Copper chloride, structure determination

The basic study was performed on copper complexes with N,N,N, N1-tetramethylethane-1,2-diamine (TMED), which were known to be very effective oxidative coupling catalysts (7,12). From our first kinetic studies it appeared that binuclear copper complexes are the active species as in some copper-containing enzymes. By applying the very strongly chelating TMED we were able to isolate crystals of the catalyst and to determine its structure by X-ray diffraction (13). Figure 1 shows this structure for the TMED complex of basic copper chloride Cu(0H)Cl prepared from CuCl by oxidation in moist pyridine. 

The copper(II) chloride and cobalt(II) chloride complexes of 199 were prepared elemental analyses indicate that in both cases there are two metal associated with each cryptand. To date, however, no crystals suitable for X-ray structural determination studies have been obtained 149). 

Ionization energies have been determined by p.e.s. for compounds in the two series (Me2N)3 Cl PS and (EtO)3 Cl PS (n —0—3), and the first ionization potential has been shown to correlate linearly with AG° values for complex formation with iodine in carbon tetrachloride. Re-examination of the reaction between tetramethyldiphosphine disulphide and hydrated copper(ii) chloride in ethanol shows the formation of a dinuclear copper(i) complex [(Me4P2S2)CuCl]2 as the major product, while its precursor, (Me4P2S2)CuCl2, is obtained in minor amounts. X-Ray structure determinations have been carried out on both compounds. 

Determination of the catalytically active species derived from 1 in solution. Spectrophotoraetric titration of the backbone ligand 5 with copper(II) acetate in methanol revealed formation of a dinuclear copper(ll) complex species Cu2L.3h(OAc) above a 1 2 molar ratio. A mononuclear copper(ll) species CuL 2h (6) dominates at a 1 1 molar ratio of 5 and copper(ll) acetate. Control experiments for the assignment of putative structures based on the obtained spectroscopic data included a UVA is spectroscopic titration of 5 with anhydrous sodium acetate in the presence of copper(ll) chloride and revealed that acetate is necessary for the formation of a copper (11) complex in methanol. The composition of 1 in methanol is the same as determined by elemental analysis for the sohd state. 

In the present study, the complex, tetra(imidazole)chlorocopper(II) chloride, [Cu(imidazole)4Cl]Cl, has been synthesized, and the structure has been determined at the Small Crystal X-ray Crystallography Beamline (11.3.1) of the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL)(Fig.l)[7]. Structural parameters are compared to similar compounds previously reported in the literature. The particles in the present study can be used to prepare nanoparticle materials, or the crystals can be grown under conditions to form nanoparticles or nanoparticle clusters. The molecular structure of the complex here can be used as a model to correlate with its magnetic and electronic properties. Structural parameters for the present complex of copper(II) are compared to similar compounds previously reported in the literature. With the data accumulated here, some previously unexplained bioinorganic chemistry and related phenomena may be explained in the context of the compounds molecular and electronic properties. 

Ethanol was used, for example, in preparation of zinc complex of 2-hydroxy-1-(N-phenylaminomethyl) 673 [246] and copper complexes of hydrazoneimines of the type 674 [247], whose structures were determined by x-ray diffraction. The complexes of salicylidenthiocarbonylhydrazones of the type 675-677 were synthesized in the same solvent [248]. The complexes 675 are formed from metal acetates [Cu(II)], 676 from nitrates [Ni(II)], and 677 from chlorides [Fe(III)] ... 

AgF, AgCl and AgBr crystallize with a sodium chloride lattice and CuCl, CuBr, and Cul with the lattice given in Figure 62 in which copper has a coordination number of four. This difference in crystal structure of the two salts is not determined by the difference in the dimensions of the Ag"+ and Cu+ ions, since according to Pauling the latter has the value 0-96 A, which is not outside the limits for a sodium chloride lattice. The decrease of the coordination number from six to four and the formation of a tetrahedral configuration are more probably determined by the covalent character of the bonds between copper and chlorine. However, it is to be emphasized that the bonds are not entirely covalent any more than they are entirely ionic, but are of an intermediate... 

A structural study of receptors 51, 52, and 49, showed three different modes of azide complexation to the binuclear copper(II) host (123) 1,1 cascaded, 1,3 cascaded, and noncascaded, respectively. These structures indicate that the nature of the macrocyclic framework of the receptor is important in determining the mode of anion coordination. Figure 5(a and b) shows the crystal structures of 52, 2 Cu(II)-azide, and 52, 2Cu(II)-chloride, respectively, for comparison (129). As can be seen, it is the length of the azide bridge that makes cascade complexation possible, whereas for the smaller mononuclear chloride anion this obviously cannot occur. Receptor 49 has also been shown to cascade bind pyrophosphate [as its bis-copper(II) complex] (130) and sulfate [as its bis-iron(II) complex](131). At about the same time, Nelson and co-workers (132) published a similar bis-copper(II) complex structure that cascaded an azide anion. 

Organometallic and Coordination Compounds. - Crystallization of ferrocene and ruthenocene substituted in the 1- and T-positions by two nitronyl nitroxide radicals gave the new crystal phases p-1 (besides the known phase a-1, a-2, and a-2 whose structures were determined by X-ray analysis and were investigated by C and H NMR spectroscopy with MAS NMR. The solid state Sn CP MAS NMR spectra of a series of triaryltin chlorides of the form ArsSnCl have been acquired. The indirect spin-spin coupling constants (J( Sn- C1)), quadrupolar-dipolar shifts (6( Sn- Cl)), and the Sn chemical shift tensors were extracted. " Powders of the zinc and copper(II) dimethyl-(MDtc), diethyl-(EDtc), and morpholinedithiocarbamate (MfDtc) complexes quantitatively absorb hexamethyleneimine (Hmi) to produce the adducts... 

At the limiting current the surface eoncentration of reaction products reaches saturation and a salt film precipitates. The potential drop at the electrode is then determined essentially by the conduction properties of the surface film. For the case of iron dissolution in concentrated chloride solution the salt film was found to have a duplex structure, consisting of an inner eompact and an outer porous layer [21]. The thickness of the compact layer, where most of the potential drop oceurs, increases linearly with applied potential. On the other hand, the rate of dissolution of the salt layer is governed by mass transport and therefore is independent of potential. Thus the anodic current remains constant even if the potential difference aeross the salt film increases. Eventually, at sufficiently high potentials, other reaction phenomena may occur that lead to a renewed current rise, in a similar way as discussed in Section 4.3.1 for the limiting current of copper deposition. 

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