Structure of CnCn+2Cn-type (n = even) beta '-triacylglycerols

The crystal structures of the beta' phase of CLC (1,3-didecanoyl-2-dodecano ylglycerol) and MPM (1,3-ditetradecanoyl-2-hexadecanoylglycerol) have been determined from single-crystal X-ray diffraction and high-resolution X-ray powder diffraction data, respectively. Both these crystals are orthorhombic with space group Iba2 and Z = 8. The unit-cell parameters of beta'-CLC are a = 57.368 (6), b = 22.783 (2) and c = 5.6945 (6) Angstrom and the final R value is 0.175. The unit-cell parameters of beta'-MPM are a = 76.21 (4), b = 22.63 (1) and c = 5.673 (2) Angstrom and the final R-p value is 0.057. B oth the beta'-CLC and beta'-MPM molecules are crystallized in a chair confo rmation, having a bend at the glycerol moiety. The zigzag planes of the acy l chains are orthogonally packed, as is typical for a beta' phase. Furtherm ore, unit-cell parameters of some other members of the CnCn+2Cn-type triacy lglycerol series have been refined on their high-resolution X-ray powder di ffraction pattern. Finally, the crystal structures are compared with the cu rrently known structures and models of triacylglycerols.