Adding multiple object dimensions in a object - Google script (js)

I'm a begginer, so sorry.

I want to get something like, and complete in my code "MDM", "SerialNumber" and "coordonates" with a loop:

    Console.log(MDM.SerialNumber.coordonates)

Or something like this would be fine also

Console.log(MDM[SerialNumber].coordonates)
Console.log(MDM[SerialNumber][coordonates])

But I want also this to work (or simililar, I just want it with indexes) :

Console.log(MDM.[0][0])

Then I would like to get an answer like "A2:B3". But when I try this, I have an error, it concerns before when I try to put my data in a loop. This is the error :

Cannot set property 'SerialNumber' of undefined

So now I'm going to explain what I tried : I have multiple columns that I want to have coordonates and data from them : And I have also multiple databases (MDM and dataBase2 (we only study MDM here, but I explain why there is "MDM"))

var MDM = new Object();      
var name= ["SerialNumber", "IMEI", "Last_Check-In", "mail", "User_ID"];

Then there is a loop, this loop permit to add what I want in a object. But it's not working at the 3rd line (MDM.this[name[i]] =...), it's where I have the error.

  for (var i = 0; i <= name.length-1; i++) {
    coordonnatesLetter[i] = col[i] + "2:" + col[i];
    colData[i] = ssMDM.getRange(coordonnatesLetter[i]);
    MDM.this[name[i]] = { coordonates: coordonnatesLetter[i], data: colData[i]};
}

I tried also something like this for the 3rd line:

MDM[name[i]]  = { coordonates: coordonnatesLetter[i], data: colData[i]};

But then I have that about errors on my console.log line: ReferenceError: "coordonates is not defined"

Maybe I should defined coordonates, but I don't know how. I'm a little lost.

Thank you