Inorganic Chemistry, Vol.43, No.23, 7516-7531, 2004
(Fluoren-9-ylidene)methanedithiolato complexes of gold: Synthesis, luminescence, and charge-transfer adducts
Piperidinium 9H-fluorene-9-carbodithioate and its 2,7-di-tert-butyl-substituted analogue [(pipH){S2CCH(C12H6R2-2,7)}, R = H (1a), t-Bu (1b)] and 2,7-bis(octyloxy)-9H-fluorene-9-carbodithioic acid [HS2CCH(C12H6(OC8H17)(2)-2,7), 2] and its tautomer [2,7-bis(octyloxy)fluoren-9-ylidene]methanedithiol [(HS)(2)C=C(C12H6(OC8H17)(2)-2,7), 3] were employed for the preparation of gold complexes with the (fluoren-9-ylidene)methanedithiolato ligand and its substituted analogues. The gold(l) compounds Q(2)[Au-2{mu-kappa(2)-S,S-S2C=C(C12H6R2-2,7)}2], where Q(+) = PPN+ or Pr4N+ for R = H (Q(2)4a) or Q(+) = Pr4N+ for R = OC8H17 [(Pr4N)(2)4c], were synthesized by reacting Q[AuCl2] with 1a or 2 (1:1) and excess piperidine or diethylamine. Complexes of the type [{Au(PR'(3))}(2){mu-kappa(2)-S,S-S2C=C(C12H6R2-2,7)}(2)] with R = H and R' = Me (5a), Et (5b), Ph (5c), and Cy (5d) or R = t-Bu and R' = Me (5e), Et (5f), Ph (5g), and Cy (5h) were obtained by reacting [AuCl(PR'(3))] with 1a,b (1:2) and piperidine. The reactions of 1a,b or 2 with Q[AuCl4] (2:1) and piperidine or diethylamine gave Q[Au{kappa(2)-S,S-S2C=C(C12H6R2-2,7)}(2)] with Q(+) = PPN+ for R = H [(PPN)6a], Q(+) = PPN+ or Bu4N+ for R = t-Bu (Q6b), and Q(+) = Bu4N+ for R = OC8H17 [(Bu4N)6c]. Complexes Q6a-c reacted with excess triflic acid to give [Au{kappa(2)-S,S-S2C=C(C12H6R2-2,7)}{kappa(2)-S,S-S2CCH(C12H6R2-2,7)}] [R = H (7a), t-Bu (7b), OC8H17 (7c)], By reaction of (Bu4N)6b with PhICl2 (1:1) the complex Bu4N[AuCl2{kappa(2)-S,S-S2C = C(C12H6(t-BU)(2)-2,7)}] [(Bu4N)8b] was obtained. The dithioato complexes [Au{SC(S)CH(C12H8)}(PCy3)] (9) and [Au-n{S-2 -CCH(C12H8)}(n)] (10) were obtained from the reactions of 1a with [AuCl(PCy3)] or [AuCl(SMe2)], respectively (1:1), in the absence of a base. Charge-transfer adducts of general composition Q[Au{kappa(2)-S,S-S2C=C(C12H6R2-2,7)}2]. 1.5TCNQ.xCH(2)Cl(2) [Q(+) = PPN+, R = H, x = 0 (11a); Q(+) = PPN+, R = t-Bu, x = 2 (11b); Q(+) = Bu4N+, R = OC8H17, x = 0 (11c)] were obtained from Q6a-c and TCNQ (1:2). The crystal structures of 5c.THF, 5e.(2)/3CH2Cl2, 5g.CH2Cl2, (PPN)6a.2Me(2)CO, and 11b were solved by X-ray diffraction studies. All the gold(l) complexes here described are photoluminescent at 77 K, and their emissions can be generally ascribed to LMMCT (Q24a,c, 5a-h, 10) or LMCT (9) excited states.