Reaction Of ZnMe2 Research Articles

Heterobimetallic ruthenium-zinc complexes with bulky N-heterocyclic carbenes: syntheses, structures and reactivity.

The ruthenium-zinc heterobimetallic complexes, [Ru(IPr)2(CO)ZnMe][BArF4] (7), [Ru(IBiox6)2(CO)(THF)ZnMe][BArF4] (12) and [Ru(IMes)'(PPh3)(CO)ZnMe] (15), have been prepared by reaction of ZnMe2 with the ruthenium N-heterocyclic carbene complexes [Ru(IPr)2(CO)H][BArF4] (1), [Ru(IBiox6)2(CO)(THF)H][BArF4] (11) and [Ru(IMes)(PPh3)(CO)HCl] respectively. 7 shows clean reactivity towards H2, yielding [Ru(IPr)2(CO)(η2-H2)(H)2ZnMe][BArF4] (8), which undergoes loss of the coordinated dihydrogen ligand upon application of vacuum to form [Ru(IPr)2(CO)(H)2ZnMe][BArF4] (9). In contrast, addition of H2 to 12 gave only a mixture of products. The tetramethyl IBiox complex [Ru(IBioxMe4)2(CO)(THF)H][BArF4] (14) failed to give any isolable Ru-Zn containing species upon reaction with ZnMe2. The cyclometallated NHC complex [Ru(IMes)'(PPh3)(CO)ZnMe] (15) added H2 across the Ru-Zn bond both in solution and in the solid-state to afford [Ru(IMes)'(PPh3)(CO)(H)2ZnMe] (17), with retention of the cyclometallation.

Pore Modification of H–SAPO-34 Using Dialkyl Zinc: Structural Characterization and Reaction Pathway

The pore structure of a microporous material H–SAPO-34 is modified using organometallic reagents such as dialkyl zinc (ZnR2, R = Me, Et) via both solution and vapor deposition techniques. After quenching with methanol and air calcination, the modified material is obtained (designated as H–SAPO-34/ZnMe2). H–SAPO-34/ZnMe2 is different compared with framework incorporated ZnAPSO-34 and zinc cation exchanged Zn/SAPO-34. Diffuse Reflectance UV/vis (DRUV) reveals a blue shift in the charge transfer band (202 nm → 195 nm) for H–SAPO-34/ZnMe2, indicating perturbations to the SAPO-34 framework as a result of ZnMe2 modification. Two new resonances (3717 and 924 cm–1) associated with dimethylzinc treatment are observed in FTIR and are attributed to a new Zn–OH moiety. A combination of solid-state 1H and 13C NMR analyses confirms that zinc is in the form of Zn–OH attaching to the framework oxygen in H–SAPO-34/ZnMe2. The reaction of ZnMe2 with H–SAPO-34 has been monitored by NMR following an in situ Chemical Vapor Deposition (CVD) treatment. On the basis of this study, a detailed reaction pathway is proposed: the Brønsted acid sites in H–SAPO-34 react with ZnMe2 upon contact, forming methane and anchoring the Zn-Me species to the framework oxygen; subsequent quenching with methanol converts Zn-Me into Zn-OMe, which is converted to Zn–OH upon air calcination. Presence of the Zn–OH species in the pores reduces the pore volume, as measured by the uptake capacity for methanol.

Structural Study of the Reaction of Methylzinc Amino Alcoholates with Oxygen

Reaction of ZnMe2 with 1,3-bis(dimethylamino)propan-2-ol (Hbdmap) in 2:1 ratio forms both [MeZn(bdmap)·ZnMe2]2 (2) and [MeZn(bdmap)]3·ZnMe2 (3) depending on the concentration of the reaction. In th...

Synthesis and Characterization of β‐Diketiminate Zinc Complexes

AbstractThe monomeric β‐diketiminate zinc complex (Mes)NacNacZnMe 1 (MesNacNac = {[2,6‐(2,4,6‐Me3‐C6H2)N(Me)C)]2CH}) was obtained in almost quantitative yield from the reaction of ZnMe2 with (Mes)NacNacH. Reaction of 1 with either Me3NHCl or a solution of HCl in Et2O yielded (Mes)NacNacZnCl 2, whereas (Mes)NacNacZnI 3 was obtained from the reaction of 1 with I2. 1–3 were characterized by elemental analyses, mass and multinuclear (1H, 13C{1H}) NMR spectroscopy, 3·THF also by single crystal X‐ray analysis.

