Salt Elimination Reactions Research Articles

Synthesis and Reaction of MnII Iodides Bearing the β‐Diketiminate Ligand: the First Divalent Manganese N‐Heterocyclic Carbene Complexes [{HC(CMeNAr)2}MnI{C[N(iPr)CMe]2}] and [{HC(CMeNAr)2}MnNHAr{C[N(iPr)CMe]2}] (Ar = 2,6‐iPr2C6H3)

AbstractThe manganese mono‐iodide [HC(CMeNAr)2]MnI(THF) (Ar = 2,6‐iPr2C6H3) (3) was prepared in good yield from the reaction of [HC(CMeNAr)2]K with MnI2 in THF. Treatment of 3 under reflux in toluene and removing all the volatiles in vacuo afforded the dimeric compound [{HC(CMeNAr)2}Mn]2(μ‐I)2 (4). Displacement of the coordinated THF in 3 by a strong Lewis base C[N(iPr)CMe]2 or by adding C[N(iPr)CMe]2 to the toluene solution of 4 readily gave the N‐heterocyclic carbene adduct [{HC(CMeNAr)2}]MnI{C[N(iPr)CMe]2} (5). Reduction of 5 with sodium/potassium alloy at room temperature unexpectedly resulted in the formation of the monomeric compound [{HC(CMeNAr)2}]MnNHAr{C[N(iPr)CMe]2} (6). Alternatively 6 was obtained by the salt elimination reaction of 5 with LiNHAr. Compounds 5 and 6 are the first examples of divalent manganese N‐heterocyclic carbene adducts and the first manganese non‐carbonyl carbene complexes. The single crystal X‐ray structural analyses reveal that compounds 3 and 6 are monomeric and compound 4 is dimeric in the solid state. The manganese centers in these compounds exhibit a distorted tetrahedral geometry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

“Constrained Geometry” Group 3 Metal Complexes of the Fluorenyl-Based Ligands [(3,6-tBu2Flu)SiR2NtBu]: Synthesis, Structural Characterization, and Polymerization Activity

Alkane elimination between Y(CH2SiMe3)3(THF)2 and the diprotio ligands [(3,6-tBu2C13H7)SiR2NHtBu] (R = Me, 1a; R = Ph, 1b) gave [η3:η1-((3,6-tBu2C13H6)SiR2NtBu)Y(CH2SiMe3)(THF)2] (R = Me, 2a; R = Ph, 2b). 2a is thermally stable in toluene solution and shows a dynamic behavior connected to THF dissociation, while 2b is thermally unstable. Reaction of 2a with H2 or PhSiH3 led to the putative hydrido complex “[(3,6-tBu2Flu)SiMe2NtBu)YH(THF)]n” (3). Deprotonation of 1a with 1 and 2 equiv of nBuLi gave [(3,6-tBu2C13H6)SiMe2NHtBu]Li (5) and [(3,6-tBu2C13H6)SiMe2NtBu]Li2 (4), respectively, both of which were characterized crystallographically. Salt elimination reactions between LnCl3(THF)n precursors (Ln = Y, La, Nd) and 1 equiv of 4 gave mixtures of complexes, from which ionic complexes that contain two chelated ligands per lanthanide center, [{η3:η1-(3,6-tBu2C13H6)SiMe2NtBu}2Ln]-[Li(solvent)n]+ (Ln = Y, solvent = THF, n = 4, 6; Ln = La, solvent = THF, n = 4, 7; Ln = La, solvent = Et2O, n = 2, 8; Ln = Nd, solvent = THF, n = 4, 9), were isolated. The neutral dimeric chloro complex [η5:η1-((3,6-tBu2C13H6)SiMe2NtBu)Nd(μ-Cl)(THF)]2 (10) was also crystallized from the crude metathesis product. The solid-state structures of 2a, 8, 9, and 10 show versatile coordination modes of the fluorenyl ligands, either η3 or η5 symmetric, involving carbon atoms of the central Cp ring (8 and 10), or unusual η3 dissymmetric, involving carbon atoms of the central Cp and one adjacent phenyl rings (2a and 9). Some of the complexes obtained were explored as catalysts for ethylene and MMA polymerization.

