Table 1.

Rotational constants (in MHz), dipole moment components (in Debye), dihedral angles (in degree), and energies relative to that of the lowest energy conformer I (E = −424.5296788 Hartree) of the two observed conformers of MHO (I and XIII) calculated at the MP2/6-311++G(d,p) level of theory.

Conf.	A	B	C	μa	μb	μc	ϑ1	ϑ2	ϑ3	ϑ4	E
I	3101.3	664.2	616.4	–0.37	0.33	–1.62	–146.54	66.52	179.98	179.95	0.00
I a	3598.9	626.6	584.6	–0.83	0.58	–9.11	–166.18	69.11	179.53	179.90
XIII	6990.7	483.4	459.9	0.07	–1.72	0.00	180.00	180.00	180.00	180.00	3.25
Exp. b	3599.0	625.4	585.8

^a Values calculated at the MP2/cc-pVDZ level of theory for the most stable conformer I (see text). ^b Experimental values obtained for conformer I. Note the agreement with the values calculated at the MP2/cc-pVDZ level.