Parallel (Face-to-Face) Versus Perpendicular (Edge-to-Face) Alignment of Electron Donors and Acceptors in Fullerene Porphyrin Dyads:  The Importance of Orientation in Electron Transfer

Guldi, Dirk M.; Luo, Chuping; Prato, Maurizio; Troisi, Alessandro; Zerbetto, Francesco; Scheloske, Michael; Dietel, Elke; Bauer, Walter; Hirsch, Andreas

doi:10.1021/ja004104l

Cited by 158 publications

(102 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is widely suggested that charge transfer or -interactions account for the supramolecular assembly (17)(18)(19). These studies indicate that the changes in image contrast observed with the MPF tips (Fig.…”

Section: Resultsmentioning

confidence: 78%

A fullerene molecular tip can detect localized and rectified electron tunneling within a single fullerene–porphyrin pair

Nishino

Ito

Umezawa

2005

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

A fullerene molecular tip was used to detect electron tunneling from a single porphyrin molecule. Electron tunneling was found to occur locally from an electron-donating moiety of the porphyrin to the fullerene through charge-transfer interaction between them. In addition, electron tunneling within the single fullereneporphyrin pair exhibited rectifying behavior in which electrons can be driven only at the direction from the porphyrin to the fullerene. It is demonstrated that localized electron tunneling enables us to spatially visualize the frontier orbital of the porphyrin involved in electron tunneling. In addition, rectification demonstrates that the fullerene-porphyrin pair constitutes a molecular rectifier. We believe that molecular tips bring insight into intermolecular electron transmission toward realization of molecular electronics as shown here. molecular electronics ͉ nanoscience ͉ scanning tunneling microscopy E lectron transmission through single molecules is currently an interdisciplinary subject of substantial interest (1) because of molecular-scale electronic device research (2, 3). It is desired to measure the molecular conduction on a single molecule rather than on an ensemble of molecules to eliminate a cooperative transport (4) and avoid averaging out the conduction through the molecules in different conformations (5). Recently, there have been significant advances in knowledge of electron transmission through a single molecule (4). However, few works have been reported on electron transmission through a single molecule to an adjacent single molecule on a nanoscale.Scanning tunneling microscopy (STM) has been an essential tool in nanosciences (6). We have studied the construction of molecular tips for STM. The molecular tip is prepared by chemical modification of an underlying metal tip, and the outermost single adsorbate probes electron tunneling to or from a sample molecule. Importantly, the tunneling current increases when sample and tip molecules form metal coordination or hydrogen-bond interactions that provide overlap of their electronic wave functions. The current increase is ascribed to facilitated tunneling through overlapped wave functions. We have demonstrated that this phenomenon can be used for selective observation of chemical species to overcome poor chemical selectivity in conventional STM (7-13). Because the overlap of electronic wave functions is important for the facilitation of electron tunneling, these results suggest that intermolecular electron tunneling can also be facilitated through a charge-transfer interaction as well as metal coordination and hydrogen-bond interactions.Here, we report on the detection of intermolecular electron tunneling within a single fullerene-porphyrin molecular pair. Electron tunneling was found to occur locally from an electrondonating moiety of the porphyrin to the fullerene through charge-transfer interaction between them, but not in the opposite direction. It was shown that localized tunneling can be applied to visualize the frontier orb...

show abstract

Section: Resultsmentioning

confidence: 78%

A fullerene molecular tip can detect localized and rectified electron tunneling within a single fullerene–porphyrin pair

Nishino

Ito

Umezawa

2005

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…9 These two compounds have been known to form a charge-transfer interaction between them. [10][11][12] Therefore, this system is suitable to investigate the effect of charge-transfer interactions on the electron tunneling between electron donating and accepting molecules.…”

Section: ·1 Electron Donating or Accepting Moietiesmentioning

confidence: 99%

Recognition of Chemical Identity of Organic Adsorbates on Solid Surfaces at the Nanoscale by Molecular STM Tips

Nishino

Umezawa

2010

ANAL. SCI.

