Methyl Substituent at C² Carbon of Acetophenone Thiosemicarbazone Induces Unusual Heterobridging in the [(Ph₃P)Cu(μ-I)₂(μ-S-Haptsc)Cu(PPh₃)] Dimer

Abstract

The sulfur of acetophenone thiosemicarbazone {(Ph)(Me)C=N-NH-C(=S)NH(2); Haptsc} and two iodine atoms form an unusual heterobridge in the dinuclear complex [(Ph(3)P)Cu(mu-I)(2)(mu-S-Haptsc)Cu(PPh(3))] (1), leading to a short Cu--Cu distance of 2.504(1) Angstrom. This uncommon heterobridging is attributed to the presence of a methyl substituent at the Schiff base C2 carbon atom of the acetophenone thiosemicarbazone.

Bonding and structure trends of thiosemicarbazone derivatives of metals—An overview

“…However, if the substituent at C 2 has a donor atom, and engages in bonding, the additional bonding modes observed are, 3 -X, N 3 , S-chelation (XV), 4 -X, N 3 , S-chelation and S-bridging (XVI), and 4 -X, N 3 , S-chelation and X-bridging (XVI) (e.g. X = N, O) [12][13][14][15][16][17][18][19][20][21].…”

“…Similarly, Rh I , Pd II and Pt II [26] in ethanol. Copper(I) complexes have been generally prepared by the direct reaction of a copper(I) halide with a thiosemicarbazone in presence of PPh 3 as co-ligand [12][13][14][15][16][109][110][111][112][113][114], or by the treatment of [Cu(MeCN) 4 ]PF 6 with a ligand in the basic medium [31]. There is only one report of electrochemical method for the preparation of Cu I -thiosemicarbazone complexes [18].…”

Synthesis, spectroscopic characterization, crystal structures, and theoretical studies of (E)-2-(2,4-dimethoxybenzylidene)thiosemicarbazone and (E)-2-(2,5-dimethoxybenzylidene)thiosemicarbazone

“…They have been evaluated over the last 50 years as antiviral, antibacterial, and anticancer therapeutics, and biological activities of them are a function of parent aldehyde or ketone moiety [2][3][4][5][6][7]. Thiosemicarbazone is an important group of multidentate ligands and usually coordinates with the metal through the imine nitrogen and sulfur atom [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] (Scheme 1).…”

Cyclopentanone thiosemicarbazone (Hcptsc) induces a new bonding pattern in (Ph3P)Cu(μ-Br)(μ3-S,N–Hcptsc)CuBr(PPh3) dimer

“…; R 2 = H, Chart 1) [3][4][5]. The exhibition of these bridging modes revealed that there is small energy difference between these bridging modes (A, B), and the type of the halogen as well as the substituents at C 2 can determine the type of a mode in the complex.Mode C has been observed only in [Cu 2 (l-I) 2 (l-S-Haptsc)(PPh 3 ) 2 ] in which two iodine and one S atoms are bridging two copper atoms [9].In this communication, the behaviour of a thiosemicarbazone in which C 2 carbon is a part of the ring (Structure II, Chart 1) is reported. In a typical reaction, cyclopentanone thiosemicarbazone (Hcptsc) with copper(I) bromide in the presence of PPh 3 in CH 3 CN has yielded a compound of stoichiometry, Cu 2 Br 2 (PPh 3 ) 2 (Hcptsc).…”