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Search for "spin crossover" in Full Text gives 3 result(s) in Beilstein Journal of Organic Chemistry.
Switchable molecular tweezers: design and applications
- Pablo Msellem,
- Maksym Dekthiarenko,
- Nihal Hadj Seyd and
- Guillaume Vives
Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45
- − anions to the open form unexpectedly resulted in the closing of the tweezers thanks to a Mn–CN–Mn bridging [45]. An antiferromagnetic coupling between the two Mn(III) centers combined with a spin crossover from high spin to low spin Mn(III) was observed. Like in the other terpy-based tweezers, a
Graphical Abstract
Figure 1: Principle of switchable molecular tweezers.
Figure 2: Principle of pH-switchable molecular tweezers 1 [19].
Figure 3: a) pH-Switchable tweezers 2 substituted with alkyl chains as switchable lipids. b) Schematic depict...
Figure 4: Modification of spectral properties of 3 by controlled induction of Pt–Pt interactions.
Figure 5: Conformational switching of di(hydroxyphenyl)pyrimidine-based tweezer 4 upon alkylation or fluoride...
Figure 6: Hydrazone-based pH-responsive tweezers 5 for mesogenic modulation.
Figure 7: pH-Switchable molecular tweezers 6 bearing acridinium moieties.
Figure 8: a) Terpyridine and pyridine-hydrazone-pyridine analogs molecular tweezers and b) extended pyridine ...
Figure 9: Terpyridine-based molecular tweezers with M–salphen arms and their field of application. Figure 9 was adapt...
Figure 10: a) Terpyridine-based molecular tweezers for diphosphate recognition [48]; b) bishelicene chiroptical te...
Figure 11: Terpyridine-based molecular tweezers with allosteric cooperative binding.
Figure 12: Terpyridine-based molecular tweezers presenting closed by default conformation.
Figure 13: Pyridine-pyrimidine-pyridine-based molecular tweezers.
Figure 14: Coordination-responsive molecular tweezers based on nitrogen-containing ligands.
Figure 15: Molecular tweezers exploiting the remote bipyridine or pyridine binding to trigger the conformation...
Figure 16: Bipyridine-based molecular tweezers exploiting the direct s-trans to s-cis-switching for a) anion b...
Figure 17: a) Podand-based molecular tweezers [66,67]. b) Application of tweezers 32 for the catalytic allosteric reg...
Figure 18: Anion-triggered molecular tweezers based on calix[4]pyrrole.
Figure 19: Anion-triggered molecular tweezers.
Figure 20: a) Principle of the weak link approach (WLA) developed by Mirkin and its application to b) symmetri...
Figure 21: Molecular tweezers as allosteric catalyst in asymmetric epoxide opening [80].
Figure 22: Allosteric regulation of catalytic activity in ring-opening polymerization with double tweezers 41.
Figure 23: a) Conformational switching of 42 by intramolecular –S–S– bridge formation. b) Shift of conformatio...
Figure 24: a) Redox-active glycoluril-TTF tweezers 44. b) Mechanism of stepwise oxidation of said tweezers wit...
Figure 25: Mechanism of formation of the mixed-valence dimers of tweezers 45.
Figure 26: Mechanism of carbohydrate liberation upon redox-mediated conformation switching of 46.
Figure 27: a) The encapsulation properties of 47 as well as the DCTNF release process from its host–guest comp...
Figure 28: Redox-active bipyridinium-based tweezers. a) With a ferrocenyl hinge 49, b) with a propyl hinge 50 ...
Figure 29: Redox-active calix[4]arene porphyrin molecular tweezers.
Figure 30: a) Mechanism of the three orthogonal stimuli. b) Cubic scheme showing the eight different states of ...
Figure 31: Redox-controlled molecular gripper based on a diquinone resorcin[4]arene.
Figure 32: a) Shinkai's butterfly tweezers and their different host–guest properties depending on the isomer. ...
Figure 33: Cyclam-tethered tweezers and their different host–guest complexes depending on their configuration.
Figure 34: Azobenzene-based catalytic tweezers.
Figure 35: Photoswitchable PIEZO channel mimic.
Figure 36: Stilbene-based porphyrin tweezers for fullerene recognition.
Figure 37: Stiff-stilbene-based tweezers with urea or thiourea functional units for a) anion binding, b) anion...
Figure 38: Feringa’s photoswitchable organocatalyst (a) and different catalyzed reactions with that system (b)....
