Isocyanide Iron Research Articles

Crystal structures and spectroscopic characterization of MBr2(CNXyl)n (M = Fe and Co, n = 4; M = Ni, n = 2; Xyl = 2,6-dimethylphenyl), and of formally zero-valent iron as a cocrystal of Fe(CNXyl)5 and Fe2(CNXyl)9.

Structures and spectroscopic characterization of the divalent complexes cis-dibromidotetrakis(2,6-dimethylphenyl isocyanide)iron(II) dichloromethane 0.771-solvate, [FeBr2(C9H9N)4]·0.771CH2Cl2 or cis-FeBr2(CNXyl)4·0.771CH2Cl2 (Xyl = 2,6-dimethylphenyl), trans-dibromidotetrakis(2,6-dimethylphenyl isocyanide)iron(II), [FeBr2(C9H9N)4] or trans-FeBr2(CNXyl)4, trans-dibromidotetrakis(2,6-dimethylphenyl isocyanide)cobalt(II), [CoBr2(C9H9N)4] or trans-CoBr2(CNXyl)4, and trans-dibromidobis(2,6-dimethylphenyl isocyanide)nickel(II), [NiBr2(C9H9N)2] or trans-NiBr2(CNXyl)2, are presented. Additionally, crystals grown from a cold diethyl ether solution of zero-valent Fe(CNXyl)5 produced a structure containing a cocrystallization of mononuclear Fe(CNXyl)5 and the previously unknown dinuclear [Fe(CNXyl)3]2(μ2-CNXyl)3, namely pentakis(2,6-dimethylphenyl isocyanide)iron(0) tris(μ2-2,6-dimethylphenyl isocyanide)bis[tris(2,6-dimethylphenyl isocyanide)iron(0)], [Fe(C9H9N)5][Fe2(C9H9N)9]. The (M)C-N-C(Xyl) angles of the isocyanide ligand are nearly linear for the metals in the +2 oxidation state, for which the ligands function essentially as pure donors. The νCN stretching frequencies for these divalent metal isocyanides are at or above that of the free ligand. Relative to FeII, in the structure containing iron in the formally zero-valent oxidation state, the Fe-C bond lengths have shortened, the C[triple-bond]N bond lengths have elongated, the (M)C-N-C(Xyl) angles of the terminal CNXyl ligands are more bent, and the νCN stretching frequencies have shifted to lower energies, all indicative of substantial M(dπ)→π* backbonding.

Structural characterization and DFT calculation of the Fe–C coordinating bond in bis(tert-butyl isocyanide) iron(II) phthalocyanine

Bis(tert-butyl isocyanide) iron(II) phthalocyanine complex in the crystalline form was obtained by a direct reaction of β- FePc with tert-butyl isocyanide. This complex crystallizes in the centrosymmetric space group P 21/c of the monoclinic system. The Fe ( II ) cation is equatorially ligated by the four N-isoindole atoms of Pc2- macrocycle and axially by the C atom of tert-butyl isocyanide on both sides of a planar FePc molecule. Gas-phase conformation of the bis(tert-butyl isocyanide) iron(II) phthalocyanine molecule obtained by molecular orbital calculations shows a similar conformation as in the crystal. In both phases (solid and gas) a similar correlation between the equatorial Fe – N and axial Fe – C bonds are observed. Steric hindrance of the tert-butyl isocyanide molecules ligated to Fe in axial positions of planar FePc leads to the lowering of the π–π interaction between the π-clouds of Pc macrorings and makes the crystals of the bis(tert-butyl isocyanide) iron(II) phthalocyanine complex better soluble in the most organic solvents than the parent FePc compound. EPR and magnetic susceptibility measurements clearly show that ligation of the intermediate spin FePc by tert-butyl isocyanide leads to the change of the ground state from S = 1 (for FePc , eg3b2g2a1g1) to S = 0 yielding the low-spin complex (( CH 3)3 C - N ≡ C )2 FePc , eg4b2g2). The calculated three-dimensional MESP maps are helpful for understanding of the interaction between the FePc and tert-butyl isocyanide molecules forming bis(tert-butyl isocyanide) iron(II) phthalocyanine complex.

