Temperature‐dependent hysteretic changes in near‐infrared transparency were achieved for a liquescent bis(trifluoromethanesulfonyl)imide‐(dihydrophenazine radical cation) salt. These hysteretic changes were attributed to dynamic dissociation and association of a dimer structure for the radical cations, which accompanied with the solid–liquid phase transitions even under neat conditions with no measurable degradation of the compound.
Abstract
A liquescent dihydrophenazine radical cation, 1.+⋅NTf2−, showed drastic changes in near‐infrared (near‐IR) transparency and opaqueness through hysteretic phase transitions with no measurable degradation of the compound even under aerated conditions. During the heating and slow cooling process (0.5 K min−1), its electronic and magnetic properties were altered clearly and repeatedly changed between solid and liquid states. The liquid state was transparent to near‐IR light (940 nm), but the solid state was opaque, despite both samples exhibiting a similar green color under room light. Additionally, the liquid state was changed to a glass state under a fast cooling process (2–10 K min−1). UV/Vis/near‐IR and electron spin‐resonance spectroscopy revealed that these drastic changes were attributable to the dynamic dissociation and association of a π‐dimer structure for 1.+ accompanying with the solid–liquid phase transitions even under the neat conditions.
https://ift.tt/2Xs5APZ
Journal of the American Chemical SocietyDOI: 10.1021/jacs.1c00189
Yusuke Ishigaki, Takashi Harimoto, Kazuma Sugawara, and Takanori Suzuki
https://ift.tt/37Uhzv4
Coupled complex : A novel crystalline proton–electron coupling system was developed using an iron(II) hydrazone complex. The complex exhibits a thermally and photoinduced proton‐transfer‐coupled spin transition. The intermediate phase has two types of iron(II) complexes with distinct spin states and proton positions. The proton transfer in one of the two ligands changes the direction and magnitude of the molecular dipole moment.
Abstract
A proton–electron coupling system, exhibiting unique bistability or multistability of the protonated state, is an attractive target for developing new switchable materials based on proton dynamics. Herein, we present an iron(II) hydrazone crystalline compound, which displays the stepwise transition and bistability of proton transfer at the crystal level. These phenomena are realized through the coupling with spin transition. Although the multi‐step transition with hysteresis has been observed in various systems, the corresponding behavior of proton transfer has not been reported in crystalline systems; thus, the described iron(II) complex is the first example. Furthermore, because proton transfer occurs only in one of the two ligands and π electrons redistribute in it, the dipole moment of the iron(II) complexes changes with the proton transfer, wherein the total dipole moment in the crystal was canceled out owing to the antiferroelectric‐like arrangement.
https://ift.tt/2X0bGYo
We report the two‐step hysteretic Fe(II) spin crossover (SCO) effect achieved in programmed layered Cs{[Fe(3‐CNpy)2] [Re(CN)8]}·H2O (1) assembly consisting of cyanido‐bridged FeII–ReV square grid sheets bonded by Cs+ ions. The presence of two non‐equivalent FeII sites and the conjunction of 2‐D bimetallic coordination network with non‐covalent interlayer interactions involving Cs+, [ReV(CN)8]3– ions, and 3‐CNpy ligands, leads to the occurrence of two steps of thermal SCO with strong cooperativity giving a double thermal hysteresis loop. The resulting spin transition phenomenon could be tuned by an external pressure giving the room temperature range of SCO as well as by visible light irradiation inducing an efficient recovery of the high spin FeII state at low temperatures. In this report, we prove that octacyanidorhenate(V) ion is an outstanding metalloligand for inducing of cooperative multi‐step, multi‐switchable FeII SCO effect.
https://ift.tt/2zMRu3y
For your pleasure, another easy to build flashing circuit: the hysteretic oscillator.
Schematic
https://preview.redd.it/80ahmlpodjj51.png?width=2777&format=png&auto=webp&s=1c5b3ebcbd27ef209f9d5e78f2234452c25b7de4
Breadboard layout
https://preview.redd.it/ygpyfvvqdjj51.png?width=2000&format=png&auto=webp&s=2b62d1a162b4875983f4ae736cf4064dc295e5f0
Assembly notes
- Apply the entire circuitry, then plug in the battery.
- The slightly longer leg of the LEDs and the capacitor indicate their plus pole.
- Bonus: If on hand, you can change the frequency by altering C1 (e.g. to 1uF to get 10 times the frequency or to 100uF for a tenth of it).
