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Cyclic and Linear Polyferrocenes with Silicon and Tin as Alternating Bridges
Author(s) -
Bagh Bidraha,
Breit Nora C.,
Dey Subhayan,
Gilroy Joe B.,
Schatte Gabriele,
Harms Klaus,
Müller Jens
Publication year - 2012
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.201200953
Subject(s) - chemistry , tin , ferrocene , gel permeation chromatography , nuclear magnetic resonance spectroscopy , crystallography , crystallization , polymer chemistry , stereochemistry , polymer , organic chemistry , electrode , electrochemistry
The synthesis and characterization of ferrocene‐based oligomers that contained two different elements (Si and Sn) as alternating bridges is described for the first time. The salt‐metathesis reaction of R 2 Si[(C 5 H 4 )Fe(C 5 H 4 Li)] 2 (R=Me, Et) with R′ 2 SnCl 2 (R′=Me, n Bu, t Bu) afforded a mixture of oligomers ( 6 Me SnMe 2 , 6 Et SnMe 2 , 6 Me Sn n Bu 2 , 6 Et Sn n Bu 2 , 6 Me Sn t Bu 2 , and 6 Et Sn t Bu 2 ). These oligomers were characterized by 1 H, 13 C, 29 Si, and 119 Sn NMR spectroscopy and by mass spectrometry. MS (MALDI‐TOF) studies of 6 Et SnMe 2 revealed the presence of linear ( l ) and cyclic ( c ) species that contained up to 20 ferrocene moieties. The molecular weights of the polymers were determined by gel‐permeation chromatography (GPC) and by dynamic‐light scattering (DLS). GPC analysis revealed average molecular weights of 2100–6300 Da with respect to polystyrene as a standard. DLS analysis yielded very similar results. Some compounds, c ‐(6 Me SnMe 2 ) 1 , c ‐(6 Me Sn t Bu 2 ) 2 , c ‐(6 Et SnMe 2 ) 1 , c ‐(6 Et Sn t Bu 2 ) 2 , l ‐(6 Me Sn n Bu 2 ) 2 , and l ‐(6 Me Sn n Bu 2 ) 3 , which contained up to six ferrocene moieties, were isolated in their pure form either by column chromatography or by crystallization. The Si‐ and Sn‐bridged macrocycles that contained four ferrocene units ( c ‐( 6 Me Sn t Bu 2 ) 2 and c ‐(6 Et Sn t Bu 2 ) 2 ) were structurally characterized by single‐crystal X‐ray analysis.