Ned J. Hardman

Stable, Monomeric Imides of Aluminum and Gallium: Synthesis and Characterization of [{HC(MeCDippN)2}MN‐2,6‐Trip2C6H3] (M=Al or Ga; Dipp=2,6‐iPr2C6H3; Trip=2,4,6‐iPr3C6H2)

A short Ga-N bond with double-bond character is displayed by the first monomeric imide of gallium, which was obtained by the reaction of [{HC(MeCDippN)2 }M:] (Dipp=2,6-iPr2 C6 H3 , M=Ga; see picture) with N3 -2,6-Trip2 C6 H3 (Trip=2,4,6-iPr3 C6 H2 ). The analogous aluminum (M=Al) compound is also readily available.

Sterically encumbered terphenyl substituted primary pnictanes ArEH2 and their metallated derivatives ArE(H)Li (Ar=C6H3-2,6-Trip2; Trip=2,4,6-triisopropylphenyl; E=N, P, As, Sb)

Abstract A series of sterically crowded primary pnictanes of formula ArEH 2 (Ar=C 6 H 3 -2,6-Trip 2 ; Trip=C 6 H 2 -2,4,6- i -Pr 3 ; E=N, 2; P, 4 ; As, 5 ; Sb, 6 ) and their lithiated pnictide salts ArE(H)Li (E=N, 7 ; P, 8 ; As, 9 ; Sb, 10 ) have been synthesized and characterized by X-ray crystallography ( 2 - 6 ), NMR, IR spectroscopy, and by combustion analysis. Details of the synthesis and structures of the azide derivative ArN 3 ( 1 ) and the arylphosphinic acid ArP(O)(OH)H ( 3 ) are also given. The amine compound 2 displays a planar geometry (within the limits of experimental error) at nitrogen which is attributable to interactions between the NH moieties and the ortho -aryl rings. The antimony compound 6 is a rare instance of a stable primary stibane and its X-ray crystal structure represents the first structural determination of such a species.

Synthesis and characterization of the monomer Ga{(NDippCMe)2CH} (Dipp = C6H3Pri2-2,6): a low valent gallium(I) carbene analogue

The reaction between solvent free Li{(NDippCMe)2CH} (Dipp = C6H3Pri2-2,6), ‘GaI’ and potassium in toluene afforded Ga{(NDippCMe)2CH} 1 which features a V-shaped, two-coordinate, six-electron gallium(I) center electronically analogous to a singlet carbene carbon.

In8(C6H3-2,6-Mes2)4 (Mes=C6H2-2,4,6-Me3): A Metal-Rich Main-Group Cluster with a Distorted Cubane Structure

A distorted In(8) cubane core (see picture) is present in the novel indium cluster In(8)(C(6)H(3)-2,6-Mes(2))(4) (Mes=C(6)H(2)-2,4,6-Me(3)), which was synthesized by the reaction of LiC(6)H(3)-2,6-Mes(2) with InCl. It has an average In-In bond length of 2.92 A and represents a new addition to the range of heavier Group 13 element clusters.

Unusual structures of lithium terphenyl derivatives

Abstract The synthesis, spectroscopic and structural characterization of three new lithium derivatives of terphenyl ligands are reported. These are the mixed lithium alkyl–lithium aryl compound {Li(t-Bu)LiC6H3-2,6-Trip2} (1, Trip=C6H2-2,4,6-i-Pr3), the dilithiated {LiC6H3-2-(C6H3-2-Me-5-t-Bu)-6-(C6H3-2-CH2Li-5-t-Bu)·Et2O}2 (2), and the ether solvated (Et2O)LiC6H3-2,6-(C6H4-4-t-Bu)2 (3). The synthesis of the terphenyl halide precursors for 2 and 3 is also given. The compound 1 resulted from the treatment of 1-IC6H3-2,6-Trip with two equivalents of Li(t-Bu) in hexane. It features the alkyl and aryl (terphenyl) groups bridged by two lithium ions. The lithium ions are further solvated by ortho aryl substituents and methyls of the t-Bu groups. This compound is a very rare example of a mixed lithium alkyl–lithium aryl species. Compound 2 was obtained in low yield from the treatment of 1-BrC6H3-2,6-(C6H3-2-Me-5-t-Bu)2 with two equivalents of Li(t-Bu). The terphenyl ligand was dilithiated by replacement of the bromine and a hydrogen from one of the methyl groups on the ortho aryl substituents. The ether solvated, dimeric, tetrametallic structure illustrated in the Table of Contents resulted. The compound 3 was obtained from the straightforward lithiation of the iodoterphenyl precursor in the presence of diethyl ether and features a lithium ion solvated by two ethers terminally bound to the ipso-carbon of the terphenyl group.

A primary monomeric alane: [N,N′‐bis(2,6‐diiso­propyl­phenyl)­pentane‐2,4‐diiminato‐N,N′]­dihydrido­aluminium

The title compound, [AlH2(C29H41N2)], is an example of a sterically encumbered monomeric primary alane. The bond lengths are within normal ranges. The N—Al distance is 1.8989 (12) A. The H atoms bonded to the aluminium center were located in a difference map and refined to Al—H distances of 1.51 (2) and 1.518 (19) A. There are no significant intermolecular interactions.

Gallium–boron donor–acceptor bonds

Examples of compounds with gallium-boron donor-acceptor bonds, HC[MeC(2,6-pri2C6H3)N]2Ga-->B(C6F5)3 3 and (eta 5-C5Me5)Ga-->B(C6F5)3 4 have been prepared by treatment of the free gallanediyls with B(C6F5)3; the structures of both compounds were determined by X-ray crystallography.

Unique structural isomerism involving tetrazole and amide/azide derivatives of gallium

The reaction between {HC(MeCDippN)2}Ga: (Dipp = C6H3Pri2 -2,6) and N3SiMe3 afforded the tetrazole {HC(MeCDippN)2}GaN(SiMe3)NNN(SiMe3) 1 and its amide/azide isomer {HC(MeCDippN)2}Ga(N3)N(SiMe3) 2 2 whose stabilities are due to the unique steric properties of the [HC(MeCDippN)2]− ligand.