Thiosemicarbazonates of copper: Crystal structures of [(furan-2-acetaldehyde-N-phenyl-thiosemicarbazonato)][bis (triphenylphosphine)]copper(I) and [bis(furan-2-formaldehyde-N- phenyl-thiosemicarbazonato)]copper(II) Tarlok S. Lobana a,⇑ , Mani Kaushal a , Rajneet K. Virk a , Isabel Garcia-Santos b , Jerry P. Jasinski c a Department of Chemistry, Guru Nanak Dev University, Amritsar 143 005, India b Departamento de Quimica Inorganica, Facultad de Farmacia, Universidad de Santiago, 15782 Santiago, Spain c Department of Chemistry, Keene State College, Keene, NH 03435-2001, USA article info Article history: Received 30 April 2018 Accepted 7 June 2018 Available online 18 June 2018 Keywords: Furan-2-formaldehyde-N 1 -phenyl thiosemicarbazone Triphenylphosphine Copper(I) Copper(II) X-ray crystallography abstract Equimolar reactions of furan-2-formaldehyde-N 1 -phenylthiosemicarbazone [(C 4 H 3 O)(H)C 2 @N 3 -N 2 (H)- C 1 (@S)-N 1 HPh; HftscN-Ph)] and furan-2-acetaldehyde-N 1 -phenylthiosemicarbazone; [(C 4 H 3 O)(CH 3 ) C 2 @N 3 -N 2 (H)-C 1 (@S)-N 1 HPh, HaftscN-Ph] with Cu(OAc)(PPh 3 ) 2 in methanol has yielded N,S-chelated Cu I complexes, [Cu(j 2 -N,S-ftscN-Ph)(PPh 3 ) 2 ] 1 and [Cu(j 2 -N,S-aftscN 1 -Ph)(PPh 3 ) 2 ] 2. Similarly, reactions of Cu(OAc) 2 ÁH 2 O with HftscN-Ph and HaftscN-Ph in 1:2 M ratio (Cu:L) in acetonitrile-methanol (1:1, v/v) has yielded N,S-chelated Cu II complexes, [Cu(j 2 -N,S-ftscN-Ph) 2 ] 3 and [Cu(j 2 -N,S-aftscN-Ph) 2 ] 4. These complexes have been characterized using elemental analysis, IR, UV–Vis, X-band ESR (3, 4), and single crystal X-ray crystallography (2, 3). ESR spectroscopy has supported axial symmetry of complex 3 confirmed by X-ray crystallography, while it revealed rhombic environments for complex 4. Complexes 1 and 2 represent rare examples of Cu I in the domain of coordination chemistry of furan based anionic thiosemicarbazones in which the thio-ligands bind as anions in N 3 ,S-chelation mode. Ó 2018 Elsevier Ltd. All rights reserved. 1. Introduction Coordination chemistry of thiosemicarbazones {R 1 R 2 C 2 @N 3 - N 2 (H)-C 1 (@S)N 1 R 3 R 4 } constitutes an important class of N, S-donor thio-ligands which have been used for the synthesis, bonding properties, structures, analytical chemistry, and pharmacological applications [1–8]. Heterocyclic thiosemicarbazones, {R 1 R 2 C 2 @N 3 - N 2 (H)-C 1 (@S)-N 1 HR 3 }, bearing R 1 group as furan (C 4 H 3 O) or thio- phene (C 4 H 3 S) rings with different R 2 and R 3 groups (Chart 1), have given rise to six types of coordination arrangements (types A to F, Chart 2) in their copper(I)/silver(I) complexes with triphenylphos- phine as a co-ligand involving j 1 -S bonding (B, C, D), m-S-bridging (A, D), N,S-chelating (E) and N,S-chelating-cum-S-bridging (F) [9–15]. The m-S-bridging was observed in dinuclear complexes, [Ag 2 Cl 2 (l-S-Httsc-NH 2 ) 2 (PPh 3 ) 2 ]Á2CH 3 CN [9], [Cu 2 Br 2 (l-S-Httsc- NH 2 ) 2 (PPh 3 ) 2 ]Á2H 2 O [10], (type A) and [M 2 X 2 (l-S-L) 2 (j 1 -S-L) 2 ] {M = Cu, X = Cl, Br, L = Hftsc-NPh [13], M = Ag, X = Cl, L = Httsc- NMe [11]} (type D). Mono-coordination by thio-ligands (j 1 -S bonding) is shown by several halogen bridged complexes, [M 2 (l- X) 2 (j 1 -S-L) 2 (PPh 3 ) 2 ] {M = Cu, X = I, L = Hftsc-NH 2 , Httsc-NH 2 [10], M = Cu, X = Cl, Br, I, L = Httsc-NR 3 [12], Hftsc-NR 3 [13],R 3 = Me, Et; M = Ag, X = Cl, Br, L = Httsc-NMe [11]} (type B), three coordinate complexes, [CuX(j 1 -S-L) 2 ] {X = Cl, Br, I; L = Httsc-NPh [12], X = I, L = Hftsc-NPh [13]}(type C) and type D complexes [11,13]. The N, S-chelation was observed in mononuclear complexes, [Cu(N, S-L) (PPh 3 ) 2 ] (type E) {L(as anion) = ttsc-NR 3 ,R 3 = Me, Et, Ph) [14]}, and finally N, S-chelation-cum-S-bridging in dinuclear complexes, [Cu 2 (l 3 -N,S-attsc-NR 3 ) 2 (Ph 3 P) 2 ] (R 3 = Me, Et, Ph) 14], and [Ag 2 (l 3 -N,S-Hftsc-NH 2 ) 2 (Ph 3 P) 2 ](NO 3 ) 2 (type F) [9]. In this paper, reactions of furan based thio-ligands, HftscN-Ph and HaftscN-Ph (Chart 1) with [Cu(OAc)(PPh 3 ) 2 ] and Cu 2 (OAc) 4 - Á2H 2 O are investigated and the products studied using various ana- lytical and structural techniques. The basic purpose was to obtain Cu I /Cu II complexes with furan based thiosemicarbazones as anions and to explore the possibility of coordination by furan ring to the metal centre, if any. https://doi.org/10.1016/j.poly.2018.06.022 0277-5387/Ó 2018 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: tarlokslobana@yahoo.co.in (T.S. Lobana). Polyhedron 152 (2018) 49–54 Contents lists available at ScienceDirect Polyhedron journal homepage: www.elsevier.com/locate/poly