A rational approach to the synthesis of silver-chromium mixed-metal coordination polymers is presented: 3-cyanoacetylacetone (HacacCN) features two potential binding sites. After deprotonation, it has been used as a chelating dionato ligand in the pseudo octahedral complex Cr(acacCN) 3; two polymorphs of this compound have been identified. In its protonated form, HacacCN was employed as a N donor toward Ag(I). Both functionalities may be exploited within the same solid: The chromium complex and silver salts of weakly coordinating anions have been successfully combined to mixed-metal coordination polymers. Cr(acacCN) 3 plays the role of a substitution-inert tecton with predictable bonding geometry which interacts with the conformationally soft silver cations via two or all three of its peripheric nitrile groups. From an equimolar amount of both constituents, six solids featuring a 1:1 ratio between Cr- and Ag-derived building blocks were obtained in good yield; their structures depend on the counteranions and the cocrystallized solvent and correspond either to 2D networks with (6,3) or augmented (4,4) topology or, in one case, adopt a 3D connectivity. In addition, three products with a Cr/Ag = 2:1 stoichiometry have been isolated: they adopt two-dimensional network structures.

Rare-earth metal alkyl complexes with tridentate [OSO]-type and tetradentate [OSSO]-type bis(phenolato) ligands, [Ln(L)(CH2SiMe3)(THF) n ] (LH2 = 2,2′-thiobis(6-tert-butyl-4-methylphenol) (tbmpH2), 1,3-dithiapropanediylbis(6-tert-butyl-4-methylphenol) (mtbmpH2), 1,4-dithiabutanediylbis(6-tert-butyl-4-methylphenol) (etbmpH2); Ln = Y (1−3), Sc (4, 5), Lu (7), Ho (9, 10)), were synthesized from the reactions of the tris(alkyl) complexes [Ln(CH2SiMe3)3(THF)2] with the corresponding bis(phenol) via alkane elimination. The alkyl complexes were characterized by NMR spectroscopy (Y, Sc, Lu) and elemental analysis as well as by X-ray crystal structure analysis (5, 7). The reaction of [Lu(CH2SiMe3)3(THF)2] with H2etbmp in a 1:2 ratio led to the formation of the bis(phenolato)-bridged dinuclear complex [Lu2(etbmp)3(THF)2] (8). The reaction of the holmium alkyl complexes 9 and 10 with PhSiH3 resulted in the formation of the corresponding hydrido complexes [Ho(L)(μ-H)(THF) n ]2 (L = tbmp, n = 3, 11; L = etbmp, n = 2, 12). The formation of the yttrium analogues could be observed by NMR spectroscopy. Complexes 2, 4, and 5 were tested in the hydrosilylation of a wide variety of aliphatic and aromatic 1-alkenes and 1,5-hexadiene with various silanes (PhSiH3, nBuSiH3, and Ph2SiH2). In the case of terminal aliphatic alkenes an anti-Markovnikov (1,2) addition takes place with 80−99% regioselectivity. The hydrosilylation of styrene afforded the Markovnikov (2,1) addition product PhHC(SiH2Ph)Me with 97% regioselectivity. The hydrosilylation of 1,5-hexadiene by PhSiH3 catalyzed by 2 resulted in the formation of a linear product, 1,6-bis(phenylsilyl)hexane (ca. 90%), and a cyclic product, (phenylsilylmethyl)cyclopentane (ca. 10%), whereas with nBuSiH3 84% of the cyclic product was obtained.

Rare-earth metal tris(borohydrides) [Ln(BH4)3(thf)3] (Ln = Y, La, Nd, Sm) are converted with one equivalent of the Brønsted acid [NEt3H]+[BPh4]- in thf into the monocationic bis(borohydride) complexes [Ln(BH4)2(thf)5]+[BPh4]-. They efficiently initiate the ring-opening polymerisation of epsilon-caprolactone.

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Lutetium alkyl complexes [Lu(L)(CH(2)SiMe(3))(THF)(n)], which contain a sulfur-linked bis(phenolato) ligand such as 2,2'-thiobis(6-tert-butyl-4-methylphenolate) (L=tbmp, 1) or 1,4-dithiabutanediyl-bis(6-tert-butyl-4-methylphenolate) (L=etbmp, 2), were isolated from the reaction of the lutetium tris(alkyl) complex [Lu(CH(2)SiMe(3))(3)(THF)(2)] with H(2)L. The monomeric structures of these complexes were confirmed by X-ray diffraction studies, showing distorted octahedral geometry around the metal centre. The reaction of [Lu(tbmp)(CH(2)SiMe(3))(THF)(2)] (1) with alcohols ROH (R=iPr, CHPh(2), CPh(3)) results in the formation of the corresponding alkoxide complexes [Lu(tbmp)(OR)(THF)(n)] (4-6). With PhSiH(3) hydride complexes [Lu(L)(mu-H)(THF)(n)](2) (L=tbmp, 7; etbmp, 8) have been prepared in moderate to good yields. They adopt a dimeric form in the solid state as revealed by the X-ray crystal structure of 7. The reactivity of the hydride complexes and their catalytic activity in the ring-opening polymerisation of L-lactide and the hydrosilylation of alkenes are also discussed.