Reduction of the aluminum iodide AlI 2 Ar iPr8 (1;2 ) with 5% w/w Na/NaCl in hexanes gave a dark red solution from which the monomeric alanediyl :AlAr iPr8 (2) was isolated in ca. 28% yield as yellow-orange crystals. Compounds 1 and 2 were characterized by X-ray crystallography, electronic and NMR spectroscopy, and theoretical calculations. The Al atom in 2 is one-coordinate, and the compound displays two absorptions in its electronic spectrum at 354 and 455 nm. It reacts with H 2 under ambient conditions to give the aluminum hydride {AlH(μ-H)Ar iPr8 } 2 , probably via a weakly bound dimer of 2 as an intermediate.

The reaction of :AlAr i Pr8 (Ar i Pr8 = C 6 H-2,6-(C 6 H 2 -2,4,6- i Pr 3 ) 2 -3,5- i Pr 2 ) with Ar Me6 N 3 (Ar Me6 = C 6 H 3 -2,6-(C 6 H 2 -2,4,6-Me 3 ) 2 ) in hexanes at ambient temperature gave the aluminum imide Ar i Pr8 AlNAr Me6 ( 1 ). Its crystal structure displayed short Al–N distances of 1.625(4) and 1.628(3) Å with linear (C–Al–N–C = 180°) or almost linear (C–Al–N = 172.4(2)°; Al–N–C = 172.5(3)°) geometries. DFT calculations confirm linear geometry with an Al–N distance of 1.635 Å. According to energy decomposition analysis, the Al–N bond has three orbital components totaling −1350 kJ mol –1 and instantaneous interaction energy of −551 kJ mol –1 with respect to :AlAr i Pr8 and Ar Me6 N̈:. Dispersion accounts for −89 kJ mol –1 , which is similar in strength to one Al–N π-interaction. The electronic spectrum has an intense transition at 290 nm which tails into the visible region. In the IR spectrum, the Al–N stretching band is calculated to appear at ca. 1100 cm –1 . In contrast, reaction of :AlAr i Pr8 with 1-AdN 3 or Me 3 SiN 3 gave transient imides that immediately reacted with a second equivalent of the azide to give Ar i Pr8 Al[(NAd) 2 N 2 ] ( 2 ) or Ar i Pr8 Al(N 3 ){N(SiMe 3 ) 2 } ( 3 ).

The reaction of the molybdenum−molybdenum triple-bonded dimer (CO) 2 CpMoMoCp(CO) 2 (Cp = η 5 -C 5 H 5 ) with the triple-bonded dimetallynes Ar iPr4 MMAr iPr4 or Ar iPr6 MMAr iPr6 (Ar3 ) 2 ; M = Ge, Sn, or Pb) under mild conditions (≤80 °C, 1 bar) afforded Ar iPr4 MMoCp(CO) 2 or Ar iPr6 MMoCp(CO) 2 in moderate to excellent yields. The reactions represent the first isolable products from a metathesis of two metal−metal triple bonds. Analogous exchange reactions with the single-bonded (CO) 3 CpMo−MoCp(CO) 3 gave ArM ̈−MoCp(CO) 3 (Ar = Ar iPr4 or Ar iPr6 ; M = Sn or Pb). The products were characterized by NMR ( 1 H, 13 C, 119 Sn, or 207 Pb), electronic, and IR spectroscopy and by X-ray crystallography.

A series of formally triply bonded diplumbyne analogues of alkynes of the general formula ArPbPbAr (Ar = terphenyl ligand with different steric properties) was synthesized by two routes. All diplumbyne products were synthesized by a simple reduction of the corresponding Pb(II) halide precursor ArPb(Br) by DIBAL-H with yields in the range 8−48%. For one of the diplumbynes Ar Pri 4 PbPbAr Pri 4 (Ar Pri 4 = C 6 H 3 -2,6-(C 6 H 3 -2,6-Pr i 2 ) 2 ) it was shown that reduction of Ar Pri 4 Pb(Br) using a magnesium(I) beta-diketiminate afforded a much improved yield in comparison (29 vs 8%) to that obtained by reduction with DIBAL-H. The more sterically crowded diplumbyne Ar Pri 8 PbPbAr Pri 8 (Ar Pri 8 = C 6 H-3,5-Pr i 2 -2,6-(C 6 H 2 -2,4,6-Pr i 3 ) 2 ) displayed a shortened Pb−Pb bond with a length of 3.0382(5) Å and wide Pb−Pb−C angles of 114.73(7)°and 116.02( 6)°consistent with multiple-bond character with a bond order of up to 1.5. The others displayed longer metal−metal distances and narrower Pb−Pb−C angles that were consistent with a lower bond order that approached one. Computational studies of the diplumbynes yielded detailed insight of the unusual bonding and explained their similar electronic spectra arising from the flexibility of the C−Pb−Pb−C core in solution. Furthermore, the importance of London dispersion interactions for the stabilization of the diplumbynes was demonstrated.

Two quasi stable lead(ii) hydrides appear to be stabilized by intermolecular dispersion forces in the crystal phase.