Guanidines metal complexes

A. Amidinate and guanidinate complexes of main group metals 1. Group 1 metal complexes useful starting materials... 

Aminosilicas have been widely studied for use in catalysis, either as a base catalyst or as a support for metal complexes (12). For example, amine functionalized silica can be used to catalyze the Knoevenagel condensation, an important C-C bond forming reaction. Also, the amine sites on the silica can be further functionalized to form supported imines, guanidine, and other species... 

Guanidine forms salts with such relatively weak acids as nitromethane, phthalimide, phenol and carbonic acid [20], Interactions between carboxylate anions of proteins and added guanidinium ion are thought [19, 56] to be weaker than the interactions with ammonium ions the role of guanidinium-carboxylate interactions in stabilizing natural protein conformations has been discussed [36c]. A few reports of metal complex formation by guanidines [57-60], and aminoguanidines [61] have appeared. 

Fig. 30 Bis(guanidinate)alkoxide rare-earth metal complexes...

Solvent Dyes (see also Section 3.10). The 1 2 chromium and cobalt complex dyes devoid of any hydrophilic substituent have a considerable solubility in organic solvents, especially alcohols, ketones, and esters. Enhanced solubility can be achieved by converting the metal-complex sodium salts into salts of organic cations [57], Such cations may be cationic dyes, long-chain aliphatic ammonium ions, or protonated guanidines. For example, the bluish red solvent dye 34 reaches a solubility in organic solvents of up to 1000 g/L [58],... 

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 Hou, Z.M. (2007) Catalytic addition of amine N-H bonds to carbodumides by half-sandwich rare-earth metal complexes efficient synthesis of substituted guanidines through amine protonolysis of rare-earth metal guanidinates. Chemistry-A European Journal, 13, 4037. 

Abstract This review deals with the synthesis and the catalytic application of noncyclopentadienyl complexes of the rare-earth elements. The main topics of the review are amido metal complexes with chelating bidentate ligands, which show the most similarities to cyclopentadienyl ligands. Benzamidinates and guanidinates will be reviewed in a separate contribution within this book. Beside the synthesis of the complexes, the broad potential of these compounds in homogeneous catalysis is demonstrated. Most of the reviewed catalytic transformations are either C-C multiple bond transformation such as the hydroamination and hydrosilylation or polymerization reaction of polar and nonpolar monomers. In this area, butadiene and isoprene, ethylene, as well as lactides and lactones were mostly used as monomers. 

If you identify metal ions, you can flush the whole instrument with 10-20 mM EDTA or guanidine to complex the metal ions and to flush them out. Another successful flushing solution is a phosphate buffer, pH 2.5. That means, on the other hand, that when working with acid buffers the problem becomes minor. After a successful flushing step, you obtain symmetrical peaks for both compounds (see Fig. 32-lb). 

Coles MP, Hitchcock PB. Bicyclic guanidinates in mono- and di-valent metal complexes, including group 1/2 and group 1/12 heterometaDic systems. Angew Chem Int Ed. 2013 66(10) 1124-1130. 

Salt metathesis [Eq. (7)] is a well-established route in the synthesis of a variety of alkaline-earth metal alkyls [186,208-210], allyls [211-214], benzylates [149,178], cyclopentadienides [17, 108, 215-219], pentadienyls [220], fluorenyls [17, 221], indenyls [222], amides [112, 113, 223], p-diketiminates [112], guanidinates [15, 194], aUcoxides [224], aryloxides [224], silanides [210, 225-228], thiolates [229], phosphanides [230, 231], selenolates [229], and germanides [232, 233]. However, the route has been rarely used for the synthesis of more reactive alkyl and aryl metal complexes, largely due to issues pertaining to ether cleavage chemistry as metathesis typically requires the presence of an ethereal solvent. 

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