Easy ring expansion and contraction in Pt–Sn bonded metallacycles

Abstract

The alkyne RCCR, R = CO₂Me, reacts with 5-membered metallacycles [PtMe₂{SnMe₂ESnMe₂E}(bu₂bpy)], E = S, Se or Te, bu₂bipy = 4,4′-di-tert-butyl-2,2′-bipyridine, yielding the corresponding 7-membered metallacycles [PtMe₂{SnMe₂ESnMe₂CR[double bond, length half m-dash]CRE}(bu₂bpy)] which slowly eliminate “Me₂SnE” to give new 5-membered metallacycles [PtMe₂{SnMe₂CR[double bond, length half m-dash]CRE}(bu₂bpy)]; further reaction of which with excess RCCR gives [PtMe₂(CR[double bond, length half m-dash]CRH)(CCR)(bu₂bpy)], a complex which contains alkyl, alkenyl and alkynyl functionalities in the same molecule.

References

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4. Selected spectroscopic data: NMR in CD₂Cl₂(refs. SiMe₄, Me₄Sn, K₂PtCl₄). 5: δ(¹H) 3.41 [s, 3H, β-CO₂Me]; 2.80 [s, 3H, α-CO₂Me]; 0.86 [s, 3H, ²J(PtH)= 59 Hz, Pt–Me]; 0.76 [s, 3H, ²J(SnH)= 46 Hz, Pt–Sn–Me^a]; 0.59 [s, 3H, ²J(SnH)= 52 Hz, Sn–Me^a]; 0.39 [s, 3H, ³J(PtH)= 4 Hz, ²J(SnH)= 46 Hz, Pt–Sn–Me^b]; 0.31 [s, 3H, ²J(SnH)= 55 Hz, Sn–Me^b]; 0.11 [s, 3H, ²J(PtH)= 62 Hz, Pt–Me]; δ(¹¹⁹Sn) 6.81 [²J(SnSn)= 151 Hz, Pt–S–C=C–Sn]; –81.45 [¹J(PtSn)= 11 860 Hz, Pt–Sn]; δ(¹⁹⁵Pt)– 1770 [¹J(SnPt)= 11 860 Hz]. 6: δ(¹H) 3.43 [s, 3H, β-CO₂Me]; 2.83 [s, 3H, α-CO₂Me]; 0.87 [s, 3H, Pt–Sn–Me]; 0.81 [s, 3H, ²J(PtH)= 59 Hz, Pt–Me]; 0.70 [s, 3H, ²J(SnH)= 51 Hz, Sn–Me^a]; 0.46 [s, 3H, ²J(SnH)= 44 Hz, Pt–Sn–Me^b]; 0.34 [s, 3H, ²J(SnH)= 53 Hz, Sn–Me^b]; 0.20 [s, 3H, ²J(PtH)= 62 Hz, Pt–Me]. 7: δ(¹H) 3.46 [s, 3H, β-CO₂Me]; 2.88 [s, 3H, α-CO₂Me]; 0.98 [s, 3H, ²J(SnH)= 56 Hz, Sn–Me]; 0.92 [s, 3H, Sn–Me]; 0.74 [s, 3H, ²J(PtH)= 60 Hz, Pt–Me]; 0.55 [s, 3H, ²J(SnH)= 45 Hz, Sn–Me]; 0.41 [s, 3H, ²J(SnH)= 52 Hz, Sn–Me]; 0.30 [s, 3H, ²J(PtH)= 61 Hz, Pt–Me]. 8: δ(¹H) 3.65 [s, 3H, CO₂Me]; 3.61 [s, 3H, CO₂Me]; 0.94 [s, 3H, ²J(PtH)= 61 Hz, ³J(SnH)= 6 Hz, Pt–Me]; 0.60 [s, 3H, ²J(SnH)= 49 Hz, ³J(PtH)= 6 Hz, Sn–Me]; 0.34 [s, 3H, ²J(SnH)= 55 Hz, ³J(PtH)= 4 Hz, Sn–Me]; 0.29 [s, 3H, ²J(PtH)= 57 Hz, Pt–Me]; δ(¹¹⁹Sn)–2.1 [¹J(SnPt)= 9904 Hz]. 