Metal−Ligand Bonding and Bonding Energetics in Zerovalent Lanthanide, Group 3, Group 4, and Group 6 Bis(arene) Sandwich Complexes. A Combined Solution Thermochemical and ab Initio Quantum Chemical Investigation

King, Wayne A.; Bella, Santo Di; Lanza, Giuseppe; Khan, Karl; Duncalf, David J.; Cloke, F. Geoffrey N.; Fragalá, Ignazio L.; Marks, Tobin J.

doi:10.1021/ja9529697

Cited by 83 publications

(113 citation statements)

References 49 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: 79%

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: 79%

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

et al. 2006

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“…In order to gain more insight into these different processes, variable-temperature 1 H NMR experiments were performed. At room temperature, the 1 H NMR spectrum of 4b in [D 8 ]toluene shows only one type of thiolate ligand environment with equivalent Trip (1)ϪC (1) 115.85 (11) 115.7(3) YbϪS (2)ϪC (37) 115.40 (11) 115.0(3) X(1)ϪMϪX (2) 166.9 164.5 S(1)ϪC (1)ϪC (2) 122.3(2) 121.7(6) S(1)ϪC (1)ϪC (6) 119.5(2) 119.7(6) S(2)ϪC (37)ϪC (38) 122.3 (3) 120.4(6) S(2)ϪC (37)ϪC (42) 120.4 (2) 121.2(6) C(1)ϪC(2)ϪC (7) 120.3 (3) 119.4(7) C(1)ϪC (6)ϪC (22) 119.6(3) 120.4(7) C(37)ϪC (38)ϪC (43) 119.9(3) 120.9(7) C(37)ϪC (42)ϪC (58) 119.6(3) 121.1(7) (13) YbϪS (1)ϪC (1) 149.0(4) S(1)ϪYbϪO (92) 136.93 (17) YbϪS (2)ϪC (37) 142.8(3) S(1)ϪYbϪO (95) 88.61 (13) S (1)ϪC (1)ϪC (6) 121.0(6) S(2)ϪYbϪO (82) 138.08 (14) S (1)ϪC …”

Section: Spectroscopic Characterizationmentioning

confidence: 99%

“…[38,39] To gain more insight into the Eu 2ϩ Ϫ or Yb 2ϩ Ϫarene interactions present in 4a and 4b, ab initio calculations on suitable model systems were performed. Quasi-relativistic pseudo-potentials of the Stuttgart/Bonn group were employed for atoms heavier than sulfur.…”

Section: Ab Initio Calculationsmentioning

confidence: 99%

σ-Donor versus η6-π-Arene Interactions in Monomeric Europium(II) and Ytterbium(II) Thiolates − An Experimental and Computational Study

Niemeyer

2001

Eur. J. Inorg. Chem.

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Keywords: Ab initio calculations / Lanthanides / π interactions / S ligands / YtterbiumThe base-free, hydrocarbon-soluble complexes M(SAr*) 2 (4a: M = Eu, orange; 4b: M = Yb, purple; Ar* = 2,6-Trip 2 C 6 H 3 ; Trip = 2,4,6-iPr 3 C 6 H 2 ) have been prepared by a protolysis reaction of the Grignard-analogous compound RLnI (R = 2-F 3 CC 6 H 4 ) with HSAr*. Compound 4b has been characterized by melting point, elemental analysis, 1 H, 13 C, and 171 Yb NMR, IR spectroscopy, UV/Vis spectrophotometry, mass spectrometry, and X-ray crystallography. Additionally, the purple Yb III complex YbI 2 (SAr*)(THF) 3 (3) and the yellow DME adduct Yb(SAr*) 2 (dme) 2 (5) have been synthesized and characterized by X-ray crystallography. The solid-state structures of 4a and 4b (as THF or benzene hemisolvates) show monomeric units with the metal atom bonded to two terminal

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“…Metal-ligand molecules have been the subject of many studies in the past decade [58][59][60][61][62][63][64][65]. Especially, TM-Bz complexes (M n (Bz) m ) are the prototypical organometallic complexes for studying the d−π bonding interactions.…”

Section: Tm-benzene Sandwich Polymersmentioning

confidence: 99%

“…Cr(Bz) 2 and Mn(Bz) 2 with a sandwich structure are also observed experimentally [61]. Although the multidecker sandwich M n (Bz) m clusters have been extensively studied theoretically [62][63][64][65], studies of the 1D [TM(Bz)] ∞ polymers are still very lacking. To our knowledge, only one semiempirical Hückle calculation was performed to examine the thermodynamical stability of the 1D [TM(Bz)] ∞ polymers [58].…”

Section: Tm-benzene Sandwich Polymersmentioning

confidence: 99%

Low Dimensional Nanomaterials for Spintronics

Yang

Xiang

2008

One-Dimensional Nanostructures

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Moore's Law in microelectronic technology will break down as the size of individual bits approaches the dimension of atoms; this has been called the end of the silicon road map. For this reason and also for enhancing the multifunctionality of devices, the spin degree of freedom of electron is being investigated for magnetoelectronics applications, i.e., spintronics. Spin-based devices are closely connected with the development of nanotechnology. In this chapter, recent developments of the low-dimensional nanomaterials for spintronics are reviewed. In the first section, the main concepts of spintronics including nanospintronics are briefly discussed. Experimental studies on transition-metal-doped nanowires and nanotubes are summarized in the second section. Extensive theoretical works in this field are reviewed in the third section. Finally, an outlook is given in the last section. SpintronicsSpintronics (a neologism for "spin-based electronics") [1,2], also known as magnetoelectronics, is an emergent technology that exploits the quantum propensity of electrons to spin as well as make use of their charge state. The spin itself is manifested as a detectable weak magnetic energy state characterized as "spin up" and "spin down". Spintronics started attracting massive interest with the discovery of giant magnetoresistance (GMR) in the 1980s, which has already been adopted as the norm in the hard disk drive (HDD) manufacturing industry. Indeed, the impact of spintronics in the HDD industry is a mere indication of things to come.Spintronics has a number of potentially groundbreaking applications that are set to drive next-generation electronics. Although GMR can arguably be considered the driving force for spintronics at present, the biggest potential of spin-based devices is in embedded memories. Magnetoresistive random access memory (MRAM) is expected to revolutionize the memory market and contribute to the development of advanced and versatile computing and personal devices. Advances in instantly 247

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Metal−Ligand Bonding and Bonding Energetics in Zerovalent Lanthanide, Group 3, Group 4, and Group 6 Bis(arene) Sandwich Complexes. A Combined Solution Thermochemical and ab Initio Quantum Chemical Investigation

Cited by 83 publications

References 49 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

σ-Donor versus η6-π-Arene Interactions in Monomeric Europium(II) and Ytterbium(II) Thiolates − An Experimental and Computational Study

Low Dimensional Nanomaterials for Spintronics

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