View full text Add to dashboard Cite

1023 IntroductionRecent interest in functional nanomaterials, such as molecular electronics and miniaturized sensors, increasingly demands atomic-and molecular-resolution analytical tools. Scanning tunneling microscopy (STM) is one of the most suitable techniques for this purpose, because it offers a unique opportunity to directly reveal surface topography as well as electronic structure at the nanoscale. It is, however, often 2010 © The Japan Society for Analytical Chemistry This paper reviews chemically selective imaging at the single-atom/molecule level by molecular STM tips. The molecular tips enable the recognition of a particular chemical species on the basis of chemical interactions with a sample molecule, including hydrogen-bond, metal-coordination, and charge-transfer interactions. The chemical selectivity can be tailored by designing functional groups of the tip molecules. Moreover, the rational design of the molecular tip allows sophisticated chemical recognition. The discrimination of DNA bases and chiral recognition on a single molecule basis are thereby achieved. The molecular tips also revealed rectified electron transmission within an electron donor-acceptor molecular pair. Self-assembled monolayers, carboxylated carbon nanotube, and conducting polymers can be utilized for the preparation of molecular tips. This technique may be coined "intermolecular tunneling microscopy" as its principle goes, and is of general significance for novel molecular imaging of chemical identities at the membrane and solid surfaces.

show abstract

“…The twofold cyclopropanation of C 60 with 1 leads with complete regioselectivity to the bisadduct 2 (Scheme 1), which involves a chiral trans-2 addition pattern. 22,23,24,25,26,27 The structure was unambiguously assigned using a combination of spectroscopy and computational investigations and more recently by single crystal X-ray analysis. 28 The two chromophors of the very rigid architecture are held together in close proximity.…”

Section: Concepts For Regioselective Bisadditions Using Tethered Openmentioning

confidence: 99%

New Concepts for Regio‐ and Stereoselective Bis‐ and Triscyclopropanations of C₆₀

Hirsch

2007

ChemInform

Self Cite

View full text Add to dashboard Cite

ABSTRACT:The synthesis of isomerically multiple adducts of C 60 with a defined three-dimensional structure is still one of the most challenging tasks of exohedral fullerene chemistry. The inherent regioselectivity of successive additions of addends such as malonates to the fullerene's [6,6]-double bonds is only moderate. In most cases difficult-to-isolate mixtures of regioisomers are obtained. The regioselectivity can be significantly improved if multifunctional addends able to undergo two or more additions are allowed to react with C 60 . Preorganization and minimization of strain energy within the addend skeleton reduce the number of sterically allowed addition patterns. Improved concepts for highly regio-and stereoselective bis-and triscyclopropanations of C 60 are described. Two examples of the bisadditions with complete regioselectivity leading to trans-2-and cis-2 are presented. Here, the two malonate binding sites are linked by rigid tetraphenylporphyrin and calix-[4]-arene spacers. Selective trisadditions were achieved with the easy-to-synthesize and easy-to-modify tripodal addends 5-7, where the malonates are held together by a focal aryl moiety. Another very elegant approach for bis-and trisadditions involves cyclo-[n]-alkylmalonates. Selection between addition patterns with and without rotational axes is possible by choosing the right combinations of the flexible alkyl chains connecting the malonates. If alkyl chains of identical lengths are used bis-and trisadducts such as 19-21 and 25 with rotational symmetry are formed with high regioselectivity. These addition patterns are avoided if cyclo-[n]-malonates containing alkyl chains of different lengths are employed. In this case adducts such as 26 and 27 with C s -symmetry are formed. The use of the chiral cyclo-[3]-malonate 28 allows for the regio-and stereoselective synthesis of the enantiomerically pure e,e,e-trisadducts 29 and 30 containing an inherently chiral addition pattern with C 3 -symmetry.

show abstract

Parallel (Face-to-Face) Versus Perpendicular (Edge-to-Face) Alignment of Electron Donors and Acceptors in Fullerene Porphyrin Dyads: The Importance of Orientation in Electron Transfer

Cited by 158 publications

References 20 publications

A fullerene molecular tip can detect localized and rectified electron tunneling within a single fullerene–porphyrin pair

A fullerene molecular tip can detect localized and rectified electron tunneling within a single fullerene–porphyrin pair

Recognition of Chemical Identity of Organic Adsorbates on Solid Surfaces at the Nanoscale by Molecular STM Tips

New Concepts for Regio‐ and Stereoselective Bis‐ and Triscyclopropanations of C₆₀

Contact Info

Product

Resources

About

Parallel (Face-to-Face) Versus Perpendicular (Edge-to-Face) Alignment of Electron Donors and Acceptors in Fullerene Porphyrin Dyads: The Importance of Orientation in Electron Transfer

Cited by 158 publications

References 20 publications

A fullerene molecular tip can detect localized and rectified electron tunneling within a single fullerene–porphyrin pair

A fullerene molecular tip can detect localized and rectified electron tunneling within a single fullerene–porphyrin pair

Recognition of Chemical Identity of Organic Adsorbates on Solid Surfaces at the Nanoscale by Molecular STM Tips

New Concepts for Regio‐ and Stereoselective Bis‐ and Triscyclopropanations of C60

Contact Info

Product

Resources

About

New Concepts for Regio‐ and Stereoselective Bis‐ and Triscyclopropanations of C₆₀