C6H11Br
		Bromine
	Nuclear Quadrupole Coupling Constants
		in equatorial Cyclohexyl Bromide
	Calculation of the bromine nqcc's in equatorial cyclohexyl bromide was made on a molecular structure derived ab initio, as described below.  These are compared in Table 1 with the experimental nqcc's of Caminati, et al. [1].  Structure parameters are given in Table 2, rotational constants in Table 3.
	In Table 1, RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation for the B1LYP/TZV(3df,3p) model for calculation of the bromine nqcc's.
	Subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  The nqcc y-axis is chosen coincident with the inertia b-axis, these are perpendicular to the molecular symmetry plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
	Table 1. Bromine nqcc's in Cyclohexyl Bromide, equatorial (MHz).     Calc. Expt. [1]     79Br Xaa 488.36 466.8(41) Xbb - 265.39 - 258.8(26) Xcc - 222.97 - 208.0 |Xac| 172.33   RMS 15.6 (5.0 %) RSD 1.58 (0.39 %)   Xxx - 262.52 Xyy - 265.39 Xzz 527.91 ETA 0.0054 Øz,a 12.93 Øa,CBr 12.38 Øz,CBr   0.54     81Br Xaa 408.06 406.0(62) Xbb - 221.72 - 219.7(63) Xcc - 186.34 - 186.3 |Xac| 143.88   RMS 1.66 (0.62 %) RSD 1.38 (0.40 %)
	Molecular Structure
	The ropt structure given in Table 2 was derived as follows:  The molecular structure was optimized at the MP2/6-311G(d,p) level of theory.  The optimized CC single bond length was then corrected using the equation obtained from linear regression analysis of the data given in Table IX of Ref. [2].  CH bond lengths were corrected using r = 1.001 × ropt, where ropt is obtained by MP2/6-31G(d,p) optimization [3].
	For the C-Br bond length, optimization was made at the MP2/6-311+G(2d,p) level of theory of the C-Br bond lengths in CH3Br, CH2Br2, HCCBr, and BrCN.  Linear regression of the calculated versus equilibrium bond lengths yields the following relationship, by which the C-Br was corrected:
			r = 0.9946 × ropt + 0.0001,   RSD = 0.0015 Å.
	The optimized C-Br bond length is 1.9634 Å which, after correction, is 1.9529 Å.
	Table 2.  Cyclohexyl Bromide, equatorial.  Heavy atom structure parameters, ropt (Å and degrees).  The complete structure is given here in Z-Matrix format.   Atomic numbering C(6)Br 1.9529 C(6)C(5) 1.5163 C(5)C(4) 1.5266 C(4)C(3) 1.5231 CCC,CBr * 128.02 C(1)C(6)C(5) 112.11 C(6)C(5)C(4) 109.76 C(5)C(4)C(3) 111.06 C(4)C(3)C(2) 111.12 * Angle that C(6)Br makes with the C(1)C(6)C(5) plane. On the rs structure of Ref. [1] and the ro structure of Ref. [4], the CBr bond lengths are respectively 1.958(5) and 1.9619(13) Å.
	Table 3.  Cyclohexyl Bromide, equatorial.  Rotational Constants (MHz).  79Br species.   Calc. ropt  Expt. [1] A  4329.4 4280.0(3) B    903.0   894.732(4) C    783.1   776.002(2)
	[1] W.Caminati, D.Damiani, and F.Scappini, J.Mol.Spectrosc. 104, 183(1984).
	[2] J.Demaison, J.Cosléou, R.Bocquet, and A.G.Lesarri, J.Mol.Spectrosc. 167,400(1994).
	[3] J.Demaison and G.Wlodarczak, Structural Chem. 5,57(1994).
	[4] E.Białkowska-Jaworska, M.Jaworski, and Z.Kisiel, J.Mol.Struct. 350,247(1995).
	Cyclohexyl Bromide, axial				Cyclohexyl Chloride, axial
	Cyclohexyl Chloride, equatorial
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	Molecules/Bromine
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						Last Modified 5 May 2006