ABSTRACT
In the title compound, [PtRe4(C12H22P)2(CO)18] or [(mu-PCy2)(CO)8Re2]2Pt(CO)2 (Cy is cyclohexyl), two phosphido-bridged dirhenium groups are linked by a Pt(CO)2 unit and show different bonding patterns for stereochemical reasons. The Re--Re distances are 3.2620 (15) and 3.0739 (15) A, and the Pt--Re distances are 2.9165 (12), 2.9025 (15) and 2.8548 (13) A.
Subject(s)
Organoplatinum Compounds/chemistry , Crystallography, X-Ray/methods , Models, Molecular , Molecular Conformation , StereoisomerismABSTRACT
An asymmetric triangular Fe(III) complex has been synthesized by an unusual Fe(II) -promoted activation of salicylaldoxime. Formation of the ligand 2-(bis(salicylideneamino)methyl)phenol in situ is believed to occur through the reductive deoximation of salicylaldoxime by ferrous ions. The trinuclear ferric complex has been characterized on the basis of elemental analysis, IR, variable-temperature magnetic susceptibility, and EPR and Mössbauer spectroscopies. The molecular structure established by X-ray diffraction consists of a trinuclear structure with a [Fe3 (µ3 -O)(µ2 -OPh)](6+) core. Two iron ions are in a distorted octahedral environment having FeN2 O4 coordination spheres, and the five-coordinated third iron ion, with an FeNO4 coordination sphere, is in a trigonal bipyramidal environment. The magnetic susceptibility measurements revealed an St = 5/2 ground state with the antiparallel exchange interactions J = - 34.3 cm(-1) , J' = - 4.7 cm(-1) , and D = - 0.90 cm(-1) . The EPR results are consistent with a ground state of S = 5/2 together with a negative D5/2 value. The Mössbauer isomer shifts together with the quadrupole splitting also provide evidence for the high-spin state of the three ferric sites. Magnetic Mössbauer spectra lead to the conclusion that the internal magnetic fields possibly lie in the plane of the three ferric ions.
ABSTRACT
The anaerobic stabilization of raw sludges of different origin was investigated. Precursors like chlorophenol and chlorobenzene isomers were added to some of the samples. The change of the PCDD/F concentrations as well as the change in the pattern of the isomers and congeners was independent of the type and amount of the added precursor. With respect to the change of the PCDD/F concentrations the digestion properties were typical in each digestion series but not applicable to other digestion processes. The quality of the digestion was characterized by measuring the change of pH, controlling the biogas flow rate and the determination of the mineralization degree. The added chlorobenzenes and chlorophenols were almost completely degraded. The aerobic digestion occurred in ventilated batch reactors leading to a significant degradation of all PCDD/F homologues. The degradation ratio depends on the origin of the sewage sludge. Independent of origin individual congeners were partially or completely degraded.
