Dinitriles metal complexes

In these dinitrile complexes, p(CN) are shifted to higher frequencies upon coordination. As in the case of ethylenediamine complexes (Sec. III-2), infrared spectroscopy has been used to determine the conformation of the ligand in metal complexes. The Cu(I) complex, which is known to contain the gauche conformation, exhibits two CH2 rocking modes at 966 and 835 cm , whereas the Ag(l) complex, Ag(sn)2Bp4, shows a single CH2 rocking mode at 770 cm , which is characteristic of the trcns conformation. ... 

The aa -bipyridyl (bipy) complexes Sc(bipy)2X3 (X = Cl, NO3, or NC8), and [bipyH]3[Sc(NC8)6] have been isolated in the former group all ligands were bonded directly to the metal atom. Reaction of 8c(02CMe)3 with o-phthalo-dinitrile gave 8cHPc and 8cPc (Pc = phthalocyanine). The former could be easily deprotonated, and treatment of the latter in DMF with alumina and HCl afforded 8cPcCl,H20. 

The metal-metal interaction in some dinuclear complexes was also shown to increase with the Pi value (reflecting the 7T-electron acceptance) of the dinitrile bridging ligand [23]. 

History. Braun and Tschemak [23] obtained phthalocyanine for the first time in 1907 as a byproduct of the preparation of o-cyanobenzamide from phthalimide and acetic anhydride. However, this discovery was of no special interest at the time. In 1927, de Diesbach and von der Weid prepared CuPc in 23 % yield by treating o-dibromobenzene with copper cyanide in pyridine [24], Instead of the colorless dinitriles, they obtained deep blue CuPc and observed the exceptional stability of their product to sulfuric acid, alkalis, and heat. The third observation of a phthalocyanine was made at Scottish Dyes, in 1929 [25], During the preparation of phthalimide from phthalic anhydride and ammonia in an enamel vessel, a greenish blue impurity appeared. Dunsworth and Drescher carried out a preliminary examination of the compound, which was analyzed as an iron complex. It was formed in a chipped region of the enamel with iron from the vessel. Further experiments yielded FePc, CuPc, and NiPc. It was soon realized that these products could be used as pigments or textile colorants. Linstead et al. at the University of London discovered the structure of phthalocyanines and developed improved synthetic methods for several metal phthalocyanines from 1929 to 1934 [1-11]. The important CuPc could not be protected by a patent, because it had been described earlier in the literature [23], Based on Linstead s work the structure of phthalocyanines was confirmed by several physicochemical measurements [26-32], Methods such as X-ray diffraction or electron microscopy verified the planarity of this macrocyclic system. Properties such as polymorphism, absorption spectra, magnetic and catalytic characteristics, oxidation and reduc-... 

At first the unsubstituted metal-free quinoxalinoporphinazine 129 was obtained in a 67% yield by heating dinitrile quinoxaline-2,3-dicarboxylic acid in benzyl alcohol and chlorobenzene at 180°C with metallic lithium followed by the treatment of the resulting complex with dilute hydrochloric acid (1969ZOB2536).A higher yield of 129 (Ri = = R4 = H,... 

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