Heteroleptic lanthanide complexe

Synthesis of Heteroleptic Lanthanide(lll) Complexes Containing Porphyrin-Based Ligands... 

Scheme 12.8 (a) Introduction of bulky ligands (L ) by direct grafting of heteroleptic lanthanide silylamide complexes on mesoporous MCM-41 (22-25) (cf route A in Scheme 12.3) (b) grafting of (homoleptic) lanthanide silylamide complexes on a mesoporous material (cf route A in Scheme 12.3) followed by a subsequent ligand exchange (cf route C in Scheme 12.3) via protonolysis of the Ln-N bond with HL (A-L). 

Heteroleptic chromium aryl compounds, preparation and characterization, 5, 298 Heteroleptic compounds actinide complexes, 4, 193 lanthanide complexes, 4, 7... 

Hydrocarbonyl compounds, lanthanide complexes, 4, 4 ( -Hydrocarbyl)bis(zirconocene), preparation, 4, 906 Hydrocarbyl-bridged cyclopentadienyl-amido complexes, with Zr(IV), 4, 864 Hydrocarbyl complexes bis-Cp Ti hydrocarbyls reactions, 4, 551 structure and properties, 4, 551 synthesis, 4, 542 cobalt with rf-ligands, 7, 51 cobalt with rf-ligands, 7, 56 cobalt with ]4-ligands, 7, 59 cobalt with rf-ligands, 7, 71 heteroleptic types, 4, 192 homoleptic types, 4, 192 into magnetic metal nanoparticles via ligand stabilization, 12, 87 via polymer stabilization, 12, 87 into noble metal nanoparticles... 

Compounds of type [Cp2LnNH2]2 were obtained by simple metathesis reaction or by thermal decomposition (200-250 °C) of complexes Cp3Ln(NH3) according to Eq. (3) [4,62]. Both the ammonia (150-160 °C, for the smaller lanthanides) and the heteroleptic amide complexes (230 °C) can be sublimed under high vacuum. The Ce(IV) amide derivatives Cp3CeNH2 and Ind2Ce(NH2)2 were also discussed as metathesis products. 

Pyrrole ligands can form both Ln-N or-bonds and tjs-n-Ln bonds. complexes with sterically less crowded pyrrole ligands [195]. The introduction of sterically demanding groups in a-position as in 2,5-di-fert-butylpyrrole led to a shielding of the nitrogen and subsequent -coordination to the lanthanide center [196]. Additionally, rj1-coordination to a sodium atom is observed in the obtained ate complex. 

The synthesis, structure, and physical and chemical properties of organo-lanthanide complexes containing only polyhaptocyclopentadienyl and cyclooctatetraenyl metal-carbon bonds are fully covered in other reviews (5-7). This section will focus on lanthanide-carbon single bonded species only. Ln—C single bonds are found almost exclusively in only two types of complexes homoleptic complexes, and heteroleptic... 

Several excellent reviews are available covering different scientific purposes and technological applications of phthalocyanines [46-51]. Here, we focus on synthetic aspects of one particular type of Pc-derivative, namely bis(phthalocyaninato) complexes of trivalent lanthanides, as well as analogous heteroleptic complexes containing porphyrin and porphyrin-like ligands. 

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-... 

As can be seen from Scheme III, lanthanide halides are suitable precursors for the synthesis of homoleptic derivatives such as silylamides [114], cyclopen-tadienyls [115] and aryloxides [116]. Such organometallies can be readily obtained in a pure form by sublimating them from the reaction mixture. They themselves are important precursors in organometallic transformations (vide infra). Heteroleptic complexes of the type CpxLn(halide)y (x + y = 2,3) are important synthetic precursors with respect to formation of various Ln-X bonds via simple metathesis reactions [2-29]. Fig. 4 indicates the lanthanide element bonds which are involved in these ubiquitous heteroleptic cyclopentadienyl systems. 

A few classic heteroleptic complexes were sythesized involving additional lanthanide iodide [146], cyclopentadienyl [147,149], amide [141], alkoxide... 

Double-decker complexes of the smaller elements (Tb-Lu) [237] are available by activated Por-precursors, namely Li2Por [238]. Lanthanide dialkylam-ides should provide an alternative route [239]. Triple-decker complexes are more readily formed compared to the Pc derivatives (Fig. 23). In an effort to force the localization of the unpaired electron on one ring, heteroleptic systems such as Por/Por and Pc/Por lanthanide sandwich complexes have been studied (Table 18 Fig. 23). 

Figure 4.42. Molecular structures of commonly used CVD precursor classes. Shown are (a) metal p-diketonate (acetylacetonate, acac) complex to grow a metal oxide film (H2 as the coreactant gas yields a metal film) (b) a heteroleptic (more than one type of ligand bound to the metal) p-diketonate complex to yield a Cu film the ancillary ligand helps prevent oligomerization, enhancing volatility (c) various types of complexes to deposit metallic, oxide, nitride, or oxynitride films (depending on coreactant gas(es) used - respective ligands are p-ketoiminato, p-diketiminato, amidinato, and guanidinato (d) a metal azolato complex commonly used to deposit lanthanide metal thin films.

However, the structures of the lanthanide ions tend to be less regular, particularly when more than one type of ligand is present in a heteroleptic complex. 

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