Comment

The title compound, (I), was prepared as described and shown in the scheme. This compound crystallizes as the zwitterion [(2-carboxylatophenyl)(phenyl)methyl]-N,N-dimethylammonium (Fig. 1). There are infinite chains of hydrogen-bonded molecules, with alternating stereochemistry at C1, running parallel to the crystallographic c axis (Fig. 2). The molecules are connected by hydrogen bonds between N1H and O1 of a neighbouring molecule [N1O1ⁱ = 2.670 (3) Å; symmetry code: (i) ]. There also appears to be intramolecular C1-H11O1 hydrogen bonding (Desiraju, 2005), as shown by the CO distance of 2.848 (3) Å. This interaction is strengthened by the increased CH acidity due to the adjacent positively-charged N atom.

Figure 1 The zwitterionic form of compound (I), showing 40% probability displacement ellipsoids and H atoms of fixed radii.

Figure 2 View of one of the infinite hydrogen-bonded chains of (I) parallel to the c axis. The HO interactions are shown as green and white lines (CrystalMaker Software Limited, 2002).

Experimental

Dimethylamine (4.7 ml of a 40 wt% solution in water, 35 mmol) and 1-bromo-2-[chloro(phenyl)methyl]benzene, (II) (Katsura et al., 1997) (500 mg, 1.78 mmol), in dimethyl sulfoxide (3.8 ml) were heated at reflux for 24 h. The product was purified by column chromatography and recrystallisation from dichloromethane/light petroleum to give [(2-bromophenyl)(phenyl)methyl]-N,N-dimethylamine, (III), as a white crystalline solid (234 mg, 45%, m.p. 333 K). Butyllithium (0.86 ml of 1.6 M hexane solution, 1.38 mmol) was added dropwise to a solution of (III) (200 mg, 0.69 mmol) in anhydrous tetrahydrofuran (4 ml) at 195 K and stirred for 2 h. The reaction mixture was warmed to room temperature whilst dry carbon dioxide was bubbled through the solution for a further 2 h. Water (5 ml) and acetic acid (0.13 ml, 2.27 mmol) were added until a pH of 7 was achieved. The product was purified by column chromatography (2:25 methanol-dichloromethane) to yield (I) as colourless crystals (136 mg, 77%). Crystals suitable for single-crystal X-ray diffraction analysis were obtained by slow evaporation of a solution in propan-2-ol.

Crystal data

C16H17NO2 Mr = 255.32 Monoclinic, C 2/c a = 24.5562 (10) Å b = 9.2464 (4) Å c = 11.9764 (5) Å = 91.559 (2)° V = 2718.3 (2) Å3 Z = 8 Dx = 1.248 Mg m-3 Mo K radiation Cell parameters from 3144 reflections = 5-27° = 0.08 mm-1 T = 150 K Block, colourless 0.32 × 0.18 × 0.14 mm

Data collection

Nonius KappaCCD diffractometer scans Absorption correction: multi-scanSCALEPACK (Otwinowski & Minor, 1997)Tmin = 0.97, Tmax = 0.99 13569 measured reflections 3079 independent reflections 1487 reflections with I > 3(I) Rint = 0.075 max = 27.5° h = -31 31 k = -11 12 l = -15 15

Refinement

Refinement on F R[F2 > 2(F2)] = 0.051 wR(F2) = 0.058 S = 1.14 1487 reflections 176 parameters H atoms treated by a mixture of independent and constrained refinement Weighting scheme: see below (/)max = 0.010 max = 0.25 e Å-3 min = -0.22 e Å-3

Table 1 Selected geometric parameters (Å, °) N1-C1 1.515 (3) N1-C9 1.485 (4) N1-C10 1.487 (3) N1-H1 1.04 (3) C1-C2 1.523 (4) C1-C11 1.516 (4) C2-C7 1.404 (4) C7-C8 1.531 (3) C8-O1 1.270 (3) C8-O2 1.232 (3) C1-N1-C9 110.3 (2) C1-N1-C10 111.8 (2) C9-N1-C10 109.0 (2) C1-N1-H1 112.9 (18) C9-N1-H1 106.7 (19) C10-N1-H1 106.0 (18) N1-C1-C2 110.8 (2) N1-C1-C11 111.7 (2) C2-C1-C11 112.6 (2) C1-C2-C7 123.4 (2) C2-C7-C8 126.6 (2) C7-C8-O1 118.7 (2) C7-C8-O2 117.6 (2) O1-C8-O2 123.7 (2)

Table 2 Hydrogen-bond geometry (Å, °) D-HA D-H HA DA D-HA N1-H1O1i 1.04 (3) 1.64 (3) 2.670 (3) 176 (3) C1-H11O1 1.00 2.02 2.848 (3) 139 Symmetry codes: (i) .

A Chebychev polynomial (Carruthers & Watkin, 1979; Prince, 1982) was used in the weighting scheme, [weight] = 1.0/[A₀T₀(x) + A₁T₁(x) + + A_n-1T_n-1(x)], where A_i are the Chebychev coefficients 0.491, 0.269 and 0.192, and x = F/F_max; robust weighting (Prince, 1982) W = [weight] [1 - (F/6F)²]². The N-bound H atom was located in a difference Fourier map and its coordinates and isotropic displacement parameter subsequently refined. Other H atoms were positioned geometrically, with C-H = 1.00 Å and U_iso(H) = 1.2U_eq(C).

Data collection: COLLECT (Nonius, 2000); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Issue 12; Betteridge et al., 2003); molecular graphics: CrystalMaker (CrystalMaker Software Limited, 2002); software used to prepare material for publication: CRYSTALS.