The effect of density functional on the optimized structure and ESP is also of interest. Figure shows the optimized values of dBN and dint obtained for the (B111N111H42) This suggests that the long-range electron-electron exchange interactions are reasonably incorporated in the B97XD functional. The interlayer ESPs calculated at the B3LYP-D3/6-31G(d) and ωB97XD/6-31G(d) levels for the (B111N111H42)2 cluster with  = 21.6° and 13.6° are given in Fig. . We did not find any critical differences between the ESPs at the B3LYP-D3/6-31G(d) and ωB97XD/6-31G(d) levels, although these two levels of calculations result in somewhat different values of dint. This implies that the underlying features of the interlayer ESP are insensitive to the DFT functional. Hence, in the main text, we only show the ESP map for the (B111N111H42)2 cluster calculated at the ωB97XD/6-31G(d) level.