Synthesis, photophysical and nonlinear optical behavior of neodymium based trisphthalocyanine Kutloano E. Sekhosana, Edith Amuhaya, Samson Khene, Tebello Nyokong ⇑ Department of Chemistry, Rhodes University, PO Box 94, Grahamstown 6140, South Africa article info Article history: Received 12 September 2014 Received in revised form 30 October 2014 Accepted 28 November 2014 Available online 9 December 2014 Keywords: Dineodymium trisphthalocyanine Fluorescence quantum yield Nonlinear optics Voltammetry abstract Tris-{1(4),8(11),15(18),22(25)-tetra(4-tertbutylphenoxy) phthalocyaninato} dineodymium (III) was synthesised and its nonlinear optical and fluorescence behavior was studied. Low fluorescence quantum yield (U F = 0.03) was obtained with a fluorescence lifetime s F = 4.31 ns for this complex. Nonlinear optical parameters for the complex were determined using the Z-scan technique and the values of Im[v (3) ] and c were of the order of 10 10 and 10 28 esu, respectively. Square wave voltammetry revealed three reduction and two oxidation couples for the complex. Ó 2014 Elsevier B.V. All rights reserved. 1. Introduction Double- or triple-decker phthalocyanines exhibit characteristic optical and electronic properties which enable them to function as materials for a wide range of applications including as electronic materials [1], in sensors [2] and in electronic displays [3,4]. The electrochemical properties of lanthanide bisphthalocyanine (LnPc 2 ) compounds (containing a range of lanthanide (Ln) central metals) have been investigated from the viewpoint of electrochro- mic displays and other applications [5–8]. The electrochemical properties of dilanthanide trisphthalocyanines (Ln 2 Pc 3 ) have how- ever received less attention [9–11]. The electrochemical behavior of neodymium bisphthalocyanine (NdPc 2 ) derivatives has been reported [12], but there have been no studies on neodymium tris- phthalocyanine (Nd 2 Pc 3 ) derivatives. Our study reports, for the first time, on the reduction and oxidation processes undergone by Nd 2 Pc 3 . The ease of oxidation of lanthanide diphthalocyanine species increase across the series [13], thus Nd 2 Pc 3 derivatives will be more difficult to oxidize compared to the metals later in the series. The properties of LnPc 2 or Ln 2 Pc 3 are affected by the nature of the metal ion and the substituents attached to the ring [14]. The range of applications of these complexes may be increased by changing ring substituents. A wide variety of ring substituents such as long alkyl side chains [15–17] and crown ethers [18,19] have been employed. Nonlinear optical (NLO) materials play a major role in the technologies that require light harvesting, storage, control and transmission. LnPc 2 complexes show NLO behavior [20–23]. It has been suggested that lanthanide bisphthalocyanines show improved optical nonlinearities due to their expanded electron p system and the presence of the heavy lanthanide central metal [24–26] which enhances the rate of intersystem crossing (ISC) to the triplet state [27]. In addition, unlike the LnPc 2 counterparts which are paramagnetic, the positive charge on the two Ln(III) in Ln 2 Pc 3 balances the negative charge in the three Pc ligands. We have recently shown that a neutral (reduced) LnPc 2 complex showed improved NLO behavior compared to the counterpart con- taining a radical [28]. Thus the neutral Ln 2 Pc 3 complexes are expected to show improved NLO characteristics compared to LnPc 2 or monomeric derivatives. Apart from very limited reports on hetero phthalocyanine-porphyrin tris derivatives [29], the NLO behavior of Ln 2 Pc 3 complexes has been un-explored. A number of Ln 2 Pc 3 have been synthesized, but containing substituents at the peripheral positions [30–34], but no reports on their NLO behavior. This work presents a Ln 2 Pc 3 derivative substituted at non-peripheral positions with tert-butylphenoxy substituents and reports on NLO behavior. Substitution at non-peripheral positions will result in reduced aggregation. The bulky tert butyl phenoxy substituents will also reduce aggregation. In summary, we report on the NLO and electrochemical behavior of Nd 2 Pc 3 derivative (Scheme 1) in this work. http://dx.doi.org/10.1016/j.ica.2014.11.029 0020-1693/Ó 2014 Elsevier B.V. All rights reserved. ⇑ Corresponding author. Tel.: +27 46 603 8260; fax: +27 46 622 5109. E-mail address: t.nyokong@ru.ac.za (T. Nyokong). Inorganica Chimica Acta 426 (2015) 221–226 Contents lists available at ScienceDirect Inorganica Chimica Acta journal homepage: www.elsevier.com/locate/ica