The state-of-the-art in the structural investigations into fullerene derivatives is surveyed. The... more The state-of-the-art in the structural investigations into fullerene derivatives is surveyed. The crystal structures of individual fullerenes and of their derivatives determined experimentally by single-crystal X-ray diffraction are systematised. The results of powder X-ray diffraction and EXAFS spectroscopy are overviewed for those classes of derivatives that have been insufficiently studied by single-crystal X-ray diffraction. Patterns of packing of the fullerene spheres encountered in crystal structures are described and representative examples of the most typical motifs are given. Reasons for the rotational disorder, which often hampers structure determination for fullerene derivatives, and its classification are considered. A model of the "rubber cavity" is introduced, which allows prediction of typical mutual orientations of disordered molecules. The redistribution of bond lengths upon σ- and π-functionalisation of the carbon core is analysed based on the information retrieved from the Cambridge Structural Database. Factors affecting the molecular packing density in crystalline derivatives of fullerenes are discussed in relation to the quality of the diffraction data attainable for them.
The state-of-the-art in the structural investigations into fullerene derivatives is surveyed. The... more The state-of-the-art in the structural investigations into fullerene derivatives is surveyed. The crystal structures of individual fullerenes and of their derivatives determined experimentally by single-crystal X-ray diffraction are systematised. The results of powder X-ray diffraction and EXAFS spectroscopy are overviewed for those classes of derivatives that have been insufficiently studied by single-crystal X-ray diffraction. Patterns of packing of the fullerene spheres encountered in crystal structures are described and representative examples of the most typical motifs are given. Reasons for the rotational disorder, which often hampers structure determination for fullerene derivatives, and its classification are considered. A model of the "rubber cavity" is introduced, which allows prediction of typical mutual orientations of disordered molecules. The redistribution of bond lengths upon σ- and π-functionalisation of the carbon core is analysed based on the information retrieved from the Cambridge Structural Database. Factors affecting the molecular packing density in crystalline derivatives of fullerenes are discussed in relation to the quality of the diffraction data attainable for them.
... Chem. 182 (1979), p. 537. Abstract | PDF (702 K) | View Record in Scopus | Cited By in Scopus... more ... Chem. 182 (1979), p. 537. Abstract | PDF (702 K) | View Record in Scopus | Cited By in Scopus (65). 12. VV Dunina, ON Gorunova, MV Livantsov, Yu.K. Grishin, LG Kuz'mina, NA Kataeva and AV Churakov Inorg. Chem. Commun. 3 (2000), p. 354. Article |.
The charge-resonance phenomenon originally identified by Badger and Brocklehurst lies at the core... more The charge-resonance phenomenon originally identified by Badger and Brocklehurst lies at the core of the basic understanding of electron movement and delocalization that is possible within p-doped aromatic (face-to-face) arrays. To this end, we now utilize a series of different aryl-donor groups (Ar) around a central platform to precisely evaluate the intramolecular electron movement among these tethered redox centers. As such, the unique charge-resonance (intervalence) absorption bands observed upon the one-electron oxidation or p-doping of various hexaarylbenzenoid arrays (Ar6C6) provide quantitative measures of the reorganization energy (lambda) and the electronic coupling element (H(ab)) that are required for the evaluation of the activation barrier (deltaG(ET)) for electron-transfer self-exchange according to Marcus-Hush theory. The extensive search for viable redox centers is considerably aided by the application of a voltammetric criterion that has led in this study to Ar = N,N-dialkyl-p-anilinyl, in which exceptionally low barriers are shown to lie in the range deltaG(ET) = 0.3-0.7 kcal mol(-1) for very fast electron hopping or peregrination around the hexagonal circuit among six equivalent Ar sites. Therefore, at transition temperatures T(t) > 0.5/R or roughly -20 degrees C, the electron-transfer dynamics become essentially barrierless since the whizzing occurs beyond the continuum of states and effectively achieves complete pi-delocalization.
