Constitutionally you cannot convict a sitting President for a Federal crime. You can only impeach. You can then try and convict should he be impeached for an actual crime (that is not necessary in impeachment, "high crimes and misdemeanors" leaves much open).
One cannot "pardon" themselves out of impeachment as it is not a criminal trial event (shown in the fact that it specifically does not attach for double jeopardy). Now he could "pardon" himself for the crimes if he does it before the vote in the Senate, but it is very likely that act itself would ensure removal from the office as it is admitting guilt (no need to pardon yourself if you are not guilty).
