Metal Substituted Carbodiimides

Chemistry and Technology of Carbodiimides Henri Ulrich 2007 John WUey Sons, Ltd. ISBN 978-0-470-06510-5 

Transition metal carbodiimides, such as MnNCN and CuNCN, and carbodiimides derived from zinc, mercury,silver and thallium are also known. A preceramic polymeric titanium carbodiimide is obtained in the reaction of TiCU with bis(trimethyl-silyl)carbodiimide. Liganded carbodiimidotitanium complexes are obtained in the reaction of CpaTiCla with Me3SnN=C=NSi(i-Pr)3. ° Also, dicyclopentadienyl titanium (IV) diisocyanates are converted into carbodiimides with LiN(SrMe3)2.  

The boron substituted carbodiimides are stable liquids or solids, and the C signals of the center carbon atoms in boron carbodiimides are at 123-127.8 ppm. In the solid state, the boron substituted carbodiimides are almost planar, but the angle on the central carbon atom (127 °) and the nitrogen atoms (146 °, 163 °) show that the molecules are not strictly linear.  

The digermyl carbodiimide, H3GeN=C=NGeH3, is a colorless liquid with a melting point of 10 °C, which is stable at room temperature for several hours.  

Some metal substituted carbodiimides, such as bis(trimethylstannyl)carbodiiimde have a structure intermediate between carbodiimide, cyanamide and ionic components. 

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Carbodiimides are a unique class of reactive organic compounds having the heterocumu-lene structure R—N=C=N—R. They can be formally considered to be the diimides of carbon dioxide or the anhydrides of 1,3-substituted ureas, and they are closely related to the monoimides of carbon dioxide, the isocyanates. The substituent R can be alkyl, aryl, acyl, aroyl, imidoyl or sulfonyl, but nitrogen, silicon, phosphorous and metal substituted carbodiimides are also known. The unsubstituted carbodiimide HN=C=NH is isomeric with cyanamide, H2NCN. Mono substituted carbodiimides, generated in the thermolysis of 1-substituted tetrazoles, can be isolated at liquid nitrogen temperature but isomerize to the cyanamides at higher temperatures. ... 

Numerous metal substituted carbodiimides are synthesized from cyanamides (see Sections 1.5 and 1.9)... 

The reactions of metal substituted carbodiimides 20 with arenesulfonyl chlorides or arene-sulfonyl isocyanates produce metal substituted N-sulfonylcarbodiimides 21 (R3M=Me3Si, Et3Ge, Bu3Sn X=C1, NCO). ... 

Similar crosslinked oligomers are obtained from cyanuric halides and bis(trimethylsilyl)-carbodiimide. The oligomeric metal substituted carbodiimides are used as precursors for... 

The remaining chapters are carbodiimides with unsaturated substituents, halogenated carbodiimides, acyl-, thioacyl- and imidoylcarbodiimides, silicon substituted carbodiimides, nitrogen substituted carbodiimides, phosphorous substituted carbodiimides, sulfur substituted carbodiimides, metal substituted carbodiimides, cyclic carbodiimides, polymeric carbodiimides and application of carbodiimides. 

The last chapter includes the numerous biochemical applications of carbodiimides, and the chapters on silicon substituted carbodiimides and metal substituted carbodiimides include their role as precursors for ceramic materials. 

Some metal substituted nitrile imines upon photolysis afford carbodiimides (see Section... 

Also, metal substituted nitrile imines undergo a light induced rearrangement reaction to give silicon-boron, silicon-germanium, silicon-silicon, silicum-phosphorus, boron-boron, and germanium-germanium carbodiimides. An example is the formation of the Si, P... 

The photolytic rearrangement of metal nitrile imines 31 also affords P-substituted carbodiimides 32 ... 

Zirconium and hafnium dialkylamides are highly reactive compounds. They undergo (i) protolytic substitution reactions with reagents such as alcohols, cyclopentadiene and bisftrimethylsilyOamine 63 64 (ii) insertion reactions with C02, CS2, COS, nitriles, phenyl isocyanate, methyl isothiocyanate, carbodiimides and dimethyl acetylenedicarboxylate 69-72 and (iii) addition reactions with metal carbonyls.73 These reactions are summarized with reference to Zr(NMe2)4 in Scheme 1. 

Catalytic addition of carbodiimides to terminal alkyne C-H bonds and amine N-H bonds provides a straightforward and efficient method for the synthesis of propiolamidines and substituted guanidines, respectively (Equations 8.38 and 8.39), which are widely used as ancillary ligands for stabilization of various metal complexes. 

Zhang, W.-X., Nishiura, M. and Hon, Z. (2007) Catalytic addition of amine N-H bonds to carbodiimides by half-sandwich rare earth metal complexes efficient synthesis of substituted guanidines through amine protonolysis of rare earth metal guanidinates. Chemistry - A... 

Substituted (indol-2-yl)-ct-allenols show divergent patterns of reactivity under metal catalysis and an intramolecular 1,3-iodine migration has been reported (Scheme 208). Computational methods have addressed rearrangements of acyl, thioacyl, and imidoyl (thio)cyanates to iso(thio)cyanates, acyl iso(thio)cyanates to (thio)acyl isocyanates, and imidoyl iso(thio)cyanates to (thio)acyl carbodiimides, RCX-YCN RCX-NCY RCY-NCX RCY-XCN (X and Y = O, S, NR ). ... 

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