Ligand nitro

Photolysis reactions often are associated with oxidation because the latter category of reactions frequently can be initiated by light. The photooxidation of phenothiazines with the formation of N- and S-oxides is typical. But photolysis reactions are not restricted to oxidation. In the case of sodium nitroprusside, it is believed that degradation results from loss of the nitro-ligand from the molecule, followed by electronic rearrangement and hydration. Photo-induced reactions are common in steroids [36] an example is the formation of 2-benzoylcholestan-3-one following irradiation of cholest-2-en-3-ol benzoate. Photoadditions of water and of alcohols to the electronically excited state of steroids have also been observed [37],... 

The interatomic distances observed in these complexes are compatible with this structure the value Co—N = 1.95 A 0.02 A for the ammonia ligands has been found54 in the crystals M [Co(NH8)2(N02)4], with M = Ag, K, and NH4, and nearly the same value has been reported for several other crystals. The value 1.96 A 0.02 A has been found54 for the nitro ligands in these crystals we conclude from comparison with the value for the ammonia ligands that the structure... 

Backwall and coworkers have extensively studied the stereochemistry of nucleophilic additions on 7r-alkenic and ir-allylic palladium(II) complexes. They concluded that nucleophiles which preferentially undergo a trans external attack are hard bases such as amines, water, alcohols, acetate and stabilized carbanions such as /3-diketonates. In contrast, soft bases are nonstabilized carbanions such as methyl or phenyl groups and undergo a cis internal nucleophilic attack at the coordinated substrate.398,399 The pseudocyclic alkylperoxypalladation procedure occurring in the ketonization of terminal alkenes by [RCC PdOOBu1], complexes (see Section 61.3.2.2.2)42 belongs to internal cis addition processes, as well as the oxidation of complexed alkenes by coordinated nitro ligands (vide in/ra).396,397... 

Schiff base-cobalt-nitro complexes are too mild as oxidants to react as such with alkenes. However, the addition of Lewis acids (e.g. BF3 Et20, LiPF6) to these complexes activates the nitro ligand and produces a variety of both stoichiometric and catalytic oxidations. Stoichiometric transformations involve the oxidation of sulfides to sulfoxides and 1,3-cyclohexadiene to benzene.467 Alcohols such as benzyl alcohol and cycloheptanol are catalytically transformed into the corresponding carbonyl compounds.467,474... 

A somewhat similar catalytic acetoxylation of ethylene to vinyl acetate by 02 has been carried out in acetic acid in the presence of a Pd(OAc)2-pyCo(TPP)N02 system.472 A stoichiometric epoxidation of alkenes such as 1-octene or propene by cobalt-nitro complexes has been shown to occur in the presence of thallium(III) benzoate. Oxygen labeling studies showed that the epoxide oxygen atom comes only from the nitro ligand (equation 197).473... 

Low-pressure N02 and layers of Con(TPP) react to form the 5-coordinate nitro-complex Coni(TPP)(N02). This in turn adds py to form the 6-coordinate complex (py)Coni(TPP)(N02). Both of these show the expected bands for TV-bound nitro ligand.504 Detailed ligand mode assignments have been given from IR and Raman spectra for Co(PGO)2, where PGO — piperazine glyox-ime.505 The IR spectra of MC12(L), where M = Co, Ni, Pd, Pt, L = 1-methyllumazine M = Co, Pt, L = 1,6,7-trimethyllumazine, are all consistent with TV.O-chelation.506... 

The Nitrite Ion. Asidefrom itsfunction as a nitro ligand (i.e. as an N-donor) this ion is known to play at least four other structural roles, as shown in (21-XLI) to (21-XLIV). In one case three of these (21-XLI), (21-XLIII) and (21-XLIV) have been found in the same compound.29 The nitrite ion itself... 

A regular octahedral CuL chromophore for the copper(II) ion is very uncommon (Figun 19.1) but does occur for the [Cu(N02)6] anion when stabilized by hi symmetry lattices such as the face-centred-cubic lattice of K2Pb[Cu(N02)6] (177)," at 298 K. All six Cu— distances of 2.11 A are equivalent from the copper site symmetry, with the actual symmetry o the anion lowered to T by the conformation of the nitro oxygen atoms. The six nitro ligand are also involved in bidentate nitro coordination to the Pb cations at 2.77 A, a distano consistent with intermediate Pb—O bonding, and which must be mainly responsible fo... 

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