Properties carbodiimides

Carbodiimide, 128 Carbon dioxide, 130 Carbon monoxide, 78 correlation with N, 39 properties, 40 C , 16, 46... 

Closely related mixed amido/imido/guanidinato tantalum complexes of the type Ta(NR R )[(R R2N)C(NR )2]( = NR ) (R R = Me, Et R = Cy, Pr R = Pr", BuO were synthesized by the insertion of carbodiimides into to tantalum-amide bonds in imidotantalum triamide precursors, and the effects of ligand substitution on thermal properties were studied by TGA/DTA measurements. In addition, selected compounds were pyrolyzed at 600 °C and the decomposition products were studied by GC-MS and NMR spectroscopy. ... 

High modulus blends can be developed by mixing TPU with acetal copolymer (trioxane ethylene oxide copolymers) [242-244]. The highly crystalline acetal forms a second continuous phase. Kumar et al. studied behavior of such blends [245]. TPU retains none of its physical properties after immersion in water at 70°C for three weeks. The hydrolysis resistance of TPU can be improved by blending with polycarbodiimides [246]. Two parts of carbodiimide with TPU offer 87% retention of its strength, 93% of elongation, and 75% of modulus under the same... 

AMCA may be coupled to amine-containing molecules through the use of the carbodiimide reaction using EDC (Chapter 3, Section 1.1). EDC will activate the carboxylate on AMCA to a highly reactive o-acylisourea intermediate. Attack by a nucleophilic primary amine group results in the formation of an amide bond (Figure 9.22). Derivatization of AMCA off its carboxylate group causes no major effects on its fluorescent properties. Thus, proteins and other macromolecules may be labeled with this intensely blue probe and easily detected by fluorescence microscopy and other techniques. 

Analogous betaines 71 are formed between azirines 69 and carbodiimides 70, the suggested mechanism being as in Scheme 19. For unsymmetrical 70, the product formed is that predicted by the electronic properties of and... 

Physical properties for step 2 macrocyclic carbodiimides are provided in Table 2. 

TABLE 2. Physical Properties of Step 2 Macrocyclic Carbodiimides Prepared by Ring Closure of Step 1 Product Using l,3-Dimethyl-3-phospholene Oxide... 

Most references to the use of EDC describe the optimal reaction medium to be at a pH between 4.7 and 6. However, the carbodiimide reaction occurs effectively up to at least pH 7.5 without significant loss of yield. See Chapter 9, Section 3 for additional information on the properties of EDC conjugation using small peptides coupled to carrier proteins. 

BODIPY 530/550 C3 is 4,4-difluoro-5,7-diphenyl-4-bora-3a,4a-diaza-s-indacene-3-propionic acid (Molecular Probes). This derivative of the basic BODIPY structure contains two phenyl rings off the No. 5 and 7 carbon atoms and a propionic acid group on the No. 3 carbon atom. The carboxylate group may be used to attach the fluo-rophore to amine-containing molecules via a carbodiimide reaction to create an amide bond. The substituents on this BODIPY fluorophore result in alterations to its spectral properties, pushing its excitation and emission maximums up to higher wavelengths. 

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