Halbach array. is that any good for understanding why opposite spin electrons, that the magnetic fields actually can cancel in macroscopic reality?

Hello dear forum members,

I'm new here and I have registered to ask a question which for some reason is difficult for me to solve on my own as I struggle to wrap my head around it. The problem pertains to electrophilic aromatic substitution reactions. I know how it works, both in theory as well as in practice when it comes to monocyclic arenes like benzene itself and how activating/deactivating ortho/para/meta directors decide over at which C-X the next group will be bonded to (please note that "X" here doesn't stand for halogens but is a placeholder for the position number of the carbon in question).
However, things got complicated for me once I moved on to polycyclic compounds because I have no idea how to "jump" back and forth between neighbouring rings. To make matters worse my textbook only explains Se-Reactions in the context of monocyclic arenes like benzene and phenol.

Let's take for example biphenyl. Assuming the Se-Reaction starts at ring A, how does a chemist ensure that his next reaction takes place at ring B? No matter whether I use activating/deactivating ortho-para-meta directors, the reactions will always take place on ring A, right? What does it take to affect the regioselectivity of the molecule in such a way to "jump" to ring B?

Another example would be the phenanthrene molecule (I have uploaded an image with the numbering system of the (4,5-epoxy)morphinan family). This one is different as ring B is essentially a cycloalkene which responds to E1/E2/E1cb-Reactions as well as Addition-Reactions, so I would assume that simply doing one of these reactions automatically removes/adds functional groups to ring B instead of the neighbouring arenes. But what if I am currently at C-3 of ring A after having substituted the H-atom with an OH-group via Se and want to skip ring B and go directly to ring C (which is also an arene that also responds to Se-Reactions) and add another OH-group at C-6? The OH-group at C-3 would be a strongly activating ortho-para director, so the next reaction will take place at either C-2 or C-4 (ring A). Para isn't possible because C-12 doesn't have any valence electrons left (and even if it had any, there is too much steric hindrance, so a reaction at ortho is much more likely).
I can't imagine that a chemist has to go through the entire ring structure and do a whole range of unnecessary and time-consuming reactions until he reaches his desired C-6 position to manipulate. There must be some kind of standard ruleset that chemists apply in order to address specific rings while leaving others alone. Something that gives us more control over the regioselectivity of the reaction we want to conduct.

Maybe the best way to answer my question would be to tell me how YOU would synthesize the compound 3,6-dihydroxyphenanthrene if you were to start with phenanthrene.

I hope I haven't expressed myself in too complicated a manner and if I did I apologize as english isn't my mother tongue. I have really researched book after book, searched websites and sifted through youtube videos but I haven't found anything that discusses how to affect the regioselectivity of a polycyclic molecule in order to conduct reactions at different rings instead of a single ring. Maybe I'm thinking in overly complicated ways and can't see the forest for the trees anymore. Whatever it is, I need help because this is driving me insane. Thank you.

Chemicals used:CuSO4(aq), Al2(SO4)3, KNO3(salt bridge), copper and aluminium electrodes.

Hi, i recetly made an experiment based on electrical potencilas shown in link below, i was thinking that it at least seems to be better thant classic zinc-copper battery (potencial of 1.1V) becase it should have more voltage maybe (based on the potencilas it should had been aroud 2V) but in reality it is just around 0.5V.
Why is that???


2 e + Cu2+   ⇌   Cu(s)   0.337V
3 e + Al3+         ⇌       Al(s)        -1.662V
the link:https://en.wikipedia.org/wiki/Standard_electrode_potential_(data_page)

Of course wikipedia says high spin is less important in affecting the ionization energy than "Electron configuration: This accounts for most elements' IE, as all of their chemical and physical characteristics can be ascertained just by determining their respective electron configuration.
Nuclear charge: If the nuclear charge (atomic number) is greater, the electrons are held more tightly by the nucleus and hence the ionization energy will be greater (leading to the mentioned trend 1 within a given period).
Number of electron shells: If the size of the atom is greater due to the presence of more shells, the electrons are held less tightly by the nucleus and the ionization energy will be smaller.
Effective nuclear charge (Zeff): If the magnitude of electron shielding and penetration are greater, the electrons are held less tightly by the nucleus, the Zeff of the electron and the ionization energy is smaller.[5]
Stability: An atom having a more stable electronic configuration has a reduced tendency to lose electrons and consequently has a higher ionization energy."

What do you want to do with this solution?
Normaly conc. H2SO4 96-98%  and H2O2 35% is used.
5 M is roughly 40% not strong enough.
Very strong corrosive etching mixture. Careful if mixed with organics, risk of explosion. Should be used only in a safe room, also outside probably is more safe.