Cyanide and isocyanide metal complexes

Responses of the Fe(CN)2(CO) Unit to Electronic Changes as Related to Its Role in [NiFe]Hydrogenase

“…Preparation of K + and Na + Salts of [CpFe(CO)(CN) 2 ] - (Cp = η 5 -C 5 H 5 ) and H[CpFe(CO)(CN) 2 ]. The [CpFe(CO)(CN) 2 ] - salts were synthesized and isolated typically on a 0.1 scale of the published procedure . Iodine as well as bromine were employed for the oxidative cleavage of [CpFe(CO) 2 ] 2 in MeOH; addition of aqueous solutions of KCN or NaCN followed by a short (20 min) reflux produced the desired salts as hygroscopic orange powders.…”

“…According to Coffey's procedure, an aqueous solution of K[CpFe(CO)(CN) 2 ] (1.20 g, 5 mmol, in 10 mL of water) was treated with excess concentrated HCl to precipitate a yellow powder, H[CpFe(CO)(CN) 2 ]. Upon removal of the H 2 O by cannula and washing the remaining solid with ether, the crude product was obtained in 75% yield.…”

“…Preparation of [Et 3 NH][CpFe(CO)(CN) 2 ]. [Et 3 NH][CpFe(CO)(CN) 2 ] was synthesized and isolated according to the published procedure,10a as follows: Addition of excess triethylamine to a 10-mL ethanolic solution of H[CpFe(CO)(CN) 2 ] (0.0808 g, 0.4 mmol) produced a dark brown solution. Further addition of a large amount of diethyl ether to the concentrated solution precipitated an air-sensitive yellow powder.…”

“…There are few vibrational studies of complexes containing mixed CN - /CO ligands with which to compare the combinational response of such ligands to electron density changes. Thus a search for a small molecule containing the pyramidal Fe(CN) 2 (CO) unit led to the simple organometallic anion, (η 5 -C 5 H 5 )Fe(CN) 2 (CO) - . The X-ray crystal structure of the piano stool complex overlays well with the Fe(CN) 2 (CO) moiety of the D. gigas enzyme, the η 5 -C 5 H 5 ring serving as the 6-electron donor analogue of the Ni-(μ-SCys) 2 (μ-OH) trigonal face of the octahedral iron unit in the oxidized enzyme (Figure ) .…”

Phosphoramidate-Mediated Conversion of Carbonyl Ligands into Isocyanide Ligands: A New Approach to Chiral Isocyanide Ligands

“…The production of cobalt complex 3 was achieved by a double alkylation reaction. [5] Despite the fact that this approach requires the use of KCN to create the necessary cyanide ligands, it continues to find application as indicated by its recent use in the synthesis of a range of alkyl, allyl and propargyl isocyanide complexes by treatment of trans-[FeH(CN)(dppe) 2 ] with suitable electrophiles. [6] The iron isocyanide complex 4 has been synthesised by reaction of pentacarbonyliron(o) with a phosphinimine.…”