I don;t think so. Cash basis taxpayers report income and deductions when they actually happen. I think you are the victim of poor planning or slow mails. The only way to deduct the trust deposit from your income would be to put the money in the trust before December 31. (One way to do this, knowing that the check was coming late, would have been to take money from your regular bank account or even a short term loan to make the trust deposit, then pay yourself back with the check.)
An april1 15 deadline for prior year charitable contributions actually passed the house in 2014 but was never signed into law that I can tell.
<a rel="nofollow" target="_blank" href="
https://www.philanthropy.com/article/An-April-15-Deadline-for/152105">https://www.philanthropy.com/a...>
Sorry, but I think you're stuck.
