David A. Atwood

Salan complexes of the group 12, 13 and 14 elements

Abstract Although derived from the well-known and heavily utilized SalenH 2 ligands, the SalanH 4 ligands ( N , N ′-bis( o -hydroxybenzyl)- o -diaminoalkyl(or aryl)) have not been historically developed with regards to the main group elements. This situation has been drastically changed over the past four years, with the report of new complexes of the SalanH 4 ligands incorporating the group 12, 13 and 14 elements. This review will outline the various types of complexes that are currently available as well as provide guidance for future studies. Complexes having a metal-to-ligand stoichiometry of 1:1, 2:1 and 3:1 are known. The 1:1 complexes are of two types. They include the group 12 and 14 elements SalanH 2 M (where MZn and Sn), and the group 13 elements, SalanH 2 MR (where MAl; RMe). The structures of the zinc compounds are characterized by the incorporation of significant numbers of hydrogen bonded solvent. The second type are the unique anions of formula, [SalanAl(Li(THF) 2 )] 2 . The 2:1 complexes, SalanHMR(MR 2 ) (where MAl and RMe, NMe 2 ) can adopt one of two isomeric ( cis or trans ) forms. The heating of concentrated samples of some of these leads to the formation of the dimeric condensation products, [SalanMR(MR 2 )] 2 . The 3:1 complexes, SalanMR(MR 2 ) 2 (where MAl, Ga; RMe, Et, t Bu) can also adopt either a cis or a trans geometry. The spectroscopic characterization of the trimetallics shows them to be non-fluxional in solution. Moreover, those that incorporate either Salophan or Salomphan exhibit anisotropic ring current effects.

Bimetallic mixed-metal complexes of the salen(tBu) ligands

Abstract The Salen ( t Bu ) ligands, Salen ( t Bu ) , (N,N′-ethylenebis(3,5-di-tert-butylsalicylideneimine) and Salpen ( t Bu ) , (N,N′-propylenebis(3,5-di-tert-butylsalicylideneimine) can be combined with GaEt3 to prepare the ‘open’ monometallic compounds, Salen ( t Bu)H(GaEt 2 ) (1) and Salpen ( t Bu)(GaEt 2 ) (2) . These, in turn, can be converted to the bimetallic derivatives, Salen ( t Bu)(GaEt 2 ) 2 (3) and Salpen ( t Bu)(GaEt 2 ) 2 (4) by addition of GaEt3. Alternatively, 3 and 4 can be made by the addition of two moles of GaEt3 to the appropriate ligand. This was the method used to prepare Salben ( t Bu)(GaEt 2 ) 2 (5) Salben ( t Bu ) = N,N ′- butylenebis (3,5- di-tert-butylsalicylideneimine) and Salhen( t Bu)(GaEt 2 ) 0 (6) [ Salhen ( t Bu ) = N,N ′- hexylenebis (3,5- di-tert-butylsalicylideneimine] . Compounds 1 and 2 can be utilized to form the unique mixed-metal derivatives L(GaEt2) (MR2) (where L = Salen ( t Bu ), M:R = Al, Me (7); Al, Et (9); and L = Salpen ( t Bu ), M:R = Al, Me (8) ; Al, Et (10). At ambient temperatures in non-polar solvents, 7–12 do not undergo exchange of either the alkyl or MR2 groups. All of the compounds were characterized by Mp, analyses, 1H NMR, IR and, in the case of 1 and 3–6, by X-ray crystallography.

Formation and Reactivity of Five‐Coordinate Gallium Supported by Salen Ligands

This work is an exploration into the synthesis and reactivity of five-coordinate gallium complexes of the ligands, Salen(tBu)H2 [N,N′-ethylenebis(3,5-di-tert-butylsalicylideneimine), (1)], Salpen(tBu)H2 [N,N′-propylenebis(3,5-di-tert-butylsalicylideneimine), (2)], Salophen(tBu)H2 [N,N′-phenylenebis(3,5-di-tert-butylsalicylideneimine), (3)], and Salomphen(tBu)H2 [N,N′-(4,5-dimethyl)phenylenebis(3,5-di-tert-butylsalicylideneimine), (4)]. Fully characterized examples include those of general formula LGaX, where L = 1, X = Cl (5), Et (6); 3, X = Cl (7), Et (10); 4, X = Cl (8), Me (9) Et (11). X-ray structural data is presented for 6, 7, 9, 10, and 11. The ability of these complexes to undergo either alkane or salt elimination reactions is described. In one reaction the unusual salt: [{Salophen(tBu)Ga(MeOH)}2]+BPh−4 (12) is obtained.