Photochemical transformation of a cyclic polysilane to a cyclic carbosilane via (η 5-C 5H 5)Fe(CO) 2)CH 2, FpCH 2, substitution

The complex FpCH 2-c-Si 5Me 9 ( 1), Fp=(η 5-C 5H 5)Fe(CO) 2, was synthesized by the salt-elimination reaction between [Fp] −Na + and ClCH 2-c-Si 5Me 9. The complex is stable indefinitely at RT, but highly reactive toward UV irradiation to yield the rearranged product FpSi(SiMe 3)(c-SiMe 2CH 2(SiMe 2) 3) ( 2) in which the initial exo-cyclic methylene group has been incorporated into a 5-membered ring and an initial ring Me 2Si group becomes an exo-cylic Me 3Si group. The structure of 2 was confirmed by single-crystal X-ray diffraction.

Ionic and covalent mixed-metal complexes by reaction of transition metal MH acids (M=Mo, Mn, Fe, Co) with [Ir(PMe 3) 4CH 3] or [Rh(PMe 3) 3CH 3] and structurally related RhM and IrM heterobimetallics (M=Mn, Fe, Ru)

Treatment of [Ir(PMe 3) 4CH 3] with equimolar quantities of the carbonyl hydrides [M(CO) n H] (M=Mn, Co; n=5, 4) or [CpM(CO) n H] (M=Mo, Fe; n=3, 2) resulted in clean protonation of the d 8 substrate producing cis-[Ir(PMe 3) 4(H)(CH 3)][X], where X −=[Mn(CO) 5] − ( 1), [Co(CO) 4] − ( 2), [CpMo(CO) 3] − ( 3), and [CpFe(CO) 2] − ( 4), respectively. Combination of [Rh(PMe 3) 3CH 3] with [Mn(CO) 5H] furnished [(Me 3P) 3Rh(μ-CO) 2Mn(CO) 3PMe 3] ( 5), which was also isolated from the salt elimination reaction between [Rh(PMe 3) 4]Cl and Na[Mn(CO) 5]. [(Me 3P) 2Rh(μ-CO) 2Fe(PMe 3)Cp] ( 6), [(Me 3P) 3Ir(μ-CO) 2Fe(PMe 3)Cp] ( 7), and [(Me 3P) 3Ir(μ-CO) 2Ru(PMe 3)Cp] ( 8) were obtained similarly by reacting [Rh(PMe 3) 4]Cl or [Ir(PMe 3) 4]Cl with the potassium salts K[CpM(CO) 2] (M=Fe, Ru). The crystal structure analysis of 3 demonstrates that in the solid state the hexacoordinate [Ir(PMe 3) 4(H)(CH 3)] + cation and its [CpMo(CO) 3] − counterion exist as well-separated ion pairs. The structures of 5– 8 comprise (Me 3P) n Rh ( n=3, 2) or (Me 3P) 3Ir groups attached to Mn(CO) 3PMe 3 or M(PMe 3)Cp fragments (M=Fe, Ru) by doubly carbonyl-bridged metalmetal bonds of normal length: RhMn, 2.6695(14); RhFe, 2.5748(6); IrFe, 2.6470(7); IrRu, 2.7348(14) Å.

A novel group of alkaline earth metal amides: syntheses and characterization of M[N(2,6-(i)Pr(2)C(6)H(3))(SiMe(3))](2)(THF)(2) (M = Mg, Ca, Sr, Ba) and the linear, two-coordinate Mg[N(2,6-(i)Pr(2)C(6)H(3))(SiMe(3))](2).

