Function of Grignard 4-coordinate complex?

Dro

What is the purpose of creating a 4-coordinate complex with the Grignard reagent and solvent?

I'm writing a lab report on the Grignard reaction we performed in my lab. My instructor said that it was important that the solvent would form a 4-coordinate complex with the Grignard reagent, but never really explained why. I'm just curious to the importance/function of this complex.

Thank you in advance,
Dro