New multicomponent ionic complexes containing [(Cation + )·(C 60 − )] fullerides and neutral Co I... more New multicomponent ionic complexes containing [(Cation + )·(C 60 − )] fullerides and neutral Co II TPP molecules were obtained [the cations are Cs + (1), tetramethylammonium (CH 3 ) 4 N + (2) and N-methylpyridinium N-MePy + (3)]. The crystal structure of 1 determined from single-crystal Xray diffraction analysis contains chains of alternating Co II TPP and C 60 ·− units with voids accommodating solvated [(Cs + )·(C 6 H 5 CN) 1.64 ]·CH 3 CN counter cations. Relatively long Co···C distances between Co II TPP and C 60 ·− in 1 (2.55−3.05 Å ) indicate the absence of noticeable bonding of [a]
The preparation of fullerene complexes with metal tetraarylporphyrins in the presence of excess f... more The preparation of fullerene complexes with metal tetraarylporphyrins in the presence of excess ferrocene (Cp 2 Fe) results in the formation of new solvent-free and multicomponent molecular crystals. New isomorphous complexes of C 60 with PyZnTPP (ZnTPP ≡ zinc 5,10,15,20-tetraphenyl-21H,23H-porphyrinate) and PyCoTPP (CoTPP ≡ cobalt(II) 5,10,15,20-tetraphenyl-21H,23H-porphyrinate) containing Cp 2 Fe and the isostructural C 70 complex with PyZnTPP have been prepared. The crystal structures of the new layered C 60 complexes CoTMPP‚C 60 (obtained in the presence of Cp 2 Fe) and CoTMPP‚2C 60 ‚3C 7 H 8 (obtained in the absence of Cp 2 Fe) have been described (CoTMPP ≡ cobalt(II) 5,10,15,20-tetrakis(p-methoxyphenyl)-21H,23H-porphyrinate). Cobalt atoms of the PyCoTPP and CoTMPP molecules are weakly coordinated to C 60 with Co‚‚‚C(C 60 ) distances in the 2.64−2.82 Å range, whereas zinc atoms of PyZnTPP, as well as cobalt atoms of the CoTMPP molecules in the solvent-free phase, form only van der Waals contacts with fullerenes. Different packing arrangements in the crystals of fullerene−porphyrin complexes have been discussed.
A new supramolecular complex of fullerene C 60 , {(ZnTPP) 4 ‚(4-TPyP)}‚(C 60 ) 2 ‚(C 6 H 5 CN) 3.... more A new supramolecular complex of fullerene C 60 , {(ZnTPP) 4 ‚(4-TPyP)}‚(C 60 ) 2 ‚(C 6 H 5 CN) 3.5 (ZnTPP: zinc(II) tetraphenylporphyrin; 4-TPyP: tetra(4-pyridyl)porphyrin) involving unusual pentamers containing five porphyrin fragments, was obtained. The crystal structure, IR and UV-vis-NIR spectra of the complex, and the molecular structure of the pentamer are presented.
Journal of the American Chemical Society Jacs, Mar 1, 2005
Qualitative structural concepts about dynamic ion pairs, historically deduced in solution as labi... more Qualitative structural concepts about dynamic ion pairs, historically deduced in solution as labile solvent-separated and contact species, are now quantified by the low-temperature isolation of crystalline (reactive) salts suitable for direct X-ray analysis. Thus, dinitrobenzenide anion (DNB -) can be prepared in the two basic ion-paired forms by potassium-mirror reduction of p-dinitrobenzene in the presence of macrocyclic polyether ligands: LC (cryptand) and LE (crown-ethers). The crystalline "separated" ion-pair salt isolated as K(LC) + //DNBis crystallographically differentiated from the "contact" ion-pair salt isolated as K(LE) + DNBby their distinctive interionic separations. Spectral analysis reveals pronounced near-IR absorptions arising from intervalence transitions that characterize dinitrobenzenide to be a prototypical mixed-valence anion. Most importantly, the unique patterns of vibronic (fine-structure) progressions that also distinguish the "separated" from the "contact" ion pair in the crystalline solid state are the same as those dissolved into THF solvent and ensure that the same X-ray structures persist in solution. Moreover, these distinctive NIR patterns are assigned with the aid of Marcus-Hush (two-state) theory to the "separated" ion pair in which the unpaired electron is equally delocalized between both NO 2-centers in the symmetric ground state of dinitrobenzenide, and by contrast, the asymmetric electron distribution inherent to "contact" ion pairs favors only that single NO2-center intimately paired to the counterion. The labilities of these dynamic ion pairs in solution are thoroughly elucidated by temperature-dependent ESR spectral changes that provide intimate details of facile isomerizations, ionic separations, and counterion-mediated exchanges.