9: δ(¹H) 3.66 [s, 3H, CO₂Me]; 3.62 [s, 3H, CO₂Me]; 1.03 [s, 3H, ²J(PtH)= 60.3 Hz, ³J(SnH)= 5 Hz, Pt–Me]; 0.58 [s, 3H, ²J(SnH)= 48 Hz, ³J(PtH)= 5 Hz, Sn–Me]; 0.34 [s, 3H, ²J(SnH)= 54 Hz, ³J(PtH)= 4 Hz, Sn–Me]; 0.32 [s, 3H, ²J(PtH)= 57 Hz, Pt–Me]; δ(¹¹⁹Sn)–5.8 [¹J(SnPt)= 10 031 Hz]. 10: δ(¹H) 3.65 [s, 3H, CO₂Me]; 3.62 [s, 3H, CO₂Me]; 1.03 [s, 3H, ²J(PtH)= 61 Hz, Pt–Me]; 0.55 [s, 3H, ²J(SnH)= 48 Hz, ³J(PtH)= 5 Hz, Sn–Me]; 0.34 [s, 3H, ²J(PtH)= 55 Hz, Pt–Me]; 0.32 [s, 3H, ²J(SnH)= 53 Hz, ³J(PtH)= 4 Hz, SnMe]. 12: δ(¹H) 6.46 [s, 2H, ³J(SeH)= 5 Hz, Se–C = C–H]; 3.83 [s, 6H, CO₂Me]; 3.75 [s, 6H, CO₂Me]; MS: m/z= 366. 13: δ(¹H) 0.54 [s, ²J(SnH)= 66 Hz, MeSn]; no other proton resonances. 14: δ(¹H) 6.54 [s, 1H, ³J(PtH)= 80 Hz, Pt–C = C–H]; 3.79 [s, 3H, CO₂Me]; 3.68 [s, 3H, CO₂Me]; 3.51 [s, 3H, CO₂Me]; 1.30 [s, 3H, ³J(PtH)= 69 Hz, Pt–Me]; –0.04 [s, 3H, ³J(PtH)= 51 Hz, Pt–Me]; δ(¹³C)–5.38 [¹J(PtC)= 575 Hz, PtMe trans to N]; 3.88 [¹J(PtC)= 477 Hz, PtMe trans to C]; 119.26 [¹J(PtC)= 780 Hz, PtC(alkenyl)]; 142.17 [¹J(PtC)= 901 Hz, PtC(alkynyl)].
5. Crystal data: 6: C₃₀H₄₈N₂O₄PtSe₂Sn₂, M= 1091.09, triclinic, space group P1̄, a= 10.8110(3), b= 12.5192(2), c= 18.975(3)Å, a= 78.895(1), β= 70.862(1), γ= 86.721(1)°, V= 1889.60(7)ų, D_c= 1.918 g cm^–3, Z= 2, T= 294 K, R= 0.0267, R_w= 0.0621, µ= 6.96 mm^–1, 6616 independent reflections. 9: C₂₈H₄₂N₂O₄PtSeSn, M= 863.38, orthorhombic, Pca2₁, a= 30.899(6), b= 12.156(2), c= 17.311(4)Å, V= 6502(2)Å₃, D_c= 1.764 g cm^–3, Z= 8, T= 150(2) K, R= 0.0293, R_w= 0.0630, µ= 6.22 mm^–1, 6852 independent reflections. 14: C₃₀H₄₀N₂O₆Pt, M= 719.73, monoclinic, P2(1)/n, a= 10.2375(6), b= 16.035(1), c= 18.889(1)Å, β= 102.624(3)°, V= 3025.9(3)ų, D_c= 1.580 g cm^–3, Z= 4, T= 150(2) K; R= 0.039, R_w= 0.0959, µ= 4.68 mm^–1, 3057 independent reflections. CCDC reference number 186/1434. See http://www.rsc.org/suppdata/dt/1999/1713/ for crystallographic files in .cif format.
6. M. R. J. Dorrity, J. F. Malone, C. P. Morley and R. R. Vaughan, Phosphorus, Sulfur Silicon Relat. Elem., 1992, 68, 37.
7. The Z stereochemistry for 12 is defined from the magnitude of ³J(SeH)= 5 Hz; the coupling would be ca., 20 Hz in the E-isomer. C. Paulmier, Selenium Reagents and Intermediates in Organic Syn-thesis, Pergamon, Toronto, 1986.