Structure of mono-acid even-numbered beta-triacylglycerols

The crystal structure of the beta polymorph of tripalmitin (1,2,3-trihexade canoylglycerol, beta-PFP) has been determined by single-crystal X-ray diffr action. The molecules crystallize in space group P (1) over bar in an asymm etric tuning-fork conformation. This structure and the already known crysta l structures of beta-tricaprin (beta-CCC) and beta-trilaurin (beta-LLL) cou ld be matched in an overlap model. Apart from a difference in chain length, the three structures are almost identical. The overlap model can be used t o predict the crystal structure of the other members of the CnCnCn-type (n = even) TAG series reasonably accurately. This is demonstrated by predictin g the crystal structure for beta-trimyristin (beta-MMM) and successively co mparing the experimental and calculated X-ray powder diagrams.