461. The crystal structure of cuprous iodide–methyl isocyanide

Abstract

The structure of cuprous iodide-methyl isocyanide, CuI,CH,-NC, has been determined by X-ray methods. The crystals are monoclinic, spacegroup CZlc, with a = 13-88, b = 13.20, c = 5.765 A, @ = 105'. The atomic positions have been determined from b-and c-axis electron-density projections and from the components C, and S, of the generalised Fourier projection calculated with the data F(hk l). There are doubl6 chains of copper and iodine atoms running parallel to the c-axis. Cu( 1) , a t the centre of the chain, is bonded tetrahedrally to four iodine atoms at 2.64 and 2.67 A. Cu(2), on alternate sides of the chain, is bonded tetrahedrally to two iodine atoms [shared with Cu( l)] a t 2.73 %i and to two CH,*NC groups which are at the sides of the chain. There are also short Cu Cu distances, indicating bonds, 2-89 and 3.42 A. CUPROUS IODIDE-METHYL ISOCYANIDE, a stable crystalline complex, was first prepared by Hartley from cuprous cyanide and methyl iodide. Decomposition yielded methyl isocyanide, but never methyl iodide; later, the compound was prepared from methyl isocyanide and cuprous iodide and is further described by Irving and Jonason.2 Attempts at molecular-weight determination in acetonitrile solution suggested that the complex is not monomeric; a similarity to Wells's tetrameric CuI,As(C,H,), seemed possible and the structure determination was undertaken. Crysta Data.-CuI,CH,*NC, M = 231.6, monoclinic, a = 13.88, b = 13-20, t = 5765 A, p = 105', U = 1020 A3, D, = 2.94 (by flotation), 2 = 8, D, = 3.02, F(000) = 832.Single-crystal oscillation and Weissenberg photographs.Space-group C2/c (No. 15), Cu-K, radiation, p = 575 cm.-l. EXPERIMENTALThe crystals are colourless needles, elongated along c. Oscillation and Weissenberg photographs were taken about the c and b axes. The intensities of the hkO and h02 reflections, and later hk 1 reflections were measured visually, and Lorentz and polarisation corrections applied. Approximate scale and temperature factors were determined from a *' Wilson plot "; more accurate values were later derived by comparison of lFcl with IFo], and from difference syntheses.The crystal used to record the hkO data was nearly square in cross section, of thickness 0.06 mm., and the needle axis was parallel to the oscillation axis. The linear absorption coefficient is 575 cm-l. Absorption corrections A(hk0) were estimated by a method based on that of Albrecht 4 for all inner, and a selection of outer reciprocal lattice points. Apart from 6 inner reflections, the correction is equivalent to an additional temperature factor, AB-

Isocyanide binding to the copper(I) centers of the catalytic core of peptidylglycine monooxygenase (PHMcc)

“…The number of isocyanides present in these complexes depends on the nature of X, and n can vary from 1 to 4. The iodo-isocyanide complex [CuI(CNMe)] n is polymeric [22]. A discrete three-coordinate copper(I) with one isocyanide, as in the present case, is rare.…”

Isocyano-Triphenylene Complexes of Gold, Copper, Silver, and Platinum. Coordination Features and Mesomorphic Behavior

“…The disappearance of the mesomorphic properties presumably originates from the modified geometry: gold ion leads to linear mononuclear derivatives, but copper(I) produces polynuclear complexes [CuX(CNR)] n . 47,48 The monomeric trans-[PtI 2 (CN-TriPh) 2 ] (7) and [Ag(CN-TriPh) 2 ]BF 4 (8) complexes also melt directly to an isotropic liquid at 47-48 ºC. In this case, it is obvious that the two isocyanide ligands, at the separation distance, would collide if they had to become coplanar.…”

Etude structurale de méthylacrylonitrile–bromure de cuivre, CH2δb C(CH3)CN.CuBr

“…Cet encha3nement min6ral, diff6rent de ceux des compos6s du type CuX.nitrile que nous avons pr6c~demment &udi6s, a d6j~ 6t~ observ~ dans CuI.CH3NC (Fisher, Taylor & Harding, 1960). Les ressemblances entre les deux structures sont frappantes: facies des cristaux identique {aiguiUes allong6es suivant [001 ], m6me groupe spatial C2/c, mailles tr~s comparables (a = 13,88, b = 13,20, c = 5,765 A; fl = 105°)}; l'assemblage mineral est rigoureusement le m6me, l'iode prenant la place du brome; la seule difference r6side dans la liaison cuivreligand qui se fait par l'atome de carbone de la fonction isonitrile, et non plus par l'atome d'azote comme c'est le cas pour C uBr.…”

“…Dans CuI. CH3NC (Fisher et al, 1960), la distance observ6e dans les m~mes conditions est 2,885 A. Les cha3nes doubles infinies (Cu2X2)oo rencontr~es dans CuX.CH3CN ou CuX.C6HsCN (X = CI, Br) conduisaient /~ des valeurs un peu sup6rieures h 3 A (Massaux & Le Bihan, 1976b).…”