Bora-amidinate as a cooperative ligand in group 2 metal catalysis.

Syntheses and crystal structures of the monomeric bora-amidinate (bam) complexes NBN-Mg·(THF) and NBN-Ca·(THF) are presented; NBN = HB[N(2,6-iPr-CH)]. The simplicity of their H NMR spectra in THF-d suggest that their monomeric solid state structures are retained in solution. NBN-Mg·(THF) in CD, however, is in equilibrium with a dimeric species.

Thermal decomposition of mono- and bimetallic magnesium amidoborane complexes.

Complexes of the type [(DIPPnacnac)MgNH(R)BH(3)] have been prepared (DIPPnacnac=CH{(CMe)(2,6-iPr(2)C(6)H(3)N)}(2)). The following substituents R have been used: H, Me, iPr, DIPP (DIPP=2,6-diisopropylphenyl). Complexes [(DIPPnac- nac)MgNH(2)BH(3)].

Peculiar binding modes of a ligand with two adjacent beta-diiminato binding sites in alkali and alkaline-earth metal chemistry.

Reaction of the diprotic ligand [Xanthdim]H(2) (a ligand system where two adjacent beta-dialdimine units are linked by a xanthyl backbone) with 2 equiv of potassium hydride or benzylcesium gave access to bimetallic alkali metal complexes. These complexes were structurally characterized by X-ray diffraction, which showed that the beta-diiminato units are orientated in a W-conformation. Treatment with 2 equiv of Mg[N(SiMe(3))(2)](2)(THF)(2) led to the formation of the heteroleptic complex [Xanthdim][MgN(SiMe(3))(2)(THF)](2), that crystallized as a highly strained monomer.

Superbulky metallocene complexes of the heavier alkaline-earth metals strontium and barium.

Superbulky sandwich complexes with the cyclopentadienyl ligand (4-nBu-C(6)H(4))(5)Cp (abbreviated here as Cp(BIG)) have been prepared by reaction of Cp(BIG)H with benzylic strontium or barium reagents. Both metallocenes have been structurally characterized by single crystal X-ray diffraction. Even for the larger metallocene (Cp(BIG))(2)Ba a highly symmetric sandwich complex with parallel Cp rings was isolated (Cp(center)-Ba = 2.