Phosphine-Tethered Carbene Ligands: Template Synthesis and Reactivity of Cyclic and Acyclic Functionalized Carbenes

Reaction of the phosphine-tethered isocyanide iron(II) complex 1, [CpFe(CO)(PCN)]I, with primary and secondary amines forms the corresponding acyclic (diamino)carbene complexes [CpFe(CO)(PCXNH)]I; ...

Synthesis, Crystal Structure, and Spectroscopy of cis-Dichlorotetrakis(2,6-Dimethylphenyl Isocyanide)Iron(II)

The compound cis-FeCl2(DMPI)4 (DMPI = 2,6-dimethylphenyl isocyanide) was synthesized and characterized by X-ray crystallography, IR spectroscopy, and 1H-NMR. The structure of the hexanes solvate was solved in space group C2/c with a = 16.4160(2), b = 15.8028(2), c = 14.1263(2) A, β = 92.345(1), V = 3661.56(8) A3, Z = 4, with R = 0.0385. The coordination geometry about the Fe(II) center was octahedral with the two chlorides cis disposed. This is the first crystal structure of a cis-dihalotetrakis(isocyanide)iron(II) complex, and the isocyanide ligands trans to the chlorides are shown to participate in π-backbonding while those cis to the chlorides do not. IR spectroscopy confirms these observations, and 1H-NMR is consistent with the presence of two different types of isocyanide ligands. The structure and spectroscopy of cis-dichlorotetrakis(2,6-dimethylphenyl isocyanide)iron(II) revealed a complex with two types of isocyanide ligands: those trans to chloride which participate in π-backbonding from iron, and those cis to chloride which do not participate in π-backbonding.

Structure of [bis(diphenylphosphino-P,P')methanide]tetrakis(phenyl isocyanide)iron(II) perchlorate 0.37-pyridine solvate

[Fe(C 7 H 5 N) 4 (C 25 H 21 P 2 )]ClO 4 •0,37C 5 H 5 N cristallise dans P2 1 /n avec a=13,912, b=21,518, c=18,705 A, β=107,86°, Z=4; affinement jusqu'a R=0,083. La structure est composee d'un cation complexe et d'un anion desordonne perchlorate, solvatee par une molecule de pyridine, qui est tres desordonnee. Son meilleur facteur d'occupation converge vers 0,37. Le cation presente une coordination octaedrique deformee autour de l'atome de fer

Reactivity of cationic isocyanide iron(II) derivatives towards nucleophilic agents

Attack of MeNH2 on two adjacent isocyanide ligands in [Fe(dppe)(CNPh)4](ClO4)2 (Ia) gives ▪ (II). II reacts with concentrated aqueous HClO4 to give ▪ (III), which contains a chelating diaminocarbene ligand. Refluxing of a dichloromethane solution of III causes opening of the carbene ring to give mer-[Fe(dppe)(CNPh)3{C(NHPh)(NHMe)}](ClO4)2 (IV). Treatment of III or IV with KOH complex regenerates II. Ia also undergoes addition of Me2NH to give ▪ (V). Reaction of the complexes [Fe(dppe)(CNR)4](ClO4)2 (Ia: R = phenyl; Ib: R = 4-methylphenyl) with KOH gives the carbonyl derivatives ▪ (VIa and VIb). Treatment of VIa with dilute aqueous HClO4 yields ▪ (VII), which takes up a second proton when treated with concentrated aqueous HClO4 to give trans-[Fe(dppe)(CNPh)2(CO){C(NHPh)2}](ClO4)2 (VIII).

