The microwave spectrum and conformation of bromomethyl cyclopropane

The microwave spectrum of gaseous bromomethyl cyclopropane

is reported in the range 12 to 36 GHz. Lines of the ⁷⁹Br and ⁸¹Br species of cis and gauche forms are assigned and partial r₀-structures derived. The rotational constants in MHz are: gauche C₃H₅CH₂⁷⁹Br, A = 11 469.285, B = 1 374.777, C = 1 295.394; gauche C₃H₅CH₂⁸¹Br, A = 11 400.100, B = 1 364.088, C = 1 283.952; cis C₃H₅CH₂⁷⁹Br, A = 8 759.918, B = 1 597.413, C = 1 522.141; cis C₃H₅CH₂⁸¹Br, A = 8 716.552, B = 1 583.761, C = 1 509.017.     

Optimizing Multi-stage Production for an Assembly-Type Supply Chain with Unequal Sized Batch Shipments

This paper studies the multi-stage logistics and inventory problem in an?assembly-type supply chain where a uniform lot size is produced uninterruptedly with a single setup at each stage. Partial lots, or sub-batches, can be transported to next stage upon completion. Unequal sub-batch sizes at each stage follow geometric series and the numbers of sub-batches across stages are allowed to be different. Since the mainline and each branch line of an assembly-type supply chain are series-type supply chains, a model of the series-type supply chain is first established and a model of the assembly-type supply chain is subsequently developed. Optimization algorithms that determine the economic lot sizes, the optimal sub-batch sizes and the number of sub-batches for each stage are developed. The polynomial-time algorithms incorporate the optimality properties derived in the paper to find the lower and upper bounds of the solutions by constructing the solution ranges and then the optimal solutions accordingly.     

Ranking Oxidant Sensitiveness: A Guide for Synthetic Utility

Common oxidants used in chemical synthesis, including newly developed perruthenates, were evaluated in the context of understanding (and better appreciating) the sensitiveness and associated potential hazards of these reagents. Analysis using sealed cell differential scanning calorimetry (scDSC) facilitated Yoshida correlations, which were compared to impact sensitiveness and electrostatic discharge experiments (ESD), that enabled sensitiveness ranking. Methyltriphenylphoshonium perruthenate (MTP3, 8 ), isoamyltriphenylphosphonium perruthenate (ATP3, 7 ) and tetraphenylphosphonium perruthenate (TP3, 9 ) were found to be the most sensitive followed by 2-iodoxybenzoic acid (IBX, 2 ) and benzoyl peroxide (BPO, 10 ), whereas the most benign were observed to be Oxone ( 12 ), manganese dioxide (MnO₂, 13 ), and N-bromosuccinimide (NBS, 17 ).     

Macroscopic and microscopic properties of solutions of aromatic compounds in an ionic liquid

Molecular dynamics simulations of binary mixtures of benzene, 1,3,5-trifluorobenzene and hexafluorobenzene with dimethylimidazolium hexafluorophosphate were carried out to examine their macroscopic and microscopic properties. The energies and volumes of mixing of these mixtures correlate well with observed microscopic properties including coordination number about the aromatic compound. The local ordering of the ions about an aromatic molecule was found to depend on the quadrupole moment of the aromatic species and to remain qualitatively the same on varying the mole fraction of the aromatic species. Interaction energies showed the most significant interactions to be between the aromatic molecule and the ions located about its equator. These findings have implications for the practical use of ionic liquids as solvents for chemical processes.     

Tuning Tetrazole Photochemistry for Protein Ligation and Molecular Imaging

Photochemistry provides a wide range of alternative reagents that hold potential for use in bimolecular functionalisation of proteins. Here, we report the synthesis and characterisation of metal ion binding chelates derivatised with disubstituted tetrazoles for the photoradiochemical labelling of monoclonal antibodies (mAbs). The photophysical properties of tetrazoles featuring extended aromatic systems and auxochromic substituents to tune excitation toward longer wavelengths (365 and 395 nm) were studied. Two photoactivatable chelates based on desferrioxamine B (DFO) and the aza-macrocycle NODAGA were functionalised with a tetrazole and developed for protein labelling with ⁸⁹Zr, ⁶⁴Cu and ⁶⁸Ga radionuclides. DFO-tetrazole ( 1 ) was assessed by direct conjugation to formulated trastuzumab and subsequent radiolabelling with ⁸⁹Zr. Radiochemical studies and cellular-based binding assays demonstrated that the radiotracer remained stable in vitro retained high immunoreactivity. Positron emission tomography (PET) imaging and biodistribution studies were used to measure the tumour specific uptake and pharmacokinetic profile in mice bearing SK-OV-3 xenografts. Experiments demonstrate that tetrazole-based photochemistry is a viable approach for the light-induced synthesis of PET radiotracers.