Electronic Properties Of The Model Organometallic Polymer [M-C=C(N)] n (M = Cu(I), Ag(I), Au(I))
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M -L
Mijjv
For the poly-phthalocyanine metal complex, the square represents the phthalocyanine(Pc); M can be different metals, such as Cr, Mn, Fe, Co, Ru or Rh; L is a small molecule as ligand, for example[1 31: CC--,
C=N, N_,N (pyz), NO\/
N (bpy), CN
/Nc(dib)
The research shows that most kinds of polymers doped or even undoped have high conductivity. The differences between M, conjugated ligands and stacking structures make the polymers possess different electronic properties. The d orbitals of center-metal and iT orbitals of conjugated molecules overlap each other. And the more the overlap is, the larger the conductivity. Rod-like organometallic poly-yne polymers with transition metals inserted in the i conjugated backbone have attracted a good deal of attention; in these materials the delocalized it -system involves the metal d-orbital, leading to noteworthy chemical and physical properties, such as third-order non-linearity and the capability of alignment in a magnetic and electrical field. A promising material, [Pd(PBu 3) 2-C C-Ph-Ph-C=C-]n (poly[palladium 1 41 bis(tributhylphosphine) diethynylbiphenyl](Pd-DEBP), was synthesized and investigated . There are many examples of organometallic polymers, particularly one of transition metal M = Cu(I), Ag(I), Au(I) with d"° electronic configuration, in which the two types, 0 (twocenter) and iT (three-center), of bonds exist as shown in Fig. 1[5,6,111. Abu-Salah synthesized the [Au 3Ag 2(C2Ph)6 ]-and[Au 3Cu2 (C2Ph) 6] which have typical two389 Mat. Res. Soc. Symp. Proc. Vol. 576 ©1999 Materials Research Society
-M-C-C(N)-
-M--_
C Fig.1 The Types of Bonds Between M and j, -Conjugated Molecules and three-center bondsi51 . Che and coworkers obtained some kinds of one- and two-dimensional organometallic polymers which contain similar poly-yne structures by utilizing metal-metal interaction between chains of the complexes. The polymers usually show stronger photophysics and photochemistry properties. The one-dimensional polymer [{Au 2(C =CPh)2 L} -] with ligand L=2,6-bis(diphenylphosphino)pyridine in which the distance of Au-Au is about 0.3252 nm, has 1 681 been synthesized and is a strong luminescent material at room temperature - . The crystal structures of Au 2(tmb)C12 (tmb = 2,5-dimethyl-2,5-diisocyanohexane) and (AuX) 2( ii -dpph) [X 1 910 1
= CI,l; dpph = bis(diphenylphosphino)haxane] were reported earlier
, in (AuCI) 2 ( L, -dpph)
the distance of Au(I)-Au(I) is 0.3124 nm. Systematical complexes [N(PPh 3)2][Au(C=CPh)2], [Au(PPh 3)(C=CPh)], [{Au(C=CPh)}2 (11 -dppe)] [dppe =1,2-bis(diphenyl-phosphino)ethane] were also synthesized [1`01. Recently the research of multi-yne organometallic complexes formed with transition metals has been reported continuouslyt 16 .. In this kind of material, the delocalised it -system and the metal d-orbitals lead to noteworthy chemical and physical properties. The theoretical analysis of bonding character and molecular orbitals can lead to the prediction of new functional materials and their experimental synthesis. On the basis
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