Amides germanium

Cleavage of all the linkers described above provide a functional group (carboxylic acid, amide, amine, etc) at the anchoring position. Silyl-based handles 71,72, and 73 as well as germanium-based handle 74 insert a C-H bond at the anchoring position and are referred to as traceless (Fig. 15) [82-... 

All studied model compounds can distinctly be divided into three groups (Table VII). The first group is composed of substances in which the sulfur, selenium or cyclopentadienyl anion acts as an anionic center. They exist only in open betaine forms, and their PES do not contain local minima corresponding to cyclic isomers. The second group contains compounds with arsonium cationic and oxide anionic centers and silicon and germanium betaines with arsonium and amide centers. They exist as cyclic isomers and their PES have no local minima corresponding to the open forms. Finally, the third group consists of six studied compounds with phosphonium cationic and oxide or amide anionic centers and arsonium-imide betaine. Their PES have minima for both cyclic and open forms separated by low barriers. 

C. Cyclopropenylidene Complexes of Divalent Germanium, Tin, and Lead Amides... 

The photochemical synthesis and characterisation (by EPR solution spectra at 20 °C in C6H14) of the first stable trivalent germanium and tin amides M [N(SiMe3)2]3 was first reported in 1974 in solution they were shown to be persistent for more than three months at ambient temperature. An alternative synthesis from a tetravalent precursor for the Ge amide is shown in Equation (9.1) (X = Cl or Br). ... 

As discussed in Section 9.2.4, the stable silylenes 2 and 4 have also been studied by cyclic voltammetry (CV) similar procedures were earned out on the isoleptic germanium(II) amides The latter were less readily oxidised or reduced than 2 and 4 the oxidation... 

Monomeric amide, alkoxide and thiolate derivatives of germanium(II), tin(II) and lead(II) are only obtained with very sterically crowded ligands. Thus, bis(2,2,6,6-... 

At a gum arabic concentration of 1.0% (w v), polysaccharide was detected at the Ge surface within the first minute of exposure to the flowing solution as shown in the first spectrum (T 0 min) in Figure 7. The intensities of both the protein and polysaccharide bands then rose rapidly in a 15-min period of time as shown in Figure 6. The 1070 cm 1 polysaccharide band plateaued at 14.7 mAU after 30 min whereas the Amide II band stabilized at 12.5 mAU after approximately 2 hr. The intensity of the 1070 cm 1 polysaccharide band dropped rapidly when Milli-Q water was pumped through the flow cell. A 90% decrease in the 1070 cm 1 band intensity occurred over the 4-hr rinse period. The final intensity of this band was not significantly different from the intensity observed when gum arabic was adsorbed onto germanium at a concentration that was 10 times less. The protein was more firmly bound to the IRE surface as indicated by the Amide II band intensity which dropped less than 10% during the rinse period. Only 15% less protein remained firmly attached to the Ge IRE when it was adsorbed from a gum arabic solution concentration of 0.1% as compared to 1%. Experiments to study adsorption of proteins and polysaccharides on copper and nickel are not yet complete, but appear to show similar trends. 

The carbonylation of alkali metal amides was described in 196785 the reaction of lithium tert-butylamide (80) with CO at 50 °C was reported in 1971 to give apparently an orange solution of ferf-butylcarbamoyllithium (81), which was trapped with trimethylelement chlorides derived from silicon, germanium and tin86. When this reaction was performed at — 75 °C it was found that carbamoyllithium equilibrated to the... 

Vibrational (IR and Raman), UV-visible, photoelectron, NMR, and Mossbauer spectroscopy have all been reported for bis(bistrimethylsilyl-methyl)tin(II) and analogous tin(II) amides. Since an unusual tin-tin double bond has been proposed for the solid state of [Sn[CH(SiMe3)2]2]2 the Raman spectrum of this compound was of interest. Unfortunately, the compound decomposed in the laser beam however, an intense band at 300 cm-1 has been assigned as the Ge—Ge stretching frequency for the analogous germanium compound (68). 

The tin(ll) and germanium(ll) amides 223 were obtained from corresponding dilithio diamide and SnCl2 or GeCl2-diox (diox = dioxane). Analogous reaction with SiCU afforded the appropriate cyclic diaminodichlorosilane 224 (Figure 7) <1996JCD3595>. 

Among other compounds, the first optically active amide derivative 142b containing an asymmetric carbon and a five-coordinated germanium was obtained by the same method or by a one-pot synthesis from A-[(S)-l-phenylethy]acetamide, hexamethyld-isilazane and CICH2GeMe2Cl. The latter method does not require the initial preparation of A-silylated amide and gives a higher overall yield of the final product. 

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