yes, I removed serial.prints from interrupt routine. Tried to request single byte and 5 bytes, neither worked. Wire library has poor explanation. Some tricks I had to find out from forum.
So far I haven't found any example sketches that use Wire.RequestFrom()
On the master side code looks like this:
unsigned int I2Cread(byte chipadress, byte dataadress) {
unsigned int data;
Wire.beginTransmission(chipadress);
//Writing a starting address to DS1307
Wire.send(dataadress);
Wire.endTransmission();
// request of data from addresses given
byte bytes = 5;
Wire.requestFrom(chipadress, bytes);
Serial.print("bytes available ");
Serial.println(int(Wire.available()));
byte highbyte;
byte lowbyte;
highbyte = (Wire.receive());
lowbyte = (Wire.receive());
data = word(highbyte, lowbyte);
return data;
}