E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Special Issue "Molecular Devices and Machines: Cooperativity and Multifunctionality"

Quicklinks

A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Chemical Sensors".

Deadline for manuscript submissions: closed (29 February 2012)

Special Issue Editor

Guest Editor
Prof. Dr. Ken Sakai

Department of Chemistry, Faculty of Science, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581, Japan
Website | E-Mail
Interests: artificial photosynthetic molecular devices; multi-electron redox catalysis; water splitting into molecular hydrogen and oxygen

Special Issue Information

Dear Colleagues,

Many important biological activities are controlled by enzymatic reactions which are quite excellent in many viewpoints. Such biological processes are often carried out in a relatively large peptide molecule, in which several successive processes as well as transportation of input and output molecules are rationally orchestrated. In other words, several key components installed in such enzymes cooperatively drive the processes in a highly sophisticated fashion. The best example is the photosynthesis in nature. Two photosystems, called PSI and PSII, are installed in green plants and are cooperatively working together to photochemically generate high-energy electrons and molecules as well as proton gradient energy, which is ultimately used to drive the ATP synthase. In this context, substantial efforts should be further made to develop artificial molecular hybrids in which more than one key components collaborate to provide some important outcomes.

Studies of sensors and molecular devices in view of such issues are yet to be explored and are expected to provide new directions for devising artificial molecular hybrids with superior overall performance. The present topical issue focuses on the molecular hybrids, such as sensors, molecular devices, molecular machines, etc., that give a response to input stimuli, like light, electron, temperature, pressure, magnetic field, electric field, etc., as well as input chemical stimuli, like gas molecules, substrates, high-energy molecules, etc. Special attention is paid to the cooperative behaviors of several different key components installed within a single molecular hybrid. Realization of a new physical or chemical property arising from the cooperative phenomenon within such hybrids is another issue to be focused.

Prof. Dr. Ken Sakai
Guest Editor

Keywords

  • molecular devices
  • molecular machines
  • cooperativity
  • multifunctionality
  • molecular hybrids
  • ion sensors
  • gas sensors
  • optical response
  • response materials
  • energy conversion and storage

Related Special Issue

Published Papers (5 papers)

View options order results:
result details:
Displaying articles 1-5
Export citation of selected articles as:

Research

Jump to: Review, Other

Open AccessArticle Half-Metallic Properties of Single-Walled Polymeric Manganese Phthalocyanine Nanotubes
Sensors 2012, 12(7), 8438-8446; doi:10.3390/s120708438
Received: 8 May 2012 / Revised: 11 June 2012 / Accepted: 12 June 2012 / Published: 25 June 2012
Cited by 3 | PDF Full-text (831 KB) | HTML Full-text | XML Full-text
Abstract
We present a theoretical study of the electronic and magnetic properties of single-walled manganese phthalocyanine (MnPc) nanotubes which can be thought of as rolled-up ribbons of the two-dimensional (2D) polymeric MnPc sheet. Our density functional theory calculations show that all of the MnPc
[...] Read more.
We present a theoretical study of the electronic and magnetic properties of single-walled manganese phthalocyanine (MnPc) nanotubes which can be thought of as rolled-up ribbons of the two-dimensional (2D) polymeric MnPc sheet. Our density functional theory calculations show that all of the MnPc nanotubes investigated here are half-metals with 100% spin polarization around the Fermi level. Following the increase of the tube diameter, the number of spin-down energy bands of MnPc nanotubes is always increased while the spin-up band gap of MnPc nanotubes approaches that of the 2D MnPc sheet in an oscillatory manner. Because the half-metallic character of MnPc nanotubes is deeply rooted in the distribution of electrons in the energy bands dominated by the Mn 3d atomic orbitals, adsorption of CO molecules on the Mn ions leads to a redistribution of electrons in the Mn 3d orbitals and thus can tune precisely the spin state and electronic transport properties of MnPc nanotubes, demonstrating promising applications of MnPc nanotubes in future molecular spintronics and single-molecule sensors. Full article
(This article belongs to the Special Issue Molecular Devices and Machines: Cooperativity and Multifunctionality)
Figures

