Electronic Structure and Properties of Transition Metal−Benzene Complexes

Pandey, Ravindra; Rao, B. K.; Jena, P.; Blanco, María del Carmen del Vando

doi:10.1021/ja0035452

Cited by 224 publications

(239 citation statements)

References 36 publications

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“…A subsequent density functional study confirmed the FM coupling in multidecker sandwich V n (Bz) n+1 clusters [8]. Motivated by the above experimental and theoretical studies, we propose that the 1D organometallic sandwich polymers [V(Bz)] ∞ are the possible candidates for spintronic devices for spinpolarized transport since the polymers with an inherently uniform size are supposed to be also FM.Metal-ligand molecules have been the subject of many studies in the past decade [9,10,11,12,13,14,15,16]. Especially, TM-Bz complexes (M n (Bz) m ) are the prototypical organometallic complexes for studying the d−π bonding interactions.…”

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confidence: 80%

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One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

et al. 2006

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We investigate the electronic and magnetic properties of the proposed one-dimensional transition metal (TM=Sc, Ti, V, Cr, and Mn) -benzene (Bz) sandwich polymers by means of density functional calculations. [V(Bz)]∞ is found to be a quasi-half-metallic ferromagnet and half-metallic ferromagnetism is predicted for [Mn(Bz)]∞. Moreover, we show that stretching the [TM(Bz)]∞ polymers could have dramatic effects on their electronic and magnetic properties. The elongated [V(Bz)]∞ displays half-metallic behavior, and [Mn(Bz)]∞ stretched to a certain degree becomes an antiferromagnetic insulator. The possibilities to stabilize the ferromagnetic order in [V(Bz)]∞ and [Mn(Bz)]∞ polymers at finite temperature are discussed. We suggest that the hexagonal bundles composed by these polymers might display intrachain ferromagnetic order at finite temperature by introducing interchain exchange coupling.PACS numbers: 71.20.Rv, 75.75.+a, 82.35.Lr It is expected that the new generation of devices will exploit spin dependent effects, what has been called spintronics [1,2]. A challenge now facing spintronics is transmitting spin signals over long enough distances to allow for spin manipulation. An ideal device for spin-polarized transport should have several key ingredients. First, it should work well at room temperature and should offer as high a magnetoresistance (MR) ratio as possible. In this sense, a half-metallic (HM) ferromagnet with the Curie temperature higher than room temperature is highly desirable since there would be only one electronic spin channel at the Fermi energy [3]. Second, the size or diameter of the materials should be uniform for large scale applications. Carbon nanotubes (CNTs) were considered as promising one-dimensional (1D) spin mediators because of their ballistic nature of conduction and relatively long spin scattering length (at least 130 nm) [4,5]. Coherent spin transport has been observed in multiwalled CNT systems with Co electrodes. The maximum MR ratio of 9% was observed in multiwalled CNTs at 4.2 K. However, as the temperature increases to 20 K, the MR ratio goes to zero, preventing any room temperature applications [4]. A theoretical work suggested that the ferromagnetic (FM) transition-metal (TM) /CNT hybrid structures may be used as devices for spin-polarized transport to further increase the MR ratio [6]. Unfortunately, although large spin polarization is found in these systems, there is no HM behavior. Another difficulty with CNT is that the devices are unlikely to be very reproducible due to the wide assortment of tube size and helicity that is produced during synthesis. Wide variation in device behavior was reported in the CNT experiment [4].Recently, an experimental study suggested that the unpaired electrons on the metal atoms couple ferromagnetically in the multidecker organometallic sandwich Vbenzene (Bz) complexes, i.e., V n (Bz) n+1 clusters [7]. The FM sandwich clusters are supposed to serve as nanomagnetic building blocks in applications such as recording media or spintronic de...

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confidence: 80%

“…Metal-ligand molecules have been the subject of many studies in the past decade [9,10,11,12,13,14,15,16]. Especially, TM-Bz complexes (M n (Bz) m ) are the prototypical organometallic complexes for studying the d−π bonding interactions.…”

mentioning

confidence: 99%

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

et al. 2006

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“…The structure of the C 6 H 6 -Ti complex has been theoretically [20][21][22][23][24][25][26][27] and experimentally [28] studied on the basis of DFT calculations and laser evaporation methods. Experimental evidence indicates the ground state to be a triplet in a planar C 6v configuration.…”

Section: Orbital Interactions and Bonding In Cmentioning

confidence: 99%

Titanium as a Potential Addition for High-Capacity Hydrogen Storage Medium

Zuliani

Bernasconi

Baerends

2012

Journal of Nanotechnology

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We study the adsorption of hydrogen molecules on a titanium atom supported by a benzene molecule using generalized gradient corrected Density Functional Theory (DFT). This simple system is found to bear important analogies with titanium adsorption sites in (8, 0) titanium-coated single-walled carbon nanotubes (SWNTs) (T. Yildirim and S. Ciraci, 2005) In particular, we show that up to four H 2 molecules can coordinate to the metal ion center, with adsorption patterns similar to those observed in TiSWNTs and no more than one molecule dissociating in the process. We analyze in detail the orbital interactions responsible for Ti-benzene binding and for the electron transfer responsible for the H 2 dissociation. We find the latter to involve a transition from a triplet to a singlet ground state as the hydrogen molecule approaches the adsorption site, similar to what has been observed in Ti-SWNTs. The total Ti-H 2 -binding energy for the first dissociative addition is somewhat inferior (∼0.4 eV) to the value estimated for adsorption on Ti-SWNTs. We analyze in detail the orbital interactions responsible for the H 2 binding.

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“…The isolobal relationship between arenes and nano carbon materials suggests that the coordination of metals to their surface should be facile [1]. In particular, η 6 -coordination of the Group 6 metals (Cr, Mo, and W) should be possible.…”

Section: Introductionmentioning

confidence: 99%

Catalyst Residue and Oxygen Species Inhibition of the Formation of Hexahapto-Metal Complexes of Group 6 Metals on Single-Walled Carbon Nanotubes

Wright

Barron

2017

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Abstract:The reaction of Group 6 metals with SWCNT has the potential to bridge the resistive SWCNT . . . SWCNT junctions by the formation of "Cr(SWCNT) 2 " complexes analogous to Cr(C 6 H 6 ) 2 . This study reports that the formation of such species is very sensitive to oxidation by a residual iron oxide catalyst used for the growth of the SWCNTs and adsorbed/bound oxygen functionality. The reaction of raw HiPco SWCNTs with M(CO) 6 and (C 7 H 8 )M(CO) 3 (M = Cr, W) or (C 6 H 6 )Cr(CO) 3 results in the formation of the Group 6 metal oxides. Annealing and acid treating the HiPco SWCNTs to reduce the catalyst content allows for the observation of zero valent metals by XPS, while the use of very high purity SWCNTs and graphene allows for the addition of primarily zero valent Group 6 metals, including the bis-hexahapto metal complex.

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Electronic Structure and Properties of Transition Metal−Benzene Complexes

Cited by 224 publications

References 36 publications

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

Titanium as a Potential Addition for High-Capacity Hydrogen Storage Medium

Catalyst Residue and Oxygen Species Inhibition of the Formation of Hexahapto-Metal Complexes of Group 6 Metals on Single-Walled Carbon Nanotubes

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