The Cambridge Crystallographic Database has been searched for the presence of intermolecular C–H⋯π(chelate ring) interactions, known to be stabilising, in the crystals of the first-row transition metal dithiocarbamates, i.e. containing anionic ligands of the type −S2CNR2, R = H, alkyl and aryl. A significant propensity to form C–H⋯π(chelate ring) interactions is noted, especially in crystals of nickel and copper dithiocarbamates. The participating hydrogen atoms are characterised as being near an electronegative atom/substituent encouraging their engagement in this supramolecular synthon. The survey shows that an open, square-planar geometry is not a prerequisite for a C–H⋯π(chelate ring) interaction but, allows, on average, more of these contacts leading to one- and two-dimensional architectures. It is concluded that a search for a C–H⋯π(chelate ring) supramolecular synthon should be included in any detailed analysis of the molecular packing of metal-containing crystals.

The remarkable propensity for the formation of C–H⋯π(chelate ring) interactions in the crystals of the first-row transition metal dithiocarbamates and the supramolecular architectures they sustain

Copper dithiocarbamate complexes have been known for ca. 120 years and find relevance in biology and medicine, especially as anticancer agents and applications in materials science as a single-source precursor (SSPs) to nanoscale copper sulfides. Dithiocarbamates support Cu(I), Cu(II) and Cu(III) and show a rich and diverse coordination chemistry. Homoleptic [Cu(S2CNR2)2] are most common, being known for hundreds of substituents. All contain a Cu(II) centre, being either monomeric (distorted square planar) or dimeric (distorted trigonal bipyramidal) in the solid state, the latter being held together by intermolecular C···S interactions. Their d9 electronic configuration renders them paramagnetic and thus readily detected by electron paramagnetic resonance (EPR) spectroscopy. Reaction with a range of oxidants affords d8 Cu(III) complexes, [Cu(S2CNR2)2][X], in which copper remains in a square-planar geometry, but Cu–S bonds shorten by ca. 0.1 A. These show a wide range of different structural motifs in the solid-state, varying with changes in anion and dithiocarbamate substituents. Cu(I) complexes, [Cu(S2CNR2)2]−, are (briefly) accessible in an electrochemical cell, and the only stable example is recently reported [Cu(S2CNH2)2][NH4]·H2O. Others readily lose a dithiocarbamate and the d10 centres can either be trapped with other coordinating ligands, especially phosphines, or form clusters with tetrahedral [Cu(μ3-S2CNR2)]4 being most common. Over the past decade, a wide range of Cu(I) dithiocarbamate clusters have been prepared and structurally characterised with nuclearities of 3–28, especially exciting being those with interstitial hydride and/or acetylide co-ligands. A range of mixed-valence Cu(I)–Cu(II) and Cu(II)–Cu(III) complexes are known, many of which show novel physical properties, and one Cu(I)–Cu(II)–Cu(III) species has been reported. Copper dithiocarbamates have been widely used as SSPs to nanoscale copper sulfides, allowing control over the phase, particle size and morphology of nanomaterials, and thus giving access to materials with tuneable physical properties. The identification of copper in a range of neurological diseases and the use of disulfiram as a drug for over 50 years makes understanding of the biological formation and action of [Cu(S2CNEt2)2] especially important. Furthermore, the finding that it and related Cu(II) dithiocarbamates are active anticancer agents has pushed them to the fore in studies of metal-based biomedicines.

Copper Dithiocarbamates: Coordination Chemistry and Applications in Materials Science, Biosciences and Beyond

Synthesis, structure and characterization of a new trinuclear magnetic semiconductor PbI4[Cu(Me2dtc)(bipy)]2

C24H16Cu2I3N4S4, orthorhombic, Pccn (no. 56), a = 23.109(6) Å, b = 15.246(4) Å, c = 17.005(4) Å, V = 5991.2 Å, Z = 8, Rgt(F) = 0.077, wRref(F ) = 0.232, T = 293 K.

Crystal structure of iodobis(1,10-phenanthroline-k2N,N′)-copper(II) iodo-(μ2-iodo)copper(I) — octasulfur (2:1), [CuI(C12N2H8)2]2[Cu2I4] · S8

