Monomeric Magnesium and Calcium Complexes containing the Rigid, Dianionic 1, 2‐Bis[(2, 5‐di‐<i>tert</i>‐butylphenyl)imino]acenaphthene (dtb‐BIAN) and 1, 2‐Bis[(2‐biphenyl)imino]acenaphthene (bph‐BIAN) Ligands

Fedushkin, Igor L.; Chudakova, Valentina A.; Skatova, Alexandra A.; Khvoinova, N. M.; Kurskii, Yuri A.; Glukhova, Tatyana A.; Fukin, Georgy K.; Dechert, Sebastian; Hummert, Markus; Schumann, Herbert

doi:10.1002/zaac.200300361

Cited by 59 publications

(41 citation statements)

References 25 publications

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“…This fact is consistent with the assumption that steric hindrance at the metal atom caused by the dtb BIAN ligand is larger than that caused by the dpp BIAN ligand. This is also confirmed by the fact that crystallization from a THF solution affords the (dtb BIAN)Mg(THF) 2 com plex with two coordinated solvent molecules, 10 whereas the (dpp BIAN)Mg(THF) 3 complex crystallizes with three solvent molecules. 9 The ESR spectrum of com plex 4 (see Fig.…”

Section: Methodssupporting

confidence: 67%

“…Recently, we have synthesized two new acenaphthenediimine ligands, viz., 1,2 bis[(2,5 di tert butylphenyl)imino]acenaphthene (dtb BIAN) and 1,2 bis[(2 biphenyl)imino]acenaphthene (bph BIAN), and prepared magnesium and calcium complexes with these ligands. 10 Recent studies demonstrated that the (dpp BIAN)Mg(THF) 3 complex, which is readily gener ated in situ, is highly reactive toward various organic com pounds. 11-13 Some reactions of this complex are accom panied by reduction of organic compounds and oxidation of the coordinated dpp BIAN dianion to the radical an ion to give paramagnetic complexes.…”

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confidence: 99%

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Magnesium and calcium complexes with two diimine radical-anion ligands. Molecular structure of the Ca complex with 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene

et al. 2004

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Four and five coordinate magnesium and calcium complexes containing two di imine radical anion ligands with compositions (dpp BIAN) 2 Mg (1), (dpp BIAN) 2 Ca (2), (dtb BIAN) 2 Mg (3), and (dtb BIAN) 2 Ca(THF) (4) (dpp BIAN is 1,2 bis[(2,6 diiso propylphenyl)imino]acenaphthene and dtb BIAN is 1,2 bis[(2,5 di tert butylphenyl)imi no]acenaphthene) were synthesized. At 120 К, the ESR spectra of complexes 1-4 in a toluene matrix show signals characteristic of biradical derivatives. The molecular structure of com pound 2 was established by X ray diffraction analysis. At 293 К, the magnetic moments of compounds 1, 2, 3, and 4 are 2.55, 2.57, 2.76, and 2.79 µ B , respectively, which are indicative of the presence of two unpaired electrons localized on the ligands.In recent years, diimines, including conformationally rigid 1,2 bis[(2,6 diisopropylphenyl)imino]acenaphthene (dpp BIAN), have been widely used as chelating ligands in transition metal chemistry. 1 Complexes of Ni, Rh, Pt, Pd, Cu, and other metals with this ligand are among the most efficient olefin polymerization catalysts. 2-6 How ever, until recently main group metal complexes with such ligands remained unknown. In 2003, we prepared first complexes of main group metals (Na, Li, Mg, and Ca) with various reduced forms of the BIAN ligand. 7 We found that alkali metals successively reduce dpp BIAN to mono di, tri , and tetraanions, 7,8 whereas exclusively the com plexes with the dpp BIAN dianion, (dpp BIAN) 2-M 2+ L n (M = Mg, Ca; L = THF, C 5 H 5 N), are formed in quanti tative yields in the reactions with Mg or Ca in THF. 9 X ray diffraction studies demonstrated that monomeric complexes, in which the metal atoms are chelated by the dpp BIAN dianion, are formed in all cases. The number of solvent molecules coordinated to the central atom in creases with increasing ionic radius of the metal atom. For example, the magnesium complex crystallizes with three coordinated solvent molecules from a THF solu tion, whereas the calcium complex crystallizes with four solvent molecules. Recently, we have synthesized two new acenaphthenediimine ligands, viz., 1,2 bis[(2,5 di tert butylphenyl)imino]acenaphthene (dtb BIAN) and 1,2 bis[(2 biphenyl)imino]acenaphthene (bph BIAN), and prepared magnesium and calcium complexes with these ligands. 10 Recent studies demonstrated that the (dpp BIAN)Mg(THF) 3 complex, which is readily gener ated in situ, is highly reactive toward various organic com pounds. 11-13 Some reactions of this complex are accom panied by reduction of organic compounds and oxidation of the coordinated dpp BIAN dianion to the radical an ion to give paramagnetic complexes. The latter were iso lated in the crystalline state and characterized by ESR spectroscopy and X ray diffraction analysis. 11-13As part of our continuing studies of Group II metal complexes with acenaphthene 1,2 diimine radical anion ligands, we made an effort to prepare complexes with two paramagnetic radical anion ligands. In the present study, we synthesized homoleptic magnesium and cal cium comp...

