and rings. In many cases, the terminal carboxylic O–H function is engaged in a “terminal” H-bond with a polar molecule of solvent (THF or acetone), instead of forming the usual head-to-head arrangement found in simple carboxylic acids. For the longer tripeptide Gly-Gly-Gly, a discrete, dimeric association is observed, in which the peptide chains show antiparallel arrangement with a complementary disposition
含
吡啶-2-甲醛(的pycA)
配体作用的络合物作为κ 2 - (N,O)螯合物[
MX(CO)3(的pycA)](M =
锰中,Re; X =
氯,
溴),或[
MOX (
甲基烯丙基)(CO)2(pyca)](X = Cl,Br),是衍生自
氨基
酯和式[
MX(CO)3(py-2-C(H)CHNCHX的肽)的亚
氨基吡啶配合物的良好前体-COOY)]或[
MOX(甲代
烯丙基)(CO)2(py-2-C(H)═NCHX-COOY)],通过pyca醛官能团与末端NH 2的席夫缩合反应
氨基
酯或肽的基团。X射线测定证实了结构,并表明在固相中,肽链通过H键组装而成,并根据
金属-
配体片段的几何形状采用不同的模式。
氢键键合模式已进行了详细分析,并使用图集方法进行了描述。在大多数情况下,
MO络合物显示出分子内的排列,其中涉及卤素(Cl或Br)和侧链的NH基团。对于Mn和Re络合物,肽侧臂形成无限链,螺旋和环。在许多情况下,末