A new synthetic approach for substitutional solid solutions in a 3D coordination polymer: Cation vacancy, and tunable photoluminescence

• Published in: Journal of solid state chemistry 2019-11, Vol.279, p.120948, Article 120948
• Main Authors: Hamisu, Aliyu M., Wardana, Fendi Y., Ariffin, Azhar, Baig, Irshad, Malliakas, Christos D., Wibowo, Arief C.
• Format: Article
• Language: English
• Subjects: Cation vacancy; Doped metal organic coordination polymer; Hetero-valent; Photoluminescence; Solid solution
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2019.120948

Solid solution featuring mixed valence in metal-organic coordination polymer (MOCP) is rare. Inspired by the flexibility of Pb2+ to undergo cation exchange, and its ability to adopt a variety of coordination numbers (CN) and chemical environments (CE), herein we report the first, to our knowledge, hetero-valent, single and multiple substituted MOCP with cation vacancy featuring tunable photoluminescence, which may pave a way towards a tunable, functional MOCP. The 3D Pb MOCP features 1D moiety which contains three unique Pb2+ sites, each with a different CN and CE, that can undergo cationic substitutions with exogenous divalent as well as aliovalent, e.g. mono- or trivalent cations under appropriate conditions. The formation of solid solution is confirmed by Single Crystal and Powder X-ray Diffractions, SEM-EDS, ICP-OES, as well as XPS. A tunable photoluminescent (PL) color exhibiting good antennae effect and retention of original 3D Pb host color is observed using as little as 6 wt% of Eu3+ dopant. More importantly, the PL intensity of Eu3+ substituted Pb MOCP increases as dopant amount increases even up to 80 wt% doping, a rather rare case and the first, to our knowledge, in MOCP solid solution. A Pb-based solid solution that involves simultaneous structural transformation from 1D into 3D and partial cation substitution is reported. Eu3+ doped compounds exhibit an increase PL intensity as the dopant amount increases, up to 80 wt%, the first to our knowledge, in solid solution MOCP. [Display omitted] •Pb-based solid solutions involve simultaneous structural transformation from 1D into 3D and partial cation substitution.•First example, to our knowledge, of a hetero-valent, single and multiple doped MOCP with cation vacancy.•Using Hard Soft Acid Base (HSAB) concept, variation of trivalent dopant amounts are accomplished.•The solid state emission intensity of Eu3+ doped Pb MOCP increases upto 80 wt% Eu3+, the first for solid solution MOCP.