All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
It is not permissible to spend this money on other than what it has been collected for, which is the benefit of the mosque. Those who donated this money should not interfere in its administration as they are no longer its owners from the time it was received by those who run the mosque. Thus, this money has become a Waqf for the mosque (in the sense that it should only be spent on it) and its property, and is no longer the donors' property. Therefore, it should be spent on what benefits the mosque whenever needed, or it should be kept until it is needed. If the Muslim community want to build the named centre, then they should collect money one more time for this purpose.
However, it is not permissible for this money to be saved in a bank which deals with Riba (interest or usury) unless it is feared that this money could be lost or stolen and there is no Islamic bank or a safe entity with whom this money could be kept. The added interest which results from this money being deposited in bank that deals with Riba should be taken out and spent on the general benefit of the Muslims, because this is the only field where such money should be spent on.
For more benefit, please refer to Fatwa 90054.
Allaah Knows best.