טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentBloch Victoria
SubjectSynthesis towards Heterobimetallic Complexes
DepartmentDepartment of Chemistry
Supervisor Professor Mark Gandelman
Full Thesis textFull thesis text - English Version


Abstract

Heterobimetallic complexes attract much attention due to their potential in the development of new stoichiometric and catalytic systems for the cooperative activation of organic substrates, discovery of new materials. Of special interest is the ability of heterobimetallic complexes to simultaneously activate two reaction partners on separate metal centers and thus bringing the activated species in close proximity to each other during the course of the reaction. Despite this activity, a rational design of an efficient catalytic bimetallic system and the mechanistic understanding of its action remain a challenging problem. The major reason for this is a practical lack of efficient reliable methods for the selective preparation of the planned hetero-bimetallic complexes.

 Therefore, the new selective and efficient methods for the synthesis of heterobimetallic complexes are required. Recently we have developed new selective and efficient methodology for combinatorial synthesis of triazole click ligands. This methodology is based on selective combination of two monomers using the Cu(I)‑catalyzed Huisgen cycloaddition to give selectively 1,4 substituted triazole bearing two ligands arms. Upon kinetic conditions these ligands binds metal centers through one of the donor arms and nitrogen of the triazole. During this work we have shown the preparation of monometallic bidentate species as well as bimetallic bidentate species. Encouraged by these observations we have envisioned that triazole based systems can be useful for the selective synthesis of homo‑and heterobimetallic complexes.

In this work we describe the preparation of bimetallic rhodium complex bearing our triazole based ligand. This complex showed strong coordination of two rhodium centers to P,N modes of the ligand. As well we prepared bidentate monometallic species based on ligands with two different arms. We have used two sets of ligands: one bearing phosphorus and sulfur arms, and the second ligand bearing phosphorus and phosphine oxide arms. Subsequently, we have prepared monometallic palladium, platinum and rhodium species. In all the cases coordination took place selectively to P and N donors. We have performed numerous attempts to introduce a second metal to the available coordination site of the ligand (namely, N,S and N, P=O). The work performed in this heterobimetallic direction is described and analyzed. The closest analog of the desired heterobimetallic species based on palladium and zinc was prepared and its structure was confirmed by crystallographic analysis. Further attempts towards selective and efficient synthesis of heterobimetallic complexes to be performed in the future and the prepared complexes will be studied in catalysis.