J. CHEM. SOC. PERKIN TRANS. II 1988 Nuclear Magnetic Resonance and X-Ray Diffraction Studies on Some Substituted Benzenesulphonamides Anna-Maija Hakkinen Department of Medical Physics, University of Helsinki, 00 170 Helsinki, Finland Pirko Ruostesuo * Department of Chemistry, University of Oulu, 90570Oulu, Finland Raikko Kivekas Department of Inorganic Chemistry, University of Helsinki, 00100 Helsinki, Finland Solid-state 13C c.p.-m.a.s. and solution 13C, 15N, and ''0 n.m.r. spectra were measured for toluene-p- suIp hona mide, N-met hyltol uene-p -su Ip hona mide, NN-dimet hyltol uene-p-su Ip honamide, p-c h loro- benzenesulphonamide, and NN-dimethyl-p-chlorobenzenesulphonamide. The 13C c.p.-m.a.s. n.m.r. resonance lines of the carbon atoms bonded to nitrogen show characteristic line broadening with slightly asymmetric doublet patterns.Some differences are evident in the 13C shielding of the carbon atoms between the solid-state and solution-state spectra. In the solution spectra the 15N and 170chemical shifts increase in conformity with the polarity order of the amides. The n.m.r. relaxation times of the methyl groups of the compounds were measured as well. The crystal structures of N-methyltoluene-p- su1 p h onamid e an d NN-dimet h y ItoIu e n e-p -s uIp h onamid e we re det e r m in ed by sin g Ie-c r yst aI X-ray diffraction technique and refined to final R values of 0.056 and 0.044, respectively. Except for some barely significant differences, the bond lengths and angles are similar in the two compounds.The most striking difference is the value of the C-C-S-N torsion angle. As well as being medically important, benzenesulphonamide derivatives are also spectroscopically interesting. The discovery of an asymmetric doublet as the characteristic feature of the 13C c.p.-m.a.s. n.m.r. spectra of organic solids containing a carbon atom bonded to nitrogen'-13 encouraged us to investigate this property in toluene-p-sulphonamides. The observed lineshape is due to the perturbation of the 13C- 14N dipolar interaction by the 14N quadrupole interaction, since the I3C--l4N dipolar energy is not necessarily averaged in one cyclic spinning. An orientation dependence may there- fore yield a characteristic lineshape. The polar properties of molecules are strongly determined by the molecular asymmetry, and the polarity of sulphonamides is relatively high.l4 The high dielectric permittivities of sulphonamides are mainly attributable to the permanent dipoles of the S=O bonds." N-Methyl substituents slightly increase and NN-dimethyl substituents increase somewhat more, the values of dipole moments in sulphonamides.'6,' ' In this work we applied high-resolution solid-state 3C c.p.-m.a.s. n.m.r. spectroscopy and solution multinuclear n.m.r. spectroscopy to the study of some N-unsubstituted, N-methyl- substituted, and NN-dimethyl-substituted sulphonamides. Solution spectroscopy was earlier used as a probe for investigating similar compounds.' *-* In addition, crystal- lographic studies were made on N-methyl- and NN-dimethyl- toluene-p-sulphonamides to get more accurate information about the molecular configurations and to obtain data useful for the interpretation of n.m.r.results. Experimental Sulphonamides were prepared from the corresponding sulphonyl chloride and ammonia or amine in dry ether at 263 K.22 Crude products were crystallized several times from ethanol or ethanol-water and for the X-ray crystallographic study from heptane by slow evaporation of the solvent. N.m.r. Spectroscopic Measurements.