Vernier templating and synthesis of a 12-porphyrin nano-ring

O’Sullivan, Melanie C.; Sprafke, Johannes K.; Kondratuk, Dmitry V.; Rinfray, Corentin; Claridge, Timothy D. W.; Saywell, Alex; Blunt, Matthew O.; O’Shea, James N.; Beton, Peter H.; Malfois, Marc; Anderson, Harry L.

doi:10.1038/nature09683

Cited by 410 publications

(303 citation statements)

References 21 publications

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“…4 shows STM images of each cyclic polymer. In common with our previous work 5,25,26 the nanorings are preferentially adsorbed in configurations overlapping, or partially overlapping, terrace steps on the Au(111) surface, and the porphyrin macrocycles lie parallel to the substrate. In many images it is possible to resolve the porphyrin units providing confirmation of the degree of polymerisation, simply by counting the bright contrast features around the perimeter of a nanoring.…”

Section: Resultsmentioning

confidence: 74%

“…Thus the contour length of a linear oligomer, or the perimeter of a nanoring, is Na, where N is the number of porphyrin repeat units. Previously we have shown that nanorings adsorbed on Au(111) exhibit flexibility [24][25][26] , and also that they can act as nanoscale traps for other adsorbed species, such as C 60 guest molecules 27 . However, in order for one nanoring to be adsorbed inside another, the dimensions of the nanoring must exceed a critical threshold.…”

mentioning

confidence: 99%

“…The cyclic structures of c-P10, c-P20, c-P30, c-P40 and c-P50 were confirmed using STM. Molecules were transferred from solution onto a Au(111) surface held under ultrahigh vacuum using electrospray deposition 5,24,25 and Fig. 4 shows STM images of each cyclic polymer.…”

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confidence: 99%

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Supramolecular nesting of cyclic polymers

et al. 2015

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Monodisperse cyclic porphyrin polymers, with diameters of up to 21 nm (750 C-C bonds), have been prepared using Vernier template-directed synthesis. The ratio of the intrinsic viscosities for cyclic and linear topologies is 0.72, indicating that these polymers behave as almost ideal flexible chains in solution. When deposited on gold surfaces, the cyclic polymers display a new mode of two-dimensional supramolecular organisation, combining encapsulation and nesting: one nanoring adopts a near-circular conformation thus allowing a second nanoring to be captured within its perimeter, in a tightly folded conformation. Scanning tunnelling microscopy reveals that nesting occurs in combination with stacking when nanorings are deposited under vacuum, whereas when they are deposited directly from solution under ambient conditions, there is stacking or nesting, but not a combination of both.The tertiary structures of biological macromolecules are achieved through folding, coiling and multiplex formation, driven by the cooperative effect of many weak interactions 1 . Synthetic monodisperse macromolecules with similar cooperative folding behaviour provide a viable approach to the programmed fabrication of 3D nanostructures [2][3][4][5] . Here we show that cyclic porphyrin polymers, with molecular weights of 30-60 kDa, self-assemble into nested structures on a gold surface. These nested assemblies are only observed when the cyclic polymer has 30 or more repeat units, in keeping with the predictions of a simple geometrical model.The importance of non-covalent self-assembly in biology has inspired many studies of supramolecular organisation on surfaces [6][7][8] , generating 2D assemblies with progressively escalating complexity, from early work on simple structures such as clusters 9 and rows 10,11 , to nanoporous arrays 12,13 , host-guest architectures [14][15][16] , hierarchical arrangements 17 , and multicomponent assemblies [17][18][19] . However, cooperative conformational control has proved difficult to achieve, and this remains a significant gulf between artificial and biological systems. One reason for this difference is that biological macromolecules are much more flexible than the component molecules studied in 2D supramolecular assemblies which are small and, with some exceptions 20,21 , are often treated as quasi-rigid building blocks. Here we illustrate how interactions between large flexible molecules can result in biomimetic cooperative conformational organisation.Studies of linear and cyclic butadiyne-linked zinc porphyrin oligomers (structures l-PN THS and c-PN, Fig. 1) have shown that the distance between the centres of the porphyrin units along the chain is a = 1.35 nm 5,22,23 . Thus the contour length of a linear oligomer, or the perimeter of a nanoring, is Na, where N is the number of porphyrin repeat units. Previously we have shown that nanorings adsorbed on Au(111) exhibit flexibility [24][25][26] , and also that they can act as nanoscale traps for other adsorbed species, such as C 60 guest molecules 2...

