The Isolation of Single MMX Chains from Solution: Unravelling the Assembly–Disassembly Process

Abstract

Herein, we provide a systematic theoretical and experimental study of the structural and optical properties of MMX (M=metal, X=halide) chains. The influence of solvent, temperature, and concentration has been analyzed to find suitable parameters for initial building-block associations in solution. By using density functional calculations, we have computed the dissociation energy of different MMX oligomers (up to the tetramer) in the gas phase. On the basis of these findings, we discuss the most likely disassembly scenario and propose a new interpretation of these compounds. We also calculated the charge redistribution that occurs upon MM+XMMX binding in vacuum. Time-dependent density functional theory (TDDFT) is used to calculate the UV/visible spectra of different MMX chains up to the tetramer in the gas phase. The implications of these theoretical findings in the analysis of our experiments are discussed in the text. The overall body of data presented suggests a new way of looking at such linear structures. By taking into account these new data, we have been able to isolate single/few MMX chains on mica.

High Resolution Scanning Tunneling Microscopy of a 1D Coordination Polymer with Imidazole‐Based N,N,O Ligands on HOPG

“…A similar assembly–disassembly process was recently reported for [Pt 2 (RCS 2 ) 4 I] n by Zamora and co‐workers 2b. c Figure 3 b represents a large‐scale STM topography of an agglomerate of polymer 8 observed on a HOPG surface. A scan of a single strand of polymer 8 is presented in Figure 3 c and d shows a high‐resolution scan of this strand.…”

“…One‐dimensional (1D) coordination polymers are promising candidates for fundamental research in the scope of molecular electronics 1–3. The self‐organization of molecules on surfaces based on noncovalent interactions has been extensively studied during the last decade 2c. d Especially, the coordinative metal–ligand bond, often assessed as critical regarding the stability of materials, offers the chance to construct one‐dimensional functional materials in a reproducible way.…”

“…It requires a detailed understanding of the design of molecular architectures and a precise adjustment of the coordination properties by synthetic strategies to control the shape of the self‐assembled structures 1. 2 Coordination polymers, usually built from metal entities and organic or inorganic ligands, are often limited regarding the processability, due to their low or nonexisting solubility 2c. So called MMX chains (M=metal, X=halide) are considerable exceptions in this regard 2c.…”

“…2 Coordination polymers, usually built from metal entities and organic or inorganic ligands, are often limited regarding the processability, due to their low or nonexisting solubility 2c. So called MMX chains (M=metal, X=halide) are considerable exceptions in this regard 2c. d Moreover, emulating the one‐ monomer approach is often applied in organic polymerization processes.…”

On the Road to MM′X Polymers: Redox Properties of Heterometallic Ni···Pt Paddlewheel Complexes

“…To answer this question we first tried experiments in solution at low temperature looking for spectroscopic evidence of supramolecular aggregation in a similar way as is observed for [Pt 2 (μ-S 2 CR) 4 I] n . 13 However, in this case no evidence of aggregation was found. In a further effort to understand why chains are not formed from the [Ni(μ-OSCPh) 4 Pt−Cl] fragments, we optimized the [Ni(μ-OSCPh) 4 PtClNi(μ-OSCPh) 4 PtCl] aggregate and studied the possible modes of cleavage.…”