-For liquid-state n.m.r., samples were prepared in C2H,]acetone (Uvasol reagent; Merck AG), in molar ratio amide: [2H,]acetone 1 :2. Measurements were made on a JEOL JNM FX-100 n.m.r. spectrometer with proton noise decoupling.An external 'Li lock was used to stabilize the field frequency ratio. Typical spectral parameters were: operating frequency 13.46,10.04, and 25.05 MHz; spectral width 10, 6, and 6 kHz; pulse width 30, 10, and 7 p;and pulse repetition 0.05, 15, and 3 s for 170, 15N,and 13C, respectively. The chemical shifts of ''0 nuclei were measured relative to the external water, those of 5N nuclei relative to nitromethane doped with Cr(acac),, and those of 13C relative to internal tetramethylsilane. The c.p.-m.a.s. 3C n.m.r. spectra were measured with a JEOL FX-200 Fourier transform n.m.r. spectrometer operating at 50.10 MHz with proton noise decoupling. The spectral width was 10 kHz, the pulse width 7 ps, and repetition time 6 s.Single contact spin locked cross polarization was established under Hartman-Hahn conditions with contact time 2 ms. The spinning frequency estimated by the position of spinning side bands was 33 kHz. The 13C n.m.r. signal of solid hexamethylbenzene was used as an external reference to determine the 3C chemical shift values, which are shown converted to the scale of tetramethylsilane in Table 8. The 13C relaxation times were measured by inversion recovery method with proton noise decoupling. X- Ray Crystallographic Measurements.-Data pertaining to the crystallographic analysis of N-methyltoluene-p-sulphon-amide and NN-dimethyltoluene-p-sulphonamideare collected in Table 1. Cell parameters were determined by least-squares methods on the basis of 25 diffractometer-measured independent reflections for each compound.No significant intensity vari- ations were observed for the standard reflections during the data collections. Both sets of data were corrected for Lorentz and polarization effects. yr-Scans for several intense reflec- tions of the compounds verified the absence of noteworthy variable absorption. The phase problems were solved by direct methods,23 by calculating the molecular scattering factors in the normalization procedure from the expected geometry of the molecules. After anisotropic refinements with X-RAY 76 system 816 J. CHEM. SOC. PERKIN TRANS. 11 1988 programs 24 the hydrogen atoms were positioned geometrically Table 1. Crystal data and details of data collection at 1.0 A from the atoms to which they were bonded.The hydrogen atom parameters of N-methyltoluene-p-sulphon-N-Methyltoluene-p-NN-Dimethyltoluene-amide were not refined, but those of NN-dimethyltoluene- sulphonamide p-sulphonamide p-sulphonamide were. The functions minimized were Xw(AF>*, where w = l/~$~.Atomic scattering factors were those included Mol. formula C*HlIN03 C9H 1 ,NO3 in the programs. Mol. weight 185.25 199.27 Crystal system Monoclinic Monoclinic4 14.3 50( 2) 9.509( 1) biA 7.020(2) 11.247(2) Results and Discussion CIA 19.507(4) 10.066(2) Crystallographic Studies.