Synthesis and Reactivity of Five-Coordinate Indium Halides and Alkyls

New five-coordinate indium halides and alkyls have been prepared which contain the bulky Schiff base ligands. Salen (1Bu) (N,N′-ethylenebis(3,5-ethylenebis (3,5-di-tert-butylsalicylideneimine) Salomphen(1Bu) (N,N′-phenylenebis(3,5-di-tert-butylsalicylideneimine)), Salomphen(1Bu) (N,N′-phenylenebis(3,5-di-tert-butylsalicylidene-imine)), and Salomphen(1Bu) (N,N′-(3,4-dimethyl) (phehylenebis(3,5-di-tert-butylsalicylidene-imine)). These are of formula LInX (where L = Salen(1Bu) X = Cl (1), Br (5), Et (9), ME (13); L = Selpen (1Bu), X = Cl(2), Br (6), Et(10), L = Salophen (1Bu), X = Cl (3), Br (7), Et (11) and L = Salomphen(1Bu), X = Cl (4), Br (8), Et (12). Compared to four-coordinate indium compounds 1–15 are remarkably unreactive with a number of profit and lithiated reagents. Only Salen(1Bu)InOSiPh3 (14) could be isolated from a rational synthesis. In a related reaction, [Salpen(1Bu)In(μ-OMe)]2 (15) was isolated in only trace quantities.

Inorganic rings with group 13 organometallics and iminodiphosphinechalcogenides

Herein we report the synthesis and characterization of the organometallic complexes [R 2 Al{(SePPh 2 ) 2 N}] (R=Me ( 1 ), Et ( 2 ), i Bu ( 3 )) and [Et 2 Ga{(SePPh 2 ) 2 N}] ( 4 ) which were obtained through alkane elimination reactions. The compounds were characterized by physical (m.p.); chemical (C, H, analysis), and spectroscopic techniques (multinuclear NMR and IR). In addition, the crystal structure of 4 was obtained by single crystal X-ray diffraction. The molecular structure of 4 reveals a metallacycle with a diethylgallium fragment coordinated symmetrically to the imidophosphinoselenate ligand in a distorted tetrahedral environment.

Synthesis and Structural Characterization of Tetradentate (N2O2) Ligand Complexes of Zinc

The potentially tetradentate-N2O2 ligands, N,N′-bis (o-hydroxybenzyl)-1,2-diaminoethane (SaleanH4), N,N′-bis(o-hydroxybenzyl)-1,3-diaminopropane (SalpanH4), N,N′-bis(o-hydroxybenzyl)-1,4-diaminobutane (SalbanH4), N,N′-bis(o-hydroxybenzyl)-1-6-diaminohexane (SalhanH4), N,N′-bis(o-hydroxybenzyl)-1,2-diaminobenzene (SalophanH4), and N, N′-bis (o-hydroxybenzyl)-1,2-dimino-4,5-dimethylbenzene (SalomphanH4), have been synthesized and used to prepare the series of zinc complexes, [SaleanH2Zn]2 (1), [Salpan H2Zn]2 (2), [SalbanH2Zn]2 (3), [SalhanH2Zn]2 (4), [SalophanH2Zn]2 (5), and [Salomphan H2Zn]2 (6), Compounds (2) and (5) have been structurally characterized with single-crystal x-ray diffractometry. The molecules consist of oxygen-bridged zinc dimers. Unique structures for (5) were determined from crystals grown from MeOH (5a) and DMF (5b). The structures possess varying numbers of solvent molecules in the unit cell. Crystal Data: (2) Space Group P1 with a = 13.076(3) A, b = 13.137(3) A, c = 13.228 (3) A, α = ...