2,6-Dimethylphenyl (“xylyl”) isocyanide complexes or iron: preparation and crystal and molecular structures of trans-dichlorotetrakis(xylyl isocyanide)iron(II), [FeCl 2(2,6-Me 2C 6H 3NC) 4] and chloropentakis(xylyl isocyanide)iron(II) tetrachloroferrate(III), [FeCl(2,6-Me 2C 6H 3NC) 5][FeCl 4

The reaction of FeCl 2 and xylyl isocyanide (L) (L = 2,6-Me 2C 6H 3NC) gives two products viz. purple FeCl 2L 4 ( 1) and orange Fe 2Cl 5L 5 ( 2). The structural identity of these complexes has been determined by single crystal X-ray diffraction studies. Crystal of 1 are tetragonal, space group P4 nc, Z = 2, in a unit cell of dimensions a 13.853(8), c 8.803(8) Å. The structure has been refined to R 0.068 ( R w 0.071) for 613 independent reflections above background. The structure comprises octahedral Fe II units with the two chlorines mutually trans. (FeCl 2.318(7), 2.288(6) Å). The four isocyanide ligands, in a cis arrangement around the metal, are essentially linear (FeCN 177.9(7), CNC 173.8(8)°). Crystals of 2 are monoclinic, space group P2 1/ a, Z = 4, in a unit cell of dimensions a 10.310(8), b 20.468(17), c 23.026(23) Å, β 99.0(1)°. The structure has been refined to R 0.077 ( R w 0.081) for 2950 independent reflections above background. The complex is a ‘mixed’ Fe II/Fe III species and consists of octahedral [FeClL 5] + cations based on Fe II, and tetrahedral [FeCl 4] − anions based of Fe III. For the cation, variations in FeC bond lengths between isocyanide ligands trans to one another and trans to chloride are discussed in terms of a trans-effect dominated by the strong τ-acceptor ability of the isocyanide ligands. Further comparisons are drawn with FeC bond lengths observed in 1 and in similar cationic Fe II systems. The [FeCl 4] − anion has tetrahedral symmetry (mean FeCl 2.157 Å, mean ClFe 109.3°). Previous studies of the tetrahedral [FeCl 4] − anion (high spin fe III) show a mean FeCl of 2.180 Å.

The crystal structure of chlorotris(diethyl phenyl phosphonite)bis(4-tolyl isocyanide)iron(II) perchlorate

The crystal structure of chlorotris(diethyl phenyl phosphonite)bis(4-tolyl isocyanide)iron(II) perchlorate

Photoelectron Spectra of Halogeno(tolyl · Isocyanide)iron(II) Complexes

ADVERTISEMENT RETURN TO ISSUEPREVArticlePhotoelectron Spectra of Halogeno(tolyl · Isocyanide)iron(II) ComplexesJohn Schindler, John Luoma, and James CusickCite this: Ind. Eng. Chem. Prod. Res. Dev. 1975, 14, 3, 212–216Publication Date (Print):September 1, 1975Publication History Published online5 January 2004Published inissue 1 September 1975https://doi.org/10.1021/i360055a602RIGHTS & PERMISSIONSArticle Views29Altmetric-Citations3LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (434 KB) Supporting Info (1)»Supporting Information Supporting Information Get e-Alerts

A spectroscopic study of bonding and structure in dihalotetrakis(tolyl isocyanide)iron(II) complexes

Both cis and trans isomers of dihalotetrakis(tolyl isocyanide)iron(II) complexes were synthesized and characterized. Nuclear magnetic resonance spectroscopy was used primarily for identification and characterization. The infrared spectra were studied in the isocyanide stretching region and the number of and intensities of the observed bands were used to infer structural information, while the measured spectral shifts were used to discuss the changes in the π-accepting abilities of the isocyanides and the correlation with the electronegativities of the halide ligands. The Mössbauer spectra of these complexes are also reported and the partial center shift and partial quadrupole splitting values of the ligands have been derived. The bonding characteristics of both the isocyanides and the halides are discussed in terms of σ and π contributions. The experimental Mössbauer data is correlated to the other spectroscopic data although it appears to be more informative, especially in the case of indicating the halide π-donor capabilities.