-Positional parameters for N-PI" 11 1.12( 1) 106.42( 1) methyltoluene-p-sulphonamide and NN-dimethyltoluene-p-Space group p21 p21In sulphonamide are collected in Tables 2 and 3.Table 4presentsvp 1833.1(7) 1032.6(3) the bond lengths and angles of the four independent molecules D,/g ~m-~ 1.34 1.28 of N-methyltoluene-p-sulphonamideincluding mean values of Z 8 4 Crystal dimensions 0.32 x 0.20 x 0.45 0.18 x 0.28 x 0.40 (mm)Diffrac tome ter Nicolet P3 Nicolet P3 Table 3. Positional parameters for the non-hydrogen atoms of NN-Radiation Mo-K, Mo-K, dimethyl toluene-p-sulphonamide (h = 0.710 69 A) (A = 0.710 69 A) Absorption coefficient 3.0 2.8 X Y z (cm-') 0.288 5(1) 0.324 4(1) 0.442 4( 1) Scan type 0 0 0.238 5(3) 0.207 7(2) 0.397 3(2) 20 Limits 5" < 20 < 53" 5" < 20 < 55" 0.433 2(2) 0.360 5(2) 0.443 7(2) Scan rate ("/min-') 2-20 2-20 0.176 6(2) 0.416 7(2) 0.343 3(2) Number of collected 4 247 2 376 0.272 l(3) 0.342 O(2) 0.611 3(2) reflections 0.172 6(3) 0.274 5(2) 0.654 2(3) Number of observed 2 477 1556 0.158 8(3) 0.288 O(3) 0.785 8(3) reflections 0.243 6(3) 0.368 8(2) 0.877 2(3) Criterion for observed IF,I > 6olF,I 0.342 O(3) 0.436 3(2) 0.830 5(3) reflections 0.357 8(3) 0.423 9(2) 0.699 6(3) Number of parameters 433 171 0.228 7(4) 0.384 9(3) 1.021 O(3) R 0.056 0.044 0.019 5(4) 0.389 3(3) 0.307 2(4) Rw 0.043 0.042 0.210 9(3) 0.543 l(3) 0.364 5(3) Table 2.Positional parameters for N-methyltoluene-p-sulphonamide.The y-co-ordinate of the sulphur atom of molecule 1 was fixed for fixing of the Molecule 1 Molecule 2 1 r-A v~ ~ ZX Y Z X Y 0.120 7(1) 0.1733 0.673 4( 1) 0.451 l(1) 0.277 l(4) -0.169 l(1) 0.192 9(3) 0.254 5(8) 0.646 5(2) 0.546 8(3) 0.369 4(2) -0.140 2(2) 0.140 2(4) -0.008 9(8) 0.709 8(3) 0.441 7(3) 0.096 l(8) -0.204 8(3) 0.106 3(4) 0.321 2(10) 0.732 2(3) 0.375 9(3) 0.418 O(8) -0.230 O( 3) 0.006 O(4) 0.158 5(11) 0.598 4(3) 0.405 4(4) 0.257 3(10) -0.096 3(3) -0.005 6(5) 0.247 8(12) 0.532 7(4) 0.456 2(4) 0.348 4(10) -0.029 9(3) -0.098 l(5) 0.241 8(11) 0.476 O(3) 0.418 4(5) 0.338 6(10) 0.025 9(3) -0.178 3(5) 0.153 2(12) 0.484 8(4) 0.330 9(5) 0.239 O( 10) 0.016 4(4) -0.165 4(4) 0.071 8(12) 0.551 3(4) 0.282 O(4) 0.147 7(11) -0.049 5(4) -0.074 O( 5) 0.070 2(12) 0.607 9(4) 0.319 5(4) 0.158 3(11) -0.106 O(3) -0.280 O(4) 0.154 2(13) 0.423 O(4) 0.288 3(5) 0.228 4(10) 0.076 2(4) 0.076 2(5) 0.515 3(13) 0.708 6(4) 0.363 5(5) 0.612 3(12) -0.208 3(4) Molecule 3 Molecule 4 A I 1 I v ZX Y z X Y 0.597 5(1) 0.055 2(3) 0.671 9(1) 0.064 O( 1) 0.637 6(4) 0.175 6(1) 0.677 O(3) -0.021 4(8) 0.651 O(2) -0.039 7(3) 0.582 2( 11) 0.150 4(3) 0.607 9(3) 0.241 l(8) 0.705 5(3) 0.092 4(5) 0.813 6(10) 0.214 7(3) 0.579 6(4) -0.092 5(9) 0.730 6(3) 0.127 4(4) 0.471 9( 11) 0.229 3(3) 0.489 O(4) 0.055 7( 11) 0.591 2(3) 0.099 9(4) 0.641 2(12) 0.097 9(3) 0.490 2(5) -0.029 7(11) 0.529 2(4) 0.040 O(4) 0.563 9(13) 0.032 4(4) 0.403 l(5) -0.028 l(11) 0.466 2(4) 0.071 O(5) 0.565 6( 13) -0.026 l(4) 0.316 O(5) 0.051 l(11) 0.468 l(4) 0.160 8(5) 0.641 8( 11) -0.022 l(4) 0.316 5(4) 0.134 3(11) 0.533 O(4) 0.220 3(4) 0.719 O(l1) 0.044 9(4) 0.403 8(5) 0.136 l(11) 0.595 9(3) 0.191 8(4) 0.715 8(11) 0.105 O(3) 0.220 7(5) 0.053 9(12) 0.400 6(4) 0.192 5(5) 0.641 l(12) -0.088 2(4) 0.566 6(5) -0.294 5( 12) 0.711 2(4) 0.1 17 2(5) 0.281 l(14) 0.202 5(4) J. CHEM.SOC. PERKJN TRANS. 