Structural and spectroscopic studies of some copper(i) halide tert-butyl isocyanide adducts

Abstract

Single-crystal structural characterizations confirm the existence of the unusual 1 : 4 copper(I) halide : unidentate ligand adducts [Cu(CNt-Bu)4]X for X = Cl, Br (two forms), I (the chloride and one form of the bromide being solvated) with crystal packing dominated by stacks of interleaving cations. Cu-C range between 1.941(2) and 1.972(4) A. The structure of the 1 : 2 chloride complex is also recorded, being [ClCu(CNt-Bu)2], with the copper(I) atom environment trigonal planar, while CuCN : (CNt-Bu) (1 : 1) is a single-stranded polymer which spirals about a crystallographic 3-axis (CN scrambled), the ligands being pendant from the ...CuCNCuCN... string. The (5Cu static broadline NMR spectra of [Cu(CNt-Bu)4]I and [Cu(CNt-Bu)4]Br.H2O in the solid state exhibit dominant, narrow -1/2 <--> +1/2 central transition resonances and associated +/-1/2 <--> +/-3/2 satellite transition resonances which are characteristic of first-order quadrupole broadened systems, while associated high-resolution 65Cu MAS NMR data provide accurate measurement of the 65Cu isotropic chemical shifts. Both approaches provide complete data on the quadrupole and chemical shift interactions which contribute to these spectra. Far-IR spectra of products of reactions involving a range of CuX : t-BuNC ratios reveal the existence of 1 : 1.5 adducts for X = Br, I. Metal-carbon and metal-halogen bands are assigned in the far-IR spectra, which indicate a binuclear double halogen-bridged structure for the 1 : 1.5 complexes.

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.…”

Tris-isocyanide copper(I) complexes: Synthetic, structural, and theoretical study

“…Reported (isocyanide)Cu I complexes are prepared by the treatment of CuX (X = Cl, Br, I) or [Cu(NCMe) 4 ]X (X = BF 4 , PF 6 ) with the appropriate amount of isocyanides [26][27][28][29]36,37]. Single known complex of the type [CuBr(CNR) n ], viz.…”

“…Many 4d and 5d isocyanide metal complexes (e.g., platinum, palladium, and gold; [1,2,4,[15][16][17][18][19][20][21][22][23][24][25]) have been reported, whereas the known 3d complexes are much less abundant. In particular, cationic (isocyanide)Cu I species are limited to [CuL 4Àn (CNR) n ] + (n = 1-4; L = ½ 2,2 0 -bipyridine, ½ 1,10-phenantroline, ½ dppe, ½ DAB, PPh 3 , pyridine; R = Me, t-Bu, Ph, Xyl, p-MeC 6 H 4 ) [26][27][28][29][30][31][32][33][34][35]. Several examples of neutral mononuclear halide complexes of the type [CuX(CNR) n ] (n = 2 or 3), viz.…”

“…Several examples of neutral mononuclear halide complexes of the type [CuX(CNR) n ] (n = 2 or 3), viz. the tris-isocyanide complexes [CuX(CNR) 3 ] (X = I, R = 4-MeC 6 H 4 [36], 2,5-(Mes) 2 C 6 H 3 [37]; X = Br, R = t-Bu [33]) and the bis-isocyanide complexes [CuCl(CNR) 2 ] (R = 2,5-(Mes) 2 C 6 H 3 [37], t-Bu [29]) were obtained and structures of two chloride and two iodide derivatives were verified by X-ray crystallography. In the cases of [CuI(CNC 6 H 3 (Mes)-2,5) 3 ] and [CuCl(CNC 6 H 3 (Mes)-2,5) 2 ], different coordination behavior is rationalized in terms of Lewis acidity of the Cu-containing fragments, which is greater for the {CuI} fragment relative to the {CuCl} fragment [37] and this explains the higher Lewis acid catalytic activity of {Cu}I salts than their {CuCl} analogues.…”

A 93Nb Solid‐State NMR and Density Functional Theory Study of Four‐ and Six‐Coordinate Niobate Systems

“…Mg, [121,122] 27 Al, [123,124] 49 Ti, [125, 126] 65 Cu [127] and 91 Zr. [128,129] As evidenced from the data presented in Figure 12 a and b, the total suite of four-and six-coordinate niobates shows no tendency to correlate (linearly or otherwise) with j y j and j a j , respectively, as both data sets describe a random scatter.…”