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Section: Methodssupporting

confidence: 67%

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confidence: 99%

Magnesium and calcium complexes with two diimine radical-anion ligands. Molecular structure of the Ca complex with 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene

et al. 2004

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“…14 Complexes 1-3 were synthesized according to pro cedures described earlier. 3,4 In all cases, solutions of complexes 1-3 in THF were prepared from the corresponding diimine (1.0 mmol) and an excess of magnesium metal and were used in hydrolysis in situ. Tetrahydrofuran, diethyl ether, and hexane were dried, stored over sodium benzophenone ketyl, and dis tilled immediately before use.…”

Section: Methodsmentioning

confidence: 99%

Protonation of magnesium and sodium complexes containing dianionic diimine ligands. Molecular structures of 1,2-bis{(2,6-diisopropylphenyl)imino}acenaphthene (dpp-BIAN), [(dph-BIAN)H2(Et2O)], and [(dpp-BIAN)HNa(Et2O)]

et al. 2004

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Hydrolysis of magnesium complexes containing the dianionic acenaphthenediimine ligands, (dpp BIAN)Mg(thf) 3 (1), (dph BIAN)Mg(thf) 3 (2), and (dtb BIAN)Mg(thf) 2 (3) (dpp BIAN is 1,2 bis{(2,6 diisopropylphenyl)imino}acenaphthene; dph BIAN is 1,2 bis{(2 diphe nyl)imino}acenaphthene; dtb BIAN is 1,2 bis{(2,5 di tert butylphenyl)imino}acenaphthene), affords the corresponding diamines (dpp BIAN)H 2 (4), (dph BIAN)H 2 (Et 2 O) (5), and (dtb BIAN)H 2 (6). Compounds 4 and 5 were isolated in the crystalline state and characterized by UV-Vis, IR, and 1 H NMR spectroscopy. Partial hydrolysis of (dpp BIAN)Na 2 (Et 2 O) 3 gave the crystalline (dpp BIAN)HNa(Et 2 O) 2 complex (7), which was also characterized by spectroscopic methods. The structures of compounds 5 and 7 and free diimine dpp BIAN were established by X ray diffraction analysis.Recently, 1,2 we have synthesized alkali and alkaline earth metal complexes with various reduced forms of 1,2 bis[(2,6 diisopropylphenyl)imino]acenaphthene (dpp BIAN). In solvating solvents, alkali metals (Li, Na) successively reduce dpp BIAN to the mono , di , tri , and tetraanions M + n (dpp BIAN) n-(M = Li, Na; n = 1, 2, 3, or 4). Reduction of dpp BIAN with metallic mag nesium or calcium in THF affords exclusively com plexes with the dpp BIAN dianion of composition (dpp BIAN) 2-M 2+ (thf) n (M = Mg, n = 3; M = Ca, n = 4). 3 We have also synthesized 4 two new ligands of this type, viz., 1,2 bis[(2,5 di tert butylphenyl)imino]ace naphthene (dtb BIAN) and 1,2 bis[(2 diphenyl)imi no]acenaphthene (dph BIAN), as well as their magne sium and calcium derivatives (dtb BIAN) 2-Mg 2+ (thf) 2 and (dph BIAN) 2-M 2+ L n (M = Mg, L = DME, n = 2; M = Ca, L = thf, n = 3).Investigation of the reactions of the (dpp BIAN)Mg(thf) 3 complex (1) with a series of organic compounds revealed their specific reactivity. For example, compound 1 reduces diphenyl ketone, resulting in oxida tion of the dpp BIAN dication to the radical anion and the formation of pinacolate [(dpp BIAN)Mg(thf)] 2 [µ O 2 C 2 Ph 4 ], whereas the reaction of 1 with 9(10H ) anthra cenone is accompanied by deprotonation of the phenol tautomer to form the anthryl 9 oxy derivative (dpp BIAN)Mg(OC 14 H 9 )(thf) 2 . 5 The reactions of com plex 1 with halogen containing inorganic (CuCl, SiCl 4 , I 2 ) and organic (Ph 3 SnCl, 1,2 dibromo 1,2 diphenylethane) compounds also lead to oxidation of the dpp BIAN dianion to the radical anion and the formation of the unsymmetrical [(dpp BIAN)Mg(µ X)(thf)] 2 (X = Cl, Br) and (dpp BIAN)MgI(DME) complexes. 6 The reactions of complex 1 with Me 3 SiCl and Me 2 NCH 2 CH 2 Cl re

