Abstract. C30H36010 , Mr=556.6, monoclinic, C2,, b=15.479(3), c=14.187(3)]k, fl = 106.36 (2) °, V= 2793/~3, Z = 4, D x = 1.32 g cm -3, 2(Cu Ka) = 1.54178/~, 12 = 7.9 cm -~, F(000) = 1184, room temperature, R = 0.064 for 1880 unique observed reflections. In this chiral bisanisylene macrocycle DO-(3), the dianhydromannitolo units adopt a 'backto-back' geometry with respect to each other. This is in 0108-2701/86/070905-04501. 50 © 1986 International Union of Crystallography 906 C3oH3601o striking contrast to the 'face-to-back' geometry displayed by 1,4:1',4' :3,6:3',6'-tetraanhydro-2,2' :5,5'-bis-(O-oxydiethylene)di-D-mannitol [DD-(1)] and 1,4:-1 ',4': 3,6:3', 6'-tetraanhydro-5,5'-O-oxydiethylene-2,2'-O-[pyridine-2,6-diylbis (methylene)]di-o-mannitol ]. The molecule DD-(3) has approximate noncrystallographic C2 symmetry about an axis passing through the centre of, and normal to, the mean plane of the macrocyclic ring. In the solid state, the molecule has diastereotopic faces with the two aryl methoxy groups both oriented away from the more open of the two ring faces.Introduction. In order to confer greater rigidity upon receptor molecules such as DD-(1) (Metcalfe, Stoddart, Jones, Crawshaw, Quick & Williams, 1981;Metcalfe, Stoddart, Jones, Crawshaw, Gavuzzo & Williams, 1981) and DD-(2) (Crawshaw, Stoddart & Williams, 1986) containing 1,4:3,6-dianhydro-D-mannitol, it was decided to appeal to 2-substituted-l,3-xylylene units as constitutional building blocks and rigid spacer groups.Since the first report (Vfgtle & Weber, 1974) of the use of these units in the synthesis of macrocyclic hosts, they have found wide application (McKervey & Mulholland, 1977;Newcomb, Moore & Cram, 1977; van der Leij, Oosternik, Hall & Reinhoudt, 1981;McKervey & O'Connor, 1982). In this paper, we report on the results of an X-ray crystallographic investigation of the macrocyclic compound DD-(3) incorporating two dianhydromannitolo rings and two m-anisylene units.Experimental. Single crystals of DD-(3) (found: C 64.8, H 6.5%; C30H36010 requires C 64.7, H 6-5%), suitable for X-ray crystallography, were grown (Crawshaw, 1982) (7) 9583 (4) 8219 (4) 7835 (4) 71 (2) 0(8) 9547 (5) 7398 (5) 8250 (5) 155 (3) C (9) 10555 (8) 7150 (6) 8765 (9) 183 (5) C (10) 11154 (6) 7949 (5) 9107 (6) 98 (3) O (11) 12239 (4) 7794 (3) 9395 (4) 122 (2) C (12) 12843 (7) 8420 (5) 10048 (6) 116 (3) C (13) 13100 (5) 9161 (4) 9521 (5) 81 (2) C (14) 12609 (4) 9957 (3) 9370 (4) 60 (2) C (15) 12836 (5) 10615 (4) 8852 (4) 72 (2) C (16) 12259 (6) 11463 (4) 8644 (5) 83 (2) O (17) 11673 (4) 11607 (3) 7694 (3) 97 (2) C (18) 10838 (4) 11019 (4) 7323 (4) 70 (2) C (19) 10329 (5) 11172 (8) 6252 (5) 107 (3) 0(20) 9314 (3) 10828 (5) 6054 (3) 118 (3) C (21) 8995 (5) 10804 (4) 6907 (5) 69 (2) C (22) 9909 (4) 11082 (4) 7726 (4) 67 (2) 0(23) 9711 (4) 11939 (4) 7979 (4) 119 (2) C (24) 8796 (7) 12250 (5) 7279 (6) 121 (3) C (25) 8139 (5) 11434 (4) 6922 (4) 68 (2) 0(26) 7390 (3) 11617 6012 (3) 74 (1) C (27) 6543 (5) 11021 (4) 5697 (5) 74 (2) C (28) 6845 (4) 10182 (4) 5294 (4) 59 (2) C (...