[n + n]-Heterometallomacrocyclic complexes (n ≥ 2) prepared from platinum(<scp>ii</scp>)-centred ditopic 2,2′:6′,2″-terpyridine ligands: dimensional cataloguing by pulsed-field gradient spin-echo NMR spectroscopy
作者:Jonathon E. Beves、Edwin C. Constable、Catherine E. Housecroft、Markus Neuburger、Silvia Schaffner、Ellen J. Shardlow
DOI:10.1039/b618197j
日期:——
The reaction of 4â²-(2-propyn-1-oxy)-2,2â²:6â²,2â³-terpyridine (HCCCH2Oterpy) with trans-[PtI2(PR3)2] (R = Et, nBu, Ph) results in the regioselective formation of the metalloditopic ligands trans-[Pt(CCCH2Oterpy)2(PR3)2], crystallographic data for which are presented. Each ditopic ligand reacts with FeCl2·4H2O to give heterometallomacrocycles, the smallest of which is a [2 + 2] macrocycle, confirmed structurally for R = Et. The NMR spectroscopic data confirm the formation of symmetrical species, i.e. macrocyclic and not polymeric species. The distribution of products has been investigated using pulsed-field gradient spin-echo (PGSE) diffusion NMR spectroscopy, and indicates that the kinetic products from the reactions of 1, 2 or 3 (L) with iron(II) are [FenLn]2n+ with n = 2, 3 or 4. For L = 1 and 2, these mixtures of products convert in solution to the thermodynamically favoured [Fe2L2]4+.
4′-(2-丙炔-1-氧基)-2,2′:6′,2″-乙烯基吡啶(HCCCH2Oterpy)与trans-[PtI2(PR3)2](R = Et, nBu, Ph)的反应导致选择性区域形成金属双位配体trans-[Pt(CCCH2Oterpy)2(PR3)2],其晶体数据已被提供。每个双位配体与FeCl2·4H2O反应生成杂金属大环,其中最小的是一个[2 + 2]大环,已通过结构确认R = Et时的情况。NMR光谱数据确认形成对称物种,即大环而非聚合物种。使用脉冲场梯度自旋回波(PGSE)扩散NMR光谱研究了产物的分布,表明1、2或3(L)与铁(II)反应的动力学产物为[FenLn]2n+,其中n = 2、3或4。对于L = 1和2,这些产物的混合物在溶液中转化为热力学上更为有利的[Fe2L2]4+。