Perfluoroalkylation of Square-Planar Transition Metal Complexes: A Strategy To Assemble Them into Solid State Materials with a π–π Stacked Lamellar Structure

Abstract

Formation of π−π stacked lamellar structure is important for high performance organic semiconductor materials. We previously demonstrated that perfluoroalkylation of aromatics and heteroaromatics was one of the strategies to design organic crystalline materials with π−π stacked lamellar structures while improving air stability as a result of the strong electron withdrawing ability of perfluoroalkyl substituents. Square-planar transition metal complexes with large π-conjugated ligands are also an important category of semiconductor materials. We have perfluoroalkylated square-planar transition metal complexes, leading to the formation of a π−π stacked lamellar crystal packing motif in the solid state. Here we report six crystal structures of Pd and Pt complexes with bis-perfluorobutylated catechol ligand as one of the two ligands that bonds to the metal centers. This structural design possesses similar molecular topology when compared to perfluoroalkylated aromatics and heteroaromatics we have reported previously, again, demonstrating the steering power of the perfluoroalkyl substituents in engineering organic and organometallic solid state materials.

New Mixed‐C^N Ligand Tris‐Cyclometalated IrIII Complexes for Highly‐Efficient Green Organic Light‐Emitting Diodes with Low Efficiency Roll‐Off

“…The crystal structures are shown in Figure and the crystal data are listed in Table S1. Complexes 3 , 4 and 6 all have distorted octahedral geometry around the iridium center which is surrounded by three C ^ N ligands, as previously reported for tris‐cyclometalated Ir complexes (Figure a) , . The facial isomers are observed for 3 and 4 , which typically endows higher quantum efficiencies compared to meridional isomers .…”

Square-Planar Heteroleptic Complexes of α-Diimine-NiII-Catecholate Type: Intramolecular Ligand-to-Ligand Charge Transfer

“…The synergistic existence of donor and acceptor organic parts in the coordination sphere of the metal center is a distinctive feature for a wide range of LL'CT chromophores. The acceptor moiety is usually represented by a neutral redox form of α-diimines (Scheme 1) with significant steric hindrances [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] and/or a rigid carbon skeleton [13,15,[25][26][27]. Thus, it provides the required planarity of the complex's structure.…”

“…A series of works describes a modification of the coordination sphere of Pd II ion by non-substituted diimine and catecholate ligand platforms with extended πsystem [25][26][27][44][45][46]. It has been recently presented the following noteworthy tendencies in the molecular design of the α-diimine-M II -catecholate compounds [13]. Thus, utilization of the conjugated organic ligands provides the π-π stacking, and perfluoroalkylation of a catecholate forces its electron-withdrawing properties to increase the complexes' stability towards atmospheric oxygen.…”

“…(1) treatment of the transition metal compound with a quinone type ligand to generate a catecholate-containing intermediate (redox process) [15]; (2) an exchange reaction with the participation of the catecholate precursor and α-diimine. The principal peculiarity of the second method (most frequently used) is in the reverse order of the introduction of ligands into the coordination sphere of the metal center (compared to the first technique) [11][12][13]15,17,19,22,25,35,44,46]. The third combined method is the "one-pot" synthesis [16,36], which was applied to obtain the complex 1 described in ref.…”

Host‐Guest Chemistry of Self‐Assembled Hemi‐Cage Systems: The Dramatic Effect of Lost Pre‐Organization

“…[14] 5. Synthesis 2,2'-Bipyridine palladium(II) chloride, [15] N,N,N',N'-tetramethylethylenediamine palladium(II) chloride [16] and ligand L 1a [17] were prepared as described in the literature.…”