High pass filter for I2C
High-pass filter?  At first, I suspected that it was a typo.
I would think that a high-pass filter would fundamentally clobber the I2C communication (before the bus capacitance and EMI get a chance to clobber it).  The level on the data line would decay by the time that it's sampled.
I2C was intended for communication within a circuit board.  Okay, one might push his luck and run I2C though some wires as long as the wires are short enough and EMI is not too bad.  Okay, one might buffer the I2C and push it a little further.  Gimbal with moving slip rings?  Consider some other communication method for the gimbal.  Or you might end up like this guy.