Can stagnate be used as a noun?

I couldn't remember stalemate for some reason so opted to use the phrase, "put us in a stagnate". In this context, would that be appropriate?

Full sentence: I'm worried that a lack of coordination would put us in a stagnate.

None of the dictionaries I've seen seem to approve of it, but I can't help but feel this is a fine usage of the word.

If we're talking about commonly recognized usage, then stagnation is the noun and stagnate is the verb. Here is stagnation, a noun, in Merriam-Webster:

: a stagnant state or condition : a state or condition marked by lack of flow, movement, or development

And here is stagnate, a verb:

: to become or remain stagnant

So for your example sentence, it would be better to write:

I'm worried that a lack of coordination would put us in stagnation. (using the noun form)

I'm worried that we would stagnate if we do not coordinate. (using the verb form)

It's hard to say why stagnate would sound fine as a nonce noun to you. For example, the -ate suffix marks stagnate as a verb from Latin, and several other verbs share that form (segregate, aggregate, aggravate, ingratiate) (OED, "-ate, suffix3"). That said, there are also nouns that have an -ate ending (senate, prelate, mandate) (OED, "-ate, suffix1"). So it would be possible to hear the word with its ending and think, "This sounds noun-ish as well as verb-ish."

That said, this hypothetical usage is rare enough that the Corpus of Contemporary American English turns up zero results for "stagnate_n" (stagnate as a noun) and "a stagnate" (stagnate with an article, so either a noun or adjective), but it turns up 152 results for "stagnate_v" (stagnate as a verb). Their largest corpus, NOW: News on the Web, turns up zero results for "stagnate_n" but 3857 results for "stagnate_v." Strangely, "a stagnate" does turn up ten results, but they all use stagnate as an adjective in a peculiar fashion. It feels like a misspelling of stagnant. A few examples:

it's a stagnate case

they just look like a stagnate team, going through the motions.

including a stagnate and aging population

So if stagnate is ever used as a noun, it's so rare that a misspelling of the adjective stagnant is more common.