NICKEL THIOETHER CHEMISTRY - SYNTHESIS, STRUCTURES AND ELECTROCHEMISTRY OF 5-CO-ORDINATE NICKEL(II) COMPLEXES OF [9]ANES3 - CRYSTAL-STRUCTURES OF [NI([9]ANES3)-(DPPM)][PF6]2, [NI([9]ANES3)(DCPE)][PF6]2-CENTER-DOT-1.25MECN AND [NI([9]ANES3)(TDPME)][PF6]2 ([9]ANES3 = 1,4,7-TRITHIACYCLONONANE, DPPM = PH2PCH2PPH2, DCPE = (C6H11)2-PC2H4P(C6H11)2, TDPME= CH3C(CH2PPH2)3)

Reaction of [Ni(L-L)Cl2] {L-L = Ph2PCH2PPh2 (dppm), RPCH2CH2PR2 [R = P h (dppe), C6H11 (dcpe) or Me (dmpe)], cis-Ph2PCH=CHPPh2 (dppv), Ph2PCH 2CH2CH2PPh2 (dppp) or MeC(CH2PPh2)3 (tdpme)) with 1 molar equivalent o f 1,4,7-trithiacyclononane([9]aneS3) afforded the complex cations [Ni( [9]aneS3)(L-L)]2+. The crystal structures of [Ni([9]aneS3)(dppm)][PF6] 2, [Ni([9]aneS3)(dcpe)]-[PF6]2.1.25MeCN and [Ni([9]aneS3)(tdpme)][PF6] 2 showed five-co-ordinate complexes with distorted square-pyramidal ge ometries about the nickel(II) centres with the S-donors of [9]aneS3 oc cupying two basal and the apical position, Ni-S(apical) 2.40-2.65 angs trom, Ni-S(basal) 2.22-2.27 angstrom, Ni-P(basal) 2.17-2.22 angstrom. The complex [Ni([9]aneS3)(dppm)][PF]2 crystallises in triclinic space group P1BAR, a = 10.9748(25), b = 13.9702(20), c = 15.7688(24) angstro m, alpha = 80.071(7), beta = 70.817(8), gamma = 76.441(8)-degrees, D(c ) = 1.374 g cm-3, Z = 2; [Ni([9]aneS3)(dcpe)][PF6]2 . 1.25MeCN crystal lises in triclinic space group P1BAR, a = 12.432(8), b = 13.382(4), c = 15.070(6) angstrom, alpha = 86.83(2), beta = 70.47(2), gamma = 77.28 (2)-degrees, D(c) = 1.445 g cm-3, Z = 2; [Ni([9]aneS3)(tdpme)][PF6]2 c rystallises in monoclinic space group Cc, a = 10.7597(16), b = 37.399( 5), c = 13.104(3) angstrom, beta = 103.746(11)-degrees, D(c) = 1.491 g cm-3, Z=4. Cyclic voltammetry of the complexes [Ni([9]aneS3)(L-L)][PF 6]2 in MeCN (0.1 mol dm-3 NBu4PF6) at 293 K at platinum electrodes sho wed one chemically reversible and one quasi-reversible one-electron re duction at 1E1/2 = -0.77 to -1.16 V, DELTAE(p) = 61-92 mV, E-2(1/2) = -1.31 to -1.93 V vs. ferrocene-ferrocenium. On the basis of ESR and el ectronic spectroscopy, these reduction products are assigned as pyrami dal d9 nickel(I) [Ni([9]aneS3)(L-L)]+ with binding of both P-donors re tained, and tetrahedral d10 nickel(0) [Ni([9]aneS3)(L-L)]0 species res pectively. The reaction of [Ni([9]aneS3)(L-L)]+ with CO in MeCN is dis cussed.