Crystal structure of the two-dimensional coordination polymer poly[di-μ-bromido-bis(μ-tetrahydrothiophene)dicopper(I)]

The polymeric title compound, [Cu2Br2(C4H8S)2] n , CP1, represents an example of a two-dimensional coordination polymer resulting from reaction of CuBr with tetrahydrothiophene (THT) in MeCN solution. The two-dimensional layers consist of two different types of rhomboid-shaped dinuclear Cu(μ2-Br)2Cu secondary building units (SBUs); one with a quite loose Cu...Cu separation of 3.3348 (10) Å and a second one with a much closer intermetallic contact of 2.9044 (9) Å. These SBUs are interconnected through bridging THT ligands, in which the S atom acts as a four-electron donor bridging each Cu(μ2-Br)2Cu unit in a μ2-bonding mode. In the crystal, the layers are linked by very weak C—H...·Br hydrogen bonds with H...Br distances of 2.95 Å, thus giving rise to a three-dimensional supramolecular network.

Single-crystal X-ray diffraction study, NMR and electrochemical analysis of a copper(i) 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis-[(6-methyl-2,2′-bipyridyl-6-yl)methoxy]calix[4]arene complex: an original M4L2 “hand-to-hand” system

An original M4L2 “hand-to-hand” copper(i)/tetra-bipyridyl-calix[4]arene complex was obtained and characterized in the solid state by X-ray diffraction. It changes in MeCN solution to its M2L analogue.

Anion receptors containing coordinatively unsaturated metal ions: copper(II) complexes with cyclam derivatives

The two coordinatively unsaturated complexes [Cu(cyclam)]2+ (cyclam: 1,4,8,11-tetraazacyclotetradecane, 1) and [Cu(Bn4cyclam)]2+ (Bn4cyclam: 1,4,8,11-tetrabenzyl-1,4,8,11-tetraazacyclotetradecane, 2) in an MeCN solution uptake an anion X− (halide, pseudohalide) to give square pyramidal ternary complexes, whose stability has been determined through spectrophotometric titration experiments. The formation of a five-cordinate complex is favored by the trans-I configuration of the [Cu(Bn4cyclam)]2+ receptor, but it is contrasted by the severe steric repulsions exerted by the benzyl substituents on the macrocyclic framework. No significant repulsive effects have been observed in anion binding to the [Cu(cyclam)]2+ receptor, exhibiting a trans-III configuration. The existence of a linear relationship between the magnitude of the red shift experienced by the d−d absorption band on anion binding and log K values is discussed.

Hydrogen and halogen bonding in a concerted act of anion recognition: F− induced atmospheric CO2 uptake by an iodophenyl functionalized simple urea receptor

Halogen bonding plays a key role in the fixation of atmospheric CO2 because air-stable crystals of HCO3− dimer by a simple urea based para-iodo substituted acyclic receptor in the presence of n-TBA salt of F− in MeCN solution.

Linear Trinuclear Copper(II) Complexes Derived from the Nucleophilic Addition Products of Dicyanonitrosomethanide [C(CN)2(NO)]–: Syntheses, Structures, and Magnetic Properties

Two novel trinuclear CuII complexes have been synthesised from the nucleophilic addition derivatives of the small cyano anion, dicyanonitrosomethanide (dcnm). The reaction of CuII with the water adduct ligand, carbamoylcyanonitrosomethanide (ccnm) and teaH3 (triethanolamine) in a basic MeOH/MeCN solution results in the formation of [Cu3(acnm)2(teaH2)2]·2MeOH (1) (acnm = amidocarbonyl(cyano)nitrosomethanide and teaH2– = singly deprotonated triethanolamine). The reaction of CuII with dicyanonitrosomethanide (dcnm) and m-xylenediamine in a basic MeOH/MeCN solution results in the formation of [Cu3(cimm)2(a3acnm)2]·6MeCN (2) (cimm = cyano(imido(methoxy)methyl)nitrosomethanide and a3acnm = {amino(3-aminomethylphenyl)methylimino}methyl(cyanonitrosomethanide)). Both complexes display linear trinuclear CuII metallic cores. Solid state DC magnetic susceptibility studies were performed on 1 and 2. Compound 1 revealed very strong antiferromagnetic interactions between central and terminal Cu atoms, while compound 2 displayed ferromagnetic interactions because of the orthogonal relationship of the terminal and the central ‘magnetic’ orbitals, which contrasts with these orbitals being coplanar in 1 thus providing strong superexchange pathways involving Cu-N-O-Cu moieties.

