A pyrimidine thiolate Rh(I) complex: structure, bonding and one-dimensional interactions in solid and in solution.

Area of Science:

• Organometallic chemistry
• Solid-state chemistry
• Supramolecular chemistry

Background:

• Square-planar d8 metal complexes with chelating and monodentate ligands typically exhibit predictable stacking patterns.
• Previous studies on similar complexes suggest ligand pi-acidity influences intermolecular interactions and solid-state structure.

Purpose of the Study:

• To synthesize and characterize the rhodium complex [Rh(Me2-pymt)(CO)2].
• To investigate the stacking pattern and intermolecular interactions in [Rh(Me2-pymt)(CO)2] using theoretical methods.
• To understand the solution behavior of the complex, including micelle formation and color changes.

Main Methods:

• Synthesis of [Rh(Me2-pymt)(CO)2] via reaction of [Rh(micro-Cl)(COD)]2 with 4,6-dimethyl-pyrimidinethiolate followed by CO substitution.
• Semi-empirical band calculations on the real crystal chains.
• Ab initio (MP2 level) calculations on a model dimer to study intermolecular interactions and conformation.

Main Results:

• The stacking pattern of [Rh(Me2-pymt)(CO)2] contradicts established models for comparable square-planar complexes.
• Electronic and steric effects were identified as key factors controlling monomer rotation and stack linearity.
• The complex displays unusual solution behavior, forming micelles and exhibiting a blue color when water is added to acetone solutions.

Conclusions:

• The stacking behavior in [Rh(Me2-pymt)(CO)2] is governed by a complex interplay of electronic and steric factors, not solely pi-acidity.
• The compound exhibits unique supramolecular assembly in the solid state and self-assembly in solution.
• This research expands the understanding of structure-property relationships in organometallic complexes.