11 1988 Table 4. Selected bond lengths (A)and angles (") for the four independent molecules of N-methyltoluene-p-sulphonamide and for NN-dimethyltoluene-p-sulphonamide N-Meth yltoluene-p-sulphonamide A -, NN-Dimethyltoluener 2 3 4 Mean value p-sulphonamideMolecule I s-O( 1) 1.437(5) 1.437(5) 1.446(5) 1.442(5) 1.44 l(4) 1.426(3) s-O(2) 1.441(6) 1.432(6) 1.444(6) 1.432(7) 1.437(6) 1.431(2) S-N 1.615(7) 1.622(5) 1.632(7) 1.6 1 O( 7) 1.620(9) 1.6 14( 2) s-C( 1) 1.768(5) 1.77 1 (7) 1.77 1 (5) 1.768(7) 1.770( 2) 1.762(2) N-C( 8) 1.453(11) 1.458(10) 1.462( 12) 1.426( 12) 1.450( 16) 1.467(4) N-C(9) 1.461(4) C(4)-C(7) 1.522(8) 1 SO1 (12) 1.519(9) 1.5 14( 12) 1.514(9) 1.505( 5) O(1)-S-O(2) 119.6(3) 120.1(3) 120.0( 3) 1 18.4(4) 119.5(8) 119.8(2) O(1)-S-N 1 07.3( 3) 107.6( 3) 107.5( 3) 107.4(4) 107.5( 1) 107.0(1) O(2)-S-N 105.8(4) 105.3(3) 105.8(3) 106.9(3) 106.0(7) 106.7(1) O(1)-s-C( 1) 10733) 107.4(3) 106.3(3) 107.2( 3) 107.1(5) 107.3( 1) 0(2)-S-C( 1) 108.3( 3) 108.9(4) 108.4( 3) 109.2(4) 108.7(4) 107.8( 1) N-S-C( 1) 107.8(3) 107.1(3) 108.3(3) 107.3( 4) 107.6(5) 107.5(1) S-N-C( 8) 118.5(5) 118.5(5) 118.2(5) 118.7(4) 1 1832) 117.7(2) S-N-C(9) 117.0(2) C(8)-N-C(9) 114.2(2) s-C( 1)-C(2) 120.4(5) 119.3(5) 120.2(5) 121.O( 5) 120.2(7) 119.9(2) S-C( 1)-C(6) 119.3(5) 120.3(4) 117.3(5) 1 18.9(4) 119.0(12) 120.1(2) Table 5.The distances (A) of the atoms from the best least-squares planes determined by the aromatic carbon atoms N-Meth yltoluene-p-sulphonamide A I , NN-Dimethyltoluene-Molecule I 2 3 4 p-sulphonamide S 0.100( 10) 0.063(9) -0.027(10) -0.021(11) 0.004(4) O(1) -0.054( 13) -0.099( 12) 0.109(12) 0.229( 15) -0.583(4) O(2) -0.784(13) -0.8 15( 1 2) 0.908( 13) 0.836( 14) -0.549(5) N 1.59 1 (14) 1.553(12) -1.501(14) -1.519(15) 1.545(5) C(7) 0.021(1 3) 0.020( 1 1) 0.021(12) -O.O03( 13) 0.005(5) C(8) 2.719( 14) 2.671(13) -2.662( 14) -2.599( 15) 2.324(6) (39) 2.302(5) n Figure 1. Molecular drawings of N-methyltoluene-p-sulphonamideand NN-dimethyltoluene-p-sulphonamide the four sets of bonds, and the bond lengths and angles of NN-dimethyltoluene-p-sulphonamide.All bond parameters of N-methyltoluene-p-sulphonamidediscussed below are mean values.Figure 1 shows the numbering systems of the compounds and Figure 2 the diagrams of N-methyltoluene-p- sulphonamide (molecule 1) and NN-dimethyltoluene-p-sul-phonamide in the direction of the S-C(l) bond. Figure 2. Diagram of molecule (1) of N-methyltoluene-p-sulphonamide and diagram of NN-dimethyltoluene-p-sulphonamideviewed in the direction of the S-C(l) bond Molecules 1 and 4 of N-methyltoluene-p-sulphonamideare approximately mirror images of molecules 2 and 3. Although almost all the individual bond lengths and angles of the four molecules are essentially the same, some significant differences in the deviations of the atoms from the planes determined by the benzene rings (Table 5) and in the torsion angle values (Table 6) indicate minor differences in the configurations of the four molecules.The asymmetric unit of NN-dimethyltoluene-p-sulphonamide consists of a single molecule with approximately 6 symmetry. The pseudo-mirror plane bisects the molecule through the atoms S, N, C( l), C(4), and C(7). 