Magnetic properties of fulleropyrrolidine adducts with two stable nitroxide radicals (2,2,6,6-tetramethylpiperidine-l-oxyl, TEMPO) were studied in toluene solution by continuous-wave time-resolved (TR) and pulsed electron paramagnetic resonance (EPR) spectroscopy in the ground and photoexcited states. Four isomers of the bisadduct, trans-1, trans-2, trans-3, and equatorial forros, having the second pyrrolidine ring at different [6-6] bonds were synthesized. In the ground states, the exchange interaction between two TEMPOs is so small that the spin state of the bisadduct is a doublet in nature. By means of spectral simulations of the EPR spectra in frozen solution at 70 K, the upper limit of the exchange interaction was estimated to be 5 MHz for the trans-1 and trans-2 and 10 MHz for the trans-3 and equatorial isomers. The simulation was also made to determine relative positions of the two TEMPO groups with respect to the pyrrolidine ring. Photoexcited states of the bisadducts with excitation of the 532 nm laser pulse were studied in frozen toluene solution at 5-100 K by using two-dimensional (2-D) pulsed nutation EPR and TREPR. The spin multiplicity of the excited state was determined by the nutation frequency. Al1 of the four bisadducts showed strong exchange couplings between two TEMPOs and fullerene triplet 3C60 , resulting in the generation of the excited quintet and triplet states. The excited triplet states have been observed and assigned for the first time in strongly coupled triplet-radical systems. The zero-field splittings of the quintet state determined from the 2-D nutation EPR spectra were analyzed as the sum of the spinspin interactions among the three paramagnetic centers, two TEMPOs and 3C~0. On the basis of these analyses, the spin distribution on the 3C60 part and the geometry of two TEMPOs are discussed.

Reduction of azo compounds with a system of a trialkylchlorosilane and lithium has been found to afford bis(trialkylsilyl)amines in the presence of a transition metal halide as a catalyst in THF. The reaction course was significantly modified by using t-butyldimethylchlorosilane as a trialkylchlorosilane.

The treatment of 2,5-bis(hydroxymethyl)pyrrole with pyrrole in the presence of hydrochloric acid gave tripyrrane in 61% yield, which afforded porphine in an improved 31% yield by the "3+1" approach.Keywords: tripyrrane, porphine, 2,5-bis(hydroxymethyl)pyrrole, "3+1" type condensation, b-substituted porphyrin b-Substituted porphyrins are usually synthesized by the 3+1' technique known as MacDonald condensation. 1 Moreover, this procedure affords new aromatic porphyrinoid systems, including benzene-and pyridine-containing macrocycles and carbaporphyrins, by utilizing other aromatic aldehydes. 2 During this condensation, tripyrranes, which are the methylene bridged linear trimers of pyrrole, are the key compounds as the "3" component. However, their synthesis is sometimes cumbersome with low yields because of having two ester or carboxyl groups at the C-2 and C-14 positions of the tripyrranes. In particular, unsubstituted tripyrrane (2) 3 , to the best of our knowledge, has not yet been isolated. 4 Therefore, our strategy to develop a facile route to 2 would provide a new way to porphine and b-substituted porphyrins by the "3+1" type procedure as well as macrocycles such as homoporphyrins, 5 N-confused porphyrins 6 and expanded porphyrins. 7Porphyrins are known to be easily obtained by treatment of the precursor porphyrinogen' with oxidizing agents such as chloranil. Therefore, the preparation of porphyrinogen by the 3+1' condensation is the important step in our synthesis. The synthesis of calix[4]arenes from phenolic trimers by Kämmerer and his co-workers 8 suggested to us an approach to tripyrrane and porphyrinogen, whose structures resemble that of calix[4]arene; in 1979 they reported a route to the methylene bridged trimer of phenols by the condensation of 2,6-bis(hydroxymethyl)-4-substituted phenols with excess 4-substituted phenols in the presence of hydrochloric acid. The trimers were then converted to calix[4]arenes using the acid-catalyzed 3+1· condensation with 2,6-bis(halogenomethyl)-4-substituted phenols. We applied this methodology to the synthesis of tripyrrane (2) (Scheme 1). The starting 2,5-bis(hydroxymethyl)pyrrole (1) 9 was obtained in good yield (84-92%) from pyrrole and formalin according to a modification of the literature method. 10 We then examined preparing 2 from 1 under various reaction conditions. Due to the lability and high reactivity of 1, it afforded only intractable tar above room temperature in the presence of acid. In alcoholic solution, the condensation products were a mixture of the dimer and trimer. The trifluoroacetic acid-catalyzed condensation of 1 with excess pyrrole was found to be quite effective, but always accompanied by a small amount of the dimer. Finally, the hydrochloric acid-catalyzed condensation in water at low temperature gave 2 in the best yield (61%).In a typical experiment, pyrrole (26.4 g, 394 mmol) was added to a stirred solution of 1 (5.0 g, 39 mmol) in water (700 cm 3 ) below 5 ºC under argon with shielding from light. After 30 min, concentrated hydrochlo...

High resolution 13C NMR spectra in solid states were observed for chlorophyll a and pheophorbide a with a high magnetic field spectrometer. The rate constants of cross polarization (TCH) and 1H spin-lattice relaxation time in the rotating frame (T1ρH) were determined. The rate constants and relaxation times reflected structural differences among them.

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