Bill of materials (BOM)
- 1x 7555 timer IC
- 1x 100k Ohm trimmer
- 1x 10k Ohm resistor
- 2x 1k Ohm resistors
- 1x 10uF capacitor
- 2x LEDs (the color doesn't matter)
- 1x breadboard
- Wire (one color is enough, multiple colors help bugfixing in more complicated circuits)
- 1x battery clip for 9-volt block
- 1x 9V battery
Required tools
- Wire stripper
Explanation and source
Magnetism is the classic example of hysteresis. Specifically, there are two well-defined saturated states - where the magnetic moments are saturated in the positive and negative directions. Because of the anisotropies in the system, as an external magnetic field is applied to the system, the magnetism typically does not transition directly from one saturated state to the other in a reversible way. That means that for a defined value of the applied field there can be more than one value of the magnetism. In effect, the magnetism is defined by both the value of the applied field and its field history. An easy to understand example is the case of 0 applied field; if a magnet was positively saturated it tends to remain positively saturated, and negative saturation stays negatively saturated.
Hysteretic behavior becomes increasingly complex when the hysteretic elements have both variations in their intrinsic behaviors and inter-element interactions - as in the case in many experimental systems.
There is an approach to separate the intrinsic and interaction behaviors by looking at how the system evolves from the mixed (partly reversed) state. The technique is called the first order reversal curve (FORC) technique (Open Access Articles: http://www.nature.com/srep/2014/140226/srep04204/full/srep04204.html http://scitation.aip.org/content/aip/journal/aplmater/2/8/10.1063/1.4894197). I have spent a lot of time during my graduate studies using this technique and developing approaches to analyze the FORC distributions. It has been implemented into the characterization suite of several magnetic technology industries.
I am really interested in expanding FORC to other hysteretic systems. Others have performed work looking at chemical hysteresis and metal-insulator phase transitions. FORC is commonly used for analysis of magnetism in geophysical samples. I have performed work with gas adsorption, ionic migration, and structural phase transition. However, these tend to be selected special cases and expansion beyond magnetism has been very very limited.
I really want to expand this technique to other fields, but am not familiar enough with them to identify the hysteretic phase transitions. That is, there must be other fields of science with a measurable variable which is controlled by a single independent variable, which can be driven both positively and negatively, and is (largely) time independent.
Beyond the sciences there are other fields (such as business, s
... keep reading on reddit ➡I don't want to step on anybody's toes here, but the amount of non-dad jokes here in this subreddit really annoys me. First of all, dad jokes CAN be NSFW, it clearly says so in the sub rules. Secondly, it doesn't automatically make it a dad joke if it's from a conversation between you and your child. Most importantly, the jokes that your CHILDREN tell YOU are not dad jokes. The point of a dad joke is that it's so cheesy only a dad who's trying to be funny would make such a joke. That's it. They are stupid plays on words, lame puns and so on. There has to be a clever pun or wordplay for it to be considered a dad joke.
Again, to all the fellow dads, I apologise if I'm sounding too harsh. But I just needed to get it off my chest.
Do your worst!
I'm surprised it hasn't decade.
For context I'm a Refuse Driver (Garbage man) & today I was on food waste. After I'd tipped I was checking the wagon for any defects when I spotted a lone pea balanced on the lifts.
I said "hey look, an escaPEA"
No one near me but it didn't half make me laugh for a good hour or so!
Edit: I can't believe how much this has blown up. Thank you everyone I've had a blast reading through the replies 😂
It really does, I swear!
They’re on standbi
Pilot on me!!
Nothing, he was gladiator.
Dad jokes are supposed to be jokes you can tell a kid and they will understand it and find it funny.
This sub is mostly just NSFW puns now.
If it needs a NSFW tag it's not a dad joke. There should just be a NSFW puns subreddit for that.
Edit* I'm not replying any longer and turning off notifications but to all those that say "no one cares", there sure are a lot of you arguing about it. Maybe I'm wrong but you people don't need to be rude about it. If you really don't care, don't comment.
When I got home, they were still there.
What did 0 say to 8 ?
" Nice Belt "
So What did 3 say to 8 ?
" Hey, you two stop making out "
I won't be doing that today!
[Removed]
This morning, my 4 year old daughter.
Daughter: I'm hungry
Me: nerves building, smile widening
Me: Hi hungry, I'm dad.
She had no idea what was going on but I finally did it.
Thank you all for listening.
You take away their little brooms
There hasn't been a post all year!