Synthesis and Structure of New Compounds with Zn−Ga Bonds: Insertion of the Gallium(I) Bisimidinate Ga(DDP) into Zn−X (X = CH3, Cl) and the Homoleptic Complex Cation [Zn(GaCp*)4]2+

Insertion reactions of the low-valent group 13 bisimidinate ligand Ga(DDP) {DDP = 2-[(2,6-diisopropylphenyl)amino]-4-[(2,6-diisopropylphenyl)imino]-2-pentene} into Zn-Me and Zn-Cl bonds are reported. The reaction of ZnMe2 with 2 equiv of Ga(DDP) yields the double-insertion product [{(DDP)GaMe}2Zn] (1), whereas the insertion of Ga(DDP) into the Zn-Cl bond of ZnCl2 in tetrahydrofuran (THF) leads to the monoinsertion product [{(DDP)GaCl}ZnCl(THF)2] (2). Treatment of 2 with Na[BArF] results in the salt [{THF.Ga(DDP)}Zn(THF)(mu-Cl)]2[BArF]2 (3), with two Cl atoms bridging the Zn centers. The structural features of the Zn-Ga-bonded compounds 1-3 were compared with related complexes and in particular with the compound [Zn(GaCp*)4][BArF]2 (4), which was synthesized by the reaction of ZnMe2, [H(OEt2)2][BArF], and GaCp* in fluorobenzene. The complex cation [Zn(GaCp*)4]2+ of 4 relates to previously reported d10 analogues [M(GaCp*)4] (M = Ni, Pd, Pt). All new compounds were fully characterized by elemental analysis, NMR spectroscopy, and single-crystal X-ray diffraction analysis.

{Zn3(Et2O)2[(EtO)PO2(C6H5NH)]6·2THF}: A Trinuclear Zinc Amidophosphate with an Hourglass Structure

The reaction of ZnMe2 and the N-substituted phosphoramidic monoester [Et2NH2][(EtO)PO2(C6H5NH)] produces the trinuclear zinc cluster Zn(3)(Et2O)2[(EtO)PO2(C6H5NH)]6.2THF, demonstrating that the P-N bond can survive under mild solvothermal reaction conditions.

A Step Too Far? Assessment of the Boroxide Ligand in Ring-Opening Polymerization

Dimesityl borinic acid, (mes)2BOH [mes = 2,4,6-Me3C6H2], has been employed as a source of boroxide ligand in lithium, zinc, and magnesium chemistry; for structural comparisons, the alkoxide ligand [OCH(mes)2]- has also been used. The lithium compounds [Li{OB(mes)2}(L)n]2 [1a, L = Et2O, n = 1; 1b, L = Py, n = 1; 1c, L = MeCN, n = 2] have been structurally characterized, showing a common bimetallic core with bridging boroxide ligands that differ in the relative rotation of the “BC2” unit about the Li2O2 metallacycle. The zinc compounds [Zn{OR}Me]2 [2, R = B(mes)2; 3, R = CH(mes)2] have been synthesized from the reaction of ZnMe2 with the corresponding ROH species. As for the Li salts, 2 and 3 display a dimeric solid-state structure with μ-OR ligands. Reaction of the in situ generated lithium boroxide 1a with MgBr2·Et2O afforded an unprecedented tetrametallic compound, [Mg{OB(mes)2}Br·LiBr(OEt2)2]2 (4), in which the lithium bromide side product is retained in a tricyclic structure containing a “Li(μ-Br)2Mg{μ-OB(mes)2}Mg(μ-Br)2Li” core. The magnesium alkyl compounds [Mg{OB(mes)2}R(THF)]2 [5, R = Me; 6, R = Bu] were obtained from the reaction of the Li salt with the Grignard reagent, MgMeBr, and protonolysis of MgBu2 with (mes)2BOH, respectively. X-ray crystallography showed formation of a dimer in each case, where in 6 only the n-butyl group was observed in the solid state. Attempts at combining the boroxide ligand with the widely used β-diketiminate ligand, [HC{C(Me)NAr}2]- (BDI), at a zinc center are discussed, and a brief study into the potential of selected zinc complexes to initiate the ring-opening polymerization of ε-caprolactone and rac-lactide is described.

