Syntheses of carbene and alkenyl derivatives of palladium. Solid-state structures of 1-C(N(CH3)C(CH3)3)CH3>>BPh4 and 1-C(NHC(CH3)3)CH3>)PF6*Et2O

Article abstract of DOI:10.1016/0022-328X(94)05248-A

The reaction of ^tBuNC and (Me2NCS2)Pd(PEt3)CH3 yields (Me2NCS2)Pd(PEt3)<η¹-C(NC(CH3)3)CH3>.Reaction of this amino acyl complex with <(CH3)3O>BF4 yields, after anion exchange, <(Me2NCS2)Pd(PEt3)<η¹-C(N(CH3)C(CH3)3)CH3>>BPh4.An analogous reaction with NH4PF6 yields <(Me2NCS2)Pd(PEt3)<η¹-C(NHC(CH3)3)CH3>>PF6.Both of these carbene complexes have been characterized crystallographically.Crystal data: <(Me2NCS2)Pd(PEt3)<η¹-C(N(CH3)C(CH3)3)CH3>>BPh4 triclinic, P1, a = 12.253(12) Angstroem, 14.422(5) Angstroem, c = 11.564(5) Angstroem, α = 97.38(3) deg, β = 93.04(6) deg, γ = 85.21(5) deg, V = 2018 Angstroem³, Z = 2, T = 298 K, R(F) = 7.6percent; <(Me2NCS2)Pd(PEt3)<η¹-C(NHC(CH3)3)CH3>>PF6*Et2O triclinic, P1, a = 12.844(2) Angstroem, b = 15.247(2) Angstroem, c = 8.312(2) Angstroem, α = 105.60(1) deg, β = 101.67(2) deg, γ = 90.20(1) deg, V = 1533 Angstroem³, Z = 2, T = 298 K, R(F) = 5.4percent.In both complexes, the overall coordination geometry is approximately planar about both the palladium atom and carbene carbon atom, and these two planes are perpendicular.Reaction of <(Me2NCS2)Pd(PEt3)<η¹-C(N(CH3)C(CH3)3)CH3>>BPh4 with LiCH3 results in deprotonation at the β-carbon yielding (Me2NCS2)Pd(PEt3)<η¹-C(N(CH3)C(CH3)3)=CH2>, and this reaction is reversed with HBF4*Et2O.The reaction of LiC(OCH2CH3)=CH2 with (Me2NCS2)Pd(PEt3)Cl yields (Me2NCS2)Pd(PEt3)<η¹-C(OCH2CH3)=CH2>.This alkenyl complex reacts with BH3 in ethanol to yield (Me2NCS2)Pd(PEt3)<η¹-CH(OCH2CH3)CH3>. (Me2NCS2)Pd(PEt3)<η¹-C(OCH2CH3)=CH2> also forms in the reaction of (Me2NCS2)Pd(PEt3)H and HC<*>COCH2CH3, along with both geometric isomers of (Me2NCS2)Pd(PEt3)<η¹-CH=CH(OCH2CH3)>.Reaction of phenylacetylene and (MeNCS2)Pd(PEt3)H yields mainly (Me2NCS2)Pd(PEt3)<η¹-C(Ph)=CH2) with small amounts of one of the other regioisomers present.Keywords: Palladium; Carbene; Alkenyl derivatives; Dithiocarbamates