ISSN:
0009-2940
Keywords:
Transition-metal ion chemistry
;
Bond activation, C-H
;
Ligand effects
;
Rate constants
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The gas-phase ion chemistry of the previously studied system Fe(n-pentanenitrile)+ is dramatically changed, when the metal ion bears substituents L (L = C2H4, C3H6, C4H6, i-C4H8, 1-C4H8, 2-C4H8, and C6H6), and the major ion-molecule reactions of Fe(L)+ with RCN (R = n-C4H9) are as follows: (i) Ligand substitution Fe(L)+ + RCN → Fe(RCN)+ + L is observed for all L studied except L = C4H6, C6H6; (ii) the formation of association complexes Fe(L)(RCN)+ takes place for all ligands L, except L = C2H4; (iii) dehydrogenation of the L is confined to L = 1-C4H8 and 2-C4H8; (iv) carbon-carbon and carbon-nitrogen bond activation of the nitrile, typical for the behaviour of bare Fe+, are absent in the reactions of all Fe(L)+ with RCN, Dehydrogenation of the nitrile is observed only for L = 1-C4H8 and 2-C4H8, and the molecular hydrogen originates exclusively from the γ/δ-position of the alkyl chain following the well-established “remote functionalization” concept. In contrast to the reaction of bare Fe+ with n-pentanenitrile, dehydrogenation in the Fe(L)(RCN)+ system is not preceded by a degenerate isomerization of RCN, bringing about equilibrations of the C(α)/C(γ) positions. Rate constants were derived and compared with those calculated by the ADO and CAP theories. All reactions of the ligated Fe(L)+ ions were found to occur with collision rate, again in contrast to the bare Fe+. Based on the ADO formalism, the dipole locking constant “c” of n-pentanenitrile was redetermined to c = 0.47.
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19931261134
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