Diane Dickie - Addition of aluminum and gallium species to aromatic and alkyl-substituted 1,4-diaza-1,3-butadiene ligands.

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      Publication Details (including relevant citation   information): Felix,Ana M., Dickie,Diane A., Horne,Ian   S., Page,Giang, Kemp,Richard A., Inorg. Chem. (Washington,   DC, U. S.), 2012, 51 (8), pp   4650-4662

      Abstract: N,N'-Diaryl-1,2-diimines RN:CHCH:NR   (R-DAB, R = 2,6-iPr2C6H3, mesityl, tBu) undergo addn. of the   alkyl group across C:N double bond in reaction with   organometallic Group IIIA compds., MenAlCl3-n, MenGaCl3-n (n =   1-3) with concomitant double bond migration, yielding complexes   [(RN:CMeCH2NR)MMen-1Cl3-n] or, in the case of GaCl3, ionic   compds. [(RN:CHCH:NR)GaCl2][GaCl4]. In combination with other   previously reported structures, certain general trends of   reactivity of these species can be deduced, although there are   still some unexplained modes of reactivity. The methylated Al   species react with arom.-substituted R-DAB ligands to provide   final products that result from C:N insertion into the Al-Me   group followed by rearrangement reactions. The addn. of Me groups   onto the backbone of the RDAB ligand is insufficient to stop the   insertion and rearrangement processes from occurring. In the case   of MeAlCl2 with the bulky Dipp-DAB ligand (Dipp = 2,6-iPr2C6H3),   the reaction could be followed spectroscopically from the   monoadduct through the inserted/rearranged final product.   Methylated Ga species, however, are much less predictable in   their behavior with arom.-substituted RDAB ligands. Depending on   the exact species and ratios used, coordinated adducts can be   formed and identified, or inserted/rearranged products similar to   the aluminum reactions can be obtained. Quite interestingly,   cation/anion pairs can also be formed in which GaCl3 or MeGaCl2   act as a chloride acceptors. This behavior was unique and   substantially different from the analogous Al reactions which   formed either a dicoordinated adduct or an inserted/rearranged   complex. When the stronger-donating alkyl-substituted R-DAB   ligands were used with Me2GaCl, only cation/anion pairs were   obtained. Surprisingly, when the same reactions were performed   using Me2AlCl as a reagent, irreproducible results were obtained.   [on SciFinder(R)]

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