A new supramolecular complex of fullerene C 60 , {(ZnTPP) 4 ‚(4-TPyP)}‚(C 60 ) 2 ‚(C 6 H 5 CN) 3.... more A new supramolecular complex of fullerene C 60 , {(ZnTPP) 4 ‚(4-TPyP)}‚(C 60 ) 2 ‚(C 6 H 5 CN) 3.5 (ZnTPP: zinc(II) tetraphenylporphyrin; 4-TPyP: tetra(4-pyridyl)porphyrin) involving unusual pentamers containing five porphyrin fragments, was obtained. The crystal structure, IR and UV-vis-NIR spectra of the complex, and the molecular structure of the pentamer are presented.
Differential scanning calorimetry, solution calorimetry, and room-temperature single-crystal X-ra... more Differential scanning calorimetry, solution calorimetry, and room-temperature single-crystal X-ray diffraction were used to study the thermodynamic and structural properties of a solvated crystal C 60 ‚2C 6 H 5 Br. In the monoclinic solvate, two orientations of C 60 were observed with fractional populations of 0.71 and 0.29. The enthalpy of solution of pure C 60 in bromobenzene was determined to be ∆ sol H[C 60 (s)] ) -11.5 ( 2.0 kJ/mol. The enthalpy of solution of the solvated crystal was ∆ sol H[C 60 ‚2C 6 H 5 Br(s)] ) +28 ( 1 kJ/mol. The phase diagram of the system C 60 -C 6 H 5 Br for T < 423 K was constructed. It predicts the existence of a maximum in the temperature-solubility relationship for C 60 in bromobenzene at 350 K. The activity of bromobenzene vapor over the solvated crystal is predicted to be reduced from its value over the pure liquid by a factor of 3.5.
The state-of-the-art in the structural investigations into fullerene derivatives is surveyed. The... more The state-of-the-art in the structural investigations into fullerene derivatives is surveyed. The crystal structures of individual fullerenes and of their derivatives determined experimentally by single-crystal X-ray diffraction are systematised. The results of powder X-ray diffraction and EXAFS spectroscopy are overviewed for those classes of derivatives that have been insufficiently studied by single-crystal X-ray diffraction. Patterns of packing of the fullerene spheres encountered in crystal structures are described and representative examples of the most typical motifs are given. Reasons for the rotational disorder, which often hampers structure determination for fullerene derivatives, and its classification are considered. A model of the "rubber cavity" is introduced, which allows prediction of typical mutual orientations of disordered molecules. The redistribution of bond lengths upon σ- and π-functionalisation of the carbon core is analysed based on the information retrieved from the Cambridge Structural Database. Factors affecting the molecular packing density in crystalline derivatives of fullerenes are discussed in relation to the quality of the diffraction data attainable for them.
The state-of-the-art in the structural investigations into fullerene derivatives is surveyed. The... more The state-of-the-art in the structural investigations into fullerene derivatives is surveyed. The crystal structures of individual fullerenes and of their derivatives determined experimentally by single-crystal X-ray diffraction are systematised. The results of powder X-ray diffraction and EXAFS spectroscopy are overviewed for those classes of derivatives that have been insufficiently studied by single-crystal X-ray diffraction. Patterns of packing of the fullerene spheres encountered in crystal structures are described and representative examples of the most typical motifs are given. Reasons for the rotational disorder, which often hampers structure determination for fullerene derivatives, and its classification are considered. A model of the &quot;rubber cavity&quot; is introduced, which allows prediction of typical mutual orientations of disordered molecules. The redistribution of bond lengths upon σ- and π-functionalisation of the carbon core is analysed based on the information retrieved from the Cambridge Structural Database. Factors affecting the molecular packing density in crystalline derivatives of fullerenes are discussed in relation to the quality of the diffraction data attainable for them.
