Donor-dictated interlocking co-complexation reactions of LiNHDipp with dimethylzinc: synthesis and structures of new methyl(amido)zincates

W. Clegg, D.V. Graham, E. Herd, E. Hevia, A.R. Kennedy, M.D. McCall, L. Russo

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

A systematic study of the interlocking co-complexation reactions between the primary lithium amide LiNHDipp (Dipp = 2,6-diisopropylphenyl) and dimethylzinc in the presence of different donor ligands is presented which concludes that the final outcome of these reactions is largely dictated by the type of structure that is formed when the donor is coordinated to the lithium amide. When chelating diamine TMEDA (N,N,N',N'-tetramethylethylenediamine) is employed [{Li(2)(NHDipp)(2)(TMEDA)}(infinity)] (1) is obtained, where Li(2)N(2) rings are connected by TMEDA bridges generating a polymeric chain arrangement which does not form a co-complex with Me(2)Zn even in the presence of an excess of TMEDA. The tridentate ligand PMDETA (N,N,N',N'',N''-pentamethyldiethylenetriamine) when reacted with LiNHDipp forms monomeric [(PMDETA)Li(NHDipp)](4) which successfully forms a mixed-metal co-complex with Me(2)Zn affording dialkyl(amido)zincate [(PMDETA)LiZn(NHDipp)(Me)(2)] (2). When the co-complexation reaction is carried out in the presence of monodentate tetrahydrofuran (THF), zincate [(THF)(3)LiZn(NHDipp)(Me)(2)] (3) is obtained which was found to partially decompose in hexane solution after long periods of time at room temperature (2 weeks) to afford the unprecedented "zinc-rich" zincate [(THF)(3)LiZn(2)(Me)(3)(NHDipp)(2)] (5). This compound presents a unique structure in the solid state previously unknown in organozincate chemistry with a trinuclear Li...Zn...Zn chain arrangement where the metals are connected by only two amido bridges and therefore both zinc centers exhibit trigonal planar geometries. 5 can be prepared in good yields by the rational reaction of LiNHDipp with a 2:1:3 mixture of Me(2)Zn, NH(2)Dipp and THF. The different solid-state structural motifs of compounds 1, 2, 4, and 5 have been revealed by X-ray crystallographic studies. Multinuclear NMR ((1)H, (13)C and (7)Li) spectroscopic data recorded in C(6)D(6) solution are also reported for compounds 1-6. Mixed-metal compounds 2 and 5 constitute the first examples of crystallographically characterized alkyl(amido)zincates containing a primary amide.
LanguageEnglish
Pages5320-5327
Number of pages7
JournalInorganic Chemistry
Volume48
Issue number12
DOIs
Publication statusPublished - 1 May 2009

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tetrahydrofuran
Complexation
locking
Amides
amides
Metals
synthesis
Lithium
Zinc
lithium
zinc
Ligands
solid state
ligands
Diamines
metal compounds
Hexanes
diamines
Chelation
metals

Keywords

  • interlocking co-complexation reactions
  • LiNHDipp
  • donor ligands
  • lithium amide
  • polymeric chain arrangement
  • organozincate chemistry

Cite this

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title = "Donor-dictated interlocking co-complexation reactions of LiNHDipp with dimethylzinc: synthesis and structures of new methyl(amido)zincates",
abstract = "A systematic study of the interlocking co-complexation reactions between the primary lithium amide LiNHDipp (Dipp = 2,6-diisopropylphenyl) and dimethylzinc in the presence of different donor ligands is presented which concludes that the final outcome of these reactions is largely dictated by the type of structure that is formed when the donor is coordinated to the lithium amide. When chelating diamine TMEDA (N,N,N',N'-tetramethylethylenediamine) is employed [{Li(2)(NHDipp)(2)(TMEDA)}(infinity)] (1) is obtained, where Li(2)N(2) rings are connected by TMEDA bridges generating a polymeric chain arrangement which does not form a co-complex with Me(2)Zn even in the presence of an excess of TMEDA. The tridentate ligand PMDETA (N,N,N',N'',N''-pentamethyldiethylenetriamine) when reacted with LiNHDipp forms monomeric [(PMDETA)Li(NHDipp)](4) which successfully forms a mixed-metal co-complex with Me(2)Zn affording dialkyl(amido)zincate [(PMDETA)LiZn(NHDipp)(Me)(2)] (2). When the co-complexation reaction is carried out in the presence of monodentate tetrahydrofuran (THF), zincate [(THF)(3)LiZn(NHDipp)(Me)(2)] (3) is obtained which was found to partially decompose in hexane solution after long periods of time at room temperature (2 weeks) to afford the unprecedented {"}zinc-rich{"} zincate [(THF)(3)LiZn(2)(Me)(3)(NHDipp)(2)] (5). This compound presents a unique structure in the solid state previously unknown in organozincate chemistry with a trinuclear Li...Zn...Zn chain arrangement where the metals are connected by only two amido bridges and therefore both zinc centers exhibit trigonal planar geometries. 5 can be prepared in good yields by the rational reaction of LiNHDipp with a 2:1:3 mixture of Me(2)Zn, NH(2)Dipp and THF. The different solid-state structural motifs of compounds 1, 2, 4, and 5 have been revealed by X-ray crystallographic studies. Multinuclear NMR ((1)H, (13)C and (7)Li) spectroscopic data recorded in C(6)D(6) solution are also reported for compounds 1-6. Mixed-metal compounds 2 and 5 constitute the first examples of crystallographically characterized alkyl(amido)zincates containing a primary amide.",
keywords = "interlocking co-complexation reactions, LiNHDipp, donor ligands, lithium amide, polymeric chain arrangement, organozincate chemistry",
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year = "2009",
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Donor-dictated interlocking co-complexation reactions of LiNHDipp with dimethylzinc: synthesis and structures of new methyl(amido)zincates. / Clegg, W.; Graham, D.V.; Herd, E.; Hevia, E.; Kennedy, A.R.; McCall, M.D.; Russo, L.

