Synthesis and Structures of β-Diketoiminate Complexes of Magnesium

Abstract

The reaction of the b-diketoiminate lithium complex (dipp)NacNacLi´OEt 2 ((dipp)NacNac = 2-((2,6-diisopropylphenyl)amino)-4-((2,6-diisopropylphenyl)imino)-pent-2-enyl) with iPrMgCl and MgI 2 yield the corresponding (dipp)NacNacMgiPr´OEt 2 (1) and (dipp)NacNacMgI´OEt 2 (2). The reaction of 2 with NaBH 4 in diethylether gives (dipp)NacNacMg(l-H) 3 BH´OEt 2 (3). The core element of compounds 1±3 is a six-membered ring formed by N(1)±C(1)±C(2)±C(3)±N(2) and magnesium. The structures of 1 and 2 show the b-diketoiminate backbone in a boat-conformation with the tetrahedrally coordinated metal center at the prow and the opposing carbon atom at the stern. The magnesium atom in 3 is octahedrally coordinated and out of the b-diketoiminate plane. Synthese und Struktur von b-Diketiminato Komplexen des MagnesiumsInhaltsu È bersicht. Die Reaktion des b-Diketiminato-LithiumKomplexes (dipp)NacNacLi´OEt 2 ((dipp)NacNac = 2-((2,6-Diisopropylphenyl)amino)-4-((2,6-diisopropylphenyl)imino)-pent-2-enyl) mit iPrMgCl bzw. mit MgI 2 fu È hrt zur Bildung des entsprechenden (dipp)NacNacMgiPr´OEt 2 (1) und (dipp)NacNacMgI´OEt 2 (2). Durch Umsetzung von 2 mit NaBH 4 in Diethylether wird das (dipp)NacNacMg-(l-H) 3 BH´OEt 2 (3) erhalten. Das zentrale Strukturelement der Verbindungen 1±3 ist ein sechsgliedriger Ring bestehend aus N(1)±C(1)±C(2)±C(3)±N(2) und Magnesium. Die Strukturen von 1 und 2 stellen die b-Diketiminatoverbindungen in einer Bootkonformation dar, mit dem tetraedrisch koordinierten Metallatom auf der einen und dem gegenu È berliegenden Kohlenstoffatom auf der anderen Seite. Das Magnesiumatom in 3 ist oktaedrisch koordiniert und liegt auûerhalb der Ebene, die durch den b-DiketiminatoLiganden gebildet wird.

Synthesis and Structural Characterization of β-Diketoiminate Complexes Containing Three-Coordinate Zinc and Copper Atoms

“…[5] Compound 4 was therefore prepared in high yields (76%) by the addition of (dipp)NacNacLi·OEt 2 to a suspension of CuI in diethyl ether at Ϫ78°C (Scheme 3). Scheme 3 Compound 4 was characterized by EI-MS spectrometry, 1 H, 13 Because of the similarity of compounds 1Ϫ7 to β-acetylacetonate complexes, a few examples and their physical properties are listed in Table 1 for comparison.…”

“…Table 1. Physical data of compounds 1Ϫ9; acac ϭ acetylacetonate, tmtch ϭ 3,3,6,6-tetramethyl-1-thia-4-cycloheptyne, Tp* ϭ hydrotris(3-cumyl-5-methylpyrazolyl)borate [2] 155 5.04 (dipp)NacNacMgiPr·Et 2 O (6) [5] 165 4.85 (dipp)NacNacAl (7) [3] Ͼ 150 (dec.) 5.18 (Tp*)Zn(cumoylacetonate) (8) [29] 183 5.43 (acac)Cu(tmtch) (9) [30] 116 5.37…”

“…[4] We have also reported on the synthesis of a β-diketoiminate boranate complex of magnesium, in which the magnesium centre is six-coordinated and octahedral. [5] While the first metals to have a prominent role in organic synthesis were magnesium and lithium, several of the transition metals have also become very important. [6] Organozinc [7] and organocopper [8] complexes are extensively used in both organic and organometallic synthesis.…”

Halogenomercury Salts of Sterically Crowded Triazenides – Convenient Starting Materials for Redox‐Transmetallation Reactions

“…The average Mg–N distance of 2.093 Å is shorter than that of the six‐coordinate magnesium triazenide [Mg{N 3 Tol 2 } 2 (thf) 2 ] (2.183 Å with Tol = 4‐Me‐phenyl) the currently only structurally characterized triazenide available for comparison 20. Shorter Mg–N bonds but longer Mg–I and Mg–O distances are observed in the heterolepticβ‐diketiminate (Dip‐nacnac) 2 MgI(OEt 2 ) [Dip‐nacnac = (Dip)NC(Me)C(H)C(Me)N(Dip) with Dip = 2,6‐ i Pr 2 C 6 H 3 ] (Mg–N = 2.040(3) Å, Mg–I = 2.689(1) Å, Mg–O = 2.010(3) Å] 21 and a number of homoleptic magnesium amidinates Mg{RNC(R′)NR} 2 (R = t Bu, R′ = Ph, av. Mg–N = 2.042(2) Å 22a; R = i Pr, R′ = Dmp, av.…”

A Soft Grip: Magnesium Complexes with a Phosphine‐Modified Phosphonium Diylidic Lewis Base

“…This is underlined by the different reactivity observed in the deprotonation of DIPP nacnacH and dppmfluH in toluene by MeMgI in Et 2 O. Whereas the reaction with DIPP nacnacHg ave the expected iodo derivative [Mg( DIPP nacnac)(I)(Et 2 O)], [19] the reaction with of dppmfluH led to the methyl-bridged magnesium complex [{Mg(dppmflu)(m-Me)} 2 ]( 3), even when the reactants were employed in a1 :1 ratio. In this case, only about 50 %c onversion of the ligand precursor was observed by 31 PNMR spectroscopy.C ompound 3 can by isolated in crystalline form from the reaction mixture andi so nly slightly contaminatedb yi odide, which occupies approximately 5% of the methanide lattice sites in the crystals.…”