Open AccessArticle Fusion-Triggered Switching of Enzymatic Activity on an Artificial Cell Membrane
Sensors 2012, 12(5), 5966-5977; doi:10.3390/s120505966
Received: 14 March 2012 / Revised: 13 April 2012 / Accepted: 3 May 2012 / Published: 9 May 2012
PDF Full-text (1120 KB) | HTML Full-text | XML Full-text
Abstract
A nanosensory membrane device was constructed for detecting liposome fusion through changes in an enzymatic activity. Inspired by a biological signal transduction system, the device design involved functionalized liposomal membranes prepared by self-assembly of the following molecular components: a synthetic peptide lipid and
[...] Read more.
A nanosensory membrane device was constructed for detecting liposome fusion through changes in an enzymatic activity. Inspired by a biological signal transduction system, the device design involved functionalized liposomal membranes prepared by self-assembly of the following molecular components: a synthetic peptide lipid and a phospholipid as matrix membrane components, a Schiff’s base of pyridoxal 5’-phosphate with phosphatidylethanolamine as a thermo-responsive artificial receptor, NADH-dependent L-lactate dehydrogenase as a signal amplifier, and Cu2+ ion as a signal mediator between the receptor and enzyme. The enzymatic activity of the membrane device was adjustable by changing the matrix lipid composition, reflecting the thermotropic phase transition behavior of the lipid membranes, which in turn controlled receptor binding affinity toward the enzyme-inhibiting mediator species. When an effective fusogen anionic polymer was added to these cationic liposomes, membrane fusion occurred, and the functionalized liposomal membranes responded with changes in enzymatic activity, thus serving as an effective nanosensory device for liposome fusion detection. Full article
(This article belongs to the Special Issue Molecular Devices and Machines: Cooperativity and Multifunctionality)
Open AccessArticle Vapochromic Behaviour of M[Au(CN)2]2-Based Coordination Polymers (M = Co, Ni)
Sensors 2012, 12(3), 3669-3692; doi:10.3390/s120303669
Received: 10 February 2012 / Revised: 9 March 2012 / Accepted: 13 March 2012 / Published: 16 March 2012
Cited by 9 | PDF Full-text (1356 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A series of M[Au(CN)2]2(analyte)x coordination polymers (M = Co, Ni; analyte = dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), pyridine; x = 2 or 4) was prepared and characterized. Addition of analyte vapours to solid M(μ-OH2)[Au(CN)2]2
[...] Read more.
A series of M[Au(CN)2]2(analyte)x coordination polymers (M = Co, Ni; analyte = dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), pyridine; x = 2 or 4) was prepared and characterized. Addition of analyte vapours to solid M(μ-OH2)[Au(CN)2]2 yielded visible vapochromic responses for M = Co but not M = Ni; the IR νCN spectral region changed in every case. A single crystal structure of Zn[Au(CN)2]2(DMSO)2 revealed a corrugated 2-D layer structure with cis-DMSO units. Reacting a Ni(II) salt and K[Au(CN)2] in DMSO yielded the isostructural Ni[Au(CN)2]2(DMSO)2 product. Co[Au(CN)2]2(DMSO)2 and M[Au(CN)2]2(DMF)2 (M = Co, Ni) complexes have flat 2-D square-grid layer structures with trans-bound DMSO or DMF units; they are formed via vapour absorption by solid M(μ-OH2)[Au(CN)2]2 and from DMSO or DMF solution synthesis. Co[Au(CN)2]2(pyridine)4 is generated via vapour absorption by Co(μ-OH2)[Au(CN)2]2; the analogous Ni complex is synthesized by immersion of Ni(μ-OH2)[Au(CN)2]2 in 4% aqueous pyridine. Similar immersion of Co(μ-OH2)[Au(CN)2]2 yielded Co[Au(CN)2]2(pyridine)2, which has a flat 2-D square-grid structure with trans-pyridine units. Absorption of pyridine vapour by solid Ni(μ-OH2)[Au(CN)2]2 was incomplete, generating a mixture of pyridine-bound complexes. Analyte-free Co[Au(CN)2]2 was prepared by dehydration of Co(μ-OH2)[Au(CN)2]2 at 145 °C; it has a 3-D diamondoid-type structure and absorbs DMSO, DMF and pyridine to give the same materials as by vapour absorption from the hydrate. Full article
(This article belongs to the Special Issue Molecular Devices and Machines: Cooperativity and Multifunctionality)
Figures

