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Rational Synthesis of Supramolecular Assemblies Based on Tetraplatinum Units: Synthesis, Characterization, and Selective Substitution Reactions of Four Different Pt 4 Clusters
Author(s) -
Tanaka Shinji,
Yagyu Akihiro,
Kikugawa Masashi,
Ohashi Masato,
Yamagata Tsuneaki,
Mashima Kazushi
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201002808
Subject(s) - chemistry , dimer , lability , crystallography , substitution reaction , platinum , supramolecular chemistry , stereochemistry , benzoic acid , electrochemistry , medicinal chemistry , crystal structure , catalysis , organic chemistry , electrode
Abstract Four different types of square‐planar Pt 4 clusters, trans ‐[Pt 4 (μ‐OCOCH 3 ) 6 (μ‐ArNCHNAr) 2 ] ( 2 : ArNCHNAr= N , N′ ‐diarylformamidinate), [Pt 4 (μ‐OCOCH 3 ) 7 (μ‐ArNCHNAr)] ( 8 ), cis ‐[Pt 4 (μ‐OCOCH 3 ) 6 (κ 4 ‐ N 4 ‐DArBp)] ( 9 : DArBp=1,3‐bis(arylbenzamidinate)propane), and [Pt 4 Cl 2 (μ‐OCOCH 3 ) 5 (κ 4 ‐ N 2 , P 2 ‐dpfam)] ( 13 : dpfam= N,N′ ‐bis[(2‐diphenylphosphino)phenyl]formamidinate), were successfully prepared by using selective substitution reactions of in‐plane acetate ligands of [Pt 4 (μ‐OCOCH 3 ) 8 ] ( 1 ), which has four in‐plane and four out‐plane acetate ligands, with appropriate capping ligands. Fundamental substitution reactions of the remaining in‐plane acetates with benzoic acid derivatives were also investigated. All newly prepared complexes were characterized from spectral and physical data and combustion analysis. X‐ray crystallographic studies of some of the clusters were also performed. Electrochemical measurements of amidinate‐modified Pt 4 clusters revealed stepwise oxidation processes of the Pt 4 core due to Pt 4 9+ /Pt 4 8+ and Pt 4 10+ /Pt 4 9+ . Based on the lability of the in‐plane acetate ligands of the modified Pt 4 clusters, reactions of cis ‐[Pt 4 (μ‐OCOCH 3 ) 6 (κ 4 ‐ N 4 ‐DArBp)] ( 9 c : Ar=C 6 H 4 t Bu‐4) with ferrocenedicarboxylic acid and p ‐phenylenedipropionic acid resulted in the selective formation of cyclic dimers 17 and 18 and the reaction of 13 with 4,4′‐biphenyldicarboxylic acid afforded a linear dimer 20 . The dimers were characterized by spectral data, as well as X‐ray analyses for 17 and 18 . The finding of two Fe 3+ /Fe 2+ redox couples in the electrochemical measurement of dimer 17 indicated that two ferrocenyl units in dimer 17 communicated electronically.