Amido-hydride structure

The product amido-hydride is the first structurally characterized transition metal complex that features both a terminal amide and hydride. The X-ray crystal structure shows that the nitrogen centre has planar coordination. This geometry results from 71-bonding between the nitrogen electron pair and the lowest unoccupied metal orbital which lies in the equatorial coordination plane of the atoms lr(Ci ethine)(H)(N). This is consistent with earlier calculations on related species. The possibility that the addition of... 

The bisphosphonate - upon reduction with lithiumaluminum hydride in ether at 0°C - produced the amide functionalized primary bisphosphine (1) in good yields [45]. This reaction proceeded to reduce the amide group in 1 to produce the amine functionaUzed primary bisphosphine (2) in <5% yields. The amido bisprimary phosphine 1 is an air stable crystalline solid whereas the amine compound 2 is an oxidatively stable liquid. Separation of 1 and 2 in pure forms was achieved using coliunn chromatography. The amidic bisprimary phosphine 1 was crystallized from chloroform and exhibits remarkable stability not only in the solid state but also in solution as well. The crystal structure of the air stable primary his-phosphine 1 as shown in Fig. 1 is unprecedented to date. 

Scheme 14 The proposed catalytic cycle for the ATH of acetophenone catalyzed by (S,S)-67 and KOtBu, or more efficiently by (S,S)-83 and KOtBu in iPrOH and the structures of the amido(ene-amido) complex 81 and amine(hydride) complex 82...

A recent exhaustive review [1] presents the known and well characterised lanthanide hydrides. Recently, a few additional original complexes have been synthesised. These include phospholyl [7] and indenyl derivatives [8], a bimetallic metallocenic structure (Scheme 1) [4], a samarium hydride supported by a calix-tetrapyrrolyl ring, with a triply bonded hydride ligand (Scheme 2) [9], metallocenes with chiral groups which has been used for the asymmetric hydrogenation [10], a tris(pyrazolyl)borate ytterbium(II) hydride [11], Cp amido-[12] and bis(amido)yttrium hydrides [13]. The latter was not isolated but obtained in situ from the methyl derivative (Scheme 2). 

Other Ligands.—Reactions of platinum(n) complexes PtHX(PR3>2 with azides, which give amido-complexes, may proceed by attack at the co-ordinated hydride. In Friedel-Crafts sulphination of Fe(butadiene)-(CO)s, attack is both at the metal and at the diene ligand, for an X-ray study has revealed that the structure of the intermediate is (49). ... 

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