Pre-inverse-crowns: synthetic, structural and reactivity studies of alkali metal magnesiates primed for inverse crown formation

A. J. Martinez-Martinez, D. R. Armstrong, B. Conway, B. J. Fleming, J. Klett, A. R. Kennedy, R. E. Mulvey, S. D. Robertson, C. T. O'Hara

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Abstract

Two new alkali metal monoalkyl-bisamido magnesiates, the potassium compound [KMg(TMP)2nBu] and its sodium congener [NaMg(TMP) 2nBu] have been synthesised in crystalline form (TMP = 2,2,6,6-tetramethylpiperidide). Devoid of solvating ligands and possessing excellent solubility in hydrocarbon solvents, these compounds open up a new gateway for the synthesis of inverse crowns. X-ray crystallography established that [KMg(TMP)2nBu] exists in three polymorphic forms, namely a helical polymer with an infinite KNMgN chain, a hexamer with a 24-atom (KNMgN)6 ring having endo-disposed alkyl substituents, and a tetramer with a 16-atom (KNMgN)4 ring also having endo-disposed alkyl substituents. Proving their validity as pre-inverse-crowns, both magnesiates react with benzene and toluene to generate known inverse crowns in syntheses much improved from the original, supporting the idea that the metallations take place via a template effect. [KMg(TMP)2nBu] reacts with naphthalene to generate the new inverse crown [KMg(TMP)2(2-C 10H7)]6, the molecular structure of which shows a 24-atom (KNMgN)6 host ring with six naphthalene guest anions regioselectively magnesiated at the 2-position. An alternative unprecedented 1,4-dimagnesiation of naphthalene was accomplished via [NaMg(TMP) 2nBu] and its NaTMP co-complex "[NaMg(TMP) 2nBu]·NaTMP", manifested in [{Na 4Mg2(TMP)4(2,2,6-trimethyl-1,2,3,4- tetrahydropyridide)2}(1,4-C10H6)]. Adding to its novelty, this 12-atom (NaNNaNMgN)2 inverse crown structure contains two demethylated TMP ligands as well as four intact ones. Reactivity studies show that the naphthalen-ide and -di-ide inverse crowns can be regioselectively iodinated to 2-iodo and 1,4-diiodonaphthalene respectively. 
LanguageEnglish
Pages771-781
Number of pages11
JournalChemical Science
Volume5
Issue number2
Early online date26 Nov 2013
DOIs
Publication statusPublished - 1 Feb 2014

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Thymidine Monophosphate
Alkali Metals
Atoms
Potassium Compounds
Ligands
X ray crystallography
Toluene
Hydrocarbons
Benzene
Molecular structure
Anions
Polymers
Solubility
Sodium

Keywords

  • pre-inverse-crowns
  • alkali metal monoalkyl-bisamido magnesiates
  • inverse crown formation
  • alkali metal magnesiates

Cite this

Martinez-Martinez, A. J. ; Armstrong, D. R. ; Conway, B. ; Fleming, B. J. ; Klett, J. ; Kennedy, A. R. ; Mulvey, R. E. ; Robertson, S. D. ; O'Hara, C. T. / Pre-inverse-crowns : synthetic, structural and reactivity studies of alkali metal magnesiates primed for inverse crown formation. In: Chemical Science. 2014 ; Vol. 5, No. 2. pp. 771-781.
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abstract = "Two new alkali metal monoalkyl-bisamido magnesiates, the potassium compound [KMg(TMP)2nBu] and its sodium congener [NaMg(TMP) 2nBu] have been synthesised in crystalline form (TMP = 2,2,6,6-tetramethylpiperidide). Devoid of solvating ligands and possessing excellent solubility in hydrocarbon solvents, these compounds open up a new gateway for the synthesis of inverse crowns. X-ray crystallography established that [KMg(TMP)2nBu] exists in three polymorphic forms, namely a helical polymer with an infinite KNMgN chain, a hexamer with a 24-atom (KNMgN)6 ring having endo-disposed alkyl substituents, and a tetramer with a 16-atom (KNMgN)4 ring also having endo-disposed alkyl substituents. Proving their validity as pre-inverse-crowns, both magnesiates react with benzene and toluene to generate known inverse crowns in syntheses much improved from the original, supporting the idea that the metallations take place via a template effect. [KMg(TMP)2nBu] reacts with naphthalene to generate the new inverse crown [KMg(TMP)2(2-C 10H7)]6, the molecular structure of which shows a 24-atom (KNMgN)6 host ring with six naphthalene guest anions regioselectively magnesiated at the 2-position. An alternative unprecedented 1,4-dimagnesiation of naphthalene was accomplished via [NaMg(TMP) 2nBu] and its NaTMP co-complex {"}[NaMg(TMP) 2nBu]·NaTMP{"}, manifested in [{Na 4Mg2(TMP)4(2,2,6-trimethyl-1,2,3,4- tetrahydropyridide)2}(1,4-C10H6)]. Adding to its novelty, this 12-atom (NaNNaNMgN)2 inverse crown structure contains two demethylated TMP ligands as well as four intact ones. Reactivity studies show that the naphthalen-ide and -di-ide inverse crowns can be regioselectively iodinated to 2-iodo and 1,4-diiodonaphthalene respectively. ",
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Pre-inverse-crowns : synthetic, structural and reactivity studies of alkali metal magnesiates primed for inverse crown formation. / Martinez-Martinez, A. J.; Armstrong, D. R.; Conway, B.; Fleming, B. J.; Klett, J.; Kennedy, A. R.; Mulvey, R. E.; Robertson, S. D.; O'Hara, C. T.

