637. The stability of transition-metal complexes

Author(s):  
H. Irving ◽  
R. J. P. Williams
2017 ◽  
Vol 8 (24) ◽  
pp. 6193-6198 ◽  
Author(s):  
Alexandra Rieger ◽  
Stephan Schnidrig ◽  
Benjamin Probst ◽  
Karl-Heinz Ernst ◽  
Christian Wäckerlin

1972 ◽  
Vol 25 (6) ◽  
pp. 1179 ◽  
Author(s):  
RS Dickson ◽  
PJ Fraser

Reactions involving p-alkyne-hexacarbonyldioobalt complexes and an excess of an alkyne have been investigated systematically to determine some of the factors affecting the formation and stabilization of CO,(CO)~C,(CF,)~R,-, complexes. Systems have been studied in which the value of n has been varied through all values from 0 to 6. The new tris(a1kyne)tetracarbonyldioobalt complex CO,(CO),C,(CF,),(CH~)~- Hz, formed from Co,(CO),(CH,C,CH,) and an excess of CF,C=_CH, has been characterized by elementary and spectroscopic analysis. Tris(a1kyne)tetracarbonyldi- cobalt compIexes have not been isolated from the systems [Co,(CO),(CF3C,CF3)+2- CH,C=CCH,], [Co,(CO),(CF,C,CF,) + 2CH3CzCH], [Co,(CO),(CF,C,CH,) + 2CH3C~C- CH,], [Co,(CO),(CH,C,CH,) + 2CF3CKXF3], [Co,(CO),(CH3C,CH,) + 2CH3C~CCH3], and [Co,(CO),(CH3C,CH,)+2CH3C~CH]. Rather, significant amounts of various CF,- and/or CH,-substituted benzenes are obtained in these reactions. These sub- stituted benzenes are presumably formed by decomposition of unstable tris(a1kyne)- tetracarbonyldicobalt complexes. The accumulated results indicate that two principal factors influence the stability of the CO,(CO)~C,(CF,),R,-, complexes. Stable complexes are isolated only when (i) at least two CF, groups are incorporated as substituents in the C,-bridging fragment, and (ii) CF, substituents are attached to the two terminal carbon atoms of the bridging fragment.


1982 ◽  
Vol 37 (4) ◽  
pp. 468-472 ◽  
Author(s):  
A. Albini ◽  
H. Kisch

Chromium and tungsten carbonyls react with 3,3,4,4-tetramethyl-1,2-diazetine (1) or its mono-N-oxide (2) to form complexes (1)M(CO)5, (1)2M(CO)4, (1)M2(CO)10, (1)2M2(CO)8, (1)3M2(CO)6 or (2)M(CO)5 and (2)2M(CO)4, resp. In the reactions of 2 some deoxygenation affords complexes of 1 as by-products. The stability of these and other complexes of the N=N group is related to the ring size of the cyclic diazene ligand.


1970 ◽  
Vol 48 (6) ◽  
pp. 1007-1010 ◽  
Author(s):  
S. S. Dube ◽  
S. S. Dhindsa

The interaction of Zn2+, Mn2+, Hg2+, and Cd2+ ions with 3,5-dinitrosalicylic acid was investigated by potentiometric titrations in aqueous 0.1 M KNO3 medium. In all cases the formation of 1:1 complex was indicated. The stability constants in the pH ranges 4.5–8.0, 4.5–8.0, 5.0–8.0, and 5.5–8.0 were determined by applying the Calvin and Melchior's extension of Bjerrum's method and the log K values were found to be 3.70, 2.95, 3.20, and 2.85, respectively. A comparative study of the complexes of 3,5-dinitrosalicylic acid with other bivalent metal ions has also been incorporated. The stability constants of the transition metal complexes obey the order Cu > Ni > Co > Zn > Mn, in agreement with Irving and William's rule.


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