212696-79-2Relevant academic research and scientific papers
Functionalized 2-Pyridyl-Substituted Metallo-1,2-enedithiolates. Synthesis, Characterization, and Photophysical Properties of (dppe)M{S 2(dppe)M{S2C2(2-pyridine(ium))(CH2 CH2OR″)} and (dppe)M[{S2C2(CH2 CH2-N-2-pyridinium)}]+ (R″ = H, Acetyl, Lauroyl; M = Pd, Pt; dppe = 1,2-Bis
Van Houten, Kelly A.,Heath, Danica C.,Barringer, Chris A.,Rheingold, Arnold L.,Pilato, Robert S.
, p. 4647 - 4653 (2008/10/08)
The complexes (dppe)M{S2C2(2-pyridine)(CH2CH 2OC(O)CH3)} (dppe = 1,2-bis(diphenylphosphino)ethane; M = Pd, Pt) were prepared from 1-(2-pyridyl)-4-acetoxy-2-bromobutan-1-one and the corresponding (dppe)M(SH)2 complexes. The acetyl group was removed from the metal complexes to yield the corresponding alcohols, (dppe)M-{S2C2(2-pyridine)(CH2CH 2OH)}. The lauroyl derivatives (dppe)M{S2C2(2-pyridine)(CH2CH 2OC(O)(CH2)10CH3)} were prepared by esterifying the alcohols with lauroyl chloride. The alkylated pyridinium complexes [(dppe)M-{S2C2(CH2CH 2-N-2-pyridinium)}]+ were generated by the addition of either p-toluenesulfonyl chloride or bis-(triazole) o-chloroaryl phosphate to (dppe)M{S2C2(2-pyridine)(CH2CH2OH)}. [(dppe)Pd{S2C2(CH2CH 2-N-2-pyridinium)}][BPh4] crystallizes in the P1 space group with a = 9.1924(2) A, b = 16.0191(2) A, c = 17.4368(3) A, α = 106.292(2)°, β = 96.235°, and γ = 95.183(2)°. The molecule is best described as a square planar palladium complex with a planar metallo-1,2-enedithiolate which is coplanar with the alkylated pyridinium. The pyridinium-substituted platinum 1,2-enedithiolate complexes have a 1,2-enedithiolate to heterocycle π* charge-transfer transition (ILCT) that is the lowest lying band. Like [(dppe)Pt{S2C2(2-pyridinium)(H)}]+, [(dppe)Pt{S2C2(CH2-CH 2-N-2-pyridinium)}]+ is luminescent in room-temperature solution with two emissive states assigned to the ILCT* singlet and triplet. The lifetime of the 1ILCT* is 0.2 ns, 1φ = 0.002, while the lifetime of the 3ILCT is 8.3 μs, 3φ = 0.01 (DMSO). While [(dppe)Pt{S2C2(CH2CH 2-N-2-pyridinium)}]+ is emissive, the [(dppe)Pt{S2C2(2-pyridinium)(CH2CH 2OR″)}]+ complexes are weak emitters at best in solution with triplet quantum yields of 0.0001 (DMSO). These photophysical studies suggest that the heterocycle and the 1,2-enedithiolate must be coplanar in the ILCT excited states for the complexes to be emissive in room-temperature solution.