TOWARD AN UNDERSTANDING OF THE OXYGEN SCAVENGING PROPERTIES OF LITHIUM ZINCATES

The reaction of ZnMe2 with 2-pyridylamine [HN(2-C5H4N)Ph 1], LitBu and thereafter with dry air has concomitantly yielded {[Ph(2-C5H4N)N]2ZnOMeLi·thf}2 1 (2) and [Ph(2-C5H4N)N]2Zn[(μ3-O) tBu]2(Li·th...

Oxygen scavenging by lithium zincates: the synthesis, structural characterisation and derivatisation of [Ph(2-C5H4N)N]2ZnRLi·nthf (R = But, Bun; n = 1, 2)

The 1 ∶ 2 reaction of ZnMe2 with N-2-pyridylaniline, Ph(2-C5H4N)NH 1, affords [Ph(2-C5H4N)N]2Zn 10, the treatment of which with BuLi and thf affords the diastereomeric lithium zincate [Ph(2-C5H4N)N]2ZnRLi·nthf (R = Bun, n = 2; 11a; R = But, n = 1, 11b). The sequential treatment of 10 (either in situ or after isolation) with organolithium substrates and molecular oxygen has afforded insights into the oxygen-scavenging capacity of mixed Group 1–Group 12 species. Hence, 10 reacts with BunLi, O2 and thf or dimethoxyethane (dme) to give {[Ph(2-C5H4N)N]2ZnOBunLi·nL}2 (n = 1, L = thf, 12a; n = 0.5, L = dme, 12b), with the structural relationship between 11a and 12a strongly suggesting that for R = Bun oxygenation proceeds by insertion into the Zn–C bond of an {[Ph(2-C5H4N)N]2ZnR}− ion. The employment of ButLi, O2 and thf together with 10 affords only the previously reported complex [Ph(2-C5H4N)N]2Zn[(μ3-O)But]2(Li·thf)24, the formation of which may be rationalised in terms of the But van der Waals radius and cone angle.

Molecular and Polymer Precursor Routes to Manganese-Doped Zinc Orthosilicate Phosphors

The zinc alkoxy(siloxy) complex {Zn[OSi(OtBu)3]2}2 has been prepared and studied as a molecular precursor to zinc orthosilicate, Zn2SiO4. This complex, prepared by reaction of ZnMe2 with HOSi(OtBu)3, has been characterized by X-ray crystallography as a dimer with two four-coordinate zinc centers. It cleanly looses isobutene, tert-butyl alcohol, and HOSi(OtBu)3 at ca. 100 °C to produce Zn2SiO4·SiO2. Reaction of ZnMe2 with (HO)2Si(OtBu)2 affords the hydrocarbon-soluble polymer [ZnOSi(OtBu)2O]n, which is proposed to have a structure consisting of four-coordinate Zn atoms linked by bridging −O(tBuO)Si(OtBu)O− groups. This polymer undergoes a very clean ceramic conversion over 150−250 °C to give the theoretical yield of carbon-free (by infrared spectroscopy and combustion analyses) Zn2SiO4·SiO2. The pyrolytic elimination products consist of water, tert-butyl alcohol, and isobutene. X-ray diffraction studies on the ceramic products show that Zn2SiO4 is the only zinc-containing, crystalline product formed. Thus this precursor approach appears to offer an advantage over sol-gel processes, which tend to produce ZnO as a side product. Hydrocarbon solutions of the polymer were used to fabricate high-quality thin films. Via pyrolysis of [ZnOSi(OtBu)2O]n/[Mn(CH2SiMe3)2]m mixtures, manganese-doped Zn2SiO4·SiO2 materials were synthesized. These materials exhibit two photoluminescence emission bands centered at 535 (major) and 605 nm (minor). The intensity of the green emission at 535 nm, which is responsible for the cathodoluminescence properties of Zn2SiO4:Mn phosphors, is highly dependent on the level of manganese doping. Concentration quenching is observed at higher manganese contents. The observed photoluminescence decay lifetime of approximately 5 ms is typical for Zn2SiO4:Mn phosphors.