Two novel two-dimensional cluster polymers {NMe4](2)[MOS3Cu3(mu(2)-I)(3)]} (M = Mo, W): synthesis, crystal structure and interesting optical alteration from self defocusing to self-focusing

摘要

Two novel cluster polymers {[NMe4](2)[MoOS3Cu3(mu(2)-I)(3)]} 1 and {[NMe4](2)[WOS3Cu3(mu(2)-I)(3)]}(n) 2 have been prepared. Bithiometalates MO2S22- (M=Mo,W), CuI, Me4NBr and 4,4'-trimethylene-dipyridine(tdp) reacted in solid state under low-heating temperature resulting in these two clusters. X-ray diffraction analysis reveals that the two polymers have the same two-dimensional network structures, which are formed from nest-shaped units along crystallographic b and c directions. I atoms take on a mu(2)-fashion in bridging all the units. An alternative view along crystallographic a direction shows that they are layered features. Their third-order non-linear optical (NLO) properties were determined by Z-scan techniques. Both compounds possess very strong NLO refractive effect with n(2) value of -5.02 x 10(-17) m(2)W(-1) for 1 and 1.20 x 10(-16) m(2)W(-1) for 2, respectively. Different from routine work, there is an alternation from cluster polymer 1-2 in their optical properties: 1 shows self-defocusing behavior, while 2 gives self-focusing effect. Effective third-order NLO susceptibilities chi((3)) were calculated to be 4.90 x 10(-11) esu 1 and 1.48 x 10(-9) esu 2. The corresponding hyperpolarizabilities gamma are 3.39 x 10(-28) and 1.02 x 10(-26) esu, respectively. (C) 2003 Elsevier B.V. All rights reserved. [References: 40]