In: Inorganic Chemistry, Vol. 48, No. 12, 01.05.2009, p. 5320-5327.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Donor-dictated interlocking co-complexation reactions of LiNHDipp with dimethylzinc: synthesis and structures of new methyl(amido)zincates

AU - Clegg, W.

AU - Graham, D.V.

AU - Herd, E.

AU - Hevia, E.

AU - Kennedy, A.R.

AU - McCall, M.D.

AU - Russo, L.

PY - 2009/5/1

Y1 - 2009/5/1

N2 - A systematic study of the interlocking co-complexation reactions between the primary lithium amide LiNHDipp (Dipp = 2,6-diisopropylphenyl) and dimethylzinc in the presence of different donor ligands is presented which concludes that the final outcome of these reactions is largely dictated by the type of structure that is formed when the donor is coordinated to the lithium amide. When chelating diamine TMEDA (N,N,N',N'-tetramethylethylenediamine) is employed [{Li(2)(NHDipp)(2)(TMEDA)}(infinity)] (1) is obtained, where Li(2)N(2) rings are connected by TMEDA bridges generating a polymeric chain arrangement which does not form a co-complex with Me(2)Zn even in the presence of an excess of TMEDA. The tridentate ligand PMDETA (N,N,N',N'',N''-pentamethyldiethylenetriamine) when reacted with LiNHDipp forms monomeric [(PMDETA)Li(NHDipp)](4) which successfully forms a mixed-metal co-complex with Me(2)Zn affording dialkyl(amido)zincate [(PMDETA)LiZn(NHDipp)(Me)(2)] (2). When the co-complexation reaction is carried out in the presence of monodentate tetrahydrofuran (THF), zincate [(THF)(3)LiZn(NHDipp)(Me)(2)] (3) is obtained which was found to partially decompose in hexane solution after long periods of time at room temperature (2 weeks) to afford the unprecedented "zinc-rich" zincate [(THF)(3)LiZn(2)(Me)(3)(NHDipp)(2)] (5). This compound presents a unique structure in the solid state previously unknown in organozincate chemistry with a trinuclear Li...Zn...Zn chain arrangement where the metals are connected by only two amido bridges and therefore both zinc centers exhibit trigonal planar geometries. 5 can be prepared in good yields by the rational reaction of LiNHDipp with a 2:1:3 mixture of Me(2)Zn, NH(2)Dipp and THF. The different solid-state structural motifs of compounds 1, 2, 4, and 5 have been revealed by X-ray crystallographic studies. Multinuclear NMR ((1)H, (13)C and (7)Li) spectroscopic data recorded in C(6)D(6) solution are also reported for compounds 1-6. Mixed-metal compounds 2 and 5 constitute the first examples of crystallographically characterized alkyl(amido)zincates containing a primary amide.

AB - A systematic study of the interlocking co-complexation reactions between the primary lithium amide LiNHDipp (Dipp = 2,6-diisopropylphenyl) and dimethylzinc in the presence of different donor ligands is presented which concludes that the final outcome of these reactions is largely dictated by the type of structure that is formed when the donor is coordinated to the lithium amide. When chelating diamine TMEDA (N,N,N',N'-tetramethylethylenediamine) is employed [{Li(2)(NHDipp)(2)(TMEDA)}(infinity)] (1) is obtained, where Li(2)N(2) rings are connected by TMEDA bridges generating a polymeric chain arrangement which does not form a co-complex with Me(2)Zn even in the presence of an excess of TMEDA. The tridentate ligand PMDETA (N,N,N',N'',N''-pentamethyldiethylenetriamine) when reacted with LiNHDipp forms monomeric [(PMDETA)Li(NHDipp)](4) which successfully forms a mixed-metal co-complex with Me(2)Zn affording dialkyl(amido)zincate [(PMDETA)LiZn(NHDipp)(Me)(2)] (2). When the co-complexation reaction is carried out in the presence of monodentate tetrahydrofuran (THF), zincate [(THF)(3)LiZn(NHDipp)(Me)(2)] (3) is obtained which was found to partially decompose in hexane solution after long periods of time at room temperature (2 weeks) to afford the unprecedented "zinc-rich" zincate [(THF)(3)LiZn(2)(Me)(3)(NHDipp)(2)] (5). This compound presents a unique structure in the solid state previously unknown in organozincate chemistry with a trinuclear Li...Zn...Zn chain arrangement where the metals are connected by only two amido bridges and therefore both zinc centers exhibit trigonal planar geometries. 5 can be prepared in good yields by the rational reaction of LiNHDipp with a 2:1:3 mixture of Me(2)Zn, NH(2)Dipp and THF. The different solid-state structural motifs of compounds 1, 2, 4, and 5 have been revealed by X-ray crystallographic studies. Multinuclear NMR ((1)H, (13)C and (7)Li) spectroscopic data recorded in C(6)D(6) solution are also reported for compounds 1-6. Mixed-metal compounds 2 and 5 constitute the first examples of crystallographically characterized alkyl(amido)zincates containing a primary amide.

KW - interlocking co-complexation reactions

KW - LiNHDipp

KW - donor ligands

KW - lithium amide

KW - polymeric chain arrangement

KW - organozincate chemistry

UR - http://dx.doi.org/10.1021/ic900313b

U2 - 10.1021/ic900313b

DO - 10.1021/ic900313b

M3 - Article

VL - 48

SP - 5320

EP - 5327

JO - Inorganic Chemistry

T2 - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 12

ER -