Ligand bending and tilted coordination in the coordinatively unsaturated NHC complex lateral-bis(N,N′-dineopentyl-benzimidazoline-2-ylidene)molybdenumtricarbonyl - Synthesis and structural investigations

Farman Ullah, Tibor Szilvási, Tamás Veszprémi, Peter G. Jones, Joachim Heinicke

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Reaction of free dineopentyl-benzimidazoline-2-ylidene 1 (ligand: np2bimy) with (η3-cycloheptatriene)Mo(CO)3, molar ratio 3:1, provides the coordinatively unsaturated lateral-(np2bimy)2Mo(CO)3 complex 2. Crystal structure analysis of 2 reveals an almost ideal cis-square pyramidal geometry with tilted coordination of the metal, interplanar angles of the np2bimy ligands to the C4Mo plane of about 70° and significant bending of the N-heterocyclic carbene rings towards each other. Quantum chemical calculations (B97-D/6-31G(d)[Mo:cc-pVTZ-PP] level of theory) reproduce this peculiar structure and show it to be more stable by 36 kJ/mol than the second energy-minimum structure with trigonal bipyramidal geometry and the carbene ligands in the axial positions. Calculations indicated no significant Mo-C(II) back-bonding or interactions of the empty d-orbital with adjacent p-orbitals of the ligands, implying that the ligand distortions, tilted coordination and the occurrence of a free coordination site are caused by the spatial demand of the N-substituents.

Original languageEnglish
Pages (from-to)22-27
Number of pages6
JournalJournal of Organometallic Chemistry
Volume783
DOIs
Publication statusPublished - May 1 2015

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Ligands
ligands
synthesis
carbenes
orbitals
Geometry
geometry
Crystal structure
Metals
occurrences
crystal structure
rings
metals
interactions
carbene
energy

Keywords

  • Carbonyl complexes
  • Coordination modes
  • Ligand deformation
  • Molybdenum
  • N-heterocyclic carbenes
  • Steric hindrance

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Organic Chemistry
  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Biochemistry

Cite this

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title = "Ligand bending and tilted coordination in the coordinatively unsaturated NHC complex lateral-bis(N,N′-dineopentyl-benzimidazoline-2-ylidene)molybdenumtricarbonyl - Synthesis and structural investigations",
abstract = "Reaction of free dineopentyl-benzimidazoline-2-ylidene 1 (ligand: np2bimy) with (η3-cycloheptatriene)Mo(CO)3, molar ratio 3:1, provides the coordinatively unsaturated lateral-(np2bimy)2Mo(CO)3 complex 2. Crystal structure analysis of 2 reveals an almost ideal cis-square pyramidal geometry with tilted coordination of the metal, interplanar angles of the np2bimy ligands to the C4Mo plane of about 70° and significant bending of the N-heterocyclic carbene rings towards each other. Quantum chemical calculations (B97-D/6-31G(d)[Mo:cc-pVTZ-PP] level of theory) reproduce this peculiar structure and show it to be more stable by 36 kJ/mol than the second energy-minimum structure with trigonal bipyramidal geometry and the carbene ligands in the axial positions. Calculations indicated no significant Mo-C(II) back-bonding or interactions of the empty d-orbital with adjacent p-orbitals of the ligands, implying that the ligand distortions, tilted coordination and the occurrence of a free coordination site are caused by the spatial demand of the N-substituents.",
keywords = "Carbonyl complexes, Coordination modes, Ligand deformation, Molybdenum, N-heterocyclic carbenes, Steric hindrance",
author = "Farman Ullah and Tibor Szilv{\'a}si and Tam{\'a}s Veszpr{\'e}mi and Jones, {Peter G.} and Joachim Heinicke",
year = "2015",
month = "5",
day = "1",
doi = "10.1016/j.jorganchem.2015.01.014",
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TY - JOUR

T1 - Ligand bending and tilted coordination in the coordinatively unsaturated NHC complex lateral-bis(N,N′-dineopentyl-benzimidazoline-2-ylidene)molybdenumtricarbonyl - Synthesis and structural investigations

AU - Ullah, Farman

AU - Szilvási, Tibor

AU - Veszprémi, Tamás

AU - Jones, Peter G.

AU - Heinicke, Joachim

PY - 2015/5/1

Y1 - 2015/5/1

N2 - Reaction of free dineopentyl-benzimidazoline-2-ylidene 1 (ligand: np2bimy) with (η3-cycloheptatriene)Mo(CO)3, molar ratio 3:1, provides the coordinatively unsaturated lateral-(np2bimy)2Mo(CO)3 complex 2. Crystal structure analysis of 2 reveals an almost ideal cis-square pyramidal geometry with tilted coordination of the metal, interplanar angles of the np2bimy ligands to the C4Mo plane of about 70° and significant bending of the N-heterocyclic carbene rings towards each other. Quantum chemical calculations (B97-D/6-31G(d)[Mo:cc-pVTZ-PP] level of theory) reproduce this peculiar structure and show it to be more stable by 36 kJ/mol than the second energy-minimum structure with trigonal bipyramidal geometry and the carbene ligands in the axial positions. Calculations indicated no significant Mo-C(II) back-bonding or interactions of the empty d-orbital with adjacent p-orbitals of the ligands, implying that the ligand distortions, tilted coordination and the occurrence of a free coordination site are caused by the spatial demand of the N-substituents.

AB - Reaction of free dineopentyl-benzimidazoline-2-ylidene 1 (ligand: np2bimy) with (η3-cycloheptatriene)Mo(CO)3, molar ratio 3:1, provides the coordinatively unsaturated lateral-(np2bimy)2Mo(CO)3 complex 2. Crystal structure analysis of 2 reveals an almost ideal cis-square pyramidal geometry with tilted coordination of the metal, interplanar angles of the np2bimy ligands to the C4Mo plane of about 70° and significant bending of the N-heterocyclic carbene rings towards each other. Quantum chemical calculations (B97-D/6-31G(d)[Mo:cc-pVTZ-PP] level of theory) reproduce this peculiar structure and show it to be more stable by 36 kJ/mol than the second energy-minimum structure with trigonal bipyramidal geometry and the carbene ligands in the axial positions. Calculations indicated no significant Mo-C(II) back-bonding or interactions of the empty d-orbital with adjacent p-orbitals of the ligands, implying that the ligand distortions, tilted coordination and the occurrence of a free coordination site are caused by the spatial demand of the N-substituents.

KW - Carbonyl complexes

KW - Coordination modes

KW - Ligand deformation

KW - Molybdenum

KW - N-heterocyclic carbenes

KW - Steric hindrance

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