818 J. CHEM. SOC. PERKIN TRANS. II 1988 Table 6. Selected torsion angles (") for N-methyltoluene-p-sulphonamideand NN-dimethyltoluene-p-sulphonamide N-Methyltoluene-p-sulphonamide AI NN-Dimethyltoluene-Molecule 1 2 3 4 p-sulphonamide O(1)-S-C( 1 )-C(2) -10.7(7) 8.2(6) O(1)-S-C( 1)-C(6) 174.5(6) -173.7(6)0(2)-S-C( 1)-C(2) -141.2(7) 139.6(5) O(2)-S-C( 1 )-C( 6) 43.9(7) -42.4(6)O(1)-S-N-C(8) 56.8(5) -55.0(6)O(l)-S-N-C(9) O(2)-S-N-C( 8) -174.3(5) 175.9(5) O(2)-S-N-C(9) C( 1 )-S-N-C( 8) -58.7(6) 60.1(6)C( 1 )-S-N-C(9) In both N-methyl toluene-p-sulphonamide and NN-dimethyl- toluene-p-sulphonamide the oxygen atoms are on the same side of the plane determined by the benzene rings.The benzene rings are essentially co-planar, the greatest deviation of an individual aromatic carbon atom from the plane being only 0.016(8) A. The individual aromatic C-C bond lengths range between 1.356( 1 1) and 1.402(9) 8, in N-methyltoluene-p-sulphonamide and 1.374(4) and 1.386(4) 8, in NN-dimethyltoluene-p-sul-phonamide, and the bond angles between 116.9(8) and 122.6(7)' in N-methyltoluene-p-sulphonamide,and 1 17.3(3) and 122.5(2)' in NN-dimethyltoluene-p-sulphonamide.These values could be assumed normal.Comparison of the bond lengths and angles of N-methyltoluene-p-sulphonamideand NN-dimethyltoluene-p- sulphonamide reveals the expected close similarity. The most striking difference lies in the configurations of the molecules, as is evident from the C-C-S-N and C-C-S-0 torsion angle values and the views presented in Figure 2. Slight differences in other features are observed as well. The bond lengths and angles of the sulphonamide groups are typical for compounds containing the Sv' atom. The sulphonyl sulphur atoms have distorted octahedral co-ordination, as the 0-S-0 angles are opened to 119.5(8)' in N-methyltoluene-p- sulphonamide and 1 19.8(2)' in NN-dimethyltoluene-p-sulphon-amide, and the other angles around the sulphur atoms, 106.0(7)-108.7(4)0 for N-methyltoluene-p-sulphonamideand 106.7(1)-107.8(1)' for NN-dimethyltoluene-p-sulphonamide, are slightly smaller than the ideal tetrahedral angle (109.5").The averaged S-0 bond length, 1.43 A, of the compounds corresponds to a double-bond order of ca. 0.67 as presented by Cr~ickshank,~~and the S-N bond lengths of 1.620(9) 8, for N-methyltoluene-p-sulphonamideand1.614(2)iifor NN-dimethyl- toluene-p-sulphonamide are comparable with the value of 1.61 8, obtained for sulphamide (double-bond order 0.25). Also, the S-C(l) bond lengths of 1.770(2) 8, for N-methyltoluene-p- sulphonamide and 1.762(3) 8, for NN-dimethyltoluene-p-sulphonamide are typical for sulphonamides.26 Steric reasons may be responsible for the slight differences in S-N-C angles [118.5(2)O in N-methyltoluene-p-sulphonamide and 1 17.7(2)O and 117.0(2)O in NN-dimethyltoluene-p-sulphon-amide]; for N-methyltoluene-p-sulphonamidecontains one and NN-dimethyltoluene-p-sulphonamide two methyl groups bonded to the nitrogen atom.The crystallographic data further reveal relatively short intermolecular N 0 distances in N-methyltoluene-p-sul- phonamide: N(molecu1e 1) 0(1) (molecule 4) 3.248(10) A, N(molecu1e 2) O(1) (molecule 1) 3.075(6) A, N(molecu1e 3) O(2) (molecule 2) 3.010(8) A, N(mo1ecule 4) 0(1) (molecule 3) 2.934(6) 8,. At least the shortest of these contacts indicate hydrogen bonds.Earlier i.r. spectroscopic studies in solution revealed hydrogen bond formation ability for this kind of compound.27 8.1(7) -12.0(8) -24.4(3) -175.4(6) 170.9(6) 156.2(3) 138.4(7) -141.3(7) -154.8(2) -45.1 (7) 41.6( 7) 25.8(2) -50.4(5) 55.1 (7) 41.6( 3) -176.4(2) -179.9(5) -176.9(6) 17 1.0(2) -46.9(2) 64.1(6) -59.8(7) -73.5(2) 68.6(2) Table 7. "0 And "N n.m.r. chemical shifts [G(p.p.m.)] in acetone and dipole moments in 1,4-dioxane for some sulphonamides Compound 6("O) 6(''N) p/Db Toluene-p-sulphonamide 158.7 -287.6 5.39 N-Met h y1t oluene-p-sulphonamide 149.8 -295.5" 5.51 NN-Dimethyltoluene-p-sulphonamide 139.0 -298.7 5.60 p-Chlorobenzenesulphonamide 160.8 -287.8 4.33 NN-Dimethyl-p-chlorobenzene--298.6 4.38 sulphonamide 'JNH 84.5 Hz.Ref. 4. N.m.r. Spectroscopic Studies.