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Variations in the Solid‐State Emissions of Clothespin‐Shaped Binuclear trans ‐Bis(salicylaldiminato)platinum(II) with Halogen Functionalities
Author(s) -
Ikeshita Masahiro,
Ito Mizuki,
Naota Takeshi
Publication year - 2019
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201900664
Subject(s) - chemistry , halogen , platinum , solid state , crystallography , benzene , phosphorescence , photochemistry , stereochemistry , catalysis , organic chemistry , alkyl , physics , quantum mechanics , fluorescence
The syntheses, aggregation motifs and solid‐state emissions of clothespin‐shaped binuclear trans ‐bis(salicylaldiminato)platinum(II) complexes 1 – 4 bearing halogen atoms (X) at the para positions of phenoxy moieties are described and compared with those of the non‐substituted analog 5 . Crystalline (±)‐ 4 (X = I, polymorph B) obtained by recrystallization from benzene exhibits intense phosphorescent emission under UV irradiation at ambient temperature, while crystals of (±)‐ 1 (X = F), (±)‐ 2 (X = Cl), (±)‐ 3 (X = Br) and (±)‐ 4 (X = I, polymorph A), obtained from poor solvents including hexanes, are less emissive under the same conditions. The emission intensities of these crystals increase in the order of (±)‐ 4 (B) > (±)‐ 5 > (±)‐ 1 – 3 , (±)‐ 4 (A). XRD analysis shows that the less emissive crystals (±)‐ 1 – 3 and (±)‐ 4 (polymorph A) form specific aggregates in which ( R )‐ and ( S )‐units with “A”‐shaped conformations are aligned in an alternating, shuttlecock‐like interpenetrating manner as a result of one‐dimensional infinite X⋯π interactions. The emissive polymorph 4 (B) exhibits a significantly different non‐interpenetrating alignment of “A”‐shaped conformational units, which are firmly bound as a result of a two‐dimensional constraint network consisting of I⋯I and Pt⋯Pt interactions. The present variations in solid‐state emission are therefore explained on the basis of the constraint dimensionality of the packing units of each complex.