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Section: Resultsmentioning

confidence: 74%

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confidence: 99%

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Supramolecular nesting of cyclic polymers

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“…[18][19][20][21][22][23][24][25][26] Due to the role in natural photosynthesis of related compounds porphyrin molecules have been extensively exploited for electron and energy transfer. [27][28][29][30] The light-harvesting properties of porphyrins 45 has led them to be considered as components in solar photovoltaic cells. [31][32][33][34] Currently, bulk hetero junctions (BHJ) are Scheme 1 Schematic representation of ZnTMPyP4 and CdTe systems 50 considered to show most promise for improved solar cell efficiency.…”

Section: Introductionmentioning

confidence: 99%

Photophysical studies of CdTe quantum dots in the presence of a zinc cationic porphyrin

et al. 2012

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The photophysical properties of 2.3 nm thioglycolic acid (TGA) coated CdTe quantum dots (QDs) prepared by a reflux method have been studied in the presence of a cationic meso-tetrakis(4-N-methylpyridyl) zinc porphyrin (ZnTMPyP4). Addition of the CdTe QDs to porphyrin in H 2 O results in a marked red-shift and hypochromism in the porphyrin absorption spectrum, indicative of a non-covalent binding interaction with the QD surface. Low equivalents of the quantum dot were required for complete quenching of the porphyrin fluorescence revealing that one quantum dot 10 may quench more than one porphyrin. Similarly addition of porphyrin to the quantum dot provided evidence for very efficient quenching of the CdTe photoluminescence, suggesting the formation of CdTe-porphyrin aggregates. Definitive evidence for such aggregates was gathered using small angle X-ray spectroscopy (SAXS). Ultrafast transient absorption data are consistent with very rapid photoinduced electron transfer (1.3 ps) and the resultant formation of a long-lived porphyrin species.

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“…The UHV environment allows the preparation of clean surfaces prior to deposition and the in-situ application of high resolution scanning probe microscopy, electron spectroscopy and X-ray absorption techniques to understand interactions at the atomic and molecular scale. The combination of such techniques with UHV-compatible electrospray deposition has successfully been applied by the authors to the deposition of complex, fragile and non-volatile molecules on surfaces prepared in UHV including giant porphyrin nanorings, [23] single molecule magnets [24] and organometallic dye molecules [25]. Whilst these studies demonstrated the intact deposition of these complex molecules with retention of their chemical, electrical and magnetic properties the question remains if proteins deposited in this manner in vacuum retain their biological activity when returned to liquid environments of relevance to their application in a wide range of fields such as sensors, diagnostics and tissue engineering.…”

Section: Introductionmentioning

confidence: 99%

Electrospray deposition in vacuum as method to create functionally active protein immobilization on polymeric substrates

Fornari

Roberts

Temperton

et al. 2015

Journal of Colloid and Interface Science

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We demonstrate in this work the deposition of a large biological molecule (fibronectin) on polymeric substrates in a high vacuum environment using an electrospray deposition system. Fibronectin was deposited and its distribution and structure investigated and retention of function (ability to promote cell adhesion) on return to liquid environment is shown. AFM was used to monitor changes in the morphology of the surface before and after fibronectin deposition, whilst the biological activity of the deposited protein is assessed through a quantitative analysis of the biomolecular adhesion and migration of fibroblast cells to the modified surfaces. For the first time we have demonstrated that using high vacuum electrospray deposition it is possible to deposit large protein molecules on polymeric surfaces whilst maintaining the protein activity. The deposition of biological molecules such as proteins with the retention of their activity onto clean well-controlled surfaces under vacuum condition, offers the possibility for future studies utilizing high resolution vacuum based techniques at the atomic and molecular scale providing a greater understanding of protein-surface interface behaviour of relevance to a wide range of applications such as in sensors, diagnostics and tissue engineering.

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Vernier templating and synthesis of a 12-porphyrin nano-ring

Cited by 410 publications

References 21 publications

Supramolecular nesting of cyclic polymers

Supramolecular nesting of cyclic polymers

Photophysical studies of CdTe quantum dots in the presence of a zinc cationic porphyrin

Electrospray deposition in vacuum as method to create functionally active protein immobilization on polymeric substrates

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