CCSD(T)-F12 ab initio computations are performed to investigate the isomerization path between HBNH and BNH2, and the six-dimensional potential energy surface of the electronic ground state X similar to 1S+ of the linear isomer. The equilibrium geometries and harmonic wavenumbers obtained at the CCSD(T)-F12a/aug-cc-pVTZ level of theory are nearly those computed with the CCSD(T)/aug-cc-pV5Z level, but with a smaller amount of CPU time for the evaluation of the total energy. The analytical representation of the potential energy surface is used in variational calculations of the rovibrational energy levels of H11BNH and isotopologues. The computed rovibrational energy levels are compared with the available experimental data, and a good agreement is generally noticed. We also propose an assignment of the rovibrational energy levels of H11BNH up to 3000 cm-1 above the zero point energy. (C) 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012