Synthesis, coordination studies and redox properties of a novel ditertiary phosphine bearing two ferrocenyl groups

The new ferrocenyl substituted ditertiary phosphine {FcCH₂N(CH₂PPh₂)CH₂}₂ [Fc = (η⁵-C₅H₄)Fe(η⁵-C₅H₅)] (1) was prepared, in 72% yield, by Mannich based condensation of the known bis secondary amine {FcCH₂N(H)CH₂}₂ with 2 equiv. of Ph₂PCH₂OH in CH₃OH. Phosphine 1 readily coordinates to various transition-metal centres including Mo⁰, Ru^II, Rh^I, Pd^II, Pt^II and Au^I to afford the heterometallic complexes {RuCl₂(p-cym)}₂(1) (2), (AuCl)₂(1) (3), cis-PtCl₂(1) (4), cis-PdCl₂(1) (5), cis-Mo(CO)₄(1) (6), trans,trans-{Pd(CH₃)Cl(1)}₂ (7) and trans,trans-{Rh(CO)Cl(1)}₂ (8). In complexes 2, 3, 7 and 8 ligand 1 displays a P,P′-bridging mode whilst for 4-6 a P,P′-chelating mode is observed. All new compounds have been fully characterised by spectroscopic and analytical methods. Furthermore the structures of 1, 2 · 2CH₂Cl₂, 3 · CH₂Cl₂, 4 · CH₂Cl₂, 6 · 0.5CHCl₃ and 8 have been elucidated by single crystal X-ray crystallography. Electrochemical measurements have been undertaken, and their redox chemistry discussed, on both noncomplexed ligand 1 and representative compounds containing this new ditertiary phosphine.     

Role of inorganic and organic anions in the formation of metallosupramolecular assemblies of silver(I) coordination polymers with the twisted ligand bis(4-pyridylthio)methane

Reaction of the twisted pyridyl dithioether ligand bis(4-pyridylthio)methane (4bpytm) with silver(I) salts afforded four complexes with 1:1 stoichiometries, namely [Ag(4bpytm)](NO₃) (1), [Ag(4bpytm)](ClO₄) (2) and [Ag(4bpytm)](ClO₄) ½CH₂Cl₂ ½dmf (2·Solv), [Ag(CH₃COO)(4bpytm)]·H₂O (3) and [Ag(CF₃COO)(4bpytm)] (4). X-ray structural analysis of these complexes showed that one-dimensional structures are obtained for 1, 2·Solv and 4 whereas a two-dimensional network is formed in 3. The ligand 4bpytm acts as an N,N′-bis(monodentate) bridging system in all cases except in 3, where an unprecedented coordination mode is obtained with the ligand acting in a tridentate manner using its two pyridine nitrogen atoms and a sulfur atom. The coordination polymers are assembled through secondary contacts: Ag···Ag in 4, Ag···S in 1, 2·Solv and 4, Ag···O in 2·Solv, and hydrogen bonding interactions between crystallization water that join the polymeric layers in 3. All of these weak interactions link the low-dimensional complexes to give high-dimensional supramolecular structures and further stabilize the crystal structures in the solid state.     

Syntheses, structures and ligand conformations of Cu(II), Co(II) and Ag(I) complexes containing the phosphinic amide ligands

The syntheses, structures and ligand conformations of the complexes trans-Cu(L1)₂(ClO₄)₂, (L1 = N-(2-pyrimidinyl)-P,P-diphenyl-phosphinic amide), 1, [trans-Co(L1)₂(CH₃OH)₂](ClO₄)₂·O(C₂H₅)₂, 2, [trans-Co(L2)₂(H₂O)₂](ClO₄)₂·2CH₃OH, (L2 = N-(2-pyridinyl)-P,P-diphenyl-phosphinic amide), 3, [cis-Co(L2)₂(NO₃)](NO₃), 4, and [Ag(L3)(NO₃)(CH₃CN)]_∞, (L3 = N-(6-methyl-2-pyridinyl)-P,P-diphenyl-phosphinic amide), 5, are reported. The L1 and L2 ligands in the monomeric complexes 1-4 chelate the metal centers through the pyrimidyl/pyridyl nitrogen atoms and the phosphinic amide oxygen atoms, whereas the L3 ligands in complex 5 bridge the metal centers, forming a 1-D zigzag chain. The chelating L2 ligands in complexes 3 and 4 adopt cis conformations and the bridging L3 ligand in complex 5 adopts a trans conformation, respectively.     

Structural diversity of organotin(IV) complexes self-assembled from hydroxamic acid and mono- or dialkyltin salts

Three hydroxamic acid ligands (HL₁ = acetohydroxamic acid; HL₂ = benzohydroxamic acid; HL₃ = N-phenylbenzohydroxamic acid), have been used to synthesize series of mono- or dialkyltin(IV) complexes, which include (i) the carboxyl acid hybrid five-coordinated dialkyltin complexes (C₄H₉)₂SnL₁L₄ (1), [(CH₃)₂SnL₂L₅]·0.5C₆H₆ (2), (HL₄ = acetic acid; HL₅ = benzoic acid); (ii) the six-coordinated mono-n-butyltin complexes (C₄H₉)SnL₁·Cl₂·H₂O (3), (C₄H₉)SnL₂·Cl₂·H₂O (4), [(C₄H₉)SnL₃·Cl₂·H₂O]·H₂O (5), [(C₄H₉Sn)