Copper, coordination compounds

Reaction of dnnamaldehyde 4.35 with (2-pyridyl)hydrazine (4.36) yielded the desired hydrazone 4.37. As anticipated, this compound coordinates readily to copper(II)nitrate in aqueous solution as... 

The properties of copper(Il) are quite different. Ligands that form strong coordinate bonds bind copper(Il) readily to form complexes in which the copper has coordination numbers of 4 or 6, such as tetraammine copper(Tl) [16828-95-8] [Cu(NH3)4], and hexaaquacopper(Il) [14946-74-8] [Cu(H,0),p+ ( see Coordination compounds). Formation of copper(Il) complexes in aqueous solution depends on the abiUty of the ligands to compete with water for coordination sites. Most copper(Il) complexes are colored and paramagnetic as a result of the unpaired electron in the 2d orbital (see Copper... 

Addition of an alkene to a compound containing a metal-H bond usually results in insertion, and it does in this case, too, to give the stabler 1° alkylmetal. Addition of CuBr to this complex might result in transmetallation, to give a C2-Cu bond. Addition of the copper compound to the unsaturated imide gives conjugate addition, perhaps by coordination of the C3=C4 tz bond and insertion into the C2-Cu bond. Workup gives the observed product. 

Some square-planar compounds of the type [Ni(AA)2]X2 are reported to undergo reversible thermochroic behavior when heated beyond the temperature range for dehydration. This behavior has been attributed to reversible square-planar to octahedral conversion.87 88 However, the thermochroic behavior of the similar copper compound, [Cu(AA)2](C104)2 (where AA is N,N-di-ethylethylenediamine), does not involve a change in coordination number rather, a change in the in-plane field strength appears to be the cause.89... 

Fuel additives - [AMNES-CYCLOALIPHATIC AMINES] (Vol 2) - [SULFONIC ACIDS] (Vol 23) -arsenic compds as [ARSENIC COMPOUNDS] (Vol 3) -boron compds as [BORON COMPOUNDS - BORIC ACID ESTERS] (Vol 4) -coordination compounds as [COORDINATION COMPOUNDS] (Vol 7) -ethers m [ETHERS] (Vol 9) -magnesium alkyls as [MAGNESIUM COMPOUNDS] (Vol 15) -polyamines as [DIAMINES AND HIGHER AMINES ALIPHATIC] (Vol 8) -htanates as [TITANIUM COMPOUNDS - ORGANIC] (Vol 24) -use of copper compounds [COPPER COMPOUNDS] (Vol 7)... 

Type II copper proteins, or low blue copper proteins, have less intense colours at normal concentrations, but even low blue copper sites have quite high absorption coefficients when compared with simple copper(II) coordination compounds. Bovine erthyrocyte superoxide dismutase (BSOD) is an example of a low blue copper(II) protein with Xmax 680 nm (e = dm3 300 mol-1 cm-1). 

The binuclear Cu/Co compound (17-F-VI) acts as a functional model for cytochrome c oxidase. The natural enzyme contains a copper atom coordinated to... 

The X-ray structure of the CO-bound fully reduced form was also determined at 2.8-A resolution (Fig. 5C, see color insert) (Yoshikawa et al., 1998). The structure of the O2 reduction site shows that CO coordinates to Foaj in a bent end-on fashion. The distances of Fea,—C and Cub—O are 1.90 and 2.47 A, respectively. The Cub—O distance, 2.47 A, indicates very weak interactions between the two atoms. This structure is consistent with the infrared results as described below. The stability of the cuprous copper compound in the trigonal planar coordination provides the weak interaction. 

The tetrameric o-(dimethylaminomethyl)phenylcopper, which is similar to (III) and probably possesses the same structural features, forms monomeric complexes with l,2-bis(diphenylphosphino)ethane and -ethylene but not with triphenylphosphine (281e). Insertion of an isonitrile into the aryl—Cu bond occurs rather than formation of a complex (281d). The new copper compound is dimeric in benzene, and a six-membered ring structure involving heteroatom coordination bonding as in (V) is proposed. Triphenylphosphine breaks down the dimer (V)... 

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