Enthalpies of Reaction of (.eta.5-C5H5)Ru(cyclooctadiene)Cl with Tertiary Phosphine Ligands: Ligand Substitution as a Gauge for Metal Basicity and A Linear Correlation of Bond Length and Bond Enthalpy

1995 ◽  
Vol 14 (1) ◽  
pp. 289-296 ◽  
Author(s):  
Michele E. Cucullu ◽  
Lubin Luo ◽  
Steven P. Nolan ◽  
Paul J. Fagan ◽  
Nancy L. Jones ◽  
...  
Keyword(s):  
Bond Length ◽  
Linear Correlation ◽  
Ligand Substitution ◽  
Phosphine Ligands ◽  
Tertiary Phosphine

Further N.M.R. Studies of the Dynamic Stereochemistry of π-Allylic Palladium(II) – Tertiary Phosphine Systems

1973 ◽  
Vol 51 (2) ◽  
pp. 274-287 ◽  
Author(s):  
M. Oslinger ◽  
J. Powell
Keyword(s):  
Variable Temperature ◽  
Chloride Ion ◽  
Ligand Substitution ◽  
Phosphine Ligands ◽  
Plane Rotation ◽  
Substitution Reactions ◽  
Tertiary Phosphine ◽  
Original Proposal ◽  
Dynamic Stereochemistry

A series of cations of the type 1,2-bis(diphenylphosphino)ethane(π-all)palladium(II) (all = allyl, 2-methylallyl, 2-tert-butylallyl, 1-methylallyl, 1,1-dimethylallyl, syn-1-tert-butyl-2-methylallyl) have been isolated as PF6− and/or BF4− salts. Variable temperature n.m.r. data fully substantiate the proposal that pyridine promoted exchange of syn and anti proton sites in such complexes occurs via a π → σ → π mechanism that involves consecutive SN2 ligand substitutions. Comparison of this variable temperature n.m.r. data with that obtained for the complexes 1,2-bis(diphenylphosphino)ethane(π-all)palladium(II) chloride (prepared in situ) has shown that the chloride ion, functioning as a nucleophile, is also effective in promoting π → σ → π reactions. Studies of bis(dimethylphenylphosphine) (π-1,1-dimethylallyl)palladium(II) chloride in CDCl3 below −30° have shown that rapid consecutive SN2 substitution reactions, in which chloride acts as a nucleophile, are also occurring in systems containing monodentate tertiary phosphine ligands. As such the PR3 promoted syn–syn and anti–anti proton site interchange observed in complexes of the type [(π-2-methylallyl)PdCl(PR3)] has been reinterpreted in terms of consecutive ligand substitution reactions involving PR3 and Cl ligands instead of the original proposal which involved an in plane rotation of the π-allylic ligand.

scholarly journals Complex transition metal hydrides: linear correlation of countercation electronegativity versus T–D bond lengths

2015 ◽  
Vol 51 (56) ◽  
pp. 11248-11251 ◽  
Author(s):  
T. D. Humphries ◽  
D. A. Sheppard ◽  
C. E. Buckley
Keyword(s):  
Transition Metal ◽  
Bond Length ◽  
Linear Correlation ◽  
Metal Hydrides ◽  
Bond Lengths ◽  
Transition Metal Hydrides ◽  
Complex Hydrides

For homoleptic 18-electron complex hydrides, an inverse linear correlation has been established between the T–deuterium bond length and the average electronegativity of the metal countercations.

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