Characterization of the complexes obtained from the addition of hydrazine to hexakis(methyl isocyanide)iron(II)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCharacterization of the complexes obtained from the addition of hydrazine to hexakis(methyl isocyanide)iron(II)A. L. Balch and J. MillerCite this: J. Am. Chem. Soc. 1972, 94, 2, 417–420Publication Date (Print):January 1, 1972Publication History Published online1 May 2002Published inissue 1 January 1972https://doi.org/10.1021/ja00757a019RIGHTS & PERMISSIONSArticle Views123Altmetric-Citations28LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (457 KB) Get e-Alerts Get e-Alerts

Addition of methylamine to hexakis(methyl isocyanide)iron(II). Formation of an unusual chelating ligand

Addition of methylamine to hexakis(methyl isocyanide)iron(II). Formation of an unusual chelating ligand

Adducts of hexacyanoferric(II) acid, trans-dicyanotetrakis(methyl isocyanide)iron(II), and trans-dicyanotetrakis(ethyl isocyanide)iron(II) with boron trihalides. Infrared and Mössbauer spectroscopic studies

Hexacyanoferric(II) acid readily absorbs boron trifluoride (but not boron trichloride) to form the adduct Fe(CNH)4(CN)2,2BF3. The trans-dicyanotetrakis(alkyl isocyanide)iron(II) complexes Fe(CNMe)4(CN)2 and Fe(CNEt)4(CN)2 readily absorb either of these boron trihalides to form adducts Fe(CNR)4(CN)2,2BX3. The i.r. and Mössbauer spectra of these adducts are interpreted in terms of structures Fe(CNR)4(CN,BX3)2 with the Lewis acids linked to the nitrogen atoms of the cyanide group. The spectra are consistent with local octahedral symmetry at iron, indicating the similar π-acid ligand properties of the groups CNR and CNBX3, although in the cyanide stretching region the two i.r. bands appropriate for D4h symmetry are observed.

Hexacoordinated pentakis(isocyanide)iron(II) compounds

New iron(II) compounds of formula [FeL 5(ligand)](ClO 4) 2 and [FeL 5X] +, where L = p-tolyl isocyanide and X = Cl or Br, have been prepared by treatment of [FeL 5OClO 3]ClO 4·H 2O with the appropriate halide or with the ligands alkyl CN, aryl CN, cyclohexyl NC, Ph 3P, Ph 3As or Ph 3Sb.

Vibrational spectra and force-constant computations of cis- and trans-dicyanotetrakis(methyl isocyanide)iron(II)

The i.r. (250–4000 cm.–1) and Raman spectra (2000–2500 cm.–1) of the cis- and trans-isomers of dicyanotetrakis (methyl isocyanide)iron(II) have been recorded. Force constants have been computed using a modified Cotton-Kraihanzel force-field and the cases in which the iterative refinement procedure failed to converge are discussed in detail. The computed C–N stretching force-constants are found to be virtually independent of the configuration of the compound.

The structure of molecular compounds. Part XIII. Crystal structure of the molecular compound of cis-dicyanotetra(methyl isocyanide)iron(II) with four molecular of chloroform

A crystal structure analysis of FeII(CN)2(MeNC)4·4CHCl3 has been made. In the crystals, which contain at least 60% by volume of chloroform, molecules of the dicyano-complex are arranged so as to form layers within which the terminal atoms of the ligand arms are at normal van der Waals contact distance. As a result of these contacts the nearly linear and rigid arms come into position which leave a set of connected cavities in the layer. Half of the chloroform molecules take up positions so that they fill space in these cavities; one chlorine atom of each molecule projects outwards so that both surfaces of the layer include chlorine atoms of this type. These comlexe layers of composition Fe(CN)2(MeNC3)4·2CHCl3 alternate with parallel layers consisting entirely of the remaining chloroform, which makes a close contact through its hydrogen atom to the nitrogen of a cyanide group. The chloroform molecules in these layers show much greater thermal motion than those partly trapped in the cavities. Interactions of the component molecules are discussed.

Some alkyl isocyanide complexes of iron

Novel cyanopentakis(methyl isocyanide)iron (II) iodide was synthesized by the controlled alkylation of the known dicyanotetrakis(methyl isocyanide)iron (II) with methyl iodide. Reaction of potassium ferrocyanide with methyl bromide gave hexakis(methyl isocyanide)iron (II) bromide, which yielded the dicyanotetrakis(methyl isocyanide)iron (II) upon thermal decomposition. These complexes were transformed into the benzyl analogues by reaction with benzyl bromide. The products characterized were the known cyanopentakis(benzyl isocyanide)iron (II) bromide and dicyanotetrakis(benzyl isocyanide)iron (II).