Andre Villas-Boas is pessimistic over his pursuit of Porto playmaker Joao Moutinho and Brazil forward Willian.
Spurs are renowned for their last-minute forays into the transfer market and Moutinho was expected to be the focus of their attention on deadline day.
But Tottenham appear unlikely to sign the 25-year-old due to a 40million euro (£31.7million) release clause in his contract.
"It's an impossible deal for the club," Villas-Boas told a press conference.
"You have to bear in mind that this is a player with a 40million euro release clause.
"This volume of money is out of Tottenham's possibility.
"Bearing in mind that this is a key player for club and country, you wouldn't say that you would get him at half the price and half the price is already bigger than Tottenham's record fee."
The Portuguese, who has added Jan Vertonghen, Gylfi Sigurdsson, Mousa Dembele and Emmanuel Adebayor this summer, also appears pessimistic about his chances of signing Willian from Shakhtar Donetsk for the same reason.
"We had initial contact with Shakhtar, again a club in a position with wealthy owners (who are) not easy to deal with," Villas-Boas added.
"We can't say that it's over but we have approached the club and at the moment it's a deal that doesn't seem to be happening."
A last-minute bid for both players cannot be ruled out given Spurs chairman Daniel Levy's history of 11th-hour deals, but it is unclear whether Porto or Shakhtar will be willing to drop their asking price for the respective players.