Novel alkaline earth metal aryl-substituted silylamides were prepared using alkane (Mg) and salt elimination reactions (Mg, Ca, Sr, and Ba). The salt elimination regime involved the treatment of the alkaline earth metal iodides with 2 equiv of the respective potassium amide KNDiip(SiMe(3)), (Diip = 2,6-i-Pr(2)C(6)H(3)). The organomagnesium source for the alkane elimination was ((n)()Bu/(s)()Bu)(2)Mg. All compounds were characterized using (1)H, (13)C NMR, and IR spectroscopy, in addition to X-ray crystallography (except Mg[NDiip(SiMe(3))](2)THF(2)). Crystal data with Mo Kalpha (lambda = 0.710 73 A) are as follows: Mg[NDiip(SiMe(3))](2), 1, a = 9.4687(6) A, b = 9.6818(6) A, c = 17.9296(1) A, alpha = 96.487(1) degrees, beta = 94.537(1) degrees, gamma = 89.222(1) degrees, V = 1608.8(2) A(3), Z = 2 (two independent molecules), triclinic, space group P(-)1, R1 (all data) = 0.0508; (n)()BuMg[NDiip(SiMe(3))]THF(2), 2, a = 9.5413(1) A, b = 16.493(2) A, c = 9.8218(1) A, beta = 108.149(2) degrees, V = 1468.7(4) A(3), Z = 2, monoclinic, space group P2(1), R1(all data) = 0.1232; Ca[NDiip(SiMe(3))](2)THF(2), 4, a = 9.7074(1) A, b = 20.9466(4) A, c = 21.6242(3) A, alpha = 73.573(1) degrees, beta = 78.632(1) degrees, gamma = 89.621(1) degrees, V = 4129.1(1) A(3), Z = 4 (two independent molecules), triclinic, space group P(-)1, R1 (all data) = 0.0902; Sr[NDiip(SiMe(3))](2)THF(2), 5, a = 20.5874(5) A, b = 9.8785(2) A, c = 20.8522(5) A, beta = 102.035(2) degrees, V = 4147.6(2) A(3), Z = 4 (two independent molecules), monoclinic, space group P2/n, R1 (all data) = 0.0756; Ba[NDiip(SiMe(3))](2)THF(2), 6, a = 20.5476(2) A, b = 10.0353(2) A, c = 20.9020(4) A, beta = 101.657(1) degrees, V = 4221.0(1) A(3), Z = 4 (two independent molecules), monoclinic, space group P2/n, R1 (all data) = 0.0573.

Synthesis and Reactivity of the Pentacoordinate Organosilicon and -germanium Compounds Containing the C,P-Chelating ο-Carboranylphosphino Ligand [ο-C2B10H10PPh2-C,P](CabC,P

The synthesis of the intramolecular donor - stabilized silyl and germyl complexes of the type (<TEX>$Cab^c.p) MMe_2X$</TEX> (2a:M=Si, X=Cl;2b;M= Ge, X=Cl;2e;M=Si,X=H) was achieved by the reaction of <TEX>$LiCab^c,p$<TEX> (1) with <TEX>$Me_2SiClX$</TEX> and <TEX>$Me_2GeCl_2$</TEX> respectively. The intramolecular M←P interacion in 2a-2c is provided by <TEX>$^1H$</TEX>, <TEX>$13^C.$<TEX>, <TEX>$31^P$<TEX> and <TEX>$29^Si$<TEX> NMR spectroscopy. The salt elimination reactions of dichlorotetramethyldisilane and -digermane with 1 afforded the <TEX>$bis(\sigma-carboranylphosphino)disilane$</TEX> and disgermane [<TEX>$(Cab^C.P)MMe_2]_2(4a;M$</TEX> = Si;4b: M=Ge). The oxidative addition reaction of 4a-4b with <TEX>$pd_2(dba)_3CHCl_3afforded$</TEX> the bis(silyl)-and bis(germyl)-palladium complexes. The chloro-bridged dipalladium complexes were obtained by the reaction of 2a-2b with <TEX>$pd_2(dba)_3CHCl_3$</TEX> The crystal structures of 5a and 7b were determined by X-ray structural studies.

Synthesis and reactivity of 1,2-bis(chlorodimethylgermyl)carborane and 1,2-bis(bromodimethylstannyl)carborane.

The 1,2-bis(chlorogermyl)- (1) and 1,2-bis(bromostannyl)carborane (2) have been prepared by the reaction of dilithio-o-carborane with Me(2)GeCl(2) and Me(2)SnBr(2), respectively. Compounds 1 and 2 are found to be good precursors for the synthesis of a variety of cyclization compounds. The Wurtz-type coupling reaction of 1 and 2 using sodium metal afforded the four-membered digerma compound 3 and five-membered tristanna compound 4, respectively. The salt elimination reactions of 1 and 2 using Li(2)N(t)Bu and Li(2)PC(6)H(5) afforded the cyclic products [structure: see text]. The 1,2-bis(dimethylgermyl)carborane 9 and 1,2-bis(dimethylstannyl)carborane 10 were prepared by the reaction of 1 and 2 with sodium cyanoborohydride. The reactions of 9 and 10 with Pd(PPh(3))(4) afforded the bis(germyl)palladium 12 and bis(stannyl)palladium 13 complexes, respectively.

