The structure of triclinic bilirubin chloroform–methanol solvate

Structure of bilirubin IXα (isopropylammonium salt) chloroform solvate, C33H34N4O62−.2C3H10N+.2CHCl3

“…l(a). Similar features were observed in the bilirubin chloroform-methanol solvate (Le Bas et al, 1980) and in the dimethyl ester of biliverdin IXa (W. S. Sheldrick, 1976). In the last compound, as in the present one, very short bond distances involving the disordered C atoms have been found.…”

“…la and 2), as found in pure bilirubin IXct (Bonnett et al, 1976;Bonnett et al, 1978), in bilirubin chloroform-methanol solvate (Le Bas et al, 1977;Le Bas et al, 1980), in mesobilirubin chloroform solvate (Becker & Shcldrick, 1978) and in diethoxybilirubin diethyl ester (Sheldrick & Becker, 1979). (×10 4) and equivalent isotropic thermal parameters (A 2 × 10 3) (2) 7674 (3) 10343 (4) 4029 (4) 66 (2) C (3) 7669 (3) 9989 (4) 3361 (3) 63 (2) C (4) 7114 (3) 9263 (4) 3208 (3) 56 (2) C (5) 6960 (3) 8740 (4) 2596 (3) 55 (2) C (6) 6461 (3) 8017 (4) 2333 (3) 51 (2) C (7) 6391 (3) 7575 (4) 1655 (3) 52 (2) C (8) 5825 (3) 6911 (4) 1602 (3) 46 (2) C (9) 5569 (3) 6943 (4) 2253 (3) 50 (2) C(10) 5000 6344 (6) 2500 60 (3) C(l 1)…”

“…Moreover, the pattern of hydrogen bonds is quite different from that found in related compounds having a ridge-tile conformation. Whereas in bilirubin itself (compound A ; Bonnett et al, 1978) and in bilirubin chloroform-methanol solvate (compound B;Le Bas et al, 1980) all the hydrogen bonds are intramolecular, as are most of those in mesobilirubin chloroform solvate (compound C;Becker & Sheldrick, 1978),~ in the present complex there are only four intramolecular hydrogen bonds, each of the BILIRUBIN IXct (ISOPROPYLAMMONIUM SALT) CHLOROFORM SOLVATE * Still shorter C-C bond lengths have been reported for three ethyl groups in 3,8,12,17-tetraethyl-4,5-dimethoxy-2,7,13,18-tetramethyl-4,5-dihydrobilin-1,19(21H,24H)-dione (CuUen, Van Opdenbosch, Meyer, Smith & Eivazi, 1982).…”

New Concepts in Bilirubin and Jaundice: Report of the Third International Bilirubin Workshop, April 6–8, 1995, Trieste, Italy

“…30 At more alkaline pH values and Cu/UCB ratios of 3:1 to 5:1, amorphous black precipitates were formed with the composition Cu 2 B. 30 If oxygen was present, similar black material developed on the surface of the yellow-brown Ca(HB) 2 salts, associated with the appearance of additional úC|O groups in the Fourier transform infrared spectrum. This probably represented multistage oxidation of the unsaturated C (4,5) and C(15, 16) stones.…”

New concepts in bilirubin and jaundice: Report of the Third International Bilirubin Workshop, April 6-8, 1995, Trieste, Italy

“…30 At more alkaline pH values and Cu/UCB ratios of 3:1 to 5:1, amorphous black precipitates were formed with the composition Cu 2 B. 30 If oxygen was present, similar black material developed on the surface of the yellow-brown Ca(HB) 2 stones.…”