair of iron(O) atoms at Fe-Ag distances of 2.627(3) and 2.652(3) Angstrom; the Fe-Ag-Fe angle is 170.98(9)degrees. The reaction of 1 with mercury(II) chloride gives {Fe(CO)(4)}(2)Hg2Cl4(mu -L), 3. The ligand also reacts with mercury(II) acetate to form a hetero-octanuclear complex [{Fe(CO)(3)Hg}(2)(mu -L)](2) 4 and a novel hetero-heptanuclear complex Fe-3(CO)(8)Hg-4(mu -L)(2),(MeCO2)(2) 5. Complex 4 displays a square metallic core in which the iron and mercury atoms occupy the corners and the centers, of the edges, respectively. The metal atoms in 5 are linked to form a kinky line with bends at the iron atoms.