The first silyl- and germylboryl complexes: synthesis from novel (dichloro)silyl- and (dichloro)germylboranes, structure and reactivity

A series of silyl- and germyl(dichloro)boranes Cl2B–ER3 (5, ER3 = Si(SiMe3)3; 6, ER3 = Ge(SiMe3)3; 7, ER3 = Si(SiMe3)2–Si(SiMe3)3; 8, ER3 = SiPh3) was obtained in good yields from the corresponding bis(dimethylamino)boranes (Me2N)2B–ER3 (1, ER3 = Si(SiMe3)3; 2, ER3 = Ge(SiMe3)3; 3, ER3 = Si(SiMe3)2–Si(SiMe3)3; 4, ER3 = SiPh3) upon reaction with BCl3, and fully characterised in solution. These compounds proved to be versatile starting materials for the synthesis of the first silyl- and germylboryl complexes by salt elimination reactions starting from anionic transition metal complexes of the type Na[(η5-C5R5)Fe(CO)2] and K[(η5-C5R5)Mn(H)(CO)2]. The novel iron and manganese boryl complexes [(η5-C5R4R′)(OC)2Fe–B(Cl)Si(SiMe3)3] (9a, R = R′ = H; 9b, R = H, R′ = Me; 9c, R = R′ = Me), [(η5-C5H5)(OC)2Fe–B(Cl)Ge(SiMe3)3] (9d), [(η5-C5H5)(OC)2Fe–B(Cl)Si(SiMe3)2Si(SiMe3)3] (9e), [(η5-C5H4Me)(OC)2(H)Mn–B(Cl)Si(SiMe3)3] (10a) and [(η5-C5H4Me)(OC)2(H)Mn–B(Cl)Ge(SiMe3)3] (10b) were obtained in yields between 35 and 70%, fully characterised in solution and in the case of 9a, d, and 10a also in the crystalline state. They are all characterised by metal–boron σ-bonds without indication of any metal-to-boron π-backdonation. There is, however, spectroscopical and structural evidence for the presence of a Mn–H–B bridge in the case of the manganese complexes 10a, b. The first transhalogenation of a metal coordinated boryl ligand was achieved by reaction of 9a with TlF affording the fluoroboryl complex [(η5-C5H5)(OC)2Fe–B(F)Si(SiMe3)3] (11), which was characterised in solution and in the solid state.

Six-coordinate aluminium cations: characterization, catalysis, and theory

The new thf supported cations, [Salen(tBu)Al(thf)2]+ (2), [Salpen(tBu)Al(thf)2]+ (3), [Salben(tBu)Al(thf)2]+ (4) [Salophen(tBu)Al(thf)2]+ (5) and [Salomphen(tBu)Al(thf)2]+ (6), with BPh4− as the counter anion, have been prepared from salt elimination reactions with the respective Salen(tBu)AlCl reagent, including one that is new, Salben(tBu)AlCl (1). The cations were observed to polymerize propylene oxide. Based upon the results of experimental and theoretical work the mechanism appears to be one in which a carbocation is the propagating species although the PDI values are remarkably low, ≈1.2 in some cases. All of the potential catalysts were characterized spectroscopically and, in the case of 3, by X-ray crystallography.

(Alkyliminomethyl)phenylamido and related complexes of zirconium and titanium

A range of trialkylsilylamido complexes of zirconium in which the silylamido functional group is attached to an o-(alkyliminomethyl)- or an o-(alkyliminoethyl)-substituted aromatic ring have been synthesised by salt elimination or aminolysis reactions and characterised by spectroscopic and diffraction methods. The monoanionic ligands (L), formally isoelectronic to the cyclopentadienyl ligand, can be introduced to zirconium by reaction of LLi with ZrCl4 under a variety of conditions giving rise to complexes of type LZrCl3 and L2ZrCl2, by reaction of LLi with Zr(NMe2)2Cl2(THF)2, and Zr(NEt2)2Cl2(THF)2 giving rise to LZrCl(NMe2)2Cl and LZrCl(NEt2)2Cl, respectively, or by reaction of LH with Zr(NMe2)4 giving rise to LZr(NMe2)3. LZr(NMe2)2Cl and LZr(NEt2)2Cl can be transformed to LZrCl3 by reaction with Me3SiCl, while LZr(NMe2)3 on heating rearranges to dimeric imido complexes by elimination of amidosilanes. Aminolysis of Zr(NMe2)2Cl2(THF)2 with LH results in a formal insertion of the imino CN into the Zr-amido bond. The combination of enolisable imine and a bulky silyl amide gave rise to a new mixed donor ligand system comprising of one silylamido and one eneamido group. Finally aminolysis of Ti(NMe2)Cl2 with LH resulted in the isolation of a C3 symmetric triamido titanium complex.

