Synthesis, structure, and reactivity of mixed-sandwich zirconacarborane methyl complex (η5-C5Me5)[η1:η5-(Me2NCH2CH2)C2B9H10]ZrMe

Nickel(II) and Palladium(II) Complexes with η5:κ1(N)-Coordinated Dicarbollide Ligands Containing Pendant Pyridine Group

A series of C- and B-substituted nido-carborane derivatives with a pendant pyridyl group was prepared. The synthesized compounds were used as ligands in the complexation reactions with bis(triphenylphosphine)nickel(II) and palladium(II) chlorides to give six new metallacomplexes with unusual η5:κ1(N)-coordination of the metal center. The single crystal structures of 1-(NC5H4-2'-S)-1,2-C2B10H11, 1-(NC5H4-2'-CH2S)-1,2-C2B10H11, Cs [7-(NC5H4-2'-CH2S)-7,8-C2B9H11] closo- and nido-carboranes and 3-Ph3P-3-(4(7)-NC5H4-2'-S)-closo-3,1,2-NiC2B9H10 and 3-Ph3P-3-(4(7)-NC5H4-2'-CH2S)-closo-3,1,2-NiC2B9H10 metallacarboranes were determined using single crystal X-ray diffraction.

Synthesis and crystal structures of nickel(ii) and palladium(ii) complexes with o-carboranyl amidine ligands

A number of new nido-carboranyl amidines 10-R(CH₂)_nNHC(Et)[double bond, length as m-dash]HN-7,8-C₂B₉H₁₁ (n = 2, R = OH, OMe, and NMe₂; n = 3, R = OH) were synthesized by the nucleophilic addition of amino alcohols and N,N-dimethylethylenediamine to the highly activated -C[triple bond, length as m-dash]N⁺- triple bond of the 10-propionitrilium derivative of nido-carborane. A similar reaction of 10-EtC[triple bond, length as m-dash]N-7,8-C₂B₉H₁₁ with ethylenediamine unexpectedly resulted in the cleavage of the C[triple bond, length as m-dash]N bond to form the ammonium derivative 10-H₃N-7,8-C₂B₉H₁₁. The complexation of the synthesized carboranyl amidines 10-MeO(CH₂)₂NHC(Et)[double bond, length as m-dash]HN-7,8-C₂B₉H₁₁ and 10-Me₂N(CH₂)₂NHC(Et)[double bond, length as m-dash]HN-7,8-C₂B₉H₁₁ with nickel and palladium phosphine complexes [(Ph₃P)₂MCl₂] (M = Ni, Pd) was studied. The reactions with 10-MeO(CH₂)₂NHC(Et)[double bond, length as m-dash]HN-7,8-C₂B₉H₁₁ result in half-sandwiched metallacarborane complexes with the retention of one triphenylphosphine ligand [3-Ph₃P-3-(8-MeOCH₂CH₂N[double bond, length as m-dash]C(Et)NH)-3,1,2-MC₂B₉H₁₀], while the reactions with 10-Me₂N(CH₂)₂NHC(Et)[double bond, length as m-dash]HN-7,8-C₂B₉H₁₁ proceed with the complete loss of the phosphine ligands and lead to the formation of complexes with the η⁵:κ²(N,N')-coordinated carboranyl amidine ligand [3,3-(8-Me₂NCH₂CH₂N[double bond, length as m-dash]C(Et)NH)-3,1,2-MC₂B₉H₁₀]. The crystal molecular structures of the synthesized complexes were determined by single crystal X-ray diffraction.