-The '5N and 7O chemical shifts of the solution spectra of the five sulphonamides are given in Table 7, and the 13C n.m.r. chemical shifts of the solution spectra and the I3C c.p.-m.a.s. chemical shifts of the solid-state spectra in Table 8. The '5N and I7Ochemical shifts of sulphur amides have earlier been found to be sensitive to the electronic environment around the sulphur atom, in particular to the oxidation state of the sulphur The changes due to N-methyl substitution (Table 7) are smaller but still notable. Comparison of the chemical shifts shows the shielding order of the nitrogen-15 nucleus in the toluene-p-sulphonamides to be as follows: NH, < NHCH, < N(CH,),.This order is in conformity with the polarity order of the amides, as the dipole moments in 1,4-dioxane are 5.39 D for toluene-p-sulphonamide, 5.5 1 D for N-methyltoluene-p-sulphonamide,and 5.60 D for NN-dimethyltoluene-p-sulphonamide.lThe shielding of the nitrogen nucleus in the p-chlorobenzenesulphonamides is similar to that in the toluene-p-sulphonamides (Table 7), viz. larger in the dimethyl-substituted compounds. The variation in the shielding of the oxygen-17 nuclei is clear and in the same direction as the shielding of the nitrogen-15 nuclei. The trends in the 15N and 170 n.m.r. chemical shifts become evident if one looks at the resonance possibilities for the sulphur amides (Scheme). l6 These resonance possibilities are also in 0 0 Scheme.conformity with the polarity measurements and with the slight shortening of the bond lengths around the sulphur atom in NN-dimethyltoluene-p-sulphonamiderelative to N-methyltoluene- p-sulphonamide, found in the crystallographic study (Table 4). A methyl substituent increases the electron density of the N J. CHEM. SOC. PERKIN TRANS. I1 1988 Table 8. 13C N.m.r. chemical shifts [S (p.p.m.)] in acetone and in solid state for some sulphonamides Compound Solvent c-1 C-2,6 c-3,5 c-4 N-CH3 C-CH, Toluene-p-sulphonamide Acetone Solid 143.1 145.5 126.7 126.5 129.9 130.3 141.8 138.3 21.3 21.1 N-Methyl toluene-p-sulphonamide Acetone Solid 137.1 133.7 127.5 128.2 130.0 128.2 143.4 143.8 29.3 3 1.3; 21.2 22.0 30.2 NN-Dimethyltoluene-p-sulphonamide Acetone Solid 133.4 140.5 128.4 125.8 130.2 128.6 144.0 143.1 38.0 33.8; 21.3 16.9 30.8 p-Chlorobenzenesulphonamide Acetone Solid 143.2 147 128.7 129 129.7 130 138.3 140 NN-Dimethyl-p-chlorobenzenesulphonamide Acetone Solid 133.7 130.7 129.2 127.3 129.7 127.3 138.1 141.2 37.4 34.0 atom and favours double-bond character in the S-N bond.Further, the change in electron density around the nitrogen atom may be reflected in the S-0 and S-C(l) bond lengths, since the S atom can utilize its vacant d-orbitals. Given the only slight differences between the bond lengths of N-methyltoluene- p-sulphonamide and NN-dimeth yltoluene-p-sulphonamide,and the fairly large standard deviations in the bond lengths of N-methyltoluene-p-sulphonamide, conclusions can only be tentative. The chemical shifts of the I3C nuclei are characteristic for the type of sulphonamide and different for the N-methyl- and NN-dimethyl-substituted compounds (Table 8).'8-2 ' Some differences are seen in the I3C chemical shifts of the c.p.