Copper(I) complexes of heterocyclic thiourea ligands

Abstract

The coordination of heterocyclic thiourea ligands (L = N-(2-pyridyl)-N´-phenylthiourea (1), N-(2-pyridyl)-N´-methylthiourea (2), N-(3-pyridyl)-N´-phenylthiourea (3), N-(3-pyridyl)-N´methylthiourea (4), N-(4-pyridyl)-N´-phenylthiourea (5), N-(2-pyrimidyl)-N´-phenylthiourea (6), N-(2-pyrimidyl)-N´-methylthiourea (7), N-(2-thiazolyl)-N´-methylthiourea (8), N-(2benzothiazolyl)-N´-methylthiourea (9), N,N´-bis(2-pyridyl)thiourea (10) and N,N´-bis(3pyridyl)thiourea (11) with CuX (X = Cl, Br, I, NO3) has been investigated. CuX:L product stoichiometries of 1:1-1:5 were found, with 1:1 being most common. X-ray structures of four 3coordinate mononuclear CuXL2 complexes (CuCl(6)2, CuCl(7)2, CuBr(6)2, and CuBr(9)2) are reported. In contrast, CuBr(1)2 is a 1D sulfur-bridged polymer. CuIL structures (L = 7, 8) are 1D chains with corner-sharing Cu2(-I)2 and Cu2(-S)2 units, and CuCl(10) is a 2D network having -Cl and N-/S-bridging L. Two [CuL2]NO3 structures are reported: a mononuclear 4-coordinate copper complex with chelating ligands (L = 10) and a 1D link-chain with N-/S-bridging L (L = 3). Two ligand oxidative cyclizations were encountered during crystallization. CuI crystallized with 6 to produce zigzag ladder polymer [(CuI)2(12)]•2CH3CN (12 = N-(pyrimidin-2yl)benzo[d]thiazol-2-amine) and CuNO3 crystallized with 10 to form [Cu2(NO3)(13)2(MeCN)]NO3 (13 = dipyridyltetraazathiapentalene).

A copper-templated, bifunctional organocatalyst: a strongly cooperative dynamic system for the aldol reaction

“…However, in the case of pyridine-thiourea ligands, only the 1,2-substituted pyridines (like T2) are known to bind in a bidentate fashion leading to discrete Cu(I) complexes. [43][44] 1,3-and 1,4-pyridine-thiourea ligands yield coordination networks with Cu(I) instead. 44 In this respect we have shown in Figure 2 how both the pyridine and thiourea moieties of T3 ligand (1,3 substitution) are necessary and clearly superior to a pyridine-free analogue, which highlights the requirement of the pyridine moiety.…”

“…[43][44] 1,3-and 1,4-pyridine-thiourea ligands yield coordination networks with Cu(I) instead. 44 In this respect we have shown in Figure 2 how both the pyridine and thiourea moieties of T3 ligand (1,3 substitution) are necessary and clearly superior to a pyridine-free analogue, which highlights the requirement of the pyridine moiety. The bidentate chelate of this T3 ligand is nevertheless unlikely due to geometric reasons, and the large excess of ligands P3 and T3 compared to Cu(I) would prevent the formation of coordination networks.…”

Di-μ-bromido-bis({2-[(4,6-dimethylpyrimidin-2-yl)disulfanyl]-4,6-dimethylpyrimidine-κ2N1,S2}copper(I))

“…For potential applications of heterocyclic thioamides and their metal complexes, see: Battistuzzi & Peyronel (1981); Holm & Solomon (1996); Cox et al (2006); Falcomer et al (2006); Sevier & Kaiser (2006); Saxena et al (2009). For related structures, see: Lemos et al (2001); Aslanidis et al (2004); Freeman et al (2008).…”

“…The studies of cooordination multidentate ligands such as heterocyclic thioamides, in complexes of closed-shell d 10 metal ions, have been shown attention from a number of researchers (Saxena et al, 2009;Cox et al, 2006;Falcomer et al, 2006) because of their interesting biochemical properties and presence in active sites of many metalloproteins (Holm & Solomon, 1996;Battistuzzi & Peyronel, 1981). Particularly, the formation of disulfide bonds is an essential step in the folding and assembly of the extracellular domains of many membrane and secreted proteins which are important features of the structure of many proteins (Sevier & Kaiser, 2006).…”

Copper(II)- and gold(III)-mediated cyclization of a thiourea to a substituted 2-aminobenzothiazole

“…This class of ligands can form six-membered chelate rings upon coordination with metal cations via the pyridyl N atom and the thiourea S atom (Mansour & Friedrich, 2017;Bharati et al, 2013), or can bridge two metal centres via the thione functionality to form polymetallic clusters (Hollmann et al, 2017;Saxena et al, 2009;Lenthall et al, 2007). Analogous to urea-based ligands, they can also serve as hydrogen-bond donors to anions via their amine groups, leading to larger supramolecular assemblies (Qureshi et al, 2016;Akhuli et al, 2013).…”