title: Preparative and structural studies on the carbonyl cyanides of iron, manganese, and ruthenium: fundamentals relevant to the hydrogenases.
abstract: The reaction of cyanide, carbon monoxide, and ferrous derivatives led to the isolation of three products, trans- and cis-[Fe(CN)(4)(CO)(2)](2)(-) and [Fe(CN)(5)(CO)](3)(-), the first two of which were characterized by single-crystal X-ray diffraction. The new compounds show self-consistent IR, (13)C NMR, and mass spectroscopic properties. The reaction of trans-[Fe(CN)(4)(CO)(2)](2)(-) with Et(4)NCN gives [Fe(CN)(5)(CO)](3)(-) via a first-order (dissociative) pathway. The corresponding cyanation of cis-[Fe(CN)(4)(CO)(2)](2)(-), which is a minor product of the Fe(II)/CN(-)/CO reaction, does not proceed at measurable rates. Methylation of [Fe(CN)(5)(CO)](3)(-) gave exclusively cis-[Fe(CN)(4)(CNMe)(CO)](2)(-), demonstrating the enhanced nucleophilicity of CN(-) trans to CN(-) vs. CN(-) trans to CO. Methylation has an electronic effect similar to that of protonation as determined electrochemically. We also characterized [M(CN)(3)(CO)(3)](n)(-) for Ru (n = 1) and Mn (n = 2) derivatives. The Ru complex, which is new, was prepared by cyanation of a [RuCl(2)(CO)(3)](2) solution.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Contakes
authors.forename: Sodio C N
authors.initials: SC
authors.lastname: Hsu
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Rauchfuss
authors.forename: Scott R
authors.initials: SR
authors.lastname: Wilson
mesh_terms: D002248:Carbon Monoxide / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D005296:Ferrous Compounds / Q000737:chemistry*; D006864:Hydrogenase / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism
chemical_list: D005296:Ferrous Compounds; D009570:Nitriles; D009942:Organometallic Compounds; D002248:Carbon Monoxide; D012428:Ruthenium; C043296:nickel-iron hydrogenase; D006864:Hydrogenase