Synthesis, characterisation and activity in catalytic epoxidation of olefins of new dinuclear nickel(ll) complexes

Two new dinuclear nickel(ll) compounds of formula [Nill2(μ-L1)2](CIO4)2·MeCN (1·MeCN) and [NiII2(μ-L2)2](CIO4)2 (2) where HL1 and HL2 stand for 3-(2-(dimethylamino)ethylimino)butan-2-one oxime and 1-(2-(dimethylamino)ethyl-imino)-1-phenylpropan-2-one oxime respectively, have been synthesised. Single crystal X-ray analyses of the complexes reveal that the nickel(ll) ions are in square-planar N3O environments and form six-membered (NiNO)2 metallacycles. Cyclic voltammetric measurements of 1·MeCN and 2 in MeCN solution show quasirreversible one-electron oxidations at E1/2 = 0.566 V and 0.603 V ( vs Fc+/Fc), respectively, attributed to NiIIINiII/NiII2 redox couples. Additional reversible NiIII2/NiIIINiII redox responses were observed at relatively higher potential near E1/2 = 0.832 V and 0.850 V ( vs Fc+/Fc), respectively, for 1·MeCN and 2. Complexes 1·MeCN and 2 display intense charge-transfer bands at ∼390 and ∼345 nm in the visible region. Chemical oxidation of complex 1·MeCN by sodium hexachloroiridate(IV) hexahydrate generates red Ni2III species with characteristic new bands at ∼520 and 427 nm in the visible region as well as the characteristic EPR signals at 77 K with g⊥ > gII. Similar phenomena were observed for complex 2 upon chemical oxidation. The dinickel(ll) complexes are catalytically active for epoxidation of olefins using iodosylbenzene as the terminal oxidant.

Polymorphism in iodotris(tri-p-tolylphosphine)silver(I)

The reaction of silver(I) iodide with tri(p-tolyl)phosphine in MeCN solution in 1:3 molar ratio yields a polymorph of the complex of the formula [AgI{P(4-MeC6H4)3}3], with the Ag atom in a distorted tetrahedral environment. A polymorphic structure of this complex (a) is compared with previously published crystal structures (b), determined at different temperatures. The two polymorphs are compared using r.m.s. overlay calculations as well as half-normal probability plots.

Reduction of a Heterocyclic Selenium(IV) Oxide LSeO by [Pd(COD)Cl2] – Crystal Structure of trans-[Pd(LSe)2Cl2]

The heterocyclic selenium(IV) oxide LSeO is reduced by [Pd(COD)Cl2] in MeCN solution to produce trans- [Pd(LSe)2Cl2] (2) (LSe = 2,3-dihydro-2-isopropyl-7-(Nisopropylcarbamoyl)- 1,2-benzisoselenazole-3-oxide). Complex 2 crystallizes in the triclinic space group P1̅ with a = 10.700(1), b = 10.871(1), c = 15.656(2) Å , α = 104.51(1), β = 94.59(1), γ = 95.25(1)◦, V = 1745.5(3) Å3, and Z = 2. The COD is oxidized to 5,6-epoxycyclooctene.

Oxidative addition chemistry of dimethyl(dipyridyl ketone)platinum(II)

The dimethylplatinum(II) complex [PtMe2(DPK)] (DPK = di-2-pyridyl ketone) undergoes easy oxidative addition to give platinum(IV) complexes. For example, reaction of [PtMe2(DPK)] with MeI gave [PtIMe3(DPK)], reaction with N-chlorosuccinimide in methanol gave [PtCl(OMe)Me2(DPK)], and reaction with [FN(CH2CH2)2NCH2Cl][BF4]2 in MeCN gave [PtF(NCMe)Me2(DPK)][BF4]. In several cases, the ketone group of the DPK ligand took part in the reactions. For example, oxidation of [PtMe2(DPK)] by air or hydrogen peroxide gave [Pt(OH)Me2(DPKOH)] (DPKOH = κ3-NN′O-(2-C5H4N)2C(OH)O), which reacted with HCl to give [PtClMe2(DPKOH)] or with excess acetyl chloride to give [PtCl2Me2(DPK)]. Reaction of [PtMe2(DPK)] with methyl triflate in MeCN solution gave [PtMe3(NCMe)(DPK)][OTf], which reacted with more MeOTf in the presence of base to give [PtMe3{DPC(OMe)2}][OTf], where DPC(OMe)2 = κ3-NN′O-(2-C5H4N)2C(OMe)2. Hydrolysis of [PtF(NCMe)Me2(DPK)][BF4] gave [Pt{NHC(=O)Me}Me2(DPKOH)], which crystallized in partially protonated form as an unusual supramolecular polymer [Pt{NHC(=O)Me}Me2(DPKOH)]·0.5HBF4.Key words: platinum, oxidative addition, ketone, pyridyl.