Homoleptic silyl complexes of arsenic and antimony

Several homoleptic silyl complexes of arsenic(III) and antimony(III), namely As(SiR 2R′) 3 (R=Me, R′=cyclohexyl (Cy); R=Me, R′=Ph; R=R′=Ph) and Sb(SiPh 3) 3, have been prepared via salt elimination reactions of R 2R′SiCl and Na 3E (E=As or Sb). The structures of two complexes, As(SiMe 2Cy) 3 and Sb(SiPh 3) 3, have been determined by X-ray crystallography. Both structures possess a three-coordinate Group 15 element centre with a pyramidal geometry of the ESi 3 core.

On some reactions of undecamethylcyclohexasilanyl-substituted silanes

A number of undecamethylcyclohexasilanyl-substituted silanes have been prepared employing a salt elimination reaction between undecamethylcyclohexasilanyl potassium and several silyl halides or triflates. This method provides access to compounds with one or two undecamethylcyclohexasilanyl units attached to one silicon atom. Several attempts to introduce a third ring failed, resulting in formation of bis(undecamethylcyclohexasilanyl). An alternative approach to the substance class using silyl anions and undecamethylcyclohexasilanyl bromide was also developed. The molecular structure of bis(undecamethylcyclohexasilanyl)methylsilane was determined by X-ray crystallography.

Synthesis, Structure, and Significance for MOCVD of Intramolecularly Base-Stabilized Monomeric Cyclopentadienylaluminum and -gallium Dihydrides

The (N,N-dialkylaminoethyl)cyclopentadienyl group 13 element dichlorides 3 and 4 of the type [(R2NCH2CH2)C5H4]MCl2 {M = Al, R = Me (3); M = Ga, R = i-Pr (4)} were prepared via salt elimination reactions of [(R2NCH2CH2)C5H4]K {R = Me (1), i-Pr (2)} with the respective group 13 element trichlorides. The reaction of 3 with LiAlH4 afforded the cyclopentadienylaluminum dihydride [(Me2NCH2CH2)C5H4]AlH2 (5) in nearly quantitative yield. Treatment of the organogallium dichlorides [(R2NCH2CH2)C5H4]GaCl2 {R = i-Pr (4), Me (6)} with LiAlH4 led via transmetalation to the organoaluminum dihydrides [(R2NCH2CH2)C5H4]AlH2 {R = Me (5), i-Pr (7)} in good yields. The reaction of 6 with LiGaH4 resulted in the formation of the organogallium dihydride [(Me2NCH2CH2)C5H4]GaH2 (8). The novel compounds 3−5, 7, and 8 were characterized by elemental analysis, NMR spectroscopy, mass spectrometry, and X-ray crystallography. In the solid state and also in solution, all compounds feature a monomeric structure with an intramolecularly coordinated dialkylamino group. The coordinative and electronic saturation of the metal center in these compounds leads to a drastically decreased reactivity toward moisture and air in comparison to nondonor-stabilized Cp−group 13 element compounds. The dynamic behavior observed in solution is based on fast haptotropic shifts in a “windshield-wiper” type process. Sufficient volatility makes the organodihydrido compounds 5 and 8 suitable precursors for the deposition of aluminum and gallium, respectively, in the MOCVD process. Ex-situ characterization with sputter auger electron spectroscopy (SAES) provides information about the chemical composition of the aluminum and gallium layers. Irradiation of 5 and 8 in solution is followed by decomposition into the respective metal and into the hydrogen-functionalized ligand [C5H5(CH2CH2NMe2)].

