The formation of discrete macrocycles wrapped around single-walled carbon nanotubes (SWCNTs) has recently emerged as an appealing strategy to functionalize these carbon nanomaterials and modify their properties.H ere,w e demonstrate that the reversible disulfide exchange reaction, which proceeds under mild conditions,c an install relatively large amounts of mechanically interlocked disulfide macrocycles on the one-dimensional nanotubes.S ize-selective functionalization of am ixture of SWCNTs of different diameters were observed, presumably arising from error correction and the presence of relatively rigid, curved p-systems in the key building blocks.Acombination of UV/Vis/NIR, Raman, photoluminescence excitation, and transient absorption spectroscopyindicated that the small (6,4)-SWCNTs were predominantly functionalizedbythe small macrocycles 1 2 ,whereas the larger (6,5)-SWCNTs were an ideal matchf or the larger macrocycles 2 2 .T his sizes electivity,w hich was rationalized computationally,c ould prove useful for the purification of nanotube mixtures,s ince the disulfide macrocycles can be removed quantitatively under mild reductive conditions.

Here, the ability of a novel near‐infrared dye to noncovalently self‐assemble onto the surface of single‐walled carbon nanotubes (SWCNTs) driven by charge‐transfer interactions is demonstrated. Steady‐state, Raman, and transient absorption spectroscopies corroborate the electron donating character of the near‐infrared dye when combined with SWCNTs, in the form of fluorescence quenching of the excited state of the dye, n‐doping of SWCNTs, and reversible charge transfer, respectively. Formation of the one‐electron oxidized dye as a result of interactions with SWCNTs is supported by spectroelectrochemical measurements. The ultrafast electronic process in the near‐infrared dye, once immobilized onto SWCNTs, starts with the formation of excited states, which decay to the ground state via the intermediate population of a fully charge‐separated state, with characteristic time constants for the charge separation of 1.5 ps and charge recombination of 25 ps, as derived from the multiwavelength global analysis. Of great relevance is the fact that charge‐transfer occurs from the hot excited state of the near‐infrared dye to SWCNTs.

Intermolecular interactions in J- and H-aggregates of π-conjugated molecules provide fascinating incentives for excitonic pathways. Investigation regarding exciton dynamics in aggregates of tricarbocyanine near-infrared dyes by transient absorption spectroscopy revealed unusual intermolecular communications not only within different aggregates but also between different aggregates. To this end, aggregation was accompanied by a short-lived excitonic component, that is, on the picosecond time scale, due to additional relaxation channels and a long-lived component, that is, on the nanosecond to microsecond time scales. All of the aforementioned are in sharp contrast to what was found for the monomer. For the monomer, monoexponential exciton dynamics of about 0.5 ns was registered. Overall, the long-lived component in aggregates accounts for 1–5% of all excitons. In J-aggregates, it involves the formation of charge transfer/polaron states. In mixtures of J- and H-aggregates, contributions from the long-lived component further increased. We conclude that interactions between J- and H-aggregates open additional channels for exciton relaxation. One of them is a photoinduced charge transfer from, for example, the bright state in J-aggregates to the dark exciton states in H-aggregates, from where electrons are transferred into the continuum of states.

In this contribution, the excited state charge-transfer interactions between single walled carbon nanotubes (SWCNTs) and a variety of phenyl, 4-bromophenyl, and thiophene substituted diketopyrrolopyrroles (DPPs), is described. Atomic force microscopy...

Herein, the microscopic and spectroscopic characterization of a novel non‐covalent electron donor−acceptor system, in which three different metalloporphyrins (1, 2, and 3) play the dual role of light harvester and electron donor with SWCNTs as electron acceptor, is described. To this end, microscopy, that is, atomic force microscopy (AFM) and transmission electron microscopy (TEM) corroborate the formation of 1‐SWCNT, 2‐SWCNT, and 3‐SWCNT. Spectroscopy by means of Raman, fluorescence, and transient absorption spectroscopy confirmed efficient charge‐transfer interaction from photoexcited metalloporphyrins to SWCNTs in the ground and excited state of 1‐SWCNT, 2‐SWCNT, and 3‐SWCNT. The complementary use of spectroelectrochemical and transient absorption measurements substantiates the formation of one‐electron oxidized metalloporphyrins after photoexcitation. Multiwavelength global analysis provides insights into the charge‐separation and recombination processes in 1‐SWCNT, 2‐SWCNT, and 3‐SWCNT upon photoexcitation. Notably, both the charge‐separation and recombination dynamics are fastest in 2‐SWCNT. Importantly, the strongest interactions in the steady‐state experiments are associated with the fastest excited state decay in the time‐resolved measurements.