Synthesis and properties of some gallium amidine complexes [GaX_yL_3–y][X = Me, Et or Cl; L = RNCR′NR (R, R′= H, alkyl or aryl); y= 0–2]. Crystal structures of [GaMe₂(PhNCPhNPh)] and [GaMe(PhNCPhNPh)₂]

Abstract

The amidinato compounds [GaMe,L] [L = RNCR'NR (R, R' = H, alkyl or aryl)], [GaMe(PhNCPhNPh),], [GaEt(PhNCMeNPh),] and [Ga(PhNCRNPh),] (R = Me or Ph) have been isolated from the reaction of the appropriate gallium trialkyl with 1, 2 and 3 mol of amidine RNCR'N(H)R, respectively. The chloro derivatives [GaCl,{ RNCR'N(H)R)] (R = Ph or p-ClC,H,; R' = Me) and [GaC12(p-C1C,H,NCMeNC,H,C1-p)l have also been prepared. The compounds have been fully characterised, and mass spectrometric data indicate that the volatile dimethylgallium derivatives exist as either monomers or dimers in the gas phase. X-Ray crystallographic studies on [GaMe,(PhNCPhNPh)] and [GaMe(PhNCPhNPh),] revealed monomeric structures and the presence of chelating amidinate ligands, with distorted tetrahedral and trigonal-bipyramidal co-ordination respectively at the metal centres. Cleavage of the Ga-Me bond occurs on photolysis in the presence of a spin-trapping agent, and thermal decomposition of the solids leads to the formation of gallium nitride.* Non-SZ units employed: G = T, eV z 1.60 x 10 l 9 J.

Synthesis and Structure of Neutral and Cationic Gallium Complexes Incorporating Bis(oxazolinato) Ligands

“…The Ga metal center in 2b adopts a slightly distorted tetrahedral geometry with a chelate bite angle [N(1)-Ga-N(2) = 91.1(2)°] similar to that in the related β-diketiminatodimethylgallium complex [HC{C(Me)N(C 6 H 3 -2,6-iPr 2 )}-GaMe 2 ] [93.92(7)°], which also contains a six-membered C 3 N 2 Ga metallacycle. [11] The Ga-N and Ga-C bond lengths in 2b [1.966(9) Å and 1.98(1) Å average, respectively] are similar to those observed in related {LX}GaMe 2 (2) 1.970(3) Ga-C(1) 1.963(9) N-C (7) 1.320(3) Ga-C(2) 2.004(10) C (7) species such as [HC{C(Me)N(C 6 H 3 -2,6-iPr 2 )}GaMe 2 ], [11] [{PhC(NPh) 2 }GaMe 2 ], [12] and [{tBuC(NCy) 2 }GaMe 2 ]. [13] The six-membered C 3 N 2 Ga metallacycle in [{BOX-(S)-iPr}GaMe 2 ] (2b) is nearly planar (C-C-Ga-N Ͻ 6°) with the carbon and nitrogen atoms adopting a trigonal-planar geometry (sum of angles ca.…”

Aluminum and Indium Complexes derived from Guanidines, Triazenes, and Amidines

“…Our chemistry involving N , N ′‐bis(2, 6‐dialkylphenyl)N E N ligands ( E = CR or N, Figure 1) has been dominated by s‐block5 and rare earth metals,6 however we also have an interest in guanidinate (including phosphaguanidinate), triazenide, and amidinate complexes of the main group elements,7 in particular those of the group 13 elements due to their potential as MOCVD precursors,8 as catalysts,9 and as precursors to low valent10 and hydride complexes 11. To this end we have predominantly focused on the use of sterically demanding ligands such as those in Figure 1 to prepare low oxidation state complexes10 and metallohydrido species,11 as well as transition metal complexes of the monovalent group 13 N‐heterocyclic carbene analogues Ga(CGiso) and In(CGIso) 12.…”

Bis(amidinate) Complexes of Silicon and Germanium

“…The coordination chemistry of amidinates is well established, not only for the transition metals [1] [2] and the lanthanoides [3] , but also for main group elements [4] [5] [6] [7] [8] . The main importance lies in the generation of elementϪni-trogen bonds as needed for CVD methods [9] , and for the synthesis of new catalysts.…”