Tetradentate −N2O2 ligand complexes of Tin(II). X-ray crystal structure of [N,N′-(1,2-ethylene) bis (salicylaldamine)]tin(II), (SaleanH2Sn)

The tetradentate −N2O2 ligands, [N,N′-(1,2-ethylenebis(salicylaldamine)] (SaleanH4 (1), [N,N′-(1,3-propylene)bis(salicylaldamine)](SalpanH4 (2)and [N,N′-(1,2-phenylenebis(salicylaldamine)] (SalophanH4) 3, were used to prepare Sn(II) complexes that are monomeric (SaleanH2Sn (7), SalpanH2Sn (8)) and dimeric ([SalophanH2Sn]2) (9)). The structure of 7 was determined by single-crystal X-ray crystallography: orthorhombic, space pbcn with a = 19.849(4), b = 10.791(3), c = 18.559(5) A and Z = 8. Compounds 8 and 9 undergo transmetallation reactions with three equivalents of AlMe3 to produce the trimetallic derivatives, SalpanAlMe(Alme2)2 (10) and SalophanAlMe(AlMe2)2 (11).

SYNTHESIS, STRUCTURE AND REACTIVITY OF SalanH2-METAL COMPLEXES

Abstract The present work is an exploration into synthesis of complexes of general formula LH2M (where M = Mn, Fe, Cu, and Al). The results obtained for L = Salophan (M = Fe (1), Cu (2)); Salomphan (M = Mn (3), Fe(4), Cu(5); Salpan (M = Fe(6), Cu(7)) and L = Salean (M = AlCl) (8) are reported. When 8 is dissolved in MeOH, [SaleanH2AlOMe]2 (9) is formed. In MeOH, and in the presence of air, 1 and 4 undergo oxidation of both the ligand and metal (Fe(II) to Fe(III) to form the “half” Schiff base complexes, [SalophanHFeOMe]2 (10) and [SalomphanHFeOMe]2 (11). Compounds 9–11 were structurally characterized. Crystal Data: (9) C36H46Al2N4O7, Space Group P-1 (no. 2) with a = 7.536(1) A, b = 10.513(2)A, c = 11.997(2) A, α = 97.72(1), β = 94.040(10)°, γ = 102.73(1), V = 914.8(3) A3 and Z = 2. With 226 parameters refined on 1226 reflections having F>6.0[sgrave](F), the final R values were R = 0.0540 and Rw = 0.0565; (10), C46H46Fe2N4O8, Space Group P-1 (no. 2) with a = 9.400(2) A, b = 10.718(4) A, c = 12.354(3) A, α ...

Chelated Anionic Aluminum

Two equivalents of the bidentate ligands, 2.4-(R)2-6-(CH2NHR′)PhOH (where R′ = alkyl and R = H (L1) and tBu(L2)) are combined with LiAlH4 to form unique chelated aluminates of the form [(L1)2Al]Li(THG)2 (R′ = iPr (1), iBu (2), tBu (3), Dipp (4) (Dipp = 2,6-(iPr)2Ph)) and [(L2)2Al]Li(THF)2(R′ = iPr (5), iBu (6), tBu (7)). Compound 7 undergoes a salt elimination when combined with Me2AlCl to form the bimetallic derivative, (L2)2Al (AlMe2) (R′ = tBu (8)). By comparison a related reaction with [ArO4Al][Li(thi)4] (Ar = 2,4-(tBu)2Ph (9)) leads to elimination of one of the aryloxide groups and the consequent formation of neutral species. All of the compounds were characterized by Mp, analyses, 1H NMR, IR and, in the case of 4 and 7–9, by X-ray crystallography.

The Trimetallic Structural Motif in Group 13 Chemistry

Abstract In the context of this Comment, a trimetallic complex will be defined as one in which three group 13 metals are contained in one complex by either one or two multidentate ligands. This motif has been observed sporadically in the literature throughout the years. Up until the present work, however, this unique structural arrangement has not been the focus of a systematic study. This Comment will comprise a discussion of such complexes, focusing on those employing the Salan class of ligands. Members of the Salan class of tetradentate (-N2O2) ligand, N,N′-bis(o-hydroxybenzyl)-1,2-diaminoethane (SaleanH4), N,N′-bis(o-hydroxybenzyl)-1,3-diaminopropane (SalpanH4), N,N′-bis(o-hydroxybenzyl)-1,2-diaminobenzene (SalophanH4), N,N′-bis(o-hydroxybenzyl)-1,2-diamino(4,5-dimethyl)benzene (SalomphanH4), form unique, monomeric trimetallic complexes when combined with three equivalents of MR3 (where M = Al, Ga; R = Me, Et, iBu). The aluminum complexes form cis ligand complexes with Salpan, Salophan and Salomphan a...