The structures of [24-pyrimidinium crown-6] [Au(CN)2]4(NO3)2•2H2O, [24-pyrimidinium crown-6][Au(CN)2]6•5H2O, and [16-pyrimidinium crown-4][Au(CN)2]4•6.5 H2O, in which aurophilic interactions produce trimers, tetramers, and chains of Au(CN)2- ions

The cyclic polypyrimidinium cations [24-pyrimidinium crown-6], [(C6H8N3)(6)](6+), and [16-pyrimidinium crown-4], (C6H8N3)(4)](4+), form colorless salts with the dicyanoaurate(I) anion. [24-Pyrimidinium crown-6][Au(CN)(2)](4)(NO3)(2). 2H(2)O (1) crystallizes in the triclinic space group <P(1)over bar> (No. 2) with unit cell dimensions a = 10.64(1) Angstrom, b = 10.73(1) Angstrom, c = 13.57(1) Angstrom, alpha = 71.72(8)degrees, beta = 82.01(9)degrees, gamma = 83.90(9)degrees, and V = 1455(3) Angstrom(3). [24-Pyrimidinium crown-6][Au(CN)(2)](6). 5H(2)O (2) crystallizes in the triclinic space group <P(1)over bar> (No. 2) with unit cell dimensions a = 11.780(5) Angstrom, b = 12.064(4) Angstrom, c = 13.268(4) Angstrom, alpha = 102.56(1)degrees, beta = 112.14(1)degrees, gamma = 101.82(1)degrees and V = 1617(1) Angstrom(3). [16-Pyrimidinium crown-4][Au(CN)(2)](4). 6.5H(2)O (3) crystallizes in the monoclinic space group C2/c (No. 15) with unit cell dimensions a = 39.50(2) Angstrom, b = 13.160(7) Angstrom, c = 17.83(7) Angstrom, beta = 90.66(3)degrees, and V = 9268(39) Angstrom(3). Structures 1 and 3 contain similar centrosymmetric zigzag tetramers of Au(CN)(2)(-) anions, with a terminal Au-Au distance of 3.271(4) Angstrom and an Au-Au central distance of 3.492(5) Angstrom for structure 1, as compared to 3.155(7) and 3.501(7) Angstrom, respectively, for 3. Structure 2 contains a nearly linear trimer of Au(CN)(2)(-) ions with Au-Au distances of 3.175(1) and 3.234(1) Angstrom. In addition to the Au(CN)(2)(-) tetramer, structure 3 also contains an infinite chain of Au(CN)(2)(-) anions consisting of repeating tetrameric units spiraling along a 2-fold axis with internal Au-Au distances of 3.128(3), 3.220(4), and 3.274(5) Angstrom and an Au-Au distance of 3.698(4) Angstrom between tetrameric units.