Syntheses and Structures of Trimethylphosphine-complexed Primary Boryl Complexes of Group 8 Metals, Cp*M(CO)2(BH2·PMe3) (M = Fe, Ru)

Abstract Photolysis of Cp*Fe(CO)2Me in the presence of BH3·PMe3 (1) produced a boryliron complex Cp*Fe(CO)2(BH2·PMe3) (2a). Complex 2a and the ruthenium analogue Cp*Ru(CO)2(BH2·PMe3) (3) were accessible by the salt-elimination reaction between K[Cp*M(CO)2] (M = Fe, Ru) and BH2Cl·PMe3.

Chiral five- and six-coordinate aluminum

The chiral five-coordinate halide compound, Salcen(tBu)AlCl (1) (Salcen = N,N′-cyclohexylenebis(3, 5-di-tert-butylsalicylideneimine) can be used in a salt elimination reaction to produce [R,R'Salcen(tBu)AlOTs] (2) as well as the chiral cationic complex, [R,R'Salcen (tBu)Al(thf)2]+ BPh4− (3). The conditions under which these types of neutral and cationic complexes form will be discussed. This should provide guidance for the eventual use of the cations as strongly Lewis acidic catalysts and organic synthetic reagents.

Synthesis and characterization of 8-(dimethylamino)-1-naphthyl derivatives of aluminum, gallium, and indium.

The group 13 dichlorides of formula Ar'MCl2 [Ar' = 8-(dimethylamino)-1-naphthyl (8-(Me2N)C10H6)], M = Al (1), Ga (2), and In (3), have been prepared via the salt elimination reaction of 1 equiv of Ar'Li with MCl3 in toluene solution at -78 degrees C. The reaction of 1 with LiAlH4 in diethyl ether solution at -78 degrees C produced the dihydride [Ar'AlH2]2 (4). The X-ray crystal structures of 1-4 have been determined and show that 1 and 2 are monomeric while 3 and 4 are dimeric in the solid state. The reaction of 1 with RLi in toluene solution at -78 degrees C results in ligand redistribution and formation of Ar'2AlR (R = Me (5), t-Bu (6)). The chloride analogue of 5 and 6, Ar'2AlCl (7), can be prepared directly from the reaction of 2 equiv of Ar'Li with AlCl3 in toluene solution at -78 degrees C. The homoleptic derivative Ar'3Al (8) was obtained when 3 equiv of Ar'Li was employed. Crystal data for 1: monoclinic, space group P2(1), a = 6.534(1) A, b = 10.801(1) A, c = 9.631(2) A, beta = 105.57(2) degrees, V = 654.8(2) A3, Z = 2, R = 0.0453. Crystal data for 2: monoclinic, space group P2(1), a = 6.552(2) A, b = 10.833(2) A, c = 9.601(2) A, beta = 106.05(2) degrees, V = 654.9(3) A3, Z = 2, R = 0.0609. Crystal data for 3: monoclinic, space group P2(1)/c, a = 7.401(2) A, b = 15.746 A, c = 10.801(4) A, beta = 92.37(3) degrees, V = 1257.6(7) A3, Z = 2, R = 0.0712. Crystal data for 4: monoclinic, space group P2(1)/c, a = 13.343(2) A, b = 11.228(2) A, c = 7.505(1) A, beta = 100.64(1) degrees, V = 1105.0(4) A3, Z = 4, R = 0.0560.

Five- and Six-Coordinate Group 4 Compounds Stabilized by beta-Ketiminate and Diketiminate Ligands: Syntheses and Comparisons between Solid-State and Solution Structures.

The preparation and reaction chemistry of beta-diketiminate titanium and zirconium complexes is described. Amine elimination reactions work well for introducing Tolnacnac or Tolnacac to the metal centers (TolnacnacH = 2-(p-tolylamino)-4-(p-tolylimino)-2-pentene; TolnacacH = 4-p-toluidinopent-3-en-2-one). In certain cases, the iminium salt of the diketimine can be used to circumvent the unfavorable reaction kinetics. Salt elimination reactions starting from group 4 metal halides and beta-diketiminate lithium reagents are the most versatile method for introducing beta-diketiminate ligands to the metal. For (beta-diketiminate)MCl(3) compounds (M = Ti, Zr) eta(5)- and eta(2)-coordination modes can be controlled by modifying the diketiminate ligands. Several structures of five- and six-coordinate metal complexes were solved by X-ray diffraction methods. Five-coordinate metal complexes adopt both trigonal bipyramidal and square pyramidal geometries, and the six-coordinate metal complexes possess pseudooctahedral metal centers. For (Tolnacnac)(2)ZrX(2) (X = Cl, OR, NMe(2)) the activation parameters for Lambda/Delta conversion have been probed by dynamic NMR and are consistent with a Bailar-twist mechanism. At a common temperature, the isomerization rates follow the order Cl > OR > NMe(2).

