+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Polymer rings and chains consisting of doubly silyl-bridged metallocenes



Polymer rings and chains consisting of doubly silyl-bridged metallocenes



Chemistry 8(22): 5219-5227



With the formation of novel organometallic macromolecules in mind, the polycondensation of transition metal ions and bridged cyclopentadienyl ligands was studied. To this end solvated salts MX2 (M = Fe, Ni, and Cr) were treated with a ligand that consisted of two doubly silyl-bridged cyclopentadienyl anions. For M = Fe and diluted solutions a series of rings Oi was obtained that consisted of a minimum of six (O6) and up to 17 (O17) ferrocene moieties in the backbone. They were separated partly by medium pressure liquid chromatography. The macrocycles were established by high-resolution MALDI-TOF mass spectroscopy which also yielded the molecular weight, the polydispersion, and the mean ring size, chi n, of the mixture of reaction products. When the reaction temperature was decreased from 25 degrees C to -20 degrees C, chi n increased from 8.1 to 10.8. Ferrocene-containing chains, lambda j, with 2 < or = j < or = 12 were obtained in addition to rings in the presence of water; the terminal groups were cyclopentadiene moieties. The reaction of two ferrocene-fused cyclopentadienyl anions with [FeCl2(thf)1.5] gave chains consisting of exclusively uneven numbers of ferrocenes. For M = Ni and Cr the formation of doubly silyl-bridged nickelocenes and chromocenes was proven by NMR spectroscopy. MALDI-TOF mass spectroscopy showed nickelocene-containing chains accompanied by some rings. For M = Fe the H,H-DQF COSY spectra established the structure of O7, O8, and O9. The oxidation of the ferrocene-containing ring O7 with I2, NOPF6, and AgPF6 gave ionic species [O7]n+ which suffered from low stability. The ring-closing reaction is discussed, and the relative abundance of the various rings is related to MNDO calculations.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 049947602

Download citation: RISBibTeXText

PMID: 12613041

DOI: 10.1002/1521-3765(20021115)8:22<5219::aid-chem5219>3.0.co;2-h


Related references

Two molecular tapes consisting of serial or parallel azido-bridged eight-membered copper rings. Angewandte Chemie 44(36): 5841-5846, 2005

Quantifying magnetic exchange in doubly-bridged Cu-X(2)-Cu (X = F, Cl, Br) chains enabled by solid state synthesis of CuF(2)(pyrazine). Chemical Communications 49(34): 3558-3560, 2013

A coordination polymer consisting of two different one-dimensional copper(II) chains. Acta Crystallographica. Section C Structural Chemistry 70(Pt 3): 285-288, 2014

A mu-chloro-bridged dinuclear ruthenium complex with 9H-carbazole: the formation of one-dimensional linear chains of star-shaped edge-fused rings. Acta Crystallographica. Section C Crystal Structure Communications 62(Pt 8): M346-M348, 2006

Fe(mu-btzmp)2(btzmp)2](ClO4)2: a doubly-bridged 1D spin-transition bistetrazole-based polymer showing thermal hysteresis behaviour. Dalton Transactions 2007(46): 5434-5440, 2007

A three-dimensional coordination polymer featuring effective ferrimagnetic hydroxide-bridged manganese(II) chains. Inorganic Chemistry 44(13): 4448-4450, 2005

Synthesis and structure of singly bridged and doubly bridged [MoFe(3)S(4)] double cubanes with bidentate phosphine ligands. Inorganic Chemistry 41(10): 2738-2746, 2002

Elucidation of the in vitro and in vivo activities of bridged 1,2,4-trioxolanes, bridged 1,2,4,5-tetraoxanes, tricyclic monoperoxides, silyl peroxides, and hydroxylamine derivatives against Schistosoma mansoni. Bioorganic and Medicinal Chemistry 23(16): 5175-5181, 2015

Metathesis route to bridged metallocenes. Journal of the American Chemical Society 124(31): 9068-9069, 2002

Polymer-supported silyl cyanide and silyl azide: Useful reagents for solid-phase applications. Biotechnology & Bioengineering 71(1): 38-43, Winter, 2000

Influence of chain topology on polymer crystallization: poly(ethylene oxide) (PEO) rings vs. linear chains. Soft Matter 12(39): 8124-8134, 2016

1,1-Olefin-bridged bis-(2-indenyl) metallocenes of titanium and zirconium. Dalton Transactions 43(35): 13219-13231, 2014

Anti tumor activity of metallocenes substituted or bridged titanocene di chlorides. European Journal of Medicinal Chemistry 16(3): 275-281, 1981

Coordination assembled rings of ferrocene-bridged trisporphyrin with flexible hinge-like motion: selective dimer ring formation, its transformation to larger rings, and vice versa. Journal of the American Chemical Society 127(7): 2201-2210, 2005