Transition-metal complexes of pyrrole pigments. 16. Cobalt complexes of 1,19-dimethyldehydrocorrins as vitamin B12 models

1980 ◽  
Vol 102 (22) ◽  
pp. 6736-6744 ◽  
Author(s):  
Yukito Murakami ◽  
Yasuhiro Aoyama ◽  
Koji Tokunaga
Keyword(s):  
Transition Metal ◽  
Vitamin B12 ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Cobalt Complexes

Transition metal complexes of substituted alkynes. II. Pentafluorophenylacetylene complexes of iron and cobalt

1968 ◽  
Vol 21 (1) ◽  
pp. 97 ◽  
Author(s):  
RS Dickson ◽  
DBW Yawney
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Cobalt Complexes ◽  
Spectroscopic Properties ◽  
Stable Complex ◽  
Structural Isomers ◽  
Nuclear Magnetic Resonance Spectra

Treatment of pentacarbonyliron with pentafluorophenylacetylene has given the stable complex tricarbonyl-2,5-bis(pentafluorophenyl)cyclopentadienoneiron. There is no evidence of the formation of other structural isomers. The complex is also formed from pentafluorophenylaoetylene and nonacarbonyldiiron or dodecacarbonyltriiron. Two alkyne-cobalt complexes have been isolated from the interaction of octacarbonyldicobalt and pentafluorophenylacetylene. One of these is a bridging alkyne complex of molecular stoicheiometry Co2(CO)6(C6F6CCH); the second is a complex of formula Co3(CO)9(CCH2C6F5). The infrared and nuclear magnetic resonance spectra of the complexes are given, and the probable structures of the compounds are deduced from these spectroscopic properties.

Transition metal complexes of substituted alkynes. VI. Substituent arrangement in some bridging tris(alkyne)-cobalt complexes

1970 ◽  
Vol 23 (3) ◽  
pp. 475 ◽  
Author(s):  
RS Dickson ◽  
PJ Fraser
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Cobalt Complexes

The new organocobalt complex CO2(CO)4(CF3C2CF3)2(CF3C2H) has been isolated from the reaction of hexafluorobut-2-yne with p-trifluoropropyne-hexacarbonyldicobalt. In addition, a second isomer of the known complex CO2(CO)4(CF3C2CF3)2(CF3C2H)2 has been isolated from the reaction of 3,3,3-tri-fluoropropyne with p-hexafluorobut-2-yne-hexacarbonyldicobalt. A detailed study of the 1H and 19F N.M.R. spectra of these and the related complexes Co2(C0)4- (CF3C2CF3)3 and CO2(CO)4(CF3C2H)3 has led to an assignment of the substituent arrangement in all of these complexes.

Transition metal complexes of substituted alkynes. IX. Factors that influence the formation of Tris(alkyne)cobalt complexes

1972 ◽  
Vol 25 (6) ◽  
pp. 1179 ◽  
Author(s):  
RS Dickson ◽  
PJ Fraser
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Spectroscopic Analysis ◽  
Cobalt Complexes ◽  
Substituted Benzenes ◽  
Factors Affecting ◽  
Principal Factors ◽  
The Stability

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.

Structure of the Second Coordination Sphere of Transition Metal Complexes. III. Ion Pairing involving Cobalt Complexes

1971 ◽  
Vol 49 (16) ◽  
pp. 2751-2754 ◽  
Author(s):  
D. R. Eaton ◽  
Linda Seville ◽  
J. P. Jesson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Symmetry Axis ◽  
Cobalt Complex ◽  
Cobalt Complexes ◽  
Ion Pair ◽  
Acetonitrile Solution

The structure of the ion pair formed between Co(II) bistripyrazolylmethane ions and PF6− ions in acetonitrile solution has been investigated. Isotropic shifts observed in the 19F nuclear magnetic resonance (n.m.r.) spectra of the anion have been used for this purpose. It is concluded that the preferred position of the anion lies close to the symmetry axis of the cobalt complex and that a contact ion pair is involved. This result is contrasted with previous studies of second sphere coordination involving neutral molecules.

Organometallphosphin-substituierte Übergangsmetallkomplexe, XXVI [1] Diearbonyl-nitrosyl-organometaUphosphin-kobalt-Komplexe / Organometalphosphine-Substituted Transition Metal Complexes, XXVI [1] Dicarbonyl Nitrosjd Organometal Phosphine Cobalt Complexes

1980 ◽  
Vol 35 (5) ◽  
pp. 594-598 ◽  
Author(s):  
Herbert Schumann ◽  
Manfred Meissner
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Nmr Spectra ◽  
Cobalt Complexes ◽  
Tert Butyl

Abstract The reactions of tricarbonyl nitrosyl cobalt with tri-tert-butylphosphine, di(tert-butyl)-trimethylsilyl-, -germyl-, -stannylphosphine, tert-butyl-bis(trimethylsilyl)-, -(germyl)-, -(stannyl)phosphine, as well as with tris(trimethylsilyl)-, -(germyl)-, and -(stannyl-phosphine result in the elimination of one CO-ligand and the formation of corresponding dicarbonyl-nitrosyl-organometal phosphine cobalt complexes. The NMR spectra of the products are reported and discussed.

Mechanochemical changes on cyclometalated Ir(iii) acyclic carbene complexes – design and tuning of luminescent mechanochromic transition metal complexes

2020 ◽  
Vol 7 (3) ◽  
pp. 786-794 ◽  
Author(s):  
Jingqi Han ◽  
Kin-Man Tang ◽  
Shun-Cheung Cheng ◽  
Chi-On Ng ◽  
Yuen-Kiu Chun ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Carbene Complexes ◽  
New Class

A new class of luminescent cyclometalated Ir(iii) complexes with readily tunable mechanochromic properties derived from the mechanically induced trans-to-cis isomerization have been developed.

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