Thermal Deamination-anation in Cobalt(III) Thiocyanate Complexes. Novel decarbonylation of the equatorial amide ligand

The solid state thermal behavior of trans-[Co(bpb)(amine)2]NCS⋅H2O complexes where (bpb)=[N,N'-bis(2-pyridinecarboxamido-N)-1,2-benzene], and amine=pyrrolidine (prldn)(1), and benzylamine (bzlan) (2), and trans-[Co(bpb)(piperidine)2]ClO4⋅H2O (3) (mixed with KSCN), has been studied using thermoanalytical techniques, infrared spectroscopy, and pyrolysis coupled to both infrared and mass spectrometry, PY/FTIR and PY/MS. The deamination-anation reaction is clearly observed for all three complexes. The estimated values of E a for the deamination-anation are: E a(1)=246.8 kJ mol−1, E a(2)=255.7 kJ mol−1, E a(3)=234.7 kJmol−1. The trend in E a values is rationalized based on the ligand field strength of the amines and the structural effects. A novel decarbonylation of the amide CO group from the equatorial ligand is observed after the release of one amine molecule. This process has been monitored for complex (1) by FTIR in the carbonyl region and by mass spectrometry for the detection of CO2 at 280°C. The activation energy of this process is estimated for complex (1) (662.5 kJ mol−1). The reaction scheme for the observed reactions is propose

Quantum field theory and Hopf algebra cohomology

We exhibit a Hopf superalgebra structure of the algebra of field operators of quantum field theory (QFT) with the normal product. Based on this we construct the operator product and the time-ordered product as a twist deformation in the sense of Drinfeld. Our approach yields formulas for (perturbative) products and expectation values that allow for a significant enhancement in computational efficiency as compared to traditional methods. Employing Hopf algebra cohomology sheds new light on the structure of QFT and allows the extension to interacting (not necessarily perturbative) QFT. We give a reconstruction theorem for time-ordered products in the spirit of Streater and Wightman and recover the distinction between free and interacting theory from a property of the underlying cocycle. We also demonstrate how non-trivial vacua are described in our approach solving a problem in quantum chemistry.Comment: 39 pages, no figures, LaTeX + AMS macros; title changed, minor corrections, references update

Emission of toxic sulfur gases from polymers coming in contact with food products and with infants

The analysis of the volatiles evolved from a number of polymer samples commonly used in domestic applications show that carbon disulfide, CS$_2$, and carbonyl sulfide, COS, are emitted in the lower range of temperatures, $i.e.$ from room temperature up to 150 °C. Emission of COS in the ppm range was also monitored from materials used in the fabrication of the teats for baby's feeding bottles and from similar devices. Given the lack of legal tolerance limits on the toxicity of COS, it is urgent that such norms be set for this compound