Search

The unsymmetrical diborane(4) derivative [(d(CH 2 P( i Pr) 2 )abB)-Bpin] ( 1 ) proved to be a versatile PBP boryl pincer ligand precursor for Co(I) ( 2a , 4a ), Rh(I) ( 2 - 3b ) and Ir(I/III) ( 2 - 3c , 5 - 6c ) complexes, in particular of the types [(d(CH 2 P( i Pr) 2 )abB)M(PMe 3 ) 2 ] ( 2a - c ) and [(d(CH 2 P( i Pr) 2 )abB)M-PMe 3 ] ( 2b - c ). Whilst similar complexes have been obtained before, for the first time, the coordination chemistry of a homologous series of PBP pincer complexes, in particular the interconversion of the five- and four-coordinate complexes 2a - c / 3a - c , was studied in detail. For Co, instead of the mono phosphine complex 2a , the dinitrogen complex [(d(CH 2 P( i Pr) 2 )abB)Co(N 2 )(PMe 3 )] ( 4a ) is formed spontaneously upon PMe 3 abstraction from 2a in the presence of N 2 . All complexes were comprehensively characterised spectroscopically in solution via multinuclear (VT-)NMR spectroscopy and structurally in the solid state through single-crystal X-ray diffraction. The unique properties of the PBP ligand with respect to its coordination chemical properties are addressed.

The substance class of the well-known Cinchona alkaloids is widened by 6'-Amino-cinchonine and 6'-Amino-cinchonidine, novel compounds which incorporate a primary amino function in the quinolinic ring system. These key intermediates open the field for a range of fruitful chemistry. Here is described a short and direct pathway for the synthesis of triazole containing derivatives of the above-mentioned substances using the [3 + 2] Huisgen cycloaddition. For this purpose, the amines were first converted into the corresponding azides. Based on this, non-substituted and silyl-protected triazoles were synthesized as examples. Furthermore, didehydrated derivatives of quincorine and quincoridine were used as addition partners, resulting in compounds that carry the quinuclidine ring of the cinchona alkaloids at both ends. Some of these compounds were examined radiographically to investigate the position of the quinuclidine ring to the triazole. The solid-state structures of compounds 10 , 11 and 28 were determined by X-ray diffraction analyses.

Chronic venous insufficiency of the lower limbs is often underestimated and, in the absence of therapy, results in increasingly severe complications, including therapy-resistant tissue defects. Therefore, early diagnosis and adequate therapy is of particular importance. External counter pulsation (ECP) therapy is a method used to assist the venous system. The main principle of ECP is to squeeze the inner leg vessels by muscle contractions, which are evoked by functional electrical stimulation. A new adaptive trigger method is proposed, which improves and supplements the current therapeutic options by means of pulse synchronous electro-stimulation of the muscle pump. For this purpose, blood flow is determined by multi-sensor plethysmography. The hardware design and signal processing of this novel multi-sensor plethysmography device are introduced. The merged signal is used to determine the phase of the cardiac cycle, to ensure stimulation of the muscle pump during the filling phase of the heart. The pulse detection of the system is validated against a gold standard and provides a sensitivity of 98% and a false-negative rate of 2% after physical exertion. Furthermore, flow enhancement of the system has been validated by duplex ultrasonography. The results show a highly increased blood flow in the popliteal vein at the knee.