Review

Jump to: Research, Other

Open AccessReview Single Molecule Electronics and Devices
Sensors 2012, 12(6), 7259-7298; doi:10.3390/s120607259
Received: 16 April 2012 / Revised: 15 May 2012 / Accepted: 17 May 2012 / Published: 30 May 2012
Cited by 52 | PDF Full-text (663 KB) | HTML Full-text | XML Full-text
Abstract
The manufacture of integrated circuits with single-molecule building blocks is a goal of molecular electronics. While research in the past has been limited to bulk experiments on self-assembled monolayers, advances in technology have now enabled us to fabricate single-molecule junctions. This has led
[...] Read more.
The manufacture of integrated circuits with single-molecule building blocks is a goal of molecular electronics. While research in the past has been limited to bulk experiments on self-assembled monolayers, advances in technology have now enabled us to fabricate single-molecule junctions. This has led to significant progress in understanding electron transport in molecular systems at the single-molecule level and the concomitant emergence of new device concepts. Here, we review recent developments in this field. We summarize the methods currently used to form metal-molecule-metal structures and some single-molecule techniques essential for characterizing molecular junctions such as inelastic electron tunnelling spectroscopy. We then highlight several important achievements, including demonstration of single-molecule diodes, transistors, and switches that make use of electrical, photo, and mechanical stimulation to control the electron transport. We also discuss intriguing issues to be addressed further in the future such as heat and thermoelectric transport in an individual molecule. Full article
(This article belongs to the Special Issue Molecular Devices and Machines: Cooperativity and Multifunctionality)
Figures

Other

Jump to: Research, Review

Open AccessConcept Paper Pressure and Temperature Spin Crossover Sensors with Optical Detection
Sensors 2012, 12(4), 4479-4492; doi:10.3390/s120404479
Received: 15 February 2012 / Revised: 17 March 2012 / Accepted: 20 March 2012 / Published: 10 April 2012
Cited by 86 | PDF Full-text (297 KB) | HTML Full-text | XML Full-text
Abstract
Iron(II) spin crossover molecular materials are made of coordination centres switchable between two states by temperature, pressure or a visible light irradiation. The relevant macroscopic parameter which monitors the magnetic state of a given solid is the high-spin (HS) fraction denoted nHS
[...] Read more.
Iron(II) spin crossover molecular materials are made of coordination centres switchable between two states by temperature, pressure or a visible light irradiation. The relevant macroscopic parameter which monitors the magnetic state of a given solid is the high-spin (HS) fraction denoted nHS, i.e., the relative population of HS molecules. Each spin crossover material is distinguished by a transition temperature T1/2 where 50% of active molecules have switched to the low-spin (LS) state. In strongly interacting systems, the thermal spin switching occurs abruptly at T1/2. Applying pressure induces a shift from HS to LS states, which is the direct consequence of the lower volume for the LS molecule. Each material has thus a well defined pressure value P1/2. In both cases the spin state change is easily detectable by optical means thanks to a thermo/piezochromic effect that is often encountered in these materials. In this contribution, we discuss potential use of spin crossover molecular materials as temperature and pressure sensors with optical detection. The ones presenting smooth transitions behaviour, which have not been seriously considered for any application, are spotlighted as potential sensors which should stimulate a large interest on this well investigated class of materials. Full article
(This article belongs to the Special Issue Molecular Devices and Machines: Cooperativity and Multifunctionality)
Figures

Journal Contact

MDPI AG
Sensors Editorial Office
St. Alban-Anlage 66, 4052 Basel, Switzerland
sensors@mdpi.com
Tel. +41 61 683 77 34
Fax: +41 61 302 89 18
Editorial Board
Contact Details Submit to Sensors
Back to Top