Near Infrared Phosphorescent, Non‐oxidizable Palladium and Platinum Perfluoro‐phthalocyanines

Abstract

New Pd(II) and Pt(II) complexes with a highly electron-deficient ligand (H2 PcF64 ) were conveniently prepared in a three-step synthesis. This is the first time that the phosphorescence of phthalocyanines with a H2 PcF64 framework has been measured. Based on these measurements, the triplet-state energies (ET ) were directly determined. Transient absorption experiments revealed broad T1 →Tn absorption spanning from ca. 350 to ca. 1000 nm and allowed determination of the triplet-state lifetimes. Removal of the Pd or Pt from the perfluoro-phthalocyanine resulted in a significant increase of the triplet lifetime for H2 PcF64 . The very efficient intersystem crossing observed for both PdPcF64 and PtPcF64 leads to residual fluorescence and suppresses the fluorescence lifetimes to less than 50 ps. The absence of Pd and Pt in the perfluoro-phthalocyanine ligand, viz. H2 PcF64 , led to a recovery of fluorescence. Cyclic voltamperometry studies pointed to complete resistance of PdPcF64 and PtPcF64 to oxidation and very strong electron affinity, which rendered these materials very good electron acceptors (n-type materials). The presence of d-orbital metals such as Pd(II) and Pt(II) in the phthalocyanine ring stabilizes their reduced forms, as indicated by the spectroelectrochemical experiments. PdPcF64 and PtPcF64 easily sensitize singlet oxygen production with very high quantum yields. Both phthalocyanines presented resistance to photodegradation in the solid state under aerobic conditions and under intense irradiation.

Facile Synthesis, Triplet‐State Properties, and Electrochemistry of Hexaiodo‐Subphthalocyanine

“…The synthesis of inexpensive yet efficient and stable triplet photosensitizers with tailored photophysical and electrochemical properties remains a challenging field of chemistry with the portfolio of photosensitizers rapidly expanding every year. It is well established that the incorporation of certain transition metals (e.g., d 10 Cu I , d 6 Re I , d 4 Re III , d 6 Ru II , d 6 Os II , d 6 Ir III , d 8 Pt II , d 8 Pd II , d 10 Au I , or d 8 Au III ) into organic ligands results in the formation of highly populated triplet states upon electronic excitation . Similarly, the functionalization of an organic molecule with atoms with high atomic numbers, such as I, Br, Ir, Pt, Ru, Os, Pb, Tl, etc., can induce spin–orbit coupling due to the heavy atom effect, thus, facilitating intersystem crossing (ISC) .…”

Visible‐Light Photoactive, Highly Efficient Triplet Sensitizers Based on Iodinated Aza‐BODIPYs: Synthesis, Photophysics and Redox Properties

“…For example, incorporation of transition metal ions such as d 10 8 Au III into the organic ligands leads to highly populated triplet states upon excitation with light. [1,3,15] Moreover,a toms with high atomic numbers (I, Br,I r, Pt, Ru, Os, Pb, Tl, etc.) can induce spin orbit coupling due to the heavy atom effect, thus facilitating intersystem crossing.…”

“…Several strategies have been developed to efficiently populate triplet excited state in organic materials. For example, incorporation of transition metal ions such as d 10 Cu I , d 6 Re I , d 4 Re III , d 6 Ru II , d 6 Os II , d 6 Ir III , d 8 Pt II , d 8 Pd II , d 10 Au I or d 8 Au III into the organic ligands leads to highly populated triplet states upon excitation with light . Moreover, atoms with high atomic numbers (I, Br, Ir, Pt, Ru, Os, Pb, Tl, etc.)…”

Preparation of Alkylated and Perfluorinated ZnPc‐modified Carbon Nanotubes and their Application as Conductive Fillers for Poly(vinylidene fluoride) Composite Dielectrics

“…A trace amount of symmetrical analogs, was noticed together with 2 , but, due to difficulty in complete removal, the eluted portion was used without further purification for subsequent reaction with MWCNT‐COOH to give Pc‐functionalized CNTs (Pc‐CNTs). Pc‐CNTs 3 and 4 were synthesized according to the previous literature: the covalent linking of 1 and 2 to CNTs was achieved through amidation with the use of a coupling agent (DCC) that activated the carboxylic acid groups of the CNT to allow a susceptible attack by the amino‐functionalized Pcs. The resulting 3 and 4 were soluble DMAc, DMF, and DMSO, but only partially soluble in THF, MeOH, and EtOH.…”