Synthesis and Properties of Palladium Diselenolenes:  X-ray Crystal Structures of [Pd{SeC(R¹)C(R²)Se}(PBu₃)₂] [R¹, R² = (CH₂)_n, n = 4, 5, 6]

Abstract

The reaction between [Pd(2)(dba)(3)] (dba = dibenzylideneacetone), tributylphosphine, and a bis(cycloalkeno)-1,4-diselenin leads to either a mononuclear diselenolene [Pd[SeC(R(1))=C(R(2))Se](PBu(3))(2)] or a dinuclear diselenolene [Pd(2)[SeC(R(1))=C(R(2))Se](2)(PBu(3))(2)] [R(1), R(2) = (CH(2))(n), n = 4, 5, 6] depending on the stoichiometry employed. Treatment of the dinuclear diselenolenes with 1,2-bis(diphenylphosphino)ethane (dppe) provides a high-yielding route to the mononuclear species [Pd[SeC(R(1))=C(R(2))Se](dppe)]. All new compounds have been characterized by standard spectroscopic and analytical techniques, in particular by multinuclear NMR spectroscopy; the structure of each of the mononuclear tributylphosphine complexes has been determined by X-ray crystallography. Computational studies show that the observed asymmetry of the diselenolenes in the solid state is a result primarily of intramolecular repulsive interactions between the ligands.

Rhenium(V) Complexes with Selenolato‐ and Tellurolato‐Substituted Schiff Bases – Released PPh3as a Facile Reductant

“…In the spectra of the well‐soluble fluorinated complexes [Re(NPhF)(L Se )Cl(PPh 3 )] and [Re(NPhCF 3 )(L Se )Cl(PPh 3 )], the 77 Se resonances are observed as doublets at 360 ppm ( 2 J Se,P = 22 Hz) and 395 ppm ( 2 J Se,P = 24 Hz). The coupling constants are within the magnitude of couplings, which have previously been observed for mixed selenolato/phosphine complexes of platinum , . The 125 Te NMR spectra show signals with a 2 J Te,P coupling of 50–60 Hz, which is also in accord with the situation in similar Pt(II) compounds .…”

Bis{μ-2-[(dimethylamino)methyl]benzenetellurolato}bis[chloridopalladium(II)] dichloromethane hemisolvate

“…The coordination chemistry of transition metal complexes with both organoselenato and organotellurato ligands is a rapidly growing area due to the ability of the resulting complexes to find applications in materials science (Morley et al, 2006;Ford et al, 2004), and investigations of oxidation additive to low valent transition metal centers. In addition to this, organotellurium compounds have been used in catalytic carbon-carbon formation.…”

Structural and spectroscopic trends in mononuclear arylchalcogenolato-palladium(II) and -platinum(II) complexes: Crystal structures of [M(TeAr)2(dppe)] {M=palladium, platinum; Ar=phenyl, 2-thienyl; dppe=1,2-bis(diphenylphosphino)ethane}

“…The intensity distributions and the frequency separations of the multiplet components are symmetric with respect to the assignment of the two 2 J P-Te constants of different magnitudes either to cis-or trans-coupling, and we cannot therefore assign unambiguously the 2 J P-Te or 2 J P-Se coupling constants. However, it has been deduced for related systems that the coupling is larger to a phosphorus in trans-position and smaller to the cis-phosphorus [32,33].…”