Hysteretic vapour response of a heterodinuclear platinum(ii)–copper(ii) complex derived from the dimer-of-dimer motif and the guest-absorbing site

Abstract

A heterodinuclear complex, syn-[PtCu(μ-pyt)2(bpy)2](2+) (syn-[PtCu]; Hpyt = pyridine-2-thiol, bpy = 2,2'-bipyridine), was synthesized by stepwise complexation. Three different crystal structures of the hexafluorophosphate salts with solvent molecules as guests at the axial sites of the Cu(ii) ions, i.e. syn-[PtCu-G] (G = acetonitrile, acetone, and methanol), were determined by X-ray analyses. In the solid-state, these complexes adopt dimer-of-dimer motifs characteristic of the syn isomers of dinuclear complexes with two pyt bridging ligands arranged in a head-to-head configuration. These dinuclear complexes have a short PtCu distance (2.75-2.81 Å) and slightly different intermolecular PtPt distances (3.43-3.51 Å), which affect the colour of the solid complexes. All the syn-[PtCu-G] systems absorbed/desorbed vapour molecules; however, they exhibit different chromic changes because of the unique structural hysteresis of the desorbed form, i.e. syn-[PtCu], according to powder X-ray diffraction measurements. In addition, guest exchange occurred in the syn-[PtM-G] complexes upon exposure to the vapour of different solvents.

Vapochromic Platinum(II) Complexes: Crystal Engineering toward Intelligent Sensing Devices

“…Our group recently extended complex 14 to a heterometallic dimer system, syn ‐[PtM(pyt) 2 (bpy) 2 ](PF 6 ) n [M = Pd II ( 15 ) and Au III ( 16 )], by taking advantage of the different affinity for metal ions of the N and S coordination sites of the pyt ligand 55,56. Namely, the thiolate S site of the pyt bridging ligand primarily coordinates to softer metal ions than the pyridine N site.…”

“…Introduction of Cu II ions in the same dimer motif was also achieved by the synthetic methods used for complexes 15 and 16 to give a PtCu‐heterometallic dimeric complex, syn ‐[PtCu(pyt) 2 (bpy) 2 ](PF 6 ) 2 ( syn ‐ 17 ) 56. The Cu II ion has a d 9 electronic configuration and can weakly bind (i.e., Jahn–Teller effect) additional ligands in the axial position, which is expected to act as a flexible guest‐binding site (Figure 20, a) 68–72.…”

“…(b) Molecular structure and (c) the dimer‐of‐dimer motif of syn ‐ 17· CH 3 CN. Reprinted with permission from the literature 56. Copyright 2014 The Royal Society of Chemistry.…”

Molecular ReI Cages: Structural and Luminescent Properties

“…Such vapochromism is ascribed to changes in intermolecular Pt II ⋅⋅⋅ Pt II interactions as the channels fill with organic vapors. Subsequently, vapor‐ and mechanically induced chromic behavior was also reported by the same group for the related half‐lantern complexes and their heterometallic Pt II –Cu II analogues . Until now, studies on metal‐containing pyridylthiolates are primarily related to the rich structural diversity, the relevance to biological systems, and potential applications as precursors for metal sulfide materials and as catalysts for many industrial processes…”

“…[12] Solvothermalr eactions can provideg ood opportunities for the generation of new structuralmotifs andlead to the synthesis of functional coordination frameworks and cages. [13] As a part of our continuing interesti nt he design and synthesis of functional metal-containing pyridylthiolates, [14] we report herein that versatile building block [{Re(CO) 4 } 3 (C 3 N 3 S 3 )] (1a) reacts with linear dipyridyl ligands [i.e.,p yrazine( pz), 4,4'-bipyridine (bpy), 1,2-bis(4-pyridyl)ethylene (bpe), bis(4-pyridyl)acetylene (bpa), and 1,4-bis(pyridyl-4-ylethynyl)benzene (bpb)] and at ripyridyl ligand [1,3,5-tris(4-pyridylethynyl)benzene (tpb)] to form as eries of molecular cages [{Re-(CO) 3 } 6 (L) 3 (C 3 N 3 S 3 ) 2 ][ L = pz (2), bpy (3), bpe (4), bpa (5), bpb (6)] and [{Re(CO) 3 } 9 (tpb) 3 (C 3 N 3 S 3 ) 3 ]( 7)u nder solvothermal conditions. Interestingly,v ariouss tructurald imensions and motifs can be systematicallyo btained depending on the different dipyridyl and tripyridyl ligandsu sed in the reaction.…”