N-heterocyclic carbene adducts of molybdenum tetra-carboxylate complexes

Research output: Contribution to journalArticle

2 Citations (Scopus)
46 Downloads (Pure)

Abstract

Treatment of the quadruply bonded dimolybdenum complexes [Mo2(μ-O2CCF3)4] (1), [Mo2(μ-O2CCH3)4] (2) and [Mo2(μ-O2CBut)4] (3) with the N-heterocyclic carbenes (NHCs), L (La = IPr, Lb =IMes, Lc = IiPr2Me2 and Ld = IEt2Me2), respectively, results in the formation of a series of 1:1 and 1:2 adducts: In the case of the larger, and more sterically demanding, carbene ligands i.e. La and Lb, coordination occurs exclusively axially with respect to the [Mo2] complexes and only once in the case La, [Mo2(μ-O2CR)4(La)] (R = Me, tBu and CF3) (1a, 2a and 3a), and twice in the case of Lb, [Mo2(μ-O2CCF3)4(Lb)2] (2b). For the less sterically demanding carbene ligands (Lc and Ld) coordination to the [Mo2] core occurs twice, with a transoidal dis-tribution about the [Mo2] unit and is exclusively in equatorial positions, resulting in partial displacement of two of the bridg-ing {μ-O2CR} ligands in each complex. In the case of complexes 1a, 2a, 3a, 2b, [Mo2(μ-OTFA)2(OTFA)2(Lc)2] (1c), [Mo2(μ-OTFA)2(OTFA)2(Ld)2] (1d) [Mo2(μ-OAc)2(OAc)2(Ld)2] (2d) the solid state molecular structures have been unambiguously characterised by single crystal X-ray diffraction. As part of our study into the reactivity of NHC ligands with [Mo2(μ-O2CCH3)4], the heteroleptic NHC adduct [Mo2(μ-OAc)2Cl2(Ld)2] (5) formed from the reaction of complex 2d with trimethylsi-lylchloride has also been isolated and structurally characterized using single crystal x-ray diffraction. As part of our study the Mo-Mo stretching frequencies of these complexes have been analyzed by Raman spectroscopy
Original languageEnglish
Pages (from-to)2494-2506
JournalOrganometallics
Volume35
Issue number15
Early online date21 Jul 2016
DOIs
Publication statusPublished - 2016

Fingerprint

Molybdenum
carbenes
carboxylates
adducts
molybdenum
Ligands
ligands
Single crystals
single crystals
Molecular structure
Stretching
Raman spectroscopy
x ray diffraction
molecular structure
reactivity
Diffraction
carbene
solid state
X ray diffraction
X rays

Keywords

  • molybdenum
  • N-Heterocyclic Carbenes
  • quadruple bond
  • adducts
  • X-ray crystallography

ASJC Scopus subject areas

  • Inorganic Chemistry

Cite this

N-heterocyclic carbene adducts of molybdenum tetra-carboxylate complexes. / Johnson, Andrew; Raithby, Paul; Robinson, Thomas; Kociok-Kohn, Gabriele.

In: Organometallics, Vol. 35, No. 15, 2016, p. 2494-2506.

Research output: Contribution to journalArticle

@article{0e658f9fd9a246ca802a69bfbe988fd9,
title = "N-heterocyclic carbene adducts of molybdenum tetra-carboxylate complexes",
abstract = "Treatment of the quadruply bonded dimolybdenum complexes [Mo2(μ-O2CCF3)4] (1), [Mo2(μ-O2CCH3)4] (2) and [Mo2(μ-O2CBut)4] (3) with the N-heterocyclic carbenes (NHCs), L (La = IPr, Lb =IMes, Lc = IiPr2Me2 and Ld = IEt2Me2), respectively, results in the formation of a series of 1:1 and 1:2 adducts: In the case of the larger, and more sterically demanding, carbene ligands i.e. La and Lb, coordination occurs exclusively axially with respect to the [Mo2] complexes and only once in the case La, [Mo2(μ-O2CR)4(La)] (R = Me, tBu and CF3) (1a, 2a and 3a), and twice in the case of Lb, [Mo2(μ-O2CCF3)4(Lb)2] (2b). For the less sterically demanding carbene ligands (Lc and Ld) coordination to the [Mo2] core occurs twice, with a transoidal dis-tribution about the [Mo2] unit and is exclusively in equatorial positions, resulting in partial displacement of two of the bridg-ing {μ-O2CR} ligands in each complex. In the case of complexes 1a, 2a, 3a, 2b, [Mo2(μ-OTFA)2(OTFA)2(Lc)2] (1c), [Mo2(μ-OTFA)2(OTFA)2(Ld)2] (1d) [Mo2(μ-OAc)2(OAc)2(Ld)2] (2d) the solid state molecular structures have been unambiguously characterised by single crystal X-ray diffraction. As part of our study into the reactivity of NHC ligands with [Mo2(μ-O2CCH3)4], the heteroleptic NHC adduct [Mo2(μ-OAc)2Cl2(Ld)2] (5) formed from the reaction of complex 2d with trimethylsi-lylchloride has also been isolated and structurally characterized using single crystal x-ray diffraction. As part of our study the Mo-Mo stretching frequencies of these complexes have been analyzed by Raman spectroscopy",
keywords = "molybdenum, N-Heterocyclic Carbenes, quadruple bond , adducts, X-ray crystallography",
author = "Andrew Johnson and Paul Raithby and Thomas Robinson and Gabriele Kociok-Kohn",
year = "2016",
doi = "10.1021/acs.organomet.6b00386",
language = "English",
volume = "35",
pages = "2494--2506",
journal = "Organometallics",
issn = "0276-7333",
publisher = "American Chemical Society",
number = "15",