In: Chemical Science, Vol. 5, No. 2, 01.02.2014, p. 771-781.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Pre-inverse-crowns

T2 - Chemical Science

AU - Martinez-Martinez, A. J.

AU - Armstrong, D. R.

AU - Conway, B.

AU - Fleming, B. J.

AU - Klett, J.

AU - Kennedy, A. R.

AU - Mulvey, R. E.

AU - Robertson, S. D.

AU - O'Hara, C. T.

PY - 2014/2/1

Y1 - 2014/2/1

N2 - Two new alkali metal monoalkyl-bisamido magnesiates, the potassium compound [KMg(TMP)2nBu] and its sodium congener [NaMg(TMP) 2nBu] have been synthesised in crystalline form (TMP = 2,2,6,6-tetramethylpiperidide). Devoid of solvating ligands and possessing excellent solubility in hydrocarbon solvents, these compounds open up a new gateway for the synthesis of inverse crowns. X-ray crystallography established that [KMg(TMP)2nBu] exists in three polymorphic forms, namely a helical polymer with an infinite KNMgN chain, a hexamer with a 24-atom (KNMgN)6 ring having endo-disposed alkyl substituents, and a tetramer with a 16-atom (KNMgN)4 ring also having endo-disposed alkyl substituents. Proving their validity as pre-inverse-crowns, both magnesiates react with benzene and toluene to generate known inverse crowns in syntheses much improved from the original, supporting the idea that the metallations take place via a template effect. [KMg(TMP)2nBu] reacts with naphthalene to generate the new inverse crown [KMg(TMP)2(2-C 10H7)]6, the molecular structure of which shows a 24-atom (KNMgN)6 host ring with six naphthalene guest anions regioselectively magnesiated at the 2-position. An alternative unprecedented 1,4-dimagnesiation of naphthalene was accomplished via [NaMg(TMP) 2nBu] and its NaTMP co-complex "[NaMg(TMP) 2nBu]·NaTMP", manifested in [{Na 4Mg2(TMP)4(2,2,6-trimethyl-1,2,3,4- tetrahydropyridide)2}(1,4-C10H6)]. Adding to its novelty, this 12-atom (NaNNaNMgN)2 inverse crown structure contains two demethylated TMP ligands as well as four intact ones. Reactivity studies show that the naphthalen-ide and -di-ide inverse crowns can be regioselectively iodinated to 2-iodo and 1,4-diiodonaphthalene respectively. 

AB - Two new alkali metal monoalkyl-bisamido magnesiates, the potassium compound [KMg(TMP)2nBu] and its sodium congener [NaMg(TMP) 2nBu] have been synthesised in crystalline form (TMP = 2,2,6,6-tetramethylpiperidide). Devoid of solvating ligands and possessing excellent solubility in hydrocarbon solvents, these compounds open up a new gateway for the synthesis of inverse crowns. X-ray crystallography established that [KMg(TMP)2nBu] exists in three polymorphic forms, namely a helical polymer with an infinite KNMgN chain, a hexamer with a 24-atom (KNMgN)6 ring having endo-disposed alkyl substituents, and a tetramer with a 16-atom (KNMgN)4 ring also having endo-disposed alkyl substituents. Proving their validity as pre-inverse-crowns, both magnesiates react with benzene and toluene to generate known inverse crowns in syntheses much improved from the original, supporting the idea that the metallations take place via a template effect. [KMg(TMP)2nBu] reacts with naphthalene to generate the new inverse crown [KMg(TMP)2(2-C 10H7)]6, the molecular structure of which shows a 24-atom (KNMgN)6 host ring with six naphthalene guest anions regioselectively magnesiated at the 2-position. An alternative unprecedented 1,4-dimagnesiation of naphthalene was accomplished via [NaMg(TMP) 2nBu] and its NaTMP co-complex "[NaMg(TMP) 2nBu]·NaTMP", manifested in [{Na 4Mg2(TMP)4(2,2,6-trimethyl-1,2,3,4- tetrahydropyridide)2}(1,4-C10H6)]. Adding to its novelty, this 12-atom (NaNNaNMgN)2 inverse crown structure contains two demethylated TMP ligands as well as four intact ones. Reactivity studies show that the naphthalen-ide and -di-ide inverse crowns can be regioselectively iodinated to 2-iodo and 1,4-diiodonaphthalene respectively. 

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KW - alkali metal monoalkyl-bisamido magnesiates

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KW - alkali metal magnesiates

U2 - 10.1039/C3SC52816B

DO - 10.1039/C3SC52816B

M3 - Article

VL - 5

SP - 771

EP - 781

JO - Chemical Science

JF - Chemical Science

SN - 2041-6520

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