Synthesis and Structural Characterization of Some Monomeric Group 13 Amides

Three monomeric, base-free tris(primary amido) compounds of the type E[N(H)Mes*]3 (1, E = Al; 2, E = Ga; 3, E = In; Mes* = 2,4,6-tri-tert-butylphenyl) have been synthesized via the salt elimination reaction of Mes*N(H)Li with ECl3. The singly base-stabilized tris(primary amido) derivatives, [E{N(H)Dipp}3(py)] (7, E = Al; 8, E = Ga; Dipp = 2,6-diisopropylphenyl), have been prepared via the amine elimination reaction of H2NDipp with [E(NMe2)3]2. The related indium compound, [In{N(H)Dipp}3(py)2] (9), which features two coordinated bases, was prepared by treatment of DippN(H)Li with InCl3 followed by pyridine. The X-ray crystal structures of 3, 8, and 9 have been determined.

Volatile Zirconium Bis(acetylacetonato)bis(alcoholato) Complexes Containing Heterosubstituted Alcoholato Ligands

Two new heteroleptic compounds Zr(acac)2(OR)2, R = SiMe3 and CH(CF3)2, have been synthesized by high-yield synthetic routes. Zr(acac)2(OSiMe3)2, 1, is formed by a salt elimination reaction between Zr(acac)2Cl2 and lithium trimethylsilanolate in pentane, while Zr(acac)2(hfip)2, 2, hfip = OCH(CF3)2, has been prepared from Zr(acac)2Cl2 and a mixture of 2 equiv each of 1,1,1,3,3,3-hexafluoroisopropanol and diethylamine in pentane. The reactions are very selective; the formation of products with other than the 2:2 stoichiometry was not observed under the conditions applied. Both the liquid 2 and the low-melting solid 1 are monomeric and distillable or sublimable in a vacuum. A measured dipole moment of 3.94 D together with spectroscopic data of 1 confirms a cis-octahedral structure, with the metal in a six-coordinated environment. Both substances show an improved hydrolysis stability over homoleptic tetraalcoholates such as Zr(O-t-Bu)4, while being much more volatile than β-diketonates such as Zr(thd)4 or Zr(h...

Syntheses and Structure Determinations of Calcium Thiolates.

The exploration of synthetic methodologies toward heavy alkaline-earth chalcogenolates resulted in the preparation and structural characterization of a family of calcium thiolates, including [Ca(SC(6)F(5))(2)(py)(4)], 1 (py = pyridine), the separated ion-triple [Ca(18-crown-6)(NH(3))(3))][SMes](2).2THF, 2 (Mes = 2,4,6-tBu(3)C(6)H(2)), and the contact triple [Ca(18-crown-6)(SMes)(2)].THF, 3. Compound 1 was prepared by treating [Ca(N(SiMe(3))(2))(2)](2) with 4 equiv of HSC(6)F(5) under addition of pyridine. The thiolates 2 and 3 were synthesized by treatment of calcium metal dissolved in dry, liquid NH(3) under addition of 2 equiv of HSMes and crown ether or, alternatively, by the reduction of MesSSMes with calcium metal in dry, liquid ammonia. We also report two reaction products isolated during attempted calcium thiolate syntheses: [CaBr(4)(THF)(2)(&mgr;(2)-Li)(2)(THF)(4)], 4, isolated as the product of a salt elimination reaction between CaBr(2) and 2 equiv of [Li(THF)(n)()S-2,4,6-(i)()Pr(3)C(6)H(2)](m)(). [(NH(4))(py)(SC(6)F(5))], 5, was obtained as the sole product in the reaction of metallic calcium with HSC(6)F(5) in liquid ammonia under addition of pyridine. All compounds were characterized by single-crystal X-ray crystallography in addition to IR and NMR spectroscopy.