}

TY - JOUR

T1 - N-heterocyclic carbene adducts of molybdenum tetra-carboxylate complexes

AU - Johnson, Andrew

AU - Raithby, Paul

AU - Robinson, Thomas

AU - Kociok-Kohn, Gabriele

PY - 2016

Y1 - 2016

N2 - Treatment of the quadruply bonded dimolybdenum complexes [Mo2(μ-O2CCF3)4] (1), [Mo2(μ-O2CCH3)4] (2) and [Mo2(μ-O2CBut)4] (3) with the N-heterocyclic carbenes (NHCs), L (La = IPr, Lb =IMes, Lc = IiPr2Me2 and Ld = IEt2Me2), respectively, results in the formation of a series of 1:1 and 1:2 adducts: In the case of the larger, and more sterically demanding, carbene ligands i.e. La and Lb, coordination occurs exclusively axially with respect to the [Mo2] complexes and only once in the case La, [Mo2(μ-O2CR)4(La)] (R = Me, tBu and CF3) (1a, 2a and 3a), and twice in the case of Lb, [Mo2(μ-O2CCF3)4(Lb)2] (2b). For the less sterically demanding carbene ligands (Lc and Ld) coordination to the [Mo2] core occurs twice, with a transoidal dis-tribution about the [Mo2] unit and is exclusively in equatorial positions, resulting in partial displacement of two of the bridg-ing {μ-O2CR} ligands in each complex. In the case of complexes 1a, 2a, 3a, 2b, [Mo2(μ-OTFA)2(OTFA)2(Lc)2] (1c), [Mo2(μ-OTFA)2(OTFA)2(Ld)2] (1d) [Mo2(μ-OAc)2(OAc)2(Ld)2] (2d) the solid state molecular structures have been unambiguously characterised by single crystal X-ray diffraction. As part of our study into the reactivity of NHC ligands with [Mo2(μ-O2CCH3)4], the heteroleptic NHC adduct [Mo2(μ-OAc)2Cl2(Ld)2] (5) formed from the reaction of complex 2d with trimethylsi-lylchloride has also been isolated and structurally characterized using single crystal x-ray diffraction. As part of our study the Mo-Mo stretching frequencies of these complexes have been analyzed by Raman spectroscopy

AB - Treatment of the quadruply bonded dimolybdenum complexes [Mo2(μ-O2CCF3)4] (1), [Mo2(μ-O2CCH3)4] (2) and [Mo2(μ-O2CBut)4] (3) with the N-heterocyclic carbenes (NHCs), L (La = IPr, Lb =IMes, Lc = IiPr2Me2 and Ld = IEt2Me2), respectively, results in the formation of a series of 1:1 and 1:2 adducts: In the case of the larger, and more sterically demanding, carbene ligands i.e. La and Lb, coordination occurs exclusively axially with respect to the [Mo2] complexes and only once in the case La, [Mo2(μ-O2CR)4(La)] (R = Me, tBu and CF3) (1a, 2a and 3a), and twice in the case of Lb, [Mo2(μ-O2CCF3)4(Lb)2] (2b). For the less sterically demanding carbene ligands (Lc and Ld) coordination to the [Mo2] core occurs twice, with a transoidal dis-tribution about the [Mo2] unit and is exclusively in equatorial positions, resulting in partial displacement of two of the bridg-ing {μ-O2CR} ligands in each complex. In the case of complexes 1a, 2a, 3a, 2b, [Mo2(μ-OTFA)2(OTFA)2(Lc)2] (1c), [Mo2(μ-OTFA)2(OTFA)2(Ld)2] (1d) [Mo2(μ-OAc)2(OAc)2(Ld)2] (2d) the solid state molecular structures have been unambiguously characterised by single crystal X-ray diffraction. As part of our study into the reactivity of NHC ligands with [Mo2(μ-O2CCH3)4], the heteroleptic NHC adduct [Mo2(μ-OAc)2Cl2(Ld)2] (5) formed from the reaction of complex 2d with trimethylsi-lylchloride has also been isolated and structurally characterized using single crystal x-ray diffraction. As part of our study the Mo-Mo stretching frequencies of these complexes have been analyzed by Raman spectroscopy

KW - molybdenum

KW - N-Heterocyclic Carbenes

KW - quadruple bond

KW - adducts

KW - X-ray crystallography

UR - http://10.1021/acs.organomet.6b00386

U2 - 10.1021/acs.organomet.6b00386

DO - 10.1021/acs.organomet.6b00386

M3 - Article

VL - 35

SP - 2494

EP - 2506

JO - Organometallics

JF - Organometallics

SN - 0276-7333

IS - 15

ER -