摘要:

The C60‐pyridine, C60py, and C60‐imidazole, C60im, adducts were found to self‐assemble in films floating onto aqueous solutions of zinc tetrakis (N‐methylpyridinium)porphyrin cation, Zn(TMPyP), or zinc tetrakis (4‐sulfonatophenyl)porphyrin anion, Zn(TPPS). This self assembling was due to axial ligation of the C60adducts (acceptors) by Zn porphyrins (donors), which lead to the formation of relatively stable donor‐acceptor dyads in the water‐air interfaces. The films were compressed in a Langmuir trough and characterized by isotherms of surface pressure vs. area per molecule as well as by the Brewster angle microscopy imaging. All systems formed stable aggregated Langmuir films of the “expanded liquid” type. Extensive compression of the films resulted in two‐dimensional phase transitions. The area per molecule at infinite dilution of the adducts in films increased in the order: water<0.1 mM Zn(TPPS)<0.1 mM Zn(TPMyP). Comparison of the determined and calculated values of area per molecule indicated that orientation of porphyrins in the complexes was parallel with respect to the interface plane. The Langmuir films were transferred, by using the Langmuir‐Blodgett technique, onto quartz slides. The UV‐vis spectroscopic study of these films revealed that Zn porphyrins were transferred together with the C60adducts and that the transfer efficiency increased in the order: C60py‐Zn(TPPS)<C60py‐Zn(TMPyP)<C60im‐Zn(TPPS)<C60im‐Zn(TMPyP), i.e., in accord with the increase of stability of the respective dyads in solutions. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1627974

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Endohedral fullerenes in general and cluster/molecule encapsulated endohedrals in particular exhibit a very complex dynamic behaviour, that has necessarily to be considered when investigating or characterizing these systems by spectrosopic measurements. Molecular dynamics (MD) simulations along with the calculation of dynamic spectra provide a detailed insight into the intra‐cage dynamics of these systems and help to clarify its impact on spectroscopic investigations. The effects are shown exemplarily for Sc3N&at;C80, Sc3N&at;C78and Sc2C2&at;C84. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1627975

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We present an AFM/STM analysis of an ionic C60derivative, complemented by Raman measurements, light microscopy and mass spectrometry. It was previously demonstrated that this molecule self‐organizes into rod‐like structures. Our SPM investigations confirmed the formation of rods and revealed in detail a chiral fashion of the latter. The chirality is suggested to originate from the angle between the apolar C60sphere and it’s charged functional group. On the micrometer scale superstructures could be observed which apparently originate from a dendritic growth process. The superstructures withstand heat treatment at 200 °C, but the functional groups are lost, and the remaining C60undergoes a three dimensional polymerization. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1627976

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Reduction of C70with strontium dissolved in liquid ammonia results in metal fulleride solvates [Sr(NH3)8]3(C70)2⋅ nNH3(n = 20−22) containing linear polymeric, anionic chains∞1[C703−]. The compound was characterised by single crystal structure determination. The accurate crystal structure, determined at atomic resolution, allowed a comparison with results of quantum chemical calculations. The detailed analysis of the bonding character reveals the preservation of the aromatic character of the phenylene‐type belt at the equator of C70to be the driving force of this unexpected type of polymerisation. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1627977

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Previous X‐Ray experiments have revealed the structure of the crystal thanks to the apparent immobility of the molecules. NMR studies demonstrate that theC60molecules and the ferrocene molecules are in fact moving fast enough to average the magnetic interactions. This is shown by the temperature evolution of the resonance curve and by the shape of the CP‐MAS spectrum at room temperature. Further investigations allow to assert that theC60molecules are undergoing 3Drotations and thatCpcycles of ferrocene are subject to planar rotations. Finally, analysis of the spectra at low MAS frequency leads to the conclusion that there are two kinds ofCpcycles. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1627978

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Hydrofullerides with hydrogen content up to 5 Wt.&percent; were obtained by direct and catalytic reaction with H2gas. Hydrogen content was monitoredin situusing gravimetric system and verified by chemical analysisex situ. It was found that pure C60reacts rapidly when exposed to H2gas at 673 K and 50–100 Bar. Gravimetric study of this reaction showed that hydrogenation is saturated at about 5 at.&percent; of hydrogen. Mass of the sample goes through a maximum and with a longer reaction time its weight start to decrease. This proves that hydrofullerides with high hydrogen content are not stable and strong hydrogenation results in collapse of C60molecules. XRD study showed that samples prepared by direct hydrogenation without catalyst retain an original FCC structure with increase of cell parameter up toa=15.1Å. Catalytic hydrogenation of C60with H2gas results in decrease of the reaction temperature and formation of hydrofullerides with new crystal structure (suggestively sc). © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1627979

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The correlation times for the Jahn‐Teller dynamics of theC60−ions in the organic ferro‐magnet TDAE‐C60have been extracted from a comparison of experimental and simulated13C NMR lineshapes. A strong correlation between spin ordering and orientational ordering has been found. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1627980

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Here we present preliminary results on Mg4C60, a new fulleride polymer. A series of MgxC60compositions were prepared by solid state synthesis. While most samples were multiphase, the nominal composition Mg4C60provided a single phase material. X‐ray powder diffraction data revealed that the structure is rhombohedral based on polymeric sheets of C60molecules. Charge transfer from Mg to C60was estimated by Raman microscopy. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1627981

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Structure analysis of alkaline earth endohedral fullerenes M&at;C74(M = Sr, Ba) has been performed by means of XANES and micro crystal synchrotron diffraction. The experimental results from XANES and simulations based on different exo‐ and endohedral model structures from ab‐initio calculations confirm the endohedral character of these compounds. The crystal structures of M&at;C74⋅Co(OEP)⋅2C6H6(M = Sr, Ba) consist of (M&at;C74)[Co(OEP)]2(M&at;C74) units arranged in a distorted primitive hexagonal packing. The molecular structure is ordered and exhibits a high level of localization of the endohedral metal atom. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1627982

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We report the spectroscopic work of two Ce‐containingincar‐fullerenes,iCeC82andiCe2C80. UV/Vis, IR, Raman, TOF‐MALDI and13C NMR were employed to investigate the structural and electronic information of these two major isomers of Ceincar‐fullerenes. Tumbling motion of two Ce atoms inside the Ih‐C80cage was confirmed and analysed by temperature‐dependant13C NMR. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1627983

出版商:AIP    

年代:1903

数据来源: AIP