Interplay of Supramolecular Organization, Metallophilic Interactions, Phase Changes, and Luminescence in Four Polymorphs of Ir^I(CO)₂(OC(CH₃)CHC(CH₃)N(p-tol))

Abstract

Four polymorphs of IrI(CO)2(OC(CH3)CHC(CH3)N(p-tol)) have been characterized by single crystal X-ray crystallography. While all contain the same molecular unit with no significant structural variations within the molecules, all show different degrees of metallophilic interactions between the planar molecules. Three of these (the amber, the pale yellow, and the orange forms) are stable at room temperature, while the fourth, the L. T. orange form, is only obtained by cooling the orange polymorph. At 77 K, the amber, pale yellow, and L. T. orange polymorphs show intense luminescence. The variations in the luminescence among the polymorphs are considered in the context of the structural differences between them and the nature of the metallophilic interactions between the iridium centers. These results demonstrate how subtle variations in molecular organization can affect the physical properties of planar d8 transition metal compounds, which are an important class of lumiphores.

Single-Crystal to Single-Crystal Phase Transition and Segmented Thermochromic Luminescence in a Dynamic 3D Interpenetrated AgI Coordination Network

“…Some coordination compounds with metallophilicity, such as a copper iodide cluster, showed varied emission colors depending on the temperature . Up to now, a number of two-coordinated Au I or four-coordinated Pt II systems have been reported as vapor-responsive luminescent compounds or mechanoluminescent materials . Relevant studies on Ag I compounds, however, are much less explored, and those materials with multi-stimuli-responsive characteristics are also rare.…”

Molecular gold strings: aurophilicity, luminescence and structure–property correlations

“…74,75 Today, numerous elements, including open-shell ions like Au(III), Pt(II), Pd(II), Ir(I) or Ru(0), are known to interact with other heavy metal ions, expanding the concept to 'metallophilic interactions', even though pure aurophilic interactions are typically the strongest among them and therefore still take a special place. 36,39,[76][77][78][79][80][81][82][83]…”

Packing polymorphism of dicarbonyl-[2-(phenylamino)pent-3-en-4-onato]rhodium(I)

“…A few years later, Rosenstein and Lamy (1969) simplified the definition to "when a substance can exist in more than one crystalline state it is said to exhibit polymorphism" [3]. Polymorphs are also described as "isomers at the individual crystal level in which the same molecule or salt crystallises in different fashions, which frequently, but not necessarily, result in differences in the space group and the cell dimensions", sometimes leading to different arrangements (packing) of the molecules in the solid state [4]. When polymorphism exists as a result of differences in crystal packing, it is called packing polymorphism.…”