TY - JOUR
T1 - N-Heterocyclic carbene-functionalized ruthenium phosphinidenes: what a difference a twist makes
AU - Aktas, H.
AU - Slootweg, J.C.
AU - Schakel, M.
AU - Ehlers, A.W.
AU - Lutz, M.
AU - Spek, A.L.
AU - Lammertsma, K.
PY - 2009
Y1 - 2009
N2 - N-Heterocyclic carbenes (NHCs)1 are ubiquitous ligands in
transition-metal chemistry and homogeneous catalysis and serve
increasingly often as a replacement for tertiary phosphines (R3P).
The two ligand classes exert often subtle but crucially different
electronic influences on the properties of catalysts.2 Exemplary is
the enhanced activity of the second-generation Grubbs metathesis
catalyst [(Cy3P)(L)Cl2RudCHPh] [L ) 1,3-dimesityl-4,5-dihydroimidazol-
2-ylidene (H2IMes)] relative to that of the firstgeneration
catalyst (L ) Cy3P), which is caused by the differences
in σ-donor/π-acceptor ability,3 shape, and symmetry of the ligands.4
Does a similar sensitivity apply to the isolobal phosphinidene5
complexes? We address here the ligand and conformational
sensitivities for [(η6-C6H6)(L)RudPMes*] [Mes* ) 2,4,6-tBu3C6H2;
L ) IiPr2Me2 (1), L ) Ph3P (2)6] by examining their solutionphase
chemistry together with their structure-activity parameters
modeled by density functional theory. We simultaneously demonstrate
the applicability of phosphinidene complexes to the synthesis
of phosphaalkenes (PdC),5a which are unique P-ligands7 and
attractive building blocks for P-functionalized polymers.8
The desired novel dark-green crystalline compound 1 (84%) was
obtained by a double dehydrohalogenation-ligation sequence9 of
the phosphine complex [(η6-C6H6)RuCl2(PH2Mes*)]6 using 3 equiv
of IiPr2Me2 in toluene (eq 1):
AB - N-Heterocyclic carbenes (NHCs)1 are ubiquitous ligands in
transition-metal chemistry and homogeneous catalysis and serve
increasingly often as a replacement for tertiary phosphines (R3P).
The two ligand classes exert often subtle but crucially different
electronic influences on the properties of catalysts.2 Exemplary is
the enhanced activity of the second-generation Grubbs metathesis
catalyst [(Cy3P)(L)Cl2RudCHPh] [L ) 1,3-dimesityl-4,5-dihydroimidazol-
2-ylidene (H2IMes)] relative to that of the firstgeneration
catalyst (L ) Cy3P), which is caused by the differences
in σ-donor/π-acceptor ability,3 shape, and symmetry of the ligands.4
Does a similar sensitivity apply to the isolobal phosphinidene5
complexes? We address here the ligand and conformational
sensitivities for [(η6-C6H6)(L)RudPMes*] [Mes* ) 2,4,6-tBu3C6H2;
L ) IiPr2Me2 (1), L ) Ph3P (2)6] by examining their solutionphase
chemistry together with their structure-activity parameters
modeled by density functional theory. We simultaneously demonstrate
the applicability of phosphinidene complexes to the synthesis
of phosphaalkenes (PdC),5a which are unique P-ligands7 and
attractive building blocks for P-functionalized polymers.8
The desired novel dark-green crystalline compound 1 (84%) was
obtained by a double dehydrohalogenation-ligation sequence9 of
the phosphine complex [(η6-C6H6)RuCl2(PH2Mes*)]6 using 3 equiv
of IiPr2Me2 in toluene (eq 1):
M3 - Article
SN - 0002-7863
VL - 131
SP - 6666
EP - 6667
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 19
ER -