-m.a.s. spectra and the corresponding solution spectra. In the solution spectra, the signals of the N-methyl carbon atoms of N-methyltoluene-p-sulphonamide and NN-dimethyltoluene-p-sulphonamide have chemical shifts of 6 29.3 and 38.0 p.p.m., respectively. In the solid state, the corresponding signals have chemical shifts of 6 30.9 (31.3; 30.2) and 32.8 (33.8; 30.8) p.p.m. The chemical shift of the N-methyl carbon of NN-dimethyl-p- chlorobenzenesulphonamide is 6 34.0 p.p.m.The differences in the chemical shifts in the solid-state and solution spectra are somewhat greater than the differences due to solvent effects. -11111111 Packing effects are assumed to be weak, since in addition to -400 0 400 -400 0 400 the hydrogen bond distances mentioned above, there are no Frequency (Ht)short intermolecular contacts: the shortest non-bonding distances are 3.32 8, in N-methyltoluene-p-sulphonamideand Figure 3. I3C C.p.-m.a.s. n.m.r. spectra of the methyl carbons of N-3.36 A in NN-dimethyltoluene-p-sulphonamide.The bond methyltoluene-p-sulphonamide(A) and NN-dimethyltoluene-p-sulph-lengths and angles are nearly the same in the four independent onamide (B) molecules of N-methyltoluene-p-sulphonamideand their effect on the I3C n.m.r.spectra in solid state is thus clearly negligible. Figure 3 shows the 13C c.p.-m.a.s. n.m.r. spectra of N-in the studied sulphonamides are similar in magnitude to the methyltoluene-p-sulphonamide and NN-dimethyltoluene-p-splittings observed earlier for the carbonyl carbon in the amide sulphonamide. The solid-state 3Cresonance lines of the carbon group and for carbons bonded to amino groups in amino acids; atoms bonded to nitrogen show a characteristic line broadening and correspondingly they are much smaller than the splittings compared with those of the carbon atoms of the para-methyl of cyano carbons at the same magnetic field strength.'-'' The groups of the aromatic rings.The resonances for the N-methyl splitting of the carbonyl and cyano carbons in cyanoacetamide the splitting of the carbons carbon atoms exhibit asymmetric doublet patterns with the are 92 and 305 Hz, re~pectively,~ peak of the higher frequency stronger in intensity. The observed bonded to the amino group in alanine, serine, and glycine is 45,' splitting is ca. 60 Hz for N-methyltoluene-p-sulphonamideand 45,7 and 61 Hz (I3Cresonance frequency 37.84 MHz)," and the 150 Hz for NN-dimethyltoluene-p-sulphonamide.The signal for splittings of the carbons bonded to the nitro and amino groups the N-methyl carbons of NN-dimethyl-p-chlorobenzene-in 2,6-dimethyl-3-nitroaniline are 56 and 102 Hz.* The 14N sulphonamide is broad (ca. 50 Hz) and the doublet pattern is quadrupole coupling constants in these amino acids 28,29 and poorly resolved.nitro compounds 30 are small and the N-C internuclear vector The effect of the I4N interaction on the resonance line is expected to lie close to the symmetry axis of the 14N electric splitting of the neighbouring carbon depends on the sign, field tensor. In cyano compounds3' the relatively large 14N-magnitude, and asymmetry parameter of the 14N quadrupole I3C interaction is explained by the larger I4N quadrupolar coupling tensor and