Carboracycles: Macrocyclic compounds composed of carborane icosahedra linked by organic bridging groups

A family of macrocyclic compounds are described, together with their precursors. These cycles are composed of icosahedral carboranes linked via their carbon vertices through 1,3-trimethylene, alpha,alpha'-1,3-xylylene, or alpha,alpha'-2,6-lutidylene groups. The compounds cyclo-(1,3-trimethylene-1',2'-closo-1',2'-C2B10H10)(4) (6a), cyclo-(1,3-trimethylene-1',2'-closo-9',12'-dimethyl- 1',2'-C2B10H8)(4) (6b), cyclo-(1,3-trimethylene-1',2'-closo-1',2'-C2B10H10)(3) (9), cyclo-(alpha,alpha'-1,3-xylylene-1',2'-closo-1',2'-C2B10H10)(2) (11a), cyclo-(alpha,alpha'-1,3-xylylene-1',7'-closo-1'7'-C2B10H10)(2) (11b), cyclo-(alpha,alpha'-1,3-xylylene-1',7'-closo-9',10'-dimethyl-1,7-C2B10H8)(2) (11c), cyclo-(alpha,alpha'-1,3-xylylene-1',2'-closo-1',2'-C2B10H10)(4) (12), cyclo-(alpha,alpha'-1,3-xylylene-1',7'-closo-1'7'-C2B10H10)(3) (13), cyclo-(alpha,alpha'-2,6-lutidylene-1',7'-closo-1'7'C2B10H10)(2) (19), and cyclo-(alpha,alpha'-2,6-lutidylene N-oxide-1',7'-closo-1',7'-C2B10H10)(2) (20) have been synthesized. The structures of 6a, 6b, 9, 11a, 11b, 11c, 12, and 19 have been determined by X-ray crystallography. Crystal data: for 6a, triclinic, space group P1, a = 11.131(2)Angstrom, b = 12.642(2)Angstrom, c = 12.996(2)Angstrom, alpha = 84.383(6)degrees, beta = 65.884(6)degrees, gamma = 97.292(5)degrees, Z = 1, R = 0.079; for 6b, monoclinic, space group P2(1)la, a = 13.500(2) Angstrom, b = 31.141(3)Angstrom, c = 13.831(2)Angstrom, beta = 99.90(1)degrees, Z = 2, R = 0.097; for 11a, monoclinic, space group C2/c, a = 14.5682(8)Angstrom, beta = 14.5046(8)Angstrom, c = 16.1998(8)Angstrom, beta = 95.631(2)degrees, Z = 4, R = 0.081; for 11b, monoclinic, space group P2(1)ln, a = 11.650(2)Angstrom, b = 10.606(2)Angstrom, c = 11.730(2)Angstrom, beta = 104.951(6)degrees, Z = 2, R = 0.069; for 11c, orthorhombic, space group Pbca, a = 12.532(2)Angstrom, b = 14.271(2)Angstrom, c = 18.143(3)Angstrom, Z = 4, R = 0.076; for 19, orthorhombic, space group Pcab (No. 61, standard setting Pbca), a = 11.0428(6)Angstrom, b = 11.3785(6)Angstrom, c = 22.533(1)Angstrom, Z = 4, R = 0.074.