A liquescent dihydrophenazine radical cation, 1 •+ •NTf 2 – , showed drastic changes in near‐infrared (near‐IR) transparency and opaqueness through hysteretic phase transitions with no measurable degradation of the compound even under aerated conditions. During the heating and slow cooling process (0.5 K min –1 ), its electronic and magnetic properties were altered clearly and repeatedly changed between diamagnetic solid and paramagnetic liquid states. The liquid state was transparent to near‐IR light (940 nm), but the solid state was opaque, despite both samples exhibiting a similar green color under room light. Additionally, the liquid state was changed to a glass state under a fast cooling process (2–10 K min –1 ). UV/vis/near‐IR and electron spin resonance spectroscopies revealed that these drastic changes were attributable to the dynamic dissociation and association of a π‐dimer structure for 1 •+ accompanying with the solid–liquid phase transitions even under the neat conditions.
https://ift.tt/2Xs5APZ
Perfect rhenium mediator: Octacyanidorhenate(V) ion is presented as a promising molecular precursor for the construction of an advanced spin‐crossover material linking a multistep spin transition with strong cooperativity. An anionic layered FeII‐ReV cyanido‐bridged framework non‐covalently bonded to Cs+ counterions is reported. It exhibits a two‐step hysteretic FeII spin‐crossover effect controlled by temperature, light irradiation, and pressure.
Abstract
A two‐step hysteretic FeII spin crossover (SCO) effect was achieved in programmed layered Cs{[Fe(3‐CNpy)2][Re(CN)8]}⋅H2O (1) (3‐CNpy=3‐cyanopyridine) assembly consisting of cyanido‐bridged FeII‐ReV square grid sheets bonded by Cs+ ions. The presence of two non‐equivalent FeII sites and the conjunction of 2D bimetallic coordination network with non‐covalent interlayer interactions involving Cs+, [ReV(CN)8]3− ions, and 3‐CNpy ligands, leads to the occurrence of two steps of thermal SCO with strong cooperativity giving a double thermal hysteresis loop. The resulting spin‐transition phenomenon could be tuned by an external pressure giving the room‐temperature range of SCO, as well as by visible‐light irradiation, inducing an efficient recovery of the high‐spin FeII state at low temperatures. We prove that octacyanidorhenate(V) ion is an outstanding metalloligand for induction of a cooperative multistep, multiswitchable FeII SCO effect.
https://ift.tt/2zMRu3y
Perfect rhenium mediator : Octacyanidorhenate(V) ion is presented as a promising molecular precursor for the construction of an advanced spin‐crossover material linking a multistep spin transition with strong cooperativity. An anionic layered FeII‐ReV cyanido‐bridged framework non‐covalently bonded to Cs+ counterions is reported. It exhibits a two‐step hysteretic FeII spin‐crossover effect controlled by temperature, light irradiation, and pressure.
Abstract
A two‐step hysteretic FeII spin crossover (SCO) effect was achieved in programmed layered Cs{[Fe(3‐CNpy)2][Re(CN)8]}⋅H2O (1 ) (3‐CNpy=3‐cyanopyridine) assembly consisting of cyanido‐bridged FeII‐ReV square grid sheets bonded by Cs+ ions. The presence of two non‐equivalent FeII sites and the conjunction of 2D bimetallic coordination network with non‐covalent interlayer interactions involving Cs+, [ReV(CN)8]3− ions, and 3‐CNpy ligands, leads to the occurrence of two steps of thermal SCO with strong cooperativity giving a double thermal hysteresis loop. The resulting spin‐transition phenomenon could be tuned by an external pressure giving the room‐temperature range of SCO, as well as by visible‐light irradiation, inducing an efficient recovery of the high‐spin FeII state at low temperatures. We prove that octacyanidorhenate(V) ion is an outstanding metalloligand for induction of a cooperative multistep, multiswitchable FeII SCO effect.
https://ift.tt/2zMRu3y
A proton–electron coupling system, exhibiting unique bistability or multistability of the protonated state, is an attractive target for developing new switchable materials on the basis of proton dynamics. In this paper, we present an iron(II) hydrazone crystalline compound, which displays the stepwise transition and bistability of proton transfer at the crystal level. These phenomena are realized through the coupling with spin transition. Although the multi‐step transition with hysteresis has been observed in various systems (e.g., valence tautomerism), the corresponding behavior of proton transfer has not been reported in crystalline systems; thus, the described iron(II) complex is the first example. Furthermore, because proton transfer occurs only in one of the two ligands and p electrons redistribute in it, the dipole moment of the iron(II) complexes changes with the proton transfer, wherein the total dipole moment in the crystal was canceled out owing to the antiferroelectric‐like arrangement. This study shows the potential for using the proton transfer phenomenon in the materials science field.
https://ift.tt/2X0bGYo
