SIMULTANEOUS FIRST-SPHERE AND 2ND-SPHERE COORDINATION - ORGANOPALLADIUM METALLORECEPTORS FOR WATER, AMMONIA, AMINES, HYDRAZINE, AND THE HYDRAZINIUM ION

The complexes [Pd(L)(CH3CN)][BF4] (L(3) = 5,8,11-trioxa-2,14-dithia[15 ]-m-cyclophane and L(5) = ,8,11,14,17-pentaoxa-2,20-dithia[21]-m-cyclo phane) were prepared by palladation of the respective thiacyclophane e mploying [Pd(CH3CN)(4)][BF4](2) These metalloreceptors were reacted wi th various small substrates (H2O, NH3, NH(2)R, NMR(2) NH2NH2, and NH2N H3+) capable of simultaneously coordinating to the Pd center and hydro gen-bonding with the peripheral ether oxygens. [Pd(L(3))(NH3)][BF4] cr ystallized in the space group Pbca with a = 21.377(4) Angstrom, b = 21 .656(5) Angstrom, c = 9.437(6) Angstrom, V = 4368(2) Angstrom(3), and Z = 8. The structure refined to R = 6.41% and R(w) = 7.03% for 659 ref lections with F-o(2) > 3 sigma(F-o(2)). [Pd(L(3))(NH2NH2)][BF4] crysta llized in the space group P ($) over bar 1 with a = 11.652(3> Angstrom , b = 12.669(4) Angstrom, c = 8.355(1) Angstrom, a = 94.13(2)degrees, beta = 94.34(2)degrees, gamma = 117.21(1)degrees, V = 1090.3(5) Angstr om(3), and Z = 2. The structure refined to R = 2.81% and R(w) = 3.40% for 2709 reflections with F-o(2) > 3 sigma(F-o(2)). [Pd(L(5))(H2O)][BF 4] crystallized in the space group P1 ($) over bar with a = 11.076(3) Angstrom, b = 15.147(5) Angstrom, c = 8.586(2) Angstrom, V = 1284(1) A ngstrom(3), and Z = 2. The structure refined to R = 3.14% and R(w) = 4 .06% for 2275 reflections with F-o(2) > 3 sigma(F-o(2)). [Pd(L(3))(NH2 NH3)][CF3SO3](2) crystallized in the space group P2(1)/c with a = 11.9 06(4) Angstrom, b = 17.19(1) Angstrom, c = 15.313(4) Angstrom beta = 1 11.18(2)degrees, V = 2923(4) Angstrom(3), and Z = 4. The structure ref ined to R = 3.13% and R(w) = 4.25% for 2954 reflections with F-o(2)) > 3 sigma(F-o(2)). [Pd(L(5))(NH2NH3)][BF4](2) crystallized in the space group P ($) over bar 1 with a = 9.391(3) Angstrom, b = 18.292(5) Angs trom, c = 9.107(2) Angstrom, a = 94.45(3)degrees, beta = 102.02(2)degr ees, gamma = 103.51(2)degrees, V = 1474.5(8) Angstrom(3), and Z = 2. T he structure refined to R = 3.69% and R(w) = 4.58% for 3059 reflection s with F-o(2) > 3 sigma(F-o(2)). Each complex shows evidence of hydrog en bonding between the Pd-bound substrate and the peripheral oxygen at oms. The major hydrogen-bonding sites are the oxygen atoms adjacent to the thioether atoms, while the extent of the hydrogen bonding is depe ndent on the size of the polyether ring and the orientation of the sub strate. Controlling the number of hydrogen bonds formed results in sel ective binding of primary amines (two hydrogen bonds) over secondary a mines (one hydrogen bond) and tertiary amines (no hydrogen bonds) as d etermined by competition reactions monitored by H-1 NMR spectroscopy.