Novel [Tp*WS3Cu2]-Based Coordination Compounds: Assembly, Crystal Structures, and Third-Order Nonlinear Optical Properties

Treatment of [Et4N][Tp*WS3] (1) (TP* = hydridotris(3,5-dimethylpyrazol-1-yl)borate) with [Cu-(MeCN)(4)]PF6 and NH4PF6 (molar ratio = 1:2:1) in excess pyridine (py) produced one discrete trinuclear cluster [Et4N][Tp*WS3Cu2(py)(3)](PF6)(2) (2). Reactions of 1 with [Cu(MeCN)(4)]PF6, NH4PF6, and 4,4'-bipyridine (4-4'-bipy) (or 1,2-bis(4-pyridyl)ethane (bpea)) (molar ratio = 1:2:1:2) afforded a two-dimensional (2D) [Tp*WS3Cu2]-based cationic polymer {[Tp*(WSCu2)-Cu-3(4,4'bipy)(1.5))](PF6)center dot 2MeCn}(n) (3 center dot 2MeCN) and a one-dimensional (1D) [Tp*WS3Cu2]-based cationic polymer {[Tp*WS3Cu2)(2)(bpea)(3)]-(PF6)center dot 2DMF}(n) (4 center dot 2DMF), respectively. Analogous reactions of 1 with CuCN, NH4PF6, and 4,4'-bipy (or 1,2-bis(4-pyridyl)ethylene (bpee)) (molar ratio = 1:2:1:2) gave rise to a 2D [Tp*WS3Cu2]-based polymer {[Tp*WS3Cu2(mu-CN)(4,4'-bipy)0.5]center dot MeCN}(n) (5 center dot MeCN) and a three-dimensional (3D) [Tp*WS3Cu2]-based anionic polymer {[Et4N][(Tp*WS3Cu2)(2){Cu-(mu-CN)(2.5)}(2) (bpee)]center dot 3MeCn}(n) (6 center dot 3MeCN), respectively. Compounds 2-6 were characterized by elemental analysis, IR, UV-vis, H-1 NMR, and single-crystal X-ray diffraction. The cluster cation of 2 has a butterfly-shaped [Tp*WS3Cu2] core structure in which one [Tp*WS3] unit binds two Cu atoms via one mu(3)-S and two mu-S atoms. 3 consists of one 2D (6,3) network in which butterfly-shaped [Tp*WS3Cu2] units are interlinked by the 4,4'-bipy ligands. 4 contains butterfly-shaped [Tp*WS3Cu2] units that are interconnected by bpea bridges to form one 1D zigzag chain. 5 holds another 2D (6,3) network in which the 1D [{Tp*WS3Cu2}(2)(mu-CN)(2)](n) chains are bridged by 4,4'bipy ligands. 6 possesses a 3-connected 3D (10(3)) anionic net in which each 2D [{(Tp*WS3Cu2)(2)Cu-2(mu-CN)(4)(bpee)(2)](n)(4n-) network in interlinked to its neighboring ones via pairs of bpee ligands. The isolation of 2-6 with unstable [Tp*WS3Cu2] cores may be ascribed to the coordination of N-donor ligands or linkers at Cu(I) centers of these cores and the formation of polydimensional [Tp*WS3Cu2]-based frameworks (in the case of 3-5). The third-order nonlinear optical (NLO) properties of 2-6 in DMF were also investigated by using a femtosecond degenerate four-wave mixing (DFWM) technique at 800 nm.