Lutetium sandwich complexes

Figure 1 Lutetium sandwich complexes 2. Electrochemistry and spectroelectrochemistry of LuPc2...

Coordination compounds composed of tetrapyrrole macrocyclic ligands encompassing a large metal ion in a sandwich-like fashion have been known since 1936 when Linstead and co-workers (67) reported the first synthesis of Sn(IV) bis(phthalocyanine). Numerous homoleptic and heteroleptic sandwich-type or double-decker metal complexes with phthalocyanines (68-70) and porphyrins (71-75) have been studied and structurally characterized. The electrochromic properties of the lanthanide pc sandwich complexes (76) have been investigated and the stable radical bis(phthalocyaninato)lutetium has been found to be the first example of an intrinsic molecular semiconductor (77). In contrast to the wealth of literature describing porphyrin and pc sandwich complexes, re-... 

For the neutral lutetium pz sandwich complexes, which exist as jr-cation radicals, ring oxidation to the bis 71-radical is easier for the pz than for its pc analogue, while ring reduction is harder, suggesting that the lutetium pz... 

Enantiomerically pure sandwich complexes of samarium and lutetium have been synthesized with the use of donor-functionalized cyclopentadienyl ligands. The reaction of [K (6 )-CsH4CH2CH(Me)OMe ], [K ( )-... 

The first molecular structure of half-sandwich lanthanide porphyrins was reported by Schaverien and Orpen (1991). The lutetium alkyl complex Lu(OEP)[CH(SiMc3)2] has a structure resembling that of the scandium analog (Arnold et al. 1993), exhibiting a square pyramidal geometry. The five-coordinated lutetiiun atom lies 0.918 A above the N4 plane, and the porphyrin ring also displays a saucer shape. 

The only class of lanthanidomesogens for which electrical properties have been investigated in detail, are the bis(phthalocyaninato)lanthanide(III) sandwich complexes. As already described in Section 8, the free electron in these complexes is associated with the extensive re-system of the phthalocyanine macrocycles. The individual Pc2Lu units can be considered nominally as Lu " Pc2 The bis(phthalocyaninato)lutetium(III) complexes are intrinsic molecular semiconductors. The generation of charge carriers can be represented by the reaction AAA A free carriers, where A is the molecular unit. The ionized pair A " A is photochemically or thermally activated. 

Band in the absorption spectrum of phthalocyanine lutetium form a thin layer is characterized by X, = 662 nm. This indicates that the sandwich complex is in neutral form. After treatment of the film an alcoholic solution happens recovery process. What does the reduction of the band intensity X = 662 nm, an increase in absorption X. = 618 nm and the appearance of the shoulder X = 708 nm. That the shape and position of the spectrum corresponds to phtlialocyanine blue forms. 

REDOX PROPERTIES OF SYMMETRICAL AND UNSYMMETRICAL SANDWICH COMPLEXES OF LUTETIUM(III) WITH PHTHALOCYANINATO AND NAPHTHALOCYANINATO LIGANDS... 

Redox Properties of Symmetrical and Unsymmetrical Sandwich Complexes of Lutetium(lll) with Phthalor aninato and Naphthalocyaninato Ligands M. L Her, A. Pondaven, Y. Cozien andF. Guyon... 

Takahashi K, Tomita Y, Hada Y, Tsubota K, Handa M, Kasuga K et al (1992) Preparation and electrochemical properties of the green 5ftterbium(III) and lutetium(III) sandwich complexes of octabutoxy-substituted phthalocyanine. Chem Lett 1992(5) 759-762... 

The unsymmetrical complexes LnPcPc can also be prepared in a stepwise manner (Scheme 8.1, D, upper part) [87, 112-114]. Treatment of phthalonitrile with excess of Lu(OAc)3- H2Oand DBU gives the half-sandwich compound LuPc(0Ac)(H20)2. The latter complex reacts with Na2Nc in 1-chloronaphthalene leading to the formation of LuPcNc [87]. Similarly, the template reaction of unsubstituted and crown-substituted phthalonitriles with lutetium acetate was carried out in boding w-hexanol in the presence of DBU [115-117]. Bi- and tri-nuclear [118] lutetium complexes could also be obtained following this approach [111, 119]. 

NMR data for half-sandwich rare-earth phthalocyanines are extremely rare. Ni et al. (1987) have measured the H and C NMR spectra of a series of R(Pc)(OAc)2H (R=Sm-Lu) and R(Pc)Cl (R=Er-Lu). Due to the intrinsic nature of the metal ions, the signals for the a and (3 protons of the phthalocyanine ring span a wide region. Figure 18 shows the variation of H NMR shift of the a protons and the OAc methyl protons in R(Pc)(OAc)2H (R=Sm-Yb) relative to those of the diamagnetic lutetium analog. It is noted that the A<5a/A<5(5 values remain almost constant for these complexes, showing that the shifts are mainly due to a dipolar contribution. 

In this chapter, a correlation between the ionic radius of the metal-complexing in double-decker phthalocyanines and positions of maxima Q-bands in the electronic absorption spectra were determined in dimethylformamide and chloroform. The increasing of ionic radius from holmium to lutetium caused a regular change in the position of the maxima Q-bands in the absorption spectra. The behavior of metal diphthalocyaninates in supramolecular systems was also investigated. It was revealed that a new band shifted to the red region appeared in absorption spectra of sandwich phthalocyaninates of lutetium, etbium and ytteibium in albumin solution. This particular behavior allows us to consider phthalocyanines as prototype of sensitive biosensor system. 

CHART 14 Inverse sandwiches of anionic naphthalene yttrium and lutetium complexes reported... 

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