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“…15 The synthe sis of two new BIAN ligands, viz., 1,2 bis[(2,5 di tert butylphenyl)imino]acenaphthene (dtb BIAN) and 1,2 bis[(2 diphenyl)imino]acenaphthene (dph BIAN), and their complexes with magnesium and calcium was documented. 16 The exchange reactions of GeCl 2 (C 4 H 8 O 2 ) with magnesium derivatives of the above three BIAN ligands afforded germylenes (dpp BIAN)Ge, (dtb BIAN)Ge, and (dph BIAN)Ge, which were struc turally characterized. 17 It was found that the (dpp BIAN)Mg(thf) 3 complex (1) readily reduces benzophenone, resulting in oxida tion of the dpp BIAN dianion to the radical anion and the formation of the corresponding pinacolate [(dpp BIAN) •-Mg(thf)] 2 [µ O 2 C 2 Ph 4 ] (2).…”

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confidence: 99%

Reactions of (dpp-BIAN)Mg(thf)3 complex (dpp-BIAN is 1,2-bis{(2,6-diisopropylphenyl)imino}acenaphthene) with halogen-containing reagents

et al. 2004

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The reactions of the acenaphthenediimine complex (dpp BIAN)Mg(thf) 3 (1) (dpp BIAN is 1,2 bis{(2,6 diisopropylphenyl)imino}acenaphthene) with various chlorine , bromine , and iodine containing reagents afforded the unsymmetrical compounds [(dpp BIAN)MgCl(thf)] 2 (6), [(dpp BIAN)MgBr(thf)] 2 (7), and (dpp BIAN)MgI(DME) (8). The reaction of com plex 1 with Me 3 SiCl in THF is accompanied by the cleavage of the THF molecule to form [{dpp BIAN(CH 2 ) 4 OSiMe 3 }MgCl] 2 (9), in which the trimethylsilanyloxybutyl group is bound to one of the carbon atoms of the diimine fragment. The reaction of complex 1 with Me 2 NCH 2 CH 2 Cl in THF produces the [dpp BIAN(H)(CH 2 ) 2 NMe 2 ] compound (10) con taining no magnesium. Paramagnetic complexes 6-8 were characterized by ESR spectro scopy. Diamagnetic compounds 9 and 10 were studied by 1 H and 13 C NMR spectroscopy. The molecular structures of complexes 6-10 were established by X ray diffraction analysis. In the crystalline state, compounds 6, 7, and 9 exist as halogen bridged dimers. In all magnesium derivatives, BIAN serves as a chelate ligand.Transition metal complexes with 1,3 diaza 1,4 buta diene ligands, in particular, acenaphthene 1,2 diimine (BIAN) derivatives, have attracted attention due to a num ber of interesting chemical properties of these complexes. These compounds exhibit catalytic activity in alkyne hydrogenation, 1 C-C bond formation, 2,3 cycloisomer ization, 4 and, particularly, in polymerization of various olefins 5-9 and acrylic monomers, 10 and copolymeriza tion of CO 2 with methylenecyclopropane 11 and of ethyl ene with norbornene. 12 Recently, we have begun studies aimed at developing new reactions of organic molecules with acenaphthene diimine complexes of main group metals. At that mo ment, neither main group metal complexes with BIAN ligands nor compounds containing BIAN in the anionic form were known. Acenaphthene 1,2 diimines have the following distinguishing features as the ligands: (1) con formational rigidity of the chelating diimine fragment;(2) presence of the lone electron pairs of the nitrogen atoms serving as centers of metal atom coordination and proton acceptor centers; (3) presence of the π system, which can act as an electron reservoir. 1,2 Bis[(2,6 diisopropylphenyl)imino]acenaphthene (dpp BIAN)Recently, 13,14 we have synthesized and characterized alkali and alkaline earth metal complexes with various

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Monomeric Magnesium and Calcium Complexes containing the Rigid, Dianionic 1, 2‐Bis[(2, 5‐di‐tert‐butylphenyl)imino]acenaphthene (dtb‐BIAN) and 1, 2‐Bis[(2‐biphenyl)imino]acenaphthene (bph‐BIAN) Ligands

Cited by 59 publications

References 25 publications

Magnesium and calcium complexes with two diimine radical-anion ligands. Molecular structure of the Ca complex with 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene

Magnesium and calcium complexes with two diimine radical-anion ligands. Molecular structure of the Ca complex with 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene

Protonation of magnesium and sodium complexes containing dianionic diimine ligands. Molecular structures of 1,2-bis{(2,6-diisopropylphenyl)imino}acenaphthene (dpp-BIAN), [(dph-BIAN)H2(Et2O)], and [(dpp-BIAN)HNa(Et2O)]

Reactions of (dpp-BIAN)Mg(thf)3 complex (dpp-BIAN is 1,2-bis{(2,6-diisopropylphenyl)imino}acenaphthene) with halogen-containing reagents

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