... Chem. 182 (1979), p. 537. Abstract | PDF (702 K) | View Record in Scopus | Cited By in Scopus... more ... Chem. 182 (1979), p. 537. Abstract | PDF (702 K) | View Record in Scopus | Cited By in Scopus (65). 12. VV Dunina, ON Gorunova, MV Livantsov, Yu.K. Grishin, LG Kuz'mina, NA Kataeva and AV Churakov Inorg. Chem. Commun. 3 (2000), p. 354. Article |.
The charge-resonance phenomenon originally identified by Badger and Brocklehurst lies at the core... more The charge-resonance phenomenon originally identified by Badger and Brocklehurst lies at the core of the basic understanding of electron movement and delocalization that is possible within p-doped aromatic (face-to-face) arrays. To this end, we now utilize a series of different aryl-donor groups (Ar) around a central platform to precisely evaluate the intramolecular electron movement among these tethered redox centers. As such, the unique charge-resonance (intervalence) absorption bands observed upon the one-electron oxidation or p-doping of various hexaarylbenzenoid arrays (Ar6C6) provide quantitative measures of the reorganization energy (lambda) and the electronic coupling element (H(ab)) that are required for the evaluation of the activation barrier (deltaG(ET)) for electron-transfer self-exchange according to Marcus-Hush theory. The extensive search for viable redox centers is considerably aided by the application of a voltammetric criterion that has led in this study to Ar = N,N-dialkyl-p-anilinyl, in which exceptionally low barriers are shown to lie in the range deltaG(ET) = 0.3-0.7 kcal mol(-1) for very fast electron hopping or peregrination around the hexagonal circuit among six equivalent Ar sites. Therefore, at transition temperatures T(t) &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.5/R or roughly -20 degrees C, the electron-transfer dynamics become essentially barrierless since the whizzing occurs beyond the continuum of states and effectively achieves complete pi-delocalization.
New multicomponent ionic complexes containing [(Cation + )·(C 60 − )] fullerides and neutral Co I... more New multicomponent ionic complexes containing [(Cation + )·(C 60 − )] fullerides and neutral Co II TPP molecules were obtained [the cations are Cs + (1), tetramethylammonium (CH 3 ) 4 N + (2) and N-methylpyridinium N-MePy + (3)]. The crystal structure of 1 determined from single-crystal Xray diffraction analysis contains chains of alternating Co II TPP and C 60 ·− units with voids accommodating solvated [(Cs + )·(C 6 H 5 CN) 1.64 ]·CH 3 CN counter cations. Relatively long Co···C distances between Co II TPP and C 60 ·− in 1 (2.55−3.05 Å ) indicate the absence of noticeable bonding of [a]
The preparation of fullerene complexes with metal tetraarylporphyrins in the presence of excess f... more The preparation of fullerene complexes with metal tetraarylporphyrins in the presence of excess ferrocene (Cp 2 Fe) results in the formation of new solvent-free and multicomponent molecular crystals. New isomorphous complexes of C 60 with PyZnTPP (ZnTPP ≡ zinc 5,10,15,20-tetraphenyl-21H,23H-porphyrinate) and PyCoTPP (CoTPP ≡ cobalt(II) 5,10,15,20-tetraphenyl-21H,23H-porphyrinate) containing Cp 2 Fe and the isostructural C 70 complex with PyZnTPP have been prepared. The crystal structures of the new layered C 60 complexes CoTMPP‚C 60 (obtained in the presence of Cp 2 Fe) and CoTMPP‚2C 60 ‚3C 7 H 8 (obtained in the absence of Cp 2 Fe) have been described (CoTMPP ≡ cobalt(II) 5,10,15,20-tetrakis(p-methoxyphenyl)-21H,23H-porphyrinate). Cobalt atoms of the PyCoTPP and CoTMPP molecules are weakly coordinated to C 60 with Co‚‚‚C(C 60 ) distances in the 2.64−2.82 Å range, whereas zinc atoms of PyZnTPP, as well as cobalt atoms of the CoTMPP molecules in the solvent-free phase, form only van der Waals contacts with fullerenes. Different packing arrangements in the crystals of fullerene−porphyrin complexes have been discussed.
