Organometallic compounds coupling constants

C NMR Chemical Shifts and Coupling Constants of Organometallic Compounds, 12, 135... 

In Table 1 are summarized representative examples of self-exchange rate constant data for a variety of different types of redox couples based on metal complexes, organometallic compounds, organics and clusters. Where available the results of temperature dependence studies are also cited. For convenience, data obtained from temperature dependence studies are presented as enthalpies and entropies of activation as calculated from the reaction rate theory expression in equation (14). 

As in the second edition, the authors survey the large number of L C NMR applications to organic molecules and natural products in a representative and systematic rather than an exhaustive way. New sections about coupling constants. organophosphorus and organometallic compounds as well as synthetic polymers have been added. The scope remains limited to high-resolution methods and molecular systems. 

Chiral Metal Atoms in Optically Active Organo-Transition-Metal Compounds, 18, 151 13C NMR Chemical Shifts and Coupling Constants of Organometallic Compounds, 12, 135 Compounds Derived from Alkynes and Carbonyl Complexes of Cobalt, 12, 323 Conjugate Addition of Grignard Reagents to Aromatic Systems, I, 221 Coordination of Unsaturated Molecules to Transition Metals, 14, 33 Cyclobutadiene Metal Complexes, 4, 95 Cyclopentadienyl Metal Compounds, 2, 365... 

There are several recent texts dealing with NMR spectroscopy in general and the reader is referred to these texts for further information 117,135, 171,186, 214). The purpose of this review is to cover only the NMR spectroscopy of organometallic compounds, paying particular attention to the chemical shifts and coupling constants of carbon atoms directly attached to metals and metalloids. 

There have been a number of reports of indirect coupling constants to carbon in organometallic compounds (see Tables XXXI and XXXII). Several trends are discernible. For transition metal complexes, the trends in V(i3C—M—3ip) and (i C—M— H) appear to follow those observed for V( P—M— H) and V( P—M— P). For complexes of ruthenium, osmium, rhodium, iridium, palladium, and platinum, it is generally found that V(A—M—B) (A, B = P, H) is large when... 

As in organic chemistry, chemical shifts, splitting patterns, and coupling constants are useful in characterizing the environments of individual atoms in organometallic compounds. The reader may find it useful to review the basic theory of NMR as presented in an organic chemistry text. More advanced discussions of NMR, especially relating to C, have been presented elsewhere. ... 

Extensive tables of chemical shifts and coupling constants can be found in B. E. Mann, C NMR Chemical Shifts and Coupling Constants of Organometallic Compounds, in Adv. Organomet. Chem., 1974,... 

Con arable small jyc coupling constants around 20 Hz are typical for binuclear yttrium compounds with bridging alkyl groups. See for example C. J. Schaverien, Organometallics 1994,13, 69. 

Carbon-13-NMR is a routine means of characterizing organometallic compounds, as well as a mechanistic probe [52-56]. The sensitivity of C-NMR is reflected in the wide range of chemical shifts and scalar coupling constants, Jc-x that allows for evaluation of subtle changes in the organometallic species at the M—C bond. This sensitivity has allowed organometallic chemists to evaluate fluxional processes and electron delocalization in... 

Beside chemical shifts and coupling constants, spin-lattice relaxation times provide frequently another important source of information for structure elucidation, in particular for metal nuclei. In the same way as indirect detection allows effective chemical shift measurement for metal nuclei whose direct observation would be very time consuming or not feasible at all, it was also applied to relaxation time measurements.Since most of the studied organometallic compounds contained only a single metal nucleus, the use of ID sequences was preferred (however, analogous 2D schemes were applied to the characterization of peptides, " and P and F served beside H as observed nucleus. 

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