Syntheses and properties of cis- and trans-dialkynyl complexes of platinum(II)

Sonogashira, Kenkichi; Fujikura, Yoshiaki; Yatake, T.; Toyoshima, Naomi; Takahashi, Shigetoshi; Hagihara, Nobue

doi:10.1016/s0022-328x(00)84078-4

Cited by 229 publications

(127 citation statements)

References 14 publications

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“…[8] To avoid random polymerization of the dendritic beads, only two of the surface moieties were functionalized with "reactive" long chain 10-(4-ethynylphenoxy)decyloxyl residues while the rest were decorated with "inert" 3-(4-tert-butylphenoxy)propoxy groups.…”

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confidence: 99%

Synthesis and Characterization of Dendritic Necklaces: A Class of Outer‐Sphere–Outer‐Sphere Connected Dendronized Organoplatinum Polymers

Chow

Leung

et al. 2003

Angew Chem Int Ed

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Some years ago Newkome and Vögtle proposed the concept of dendritic networks [1] whereby simple dendrimer/dendron subunits could be connected together to form macromolecular assemblies with nanoscopic dimensions.[2] At about the same time, Schlüter and co-workers began to report their pioneering works on the synthesis and characterization of a special kind of dendritic networks, also known as cylindrical dendronized polymers, [3,4] based on an inner-sphere-innersphere connection [2] approach, that is, the resulting dendronized polymers may be viewed as constructed from the connection of individual dendrons through their internal focal-point functional groups. A large number of such innersphere-inner-sphere connected dendronized polymers were reported. Some of them were shown to have cylindrical geometry [4] while some were known to self-assemble into spherical nanostructures.[5] To our surprise, examples of dendritic networks created by the alternative outer-sphere-outer-sphere connection strategy [2] are less studied. A few examples were already reported but invariably they all involve a random polymerization of dendrimer subunits that have a large number of reactive functional groups on the dendrimer surface.[6] We report herein a new variant of the outer-sphere-outer-sphere connection strategy that allows us to prepare a novel class of nanoscopic dendritic networks (hereafter called dendritic necklaces because of their structural resemblance to untied necklaces) by the controlled polymerization of dendrimer subunits containing only two reactive surface functional moieties (Figure 1). [7] We also show that the resulting dendritic necklaces, in contrast to randomly connected dendritic networks, can be fully characterized by solution techniques such as NMR, MS, GPC and laser light scattering (LLS) to enable a thorough assessment of their structural identity and purity. Employing organoplatinum coordination chemistry as a method for the polymerization of bis(ethynyl) surface-functionalized G1-G3 dendritic beads 1-3, we demonstrate that higher-order 1D dendritic necklaces with high degree-of-polymerization values (DP, from 30-880) could be prepared in high yields. We also describe a general synthetic protocol for the construction of dendrimers that contain a limited number of functional groups on the surface sector.Because bis(ethynyl) polyether-based dendrimers readily form trans-dialkynyl organoplatinum(ii) complexes upon treatment with trans-[(Et 3 P) 2 PtCl 2 ], this reaction was chosen to link the dendrimers 1-3 together.[8] To avoid random polymerization of the dendritic beads, only two of the surface moieties were functionalized with "reactive" long chain 10-(4-ethynylphenoxy)decyloxyl residues while the rest were decorated with "inert" 3-(4-tert-butylphenoxy)propoxy groups.The synthesis of the target dendritic monomers 1-3 required the availability of three bromo-dendrons 10, 11, and 12[9] (Scheme 1). Hence, the G1-dendrimer 4 and G2-

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confidence: 99%

Synthesis and Characterization of Dendritic Necklaces: A Class of Outer‐Sphere–Outer‐Sphere Connected Dendronized Organoplatinum Polymers

Chow

Leung

et al. 2003

Angew Chem Int Ed

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“…12 The magnetic anisotropy of these polymers may be controlled by incorporating different transition metal atoms in the polymer backbone. 13,14 This paper now reports the first preliminary example of the synthesis of the zirconocene polyyne polymers, and to our knowledge this also represents the first example of the metal poly-yne polymer containing cyclopentadiene substituents with a view to their special properties.…”

Section: Introductionmentioning

confidence: 87%

Synthesis of zirconocene-acetylene and zirconocene-diacetylene polymer

Sahoo

Swain

1999

J. Polym. Sci. A Polym. Chem.

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“…The stretching frequency of (C≡C) is shifted from 2117 to 2081 cm -1 when the remaining chloride was replaced by the second acetylide group. The M-C and C≡C stretching frequencies are used to determine the geometry of the square planar metal ethynyl complexes (Sonogashira et al 1978, Long et al 2002, Saha et al 2005. For example, cis-[(PBu 3 ) 2 Pt(C≡C-C≡CH) 2 ] has a C 2v symmetry and showed two absorption bands for each v(C≡C) and v(M-C) (Sonogashira et al 1978).…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

“…The M-C and C≡C stretching frequencies are used to determine the geometry of the square planar metal ethynyl complexes (Sonogashira et al 1978, Long et al 2002, Saha et al 2005. For example, cis-[(PBu 3 ) 2 Pt(C≡C-C≡CH) 2 ] has a C 2v symmetry and showed two absorption bands for each v(C≡C) and v(M-C) (Sonogashira et al 1978). In our case, only one absorption band for each of the v(C≡C) and v(M-C) was observed, suggesting that compound 4 and 5 have trans geometry around the platinum metal centre.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%