A new supramolecular complex of fullerene C 60 , {(ZnTPP) 4 ‚(4-TPyP)}‚(C 60 ) 2 ‚(C 6 H 5 CN) 3.... more A new supramolecular complex of fullerene C 60 , {(ZnTPP) 4 ‚(4-TPyP)}‚(C 60 ) 2 ‚(C 6 H 5 CN) 3.5 (ZnTPP: zinc(II) tetraphenylporphyrin; 4-TPyP: tetra(4-pyridyl)porphyrin) involving unusual pentamers containing five porphyrin fragments, was obtained. The crystal structure, IR and UV-vis-NIR spectra of the complex, and the molecular structure of the pentamer are presented.
Journal of the American Chemical Society Jacs, Mar 1, 2005
Qualitative structural concepts about dynamic ion pairs, historically deduced in solution as labi... more Qualitative structural concepts about dynamic ion pairs, historically deduced in solution as labile solvent-separated and contact species, are now quantified by the low-temperature isolation of crystalline (reactive) salts suitable for direct X-ray analysis. Thus, dinitrobenzenide anion (DNB -) can be prepared in the two basic ion-paired forms by potassium-mirror reduction of p-dinitrobenzene in the presence of macrocyclic polyether ligands: LC (cryptand) and LE (crown-ethers). The crystalline "separated" ion-pair salt isolated as K(LC) + //DNBis crystallographically differentiated from the "contact" ion-pair salt isolated as K(LE) + DNBby their distinctive interionic separations. Spectral analysis reveals pronounced near-IR absorptions arising from intervalence transitions that characterize dinitrobenzenide to be a prototypical mixed-valence anion. Most importantly, the unique patterns of vibronic (fine-structure) progressions that also distinguish the "separated" from the "contact" ion pair in the crystalline solid state are the same as those dissolved into THF solvent and ensure that the same X-ray structures persist in solution. Moreover, these distinctive NIR patterns are assigned with the aid of Marcus-Hush (two-state) theory to the "separated" ion pair in which the unpaired electron is equally delocalized between both NO 2-centers in the symmetric ground state of dinitrobenzenide, and by contrast, the asymmetric electron distribution inherent to "contact" ion pairs favors only that single NO2-center intimately paired to the counterion. The labilities of these dynamic ion pairs in solution are thoroughly elucidated by temperature-dependent ESR spectral changes that provide intimate details of facile isomerizations, ionic separations, and counterion-mediated exchanges.
A new supramolecular complex of fullerene C 60 , {(ZnTPP) 4 ‚(4-TPyP)}‚(C 60 ) 2 ‚(C 6 H 5 CN) 3.... more A new supramolecular complex of fullerene C 60 , {(ZnTPP) 4 ‚(4-TPyP)}‚(C 60 ) 2 ‚(C 6 H 5 CN) 3.5 (ZnTPP: zinc(II) tetraphenylporphyrin; 4-TPyP: tetra(4-pyridyl)porphyrin) involving unusual pentamers containing five porphyrin fragments, was obtained. The crystal structure, IR and UV-vis-NIR spectra of the complex, and the molecular structure of the pentamer are presented.
Differential scanning calorimetry, solution calorimetry, and room-temperature single-crystal X-ra... more Differential scanning calorimetry, solution calorimetry, and room-temperature single-crystal X-ray diffraction were used to study the thermodynamic and structural properties of a solvated crystal C 60 ‚2C 6 H 5 Br. In the monoclinic solvate, two orientations of C 60 were observed with fractional populations of 0.71 and 0.29. The enthalpy of solution of pure C 60 in bromobenzene was determined to be ∆ sol H[C 60 (s)] ) -11.5 ( 2.0 kJ/mol. The enthalpy of solution of the solvated crystal was ∆ sol H[C 60 ‚2C 6 H 5 Br(s)] ) +28 ( 1 kJ/mol. The phase diagram of the system C 60 -C 6 H 5 Br for T < 423 K was constructed. It predicts the existence of a maximum in the temperature-solubility relationship for C 60 in bromobenzene at 350 K. The activity of bromobenzene vapor over the solvated crystal is predicted to be reduced from its value over the pure liquid by a factor of 3.5.
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