C13H14CuIn3S2, triclinic, P1 (no. 2), a = 8.8080(1) Å, b = 10.1039(5) Å, c = 11.2436(2) Å, + = 66.70(2)°, * = 76.20(2)°, ( = 66.36(2)°, V = 838.0 Å, Z = 2, Rgt(F) = 0.038, wRref(F) = 0.108, T = 293 K. Source of material A mixture of Cu(OAc)2 · H2O (40 mg, 0.2 mmol), NaS2CNMe2 · 2H2O (45 mg, 0.2 mmol), 2,2'-bipyridine (31 mg, 0.2.mmol) and NaI.·.2H2O (37 mg, 0.2 mmol) was stirred in dimethylformamide (20 mL) at room temperature in air for about one day. The vapor of i-PrOH was diffused slowly into the resulting solution, and after about one month gray block-shaped crystals (32.mg) were obtained. Experimental details The H atoms were positioned geometrically and refined as riding atoms with d(C—H) = 0.93 (aromatic) or 0.96 Å (methyl) and Uiso(H) = 1.2 Ueq(Caromatic) or 1.5 Ueq(Cmethyl). Discussion Organonitrogen ligands, such as 2,2'-bipyridine (bipy), 1,10phenanthroline, 4,4'-bipyridine and their derivatives as suitable spacers have been extensively used in the construction of coordination complexes [1-3]. They not only are versatile ligands for coordination bonding but also can form aromatic --stacking interactions, C–H···interactions and hydrogen bonding which are important supramolecular force enhancing the stability of the complexes in both solution and solid states [4,5]. In the title crystal structure, the Cu(II) atom is five-coordinated in a distorted square pyramidal manner by one I atom in the apical position with d(Cu—I) = 2.9485(9) Å, two S atoms from a S2CNMe2 ligand [d(Cu—S1) = 2.296(1) Å and d(Cu—S2) = 2.323(1) Å] and two N atoms from a bipy ligand in the basal plane [d(Cu—N2) = 2.004(4) Å and d(Cu—N3) = 2.015(4) Å]. Two adjacent s t ructural uni ts are l inked to a dimer [CuI(bipy)(S2CNMe2)]2 by face-to-face --interactions between bipy ring R1 (N2/C4-C8) to adjacent symmetry-related ring R2 (N3/C9-C13) with dihedral angle of 3.68°, centroid-tocentroid distance of 4.470(4) Å, and plane-to-plane distance of 3.372 Å [6]. The dimers are further connected through C2–H2C···(R2) interactions (∠C–H···R = 125.00° and d(C···R) = 3.559(7) Å) and C2–H2B···I hydrogen bonds (∠C–H···I = 164.00° and d(C···I) = 3.963(6) Å) to form 2D structure in the (001) plane [6]. Z. Kristallogr. NCS 225 (2010) 347-348 / DOI 10.1524/ncrs.2010.0151 347 © by Oldenbourg Wissenschaftsverlag, München Crystal: gray block, size 0.20 × 0.20 × 0.20 mm Wavelength: Mo K+ radiation (0.71073 Å) .: 33.87 cm−1 Diffractometer, scan mode: Rigaku Mercury CCD, ' 2,max: 55° N(hkl)measured, N(hkl)unique: 6208, 3630 Criterion for Iobs, N(hkl)gt: Iobs > 2 )(Iobs), 2629 N(param)refined: 181 Programs: PLATON [6], SHELXS-97, SHELXL-97, SHELXTL [7] Table 1. Data collection and handling. H(2A) 2i 0.0220 0.0026 0.3699 0.098 H(2B) 2i 0.0638 −0.1127 0.2961 0.098 H(2C) 2i −0.0750 0.0490 0.2513 0.098 H(3A) 2i 0.2669 0.0973 0.0173 0.117 H(3B) 2i 0.0815 0.1104 0.0254 0.117 H(3C) 2i 0.2202 −0.0515 0.0696 0.117 H(4A) 2i 0.2266 0.2015 0.5966 0.086 H(5A) 2i 0.2799 0.2047 0.7853 0.095 H(6A) 2i 0.5078 0.2650 0.7841 0.094 H(7A) 2i 0.6743 0.3250 0.5909 0.079 H(10A) 2i 0.8203 0.3801 0.3994 0.084 H(11A) 2i 0.9495 0.4448 0.1900 0.089 H(12A) 2i 0.8502 0.4302 0.0251 0.088 H(13A) 2i 0.6290 0.3466 0.0720 0.074 Table 2. Atomic coordinates and displacement parameters (in Å). Atom Site x y z Uiso

Crystal structure of (2,2′-bipyridine-κ2N,N′)-(N,N-dimethyldithiocarbamato- κ2S,S′)copper(II) iodide, CuI(C10H8N2)(C3H6NS2)

A new mononuclear Cu(Ⅱ) dithiocarbamate complex CuI(prdtc)(phen) 1(prdtc = N-pyrrolidinyldithiocarbamate,phen = 1,10-phenanthroline) was synthesized and characterized by elemental analysis,IR spectrum,and single-crystal X-ray diffraction.The crystal belongs to the monoclinic system,space group P21/c with a = 8.7110(9),b = 14.7143(14),c = 14.8507(15) ,β = 109.721(6)o,V = 1791.9(3) 3,Z = 4,Dc = 1.916 g/cm3,C17H16CuIN3S2,Mr = 516.89,λ(MoKa) = 0.71073 ,μ = 3.178 mm-1,F(000) = 1012,the final R = 0.0369 and wR = 0.0987.A total of 4082 unique reflections were collected,of which 2916 with I 2σ(I) were observed.The Cu(Ⅱ) atom is five-coordinated in a distorted square-pyramidal geometry by one I atom in the apical position,two S atoms from a prdtc ligand and two N atoms from a phen ligand in the basal plane.There exist face-to-face aromatic π-π stacking interactions between adjacent phen ligands stabilizing the structure and making the complex assemble into a 1D structure along the a axis.It can be concluded that the difference of the dtc flexibility and reaction conditions result in the structural difference between complex 1 and CuI(dmdtc)(phen)(dmdtc = N,N-dimethyldithiocarbamate).

Ji-Hua

Papers

Synthesis and Crystal Structure of a New Cu（II） Dithiocarbamate Complex CuI（prdtc）（phen）