on the orientation of the I4N electric field coupling constant and shorter N-C distance. The axial gradient with respect to the N-C internuclear vector and the symmetry of the I4N electric field gradient is a fairly good magnitude of this vector.approximation in the cyano compounds. The sign of the The splittings of the resonances of the amide methyl carbons quadrupole coupling constant is positive for the amino carbons J. CHEM. SOC. PERKIN TRANS. II 1988 Table 9. Spin lattice relaxation times (TI)of methyl carbons for some sulphonamides in 1:2 molar ratio amide-chloroform solutions and in solid state T,/sSolvent or r-*-, Compound solid N-CH, CH,C,H, N-Methyltoluene-p-sulphonamide NN-Dimet h yltoluene-p-sulphonamide Chloroform Solid Solid 2.6 8.3 4.5 2.6 8.5 8.6 NN-Dimethyl-p-chloro-benzenesulphonamide Chloroform Solid 3.0 3.8 of the amino acids and negative for the cyano carbons and the carbons bonded to the nitro group mentioned above. In NN-dimethyltoluene-p-sulphonamidethe N-methyl car- bons do not lie on the principal axis of the 14N electric field tensor, which is assumed to be approximately in the direction of the C(1)-S-N axis; instead, the N-C vector makes an angle of 62-63’ with respect to the C(1)-S-N axis.Because of the approximate axial symmetry in NN-dimethyltoluene-p-sul-phonamide the asymmetry parameter of the 14N electric field gradient is expected to be negligible. In N-methyltoluene-p- sulphonamide, on the other hand, a non-zero asymmetry parameter, together with the different molecular configuration and the formation of hydrogen bonds, could affect the splitting of the amide methyl carbon signal, making it smaller than the splitting in NN-methyltoluene-p-sulphonamide. The relaxation data (Table 9) reveal a similar molecular motion in the sulphonamides in solution.The relaxation times of the aromatic carbons directly bonded to hydrogen atoms, ca. 0.9 and 1.2 s for N-methyltoluene-p-sulphonamideand NN-dimethyl-p-chlorobenzenesulphonamide,respectively, indicate a relatively rapid tumbling of the whole molecule in non-viscous solutions. In the solid state the molecular motion is slowed down and lengthening of the relaxation times is observed. In N-methyltoluene-p-sulphonamidethe relaxation times of the different methyl carbons are similar within the limits of the experimental error. In the NN-dimethyl-substituted sul-phonamides the relaxation times of the amide methyl carbons are much smaller (relaxation rates about two times faster) than those of the methyl carbons connected to the aromatic rings and the relaxation time of the amide methyl carbon in N-methyltoluene-p-sulphonamide.This may be because in the solid state the nearby protons have the same spin temperature and behave as an assembly. Taken together, the present results support the view that both electronic and steric factors are influencing the n.m.r.parameters of the C, N, and 0nuclei of sulphonamides, whether the spectra are run in solid or in solution state. Among other things the changes of lineshapes of I3C c.p.-m.a.s. spectra open an additional perspective to study electronic distribution around nitrogen nucleus in molecules. Acknowledgements One of us (P. R.) is grateful to the Emil Aaltonen Foundation for financial support.References 1 M. Alla, E. Kundla, and E. 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