Say a freebase harmaline material is mixed with a monofumaratedmt material at equal molarities, would a harmalinedmtfumarate be formed?

It depends on the stoichiometry of the DMT fumarate, and it's not entirely clear what you mean by "monofumaratedmt" in that respect. Given that the 1:1 fumarate can be called "bifumarate", the term "monofumarate" would seem to imply the 2:1 'normal' DMT fumarate. Also, the term "molarity" refers to concentration in solution but the way you say "freebase harmaline material" somewhat implies the solid form. Whatever, let's take a look at the possibilities:

If you were to mix equimolar quantities of freebase harmaline powder and DMT hydrogenfumarate [aka bifumarate] (i.e. the 1:1 material) powder you would, at least initially, simply have a mixture of the two powders. Depending on the conditions, it would remain as such for an indefinite period of time. Adsorbed water in the powder along with absorption of moisture from the air might slowly lead to proton transfer and the formation of a mixed harmaline/DMT fumarate. The larger the particles, the slower this would occur. Without an actual experiment it's difficult to say whether this would subsequently differentiate into a mixture of crystals of harmaline fumarate and DMT fumarate, both in the 2:1 stoichiometry.

If it were to react like this there would likely also be a small amount of protonated fumarate in the mixture resulting from the protonation equilibrium between the two weak bases, harmaline and fumarate, whereas virtually all of the DMT would remain protonated.

Following that last bit of reasoning, if you were to mix the 'normal' 2:1 DMT fumarate with harmaline freebase, subject to the aforementioned caveats there would be an equilibrium between protonation in DMT and in harmaline, with protonated DMT remaining the greatly preponderating form. Amounts of monoprotonated fumarate (i.e. hydrogenfumarate monoanion) would likely remain negligible.

The practical upshot of all this would be more to answer the question of what happens when the mixture gets dissolved in water. In the case of the bifumarate, it seems likely that all of the harmaline would dissolve through protonation from the hydrogenfumarate. The inevitable small amount of dissolved carbon dioxide present would also contribute a little, meaning that the harmaline would dissolve faster with stirring not only because of the increased mixing of solvent and undissolved matter, but also because this helps more CO2 to dissolve once some of it becomes converted to bicarbonate.

[The inverse of this effect is seen when precipitating harmala bases with sodium carbonate - a time delay can be observed in the precipitation while carbon dioxide comes out of solution. This is something which Van der Sypt mentioned in his now classic paper.]

Moving on to the harmaline/DMT (2:1) fumarate, only small amounts of the harmaline would dissolve, largely due to dissolved carbon dioxide, and a tiny amount from the protonation equilibrium between harmaline and DMT. Various moderately fiddly calculations using temperature, concentration, pKa and pKb can be used to determine just how much of the harmaline might end up dissolving.

The other possibilities include mixing harmaline powder with solution of the DMT fumarate and the mixing of two solutions. Here you'd likely see different results, at least slightly, depending on which one gets added to the other, and the rate at which it is added. Given sufficient time, though, the end results would mostly tend towards the same equilibrium given equivalence of other factors (e.g., particle size) in the cases to be considered.

Of course, considering the aim of this mixture would presumably be oral consumption none of this is especially relevant since the harmaline would become protonated by stomach acid anyhow. In that respect it would perhaps be better to use a mixture with 2 parts harmaline and 1 part DMT since the MAO inhibition would be insufficient - or the DMT dose would be way too high - if using a 1:1 mixture, unless you were to pre-dose with just harmaline or harmine.

(Yes, I drank a large coffee before typing this hahahahahaha!)

The goal is to couple the dmt and harmine or harmaline in a single molecule. Say we bypass the gastrointestinal route somewhat by IM or whatever. Wouldn't the dmt-harmala molecule be dmt active and protected somewhat by harmala?

You pretty much covered all the chemical possibilities there downwards from zero. A thank you to you and your super strong coffee!

You seem to utterly misapprehend how this stuff works

What you're now describing here would be a different molecule than either of its two constituent molecules, with correspondingly different properties. You would have to be specific about where the two molecules are joined to each other to have any chance of beginning to predict their possible pharmacology.

Specific coupling would require specific chemical synthesis, most likely by using highly specialized catalysts or enzymes (which are, of course, even more specialized kinds of catalysts). The location of the coupling would also define which types of chemical reactions might be most likely to produce the desired product. Whereas throwing it all into a pot of acetone and adding a pinch of potassium permanganate, for example, most likely would produce a mess rather than something you'd want to introduce into your body by any route.

What, anyhow, is your basis for imagining this molecular coupling? Do you understand how this differs from a mixed salt? Were you perhaps reading TMcK's 'The Invisible Landscape' or 'True Hallucinations' rather than a more reputable chemistry work? It sounds like you were maybe thoroughly baked when you came up with this one, tbh. (I know cos I've been there too )

Thoroughly baked and misaprehended, got that one right! 😂 Also obviously not an organic chemist.

I just imagined a dmt and harmala molecules coupled by the fumaric molecule. A combo salt.

And yes, I have read the two books, which might have contributed to my silly imagination and ignorance.

Haha, all good. Tbf, they were pretty easy guesses given the territory

But salts dissociate into their constituent ions once dissolved in water (or other suitably polar solvent). The major distinction to be aware of here is the difference between ionic and covalent bonding.

A large number of dimeric and oligomeric alkaloids (including indolic ones) are known in nature though, so the idea isn't entirely far-fetched. Psychotridine is an interesting example of a pentameric alkaloid, for example.