6533b85cfe1ef96bd12bd2fb

RESEARCH PRODUCT

Complexes of tryptophan dipeptides with the R2Sn(IV)2+ ion (R=Me, Ph): Spectroscopic studies, solution properties and structural implications

subject

description

Tryptophan dipeptides such as L-tryptophyl-L-alanine (H 2 TrpAla), L-tryptophyl-L-tyrosine (H 2 TrpTyr), L-tryptophyl-L-tryptophan (H 2 TrpTrp), along with L-histidyl-L-tyrosine (H 2 HisTyr), were reacted with R 2 SnO (R=Me, Ph) yielding the corresponding complexes. The complexes have been characterized by IR and 119 Sn Mossbauer spectroscopy in the solid state and by 1 H and 13 C NMR in CD 3 OD solutions. Monomeric species were detected, with the tin atom arranged in a pentacoordinated trigonal-bipyramidal structure. The dipeptides are coordinated via the terminal amino group, deprotonated peptide nitrogen and terminal carboxylate group. No side-chain appears to be involved in bonding. Determination of rotamer populations for selected compounds was accomplished by vicinal coupling constant analysis and side-chain orientations are interpreted. In this connection, the potential applications of these compounds as drugs is discussed