Hybrid multi-porphyrin supramolecular assemblies: Synthesis and structure elucidation by 2D DOSY NMR studies

Coordination‐Driven Dimerization of Zinc Chlorophyll Derivatives Possessing a Dialkylamino Group

“…Figure 7 shows the temperature-dependent 1 HNMR spectra of Zn-1.A t 223 K, several sets of proton signals were observed. The protons ignals of 5-H and 3 1 -N(CH 3 ) 2 of Zn-2 and Zn-3 also shiftedt oh igh magnetic fields and broadened with ad ecrease in temperature (Figures S8 and S9), resulting in an open dimer which was also observed for Zn-1.T he meso-protons at the C5, C10, and C20 positions of Zn-2 at 263 Kand those of Zn-3 at 223 Kwere similar in shape to those of Zn-1 at 323 K. These observations were DOSY methods have been used for estimating molecular weights of polymers, [30][31][32][33] and has been recently applied to elucidatet he supramolecular structure of chlorophyll assemblies. [26][27][28][29] Since the shift values of 10-H and 20-H were smaller ( Figure 7, blue square), at low temperature, they were located at relativelyd istant positions from the other chlorin moiety in the resulting supramolecule.…”

“…The complexly split NMR peaks of Zn-1 at 223 Ks howeds everal conformers were present as closed dimers whose structures were not precisely determined. The protons ignals of 5-H and 3 1 -N(CH 3 ) 2 of Zn-2 and Zn-3 also shiftedt oh igh magnetic fields and broadened with ad ecrease in temperature (Figures S8 and S9), resulting in an open dimer which was also observed for Zn-1.T he meso-protons at the C5, C10, and C20 positions of Zn-2 at 263 Kand those of Zn-3 at 223 Kwere similar in shape to those of Zn-1 at 323 K. These observations were DOSY methods have been used for estimating molecular weights of polymers, [30][31][32][33] and has been recently applied to elucidatet he supramolecular structure of chlorophyll assemblies. The Wasielewski and Otsuki research groups described the formation of cyclic trimer and tetramero fc hlorophyll derivatives possessing ap yridinyl group in the substituents at the C20 and C3 positions in an organic solventb yD OSY procedures.…”

Accuracy of Determination of Self-Diffusion Coefficients in Studies of Porphyrin-Based Complexes by 2D DOSY

“…[12][13][14][15] Modern NMR methods play a special role in studied of formation of intermolecular complexes and associates, [16][17][18] and in identifying supramolecular assemblies. [19][20][21][22][23][24] In studies of intermolecular interactions in porphyrin complexes, a number of efficient approaches can be applied, including classical analysis of chemical shifts and relaxation times and modern two-dimensional methods such as nuclear Overhauser effect [25][26][27] and diffusion-ordered spectroscopy (DOSY).…”

“…[19][20][21][22][23][24] In studies of intermolecular interactions in porphyrin complexes, a number of efficient approaches can be applied, including classical analysis of chemical shifts and relaxation times and modern two-dimensional methods such as nuclear Overhauser effect [25][26][27] and diffusion-ordered spectroscopy (DOSY). [11,13,[28][29][30][31][32][33][34] Each of them has its own strong and weak sides. Temperature dependency of the integral intensities of cross-peaks in 2D NOESY spectra can yield reliable information on the molecular interaction in the presence of chemical exchange.…”

Determination of the Methylpheophorbide а Association Degree by Diffusion Ordered NMR Spectroscopy (DOSY)

“…[4][5][6][7] It is known that DOSY method can be used for study of the molecules association in a solution, this method allows to fix the formation of molecular associates with relatively strong hydrogen bonds or ionic interactions between molecules. [8][9][10] Determination of the Methylpheophorbide а Association Degree by DOSY DOSY method was also used for multiporphyrin systems molecular weights estimation, but the porphyrin macrocycles in the objects of these investigations are connected with involvement of covalent bonds, [11] or through strong coordination interactions, [12][13][14][15][16][17] or hydrogen bonds. [18] The porphyrin associates with weaker intermolecular interactions have not been investigated by this method.…”