Synthesis, crystal structure, supramolecular associations and third-order non-linear optical (NLO) properties of some organotellurium (IV) derivatives Prakash C. Srivastava a,⇑ , Vikas Singh a , Shrinkhala Dwivedi a , Tripurari Pujan a , Arun K. Bhuj a , Ray J. Butcher b , M. Bala Murali Krishna c , D. Narayana Rao c a Department of Chemistry, Lucknow University, Lucknow 226007, India b Department of Chemistry, Howard University, Washington, DC 20059, USA c School of Physics, University of Hyderabad, Hyderabad 500046, India article info Article history: Received 17 February 2012 Accepted 21 April 2012 Available online 15 May 2012 P.C.S. dedicates this work to esteemed Prof. M.F. Lappert, University of Sussex, England. Keywords: Organotellurium (IV) dicarboxylates, Organotellurium (IV) dithiocarbamates Supramolecular assemblies Third order non-linear optical properties abstract Reactions of acyclic and cyclic organotellurium (IV) compounds [R 2 TeI 2 {R 2 = (C 2 H 5 ) 2 ,(n-C 3 H 7 ) 2 ,C 5 H 10 }] with the silver salt of carboxylic acids and sodium diethyldithiocarbamate form the organotellurium (IV) complexes (C 2 H 5 ) 2 Te(4-NO 2 C 6 H 4 OCO) 2 (1), (C 2 H 5 ) 2 Te(C 6 H 5 CH@CHOCO) 2 (2), (n-C 3 H 7 ) 2 Te(C 6 H 5 OCO) 2 (3), (n-C 3 H 7 ) 2 Te(4-NO 2 C 6 H 4 OCO) 2 (4), (n-C 3 H 7 ) 2 Te(3,5-NO 2 C 6 H 3 OCO) 2 (5), (n-C 3 H 7 ) 2 Te(4-OCH 3 C 6 H 4 OCO) 2 (6), (n-C 3 H 7 ) 2 Te(C 6 H 5 CH@CHOCO) 2 (7), C 5 H 10 Te(C 6 H 5 CH@CHOCO) 2 (8) and C 5 H 10 TeCl[S@CSN- (C 2 H 5 ) 2 ](9). The X-ray structures of some of these organotellurium (IV) derivatives indicate that they possess wTBP geometry and dimeric and tetrameric supramolecular associations are achieved through cooperative participation of inter- and/or intramolecular TeO secondary bonds and/or C–HO hydrogen bonds. The intramolecular TeO secondary bond lengths seem to be dependent on the cis- and trans- position placements of free oxygens of the carboxylate groups. It is found that the third-order non-linear optical susceptibilities (v (3) ) of these complexes are in the range 7.21–8.20  10 14 esu and the second order hyperpolarizabilities (c) are in the range 4.89–5.56  10 32 esu. The presence of the telluracycl- opentane (C 5 H 10 Te) cyclic organic group and cinnamate (C 6 H 5 CH@CHOCO)/diethyldithiocarbamate (S@CSN(C 2 H 5 ) 2 ) ligands having conjugation in the organotellurium (IV) derivatives (8 and 9), appears to be responsible for the higher v (3) and c values. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction The design of materials with good third-order non-linear optical (NLO) properties for applications, such as power limiting for sensor protection, optically addressed optical switches for photonics switching, all optical signal processing and optical computing, is a challenging undertaking [1–10]. A promising approach to devel- oping materials with improved third-order NLO properties is to incorporate transition metal centers into organic materials [11,12]. In search of new complexes having good third order NLO properties, contrary to the above, we have incorporated a main group element (Te) into organic moieties, resulting in the forma- tion of organotellurium complexes, and have evaluated their third order non-linear optical (NLO) properties. It might be worthwhile to mention that alkyl tellurium deriva- tives, particularly Te 123m labeled isopropyl tellurium derivatives, have been used as adrenal imaging agents in nuclear medicine [13]. Thus, besides the possible use of allyl tellurium derivatives (as reported in the present investigation) as NLO materials, they appear to be possible potential candidates as imaging agents in the field of nuclear medicine [13]. In search of new complexes having larger third order non-linear optical susceptibilities, we carried out the reactions of R 2 TeX 2 [R 2 = (C 2 H 5 ) 2 ,(n-C 3 H 7 ), C 5 H 10 ;X 2 = Cl, I] with silver carboxylates and sodium diethylthiocarbamate, resulting in the formation of (C 2 H 5 ) 2 Te(4-NO 2 C 6 H 4 OCO) 2 (1), (C 2 H 5 ) 2 Te(C 6 H 5 CH@CHOCO) 2 (2), (n-C 3 H 7 ) 2 Te(C 6 H 5 OCO) 2 (3), (n-C 3 H 7 ) 2 Te(4-NO 2 C 6 H 4 OCO) 2 (4), (n- C 3 H 7 ) 2 Te(3,5-NO 2 C 6 H 3 OCO) 2 (5), (n-C 3 H 7 ) 2 Te(4-OCH 3 C 6 H 4 OCO) 2 (6), (n-C 3 H 7 ) 2 Te(C 6 H 5 CH@CHOCO) 2 (7), C 5 H 10 Te(C 6 H 5 CH@CHO- CO) 2 (8) and C 5 H 10 TeCl[S 2 CN(C 2 H 5 ) 2 ](9). The crystal structures of 1, 2 and 9 have already been reported by us previously [14,15]. Herein we report the crystal structures and supramolecular associ- ations of 3, 4, 6, 7 and 8, and the third order NLO properties of 1, 2, 4, 6, 7, 8 and 9 in CHCl 3 with a 30 ps laser pulse at 532 nm. It is observed that the organotellurium derivatives containing the telluracyclopentane (C 5 H 10 Te) cyclic organic group and cinnamate (C 6 H 5 CH@CHOCO)/diethyldithiocarbamate (S@CSN(C 2 H 5 ) 2 ) li- gands having conjugation (8 and 9) exhibit higher v (3) and c values. 0277-5387/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.poly.2012.04.035 ⇑ Corresponding author. Tel.: +91 0522 4070715. E-mail address: pcsrivastava31@rediffmail.com (P.C. Srivastava). Polyhedron 42 (2012) 36–42 Contents lists available at SciVerse ScienceDirect Polyhedron journal homepage: www.elsevier.com/locate/poly