Patent ID: 7736902

Claim:
A method for determining the absolute configuration of an asymmetric carbon of a chiral compound on the basis of the sign of the Cotton effect by analyzing a solution containing the chiral compound and a porphyrin dimer by circular dichroism spectroscopy, wherein the porphyrin dimer: (a) has a carbon chain-crosslinked porphyrin dimer structure, (b) is such that one porphyrin ring of the dimer has a Zn 2+ metal center and the other porphyrin ring of the dimer is a free porphyrin ring, and (c) is such that the free porphyrin ring has a methyl group or substituent bulkier than a methyl group at one or more of the second carbons from the carbon bonded to the crosslinking carbon chain around the outer periphery of the free porphyrin ring, and the chiral compound: (i) is capable of coordinating to the porphyrin dimer, (ii) has an asymmetric carbon directly bonded to a group capable of coordinating to the porphyrin dimer, or an asymmetric carbon adjacent to the carbon atom bonded to a group capable of coordinating to the porphyrin dimer, and (iii) is a diamine or an amino alcohol.