Influence of O-H···Pt interactions on photoluminescent response in the (Bu4N)2{[Pt(bph)(CN)2][phenylene-1,4-diresorcinol]} framework

Chemistry. 2024 May 16:e202400797. doi: 10.1002/chem.202400797. Online ahead of print.

Abstract

Tunable photoluminescence (PL) is one of the hot topics in current materials science, and research performed on the molecular phases is at the forefront of this field. We present the new (Et4N)2[PtII(bph)(CN)2]·rez3·1/3H2O (Pt2rez3) (bph = biphenyl-2,2'-diyl; rez3 = 3,3",5,5"-tetrahydroxy-1,1':4',1"-terphenyl, phenylene-1,4-diresorcinol coformer, a linear quaternary hydrogen bond donor) co-crystal salt based on the recently appointed promising [PtII(bph)(CN)2]2- luminophore. Within the extended hydrogen-bonded subnetwork [PtII(bph)(CN)2]2- complexes and rez3 coformer molecules form two types of contacts: the rez3O-H···Ncomplex ones in the equatorial plane of the complex and non-typical rez3O-H···Pt ones along its axial direction. The combined structural, PL, and DFT approach distinguished the rez3O-H···Pt synthons to promote the noticeable uniform redshift of bph ligand centered (LC) emission compared to the LC emission of (Et4N)2[PtII(bph)(CN)2]·H2O (Pt2) precursor owing to the direct interference of the phenol group into the PtII-bph orbital system via altering the CT processes. The high-resolution emission spectra for Pt2 and Pt2rez3 were successfully reproduced at 77 K by using the Franck-Cordon expressions. The possibility to tune PL properties along the plausible continuum of rez3O-H···Pt synthons is indicated, considering various scenarios of molecular occupation of the space above and below the complex plane.

Keywords: Hydrogen bonds; Luminescence; co-crystal; platinates; supramolecular chemistry.