| 19746954 |
Burrows AD, Harrington RW, Kirk AS, Mahon MF, Marken F, Warren JE, Whittlesey MK: Synthesis, characterization, and electrochemistry of a series of iron (II) complexes containing self-assembled 1,5-diaza-3,7-diphosphabicyclo [3.3.1] nonane ligands. Inorg Chem. 2009 Oct 19;48(20):9924-35.
The reaction between PPh (CH (2) OH)(2), iron (II) sulfate, ammonium sulfate, and formaldehyde in aqueous solution gives the iron (II) complex [Fe (kappa (2)-O (2) SO (2)) L (2)] (1), where L is the bidentate phosphine ligand 3,7-diphenyl-1,5-diaza-3,7-diphosphabicyclo [3.3.1] nonane. During the course of the reaction, the ligand L self-assembles on the metal center. The reaction between PPh (CH (2) OH)(2), iron (II) chloride, ammonium chloride, and formaldehyde under similar conditions gives cis-[FeCl (2) L (2)] (cis-2). The complex cis-2 is converted into trans-2 in Et (2) O, whereas in water it is converted into cis-[Fe (OH (2))(2) L (2)](2+), though both of these interconversions are reversible. The chloro ligands in cis-2 are readily displaced by reaction with thiocyanate, azide, and carbonate to give cis- and trans-[Fe (NCS)(2) L (2)] (cis- and trans-3), cis- and trans-[Fe (N (3))(2) L (2)] (cis- and trans-4), and [Fe (kappa (2)-O (2) CO) L (2)] (5), respectively. The complex cis-2 reacts with CO in water to give trans-[FeCl (CO) L (2)] Cl (trans-6), whereas trans-2 reacts with CO in diethyl ether to give cis-[FeCl (CO) L (2)] Cl (cis-6), though cis-6 isomerizes in water to form trans-6. The reaction of cis-2 with sodium borohydride gives the hydride chloride complex trans-[FeCl (H) L (2)] (7). Electrochemical studies have been undertaken on complexes 1, cis-2, and 7. These reveal reversible oxidations for cis-2 and 7, with the latter giving rise to an unusual 17-electron iron (III) hydride chloride complex. Crystal structures have been obtained for 1, trans-2, trans-3, 5, and 7. |
12(0,0,1,7) |