Copper(I) Complexes with a NS(2)-Macrocyclic Ligand Bearing a Pendant Naphthyl Group: Structures of {N-[2-(1-Naphthyl)ethyl]-1-aza-4,8-dithiacyclodecane}copper(I)-Ligand, where Ligand = eta(2)-Naphthalene, Acetonitrile, or Triphenylphosphine.

A new macrocyclic ligand with a pendant naphthalene group, N-[2-(1-naphthyl)ethyl]-1-aza-4,8-dithiacyclodecane (L), has been synthesized and characterized. The copper(I)-acetonitrile complex [LCu(CH(3)CN)](PF(6)) (1) was synthesized from L and [Cu(CH(3)CN)(4)](PF(6)). The acetonitrile ligand from 1 was easily removed to give [LCu](PF(6)) (2). Complexes 1 and 2 have been crystallographically characterized. 1: C(21)H(28)N(2)CuF(6)PS(2), triclinic, P&onemacr;, a = 11.1901(10) Å, b = 11.2735(12) Å, c = 12.1350(10) Å, alpha = 98.996(8) degrees, beta = 117.188(6) degrees, gamma = 105.354(7) degrees, Z = 2, R1 = 0.0505 (wR2 = 0.1418). 2.0.5hexane: C(22)H(31)NCuF(6)PS(2), monoclinic, P2(1)/c, a = 15.7318(15) Å, b = 8.9164(10) Å, c = 17.205(5) Å, beta = 102.431(6) degrees, Z = 4, R1 = 0.0587 (wR2 = 0.1545). In addition, a cocrystallized mixture of both complexes was crystallographically characterized. 1&2.hexane: C(46)H(61)N(3)Cu(2)F(12)P(2)S(4), triclinic, P&onemacr;, a = 10.8308(9) Å, b = 12.6320(8) Å, c = 19.9412(13) Å, alpha = 80.445(5) degrees, beta = 76.405(6) degrees, gamma = 78.825(5) degrees, Z = 2, R1 = 0.0661 (wR2 = 0.1871). The solid-state structure of 2 features the pendant naphthalene group bound in an eta(2)-fashion, which is highly unusual for copper complexes. In CDCl(3), 2 exhibits fluxional behavior with the barrier to the process estimated, DeltaG() = 12-13 kcal. Variable temperature NMR spectroscopy gave compelling evidence for solution binding of the naphthalene group in 2, apparently the first example for copper(I). The fluxional process seen for 1 is best described as interconversion of the two enantiomers via a species with an unbound naphthalene group. Consistent with the weak binding of the naphthalene group, it is readily replaced with other ligands, such as triphenylphosphine to form [LCu(PPh(3))](PF(6)) (3). Complex 3 has also been structurally characterized: C(37)H(40)NCuF(6)P(2)S(2), monoclinic, P2(1)/c, a = 11.462(2) Å, b = 15.972(2) Å, c = 19.835(9) Å, beta = 94.50(3) degrees, Z = 4, R1 = 0.0906 (wR2 = 0.1889).