Photophysical, dynamic and redox behavior of tris(2,6-diisopropylphenyl)phosphine

Structural Changes Upon Oxidation of (PtBu2)2 and 1,4‐(CH2)2(PtBu)4: Transannular P–P Interactions in Cations of the 1,4‐C2P4 Ring

“…This difference contributes to the longer lifetimes for the species under CV conditions, as well as allowing for the trapping of an EPR signal for 2 + • where none could be detected for 1 +• (see below). Decomposition due to adventitious moisture is a possible mechanism for the decay of these radical cations in nonaqueous solvents .…”

Chemical and Electrochemical Oxidation of Tris(3,5‐di‐tert‐butylphenyl)phosphine – High Z′ Crystal Structures and Conformational Effects Associated with Bulky meta Substituents

“…Our extensive experience with hydrophobic phosphines bearing bulky 2,6‐substituents, such as tris(2,6‐diisopropylphenyl)phosphine (Dipp 3 P),, tris(2,4,6‐triisopropylphenyl)phosphine (Tripp 3 P) and tris(2,4,6‐trimethylphenyl)phosphine (Mes 3 P), was not transferable to our target ruthenium complexes as they are too sterically congested to coordinate to the metal and we thus turned to analogous 3,5‐disubstituted ligands. We were particularly attracted to 1 and 2 but for completeness included 4‐MeO substituted phosphine 3 and the corresponding 4 (which is one of the most basic Ar 3 P).…”

“…We were particularly attracted to 1 and 2 but for completeness included 4‐MeO substituted phosphine 3 and the corresponding 4 (which is one of the most basic Ar 3 P). Solution redox potentials have been recognized as excellent measures of phosphine donor ability and thus the voltammetric behavior of the series 1 – 4 have been determined , , . Since chalcogenides of 1 were not know and no crystal structures of the series 1 , 5 – 7 has been reported, we synthesized them all and determined their structures to obtain pyramidality indices [i.e.…”

“…Since chalcogenides of 1 were not know and no crystal structures of the series 1 , 5 – 7 has been reported, we synthesized them all and determined their structures to obtain pyramidality indices [i.e. the sum of the angles around phosphorus, Σ(∠CPC)] for comparison to bulky 2,6‐disubstituted phosphines . It is now recognized that different types of steric effects can occur in pyramidal phosphines.…”

“…However, systematic 2,6‐disubstitution also generates steric pressure (Scheme B) between the endo substituents. This repulsive interaction can significantly decrease the pyramidality of PAr 3 , which raises the HOMO energy (inducing greater basicity) and enhances the steric shield by forcing the exo substituents closer around the phosphorus donor , . Systematic 3‐substitution provides an opportunity for the flanking exo groups to create a coordination pocket (dashed perimeter in Scheme C) without direct interference with the donor site (distal steric bulk) .…”