Figure 39: a) Irie and Takeshita’s thioindigo-based molecular tweezers. b) Family of hemithioindigo-based mole...
Figure 40: Dithienylethylene crown ether-bearing molecular tweezers reported by Irie and co-workers.
Photochromic diarylethene ligands featuring 2-(imidazol-2-yl)pyridine coordination site and their iron(II) complexes
- Andrey G. Lvov,
- Max Mörtel,
- Anton V. Yadykov,
- Frank W. Heinemann,
- Valerii Z. Shirinian and
- Marat M. Khusniyarov
Beilstein J. Org. Chem. 2019, 15, 2428–2437, doi:10.3762/bjoc.15.235
- cyclohexenone bridges show good cycloreversion quantum yields of 0.20–0.32. The thermal stability of closed-ring isomers reveals half-lives of up to 20 days in solution at room temperature. The ligands were used to explore coordination chemistry with iron(II) targeting photoswitchable spin-crossover complexes
- , which possess prominent luminescent and spectral properties, including photocyclization with visible and NIR light. Using the photochromic ligand I, a spin-crossover (SCO) Fe(II) complex was developed, which allowed a reversible paramagnetic (high-spin, S = 2) → diamagnetic (low-spin, S = 0) transition
Graphical Abstract
Figure 1: Families of diarylethene-bases ligands with spatial proximity of coordination site (blue) and photo...
Scheme 1: Synthesis of photochromic ligands.
Figure 2: Electronic spectra of diarylethene 6 upon UV irradiation (313 nm, toluene, c = 3.4 × 10−5 M). Inset...
Scheme 2: Reversible photocyclization of ligand 6.
Figure 3: Molecular structure of complexes 8 (top) and 9 (bottom) at 100 K. The H atoms are omitted for clari...
Figure 4: Variable temperature χT product (blue) and χ (green) of 8 (top) and 9 (bottom) measured at an exter...
Spin state switching in iron coordination compounds
- Philipp Gütlich,
- Ana B. Gaspar and
- Yann Garcia
Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39
- exhibit thermally induced spin transition, known as spin crossover, depending on the nature of the coordinating ligand sphere. Spin transition in such compounds also occurs under pressure and irradiation with light. The spin states involved have different magnetic and optical properties suitable for their
- detection and characterization. Spin crossover compounds, though known for more than eight decades, have become most attractive in recent years and are extensively studied by chemists and physicists. The switching properties make such materials potential candidates for practical applications in thermal and
- pressure sensors as well as optical devices. The article begins with a brief description of the principle of molecular spin state switching using simple concepts of ligand field theory. Conditions to be fulfilled in order to observe spin crossover will be explained and general remarks regarding the
Graphical Abstract
Figure 1: Change of electron distribution between HS and LS states of an octahedral iron(II) coordination com...
Figure 2: Types of spin transition curves in terms of the molar fraction of HS molecules, γHS(T), as a functi...
Figure 3: Single crystal UV–vis spectra of the spin crossover compound [Fe(ptz)6](BF4)2 (ptz = 1-propyltetraz...
Figure 4: Thermal spin crossover in [Fe(ptz)6](BF4)2 (ptz = 1-propyltetrazole) recorded at three different te...
Figure 5: (a) Mössbauer spectra of the LS compound [Fe(phen)3]X2 recorded over the temperature range 300–5 K....
Figure 6: (left) Demonstration of light-induced spin state trapping (LIESST) in [Fe(ptz)6]BF4)2 with 57Fe Mös...
Figure 7: Schematic representation of the pressure influence (p2 > p1) on the LS and HS potential wells of an...
Figure 8: χMT versus T curves at different pressures for [Fe(phen)2(NCS)2], polymorph II. (Reproduced with pe...
Figure 9: Molecular structure (a) and γHS(T) curves at different pressures for [CrI2(depe)2] (b) (Reproduced ...
Figure 10: HS molar fraction γHS versusT at different pressures for [Fe(phy)2](BF4)2. The hysteresis loop broa...
Figure 11: Proposed structure of the polymeric [Fe(4R-1,2,4-triazole)3]2+ spin crossover cation (a) and plot o...
Figure 12: Temperature dependence of the HS fraction γHS(T), determined from Mössbauer spectra of [Fe(II)xZn1-x...
Figure 13: Influence of the noncoordinated anion on the spin transition curve γHS(T) near the transition tempe...
Figure 14: Spin transition curves γHS(T) for different solvates of the SCO complexes. [Fe(II)(2-pic)3]Cl2·Solv...
Figure 15: ST curves γHS(T) of the deuterated solvates of [Fe(II)(2-pic)3]Cl2·Solv with Solv = C2D5OH and C2H5...
Figure 16: Sketch of the two-step spin transition; [LS–LS] pair is diamagnetic, [LS–HS] is paramagnetic and th...
Figure 17: (left) Temperature dependence of χMT for {[Fe(L)(NCX)2]2bpym}(L = bpym or bt and X = S or Se). (rig...
Figure 18: Temperature dependence of χMT for [bpym, NCS−] (left) and [bpym, NCSe−] (right) at different pressu...
Figure 19: 57Fe Mössbauer spectra of [bpym, NCSe−] measured at 4.2 K at zero field (a) and at 5 T (b) (see tex...
Figure 20: Temperature dependence of χMT for [Fe2(L)3](ClO4)4·2H2O showing a complete two-step spin conversion...
Figure 21: (a) View of the dinuclear unit in the crystal structure of [Fe2(Hsaltrz)5(NCS)4]·4MeOH. (b) Tempera...
Figure 22: (left) AFM pattern recorded in tapping mode at room temperature on hexagonal single crystals of [Fe3...
Figure 23: (right) Stepwise SCO in an Fe4 [2 × 2] grid, which reveals a smooth magnetic profile under ambient ...
Figure 24: (left) View of the discrete nanoball made of Fe(II) SCO units as well as Cu(I) building blocks. (ri...
Figure 25:
(left) Linear dependency between T1/2 in the heating (Δ) and cooling (![[Graphic 1]](/bjoc/content/inline/1860-5397-9-39-i3.png?max-width=637&scale=1.18182)
) modes versus the anion volu...
Figure 26: (left) View of the linear chain structure of [Fe(1,2-bis(tetrazol-1-yl)propane)3]2+ along the a axi...
Figure 27: (left) View of the 2D layered structure of [Fe(btr)2(NCS)2]·H2O (at 293 K). The water molecules (in...
Figure 28: (left) Three interpenetrated square networks for [Fe(bpb)2(NCS)2]·MeOH. (right) χMT versus T plot s...
Figure 29: Part of the crystal structure of [Fe{N(entz)3}](BF4)2 (T = 293 K) [335,336]. (Reproduced with permission fro...
Figure 30: (left) Projection of the crystal structure of [Fe(btr)3](ClO4)2 along the c axis revealing a 3D str...
Figure 31: Size-dependent SCO properties in [Fe(pz)Pt(CN)4] (left), change of color upon spin state transition...
Figure 32: Schematic showing the epitaxial growth of polymer {Fe(pz)[Pt(CN)4]} and the spin transition propert...
Figure 33: Microcontact printing (μCP) of nanodots on Si-wafer of [Fe(ptz)6](BF4)2 after deposition of crystal...
Figure 34: (left) Projection of the two independent cations of [Fe(C6–trenH)]2+ with atom numbering scheme (15...
Figure 35: (a) χMT versus T for [Fe(C16-trenH)]Cl2·0.5H2O and variation of the distance d with temperature (T)...
Figure 36: Schematic illustration of the structure of compounds [Fe(Cn-tba)3]X2 adopting a columnar mesophase ...
Figure 37: Temperature dependence of the magnetic moment (M) at 1000 Oe and DSC profiles (inset; 5 °C/min) of ...
Figure 38: Porous structure of the SCO-PMOFs {Fe(pz)[M(II)(CN)4]} (left), representation of the host–guest int...
Figure 39: Porous structure of the guest-free SCO-PMOF’s {Fe(pz)[M(II)(CN)4]} (left), magnetic properties of t...
Figure 40: (left) The 3D porous structure of {Fe(pz)[Pt(CN)4]}·0.5(CS(NH2)2) (1) and {Fe(pz)[Pd(CN)4]}·1.5H2O·...
Figure 41: Top: The 3D porous structure of {Fe(dpe)[Pt(CN)4]}·phenazine in a direction close to [101] emphasiz...
Figure 42: View of the segregated stacking of [Ni(dmit)2]− and [Fe(sal2-trien)]+ in [Fe(qsal)2][Ni(dmit)2]3·CH3...
Figure 43: Thin films based on Fe(III) compounds coordinated to Terthienyl-substituted QsalH ligands [434] together...
Figure 44: Left: Temperature-dependent emission spectra for [Fe2(Hsaltrz)5(NCS)4]·4MeOH at λex = 350 nm over t...
