Hi,
PCF2131:
The appropriate I2C-bus slave address is 1010011. The entire I 2C-bus slave address byte is shown in Table 87 of the datasheet: https://www.nxp.com/docs/en/data-sheet/PCF2131DS.pdf
PCF2129:
The appropriate I2C-bus slave address is 1010001. The entire I2C-bus slave address byte is shown in Table 77 of the datasheet: https://www.nxp.com/docs/en/data-sheet/PCF2129.pdf
PCF2127:
The appropriate I2C-bus slave address is 1010001. The entire I2C-bus slave address byte is shown in Table 88 of the datasheet: https://www.nxp.com/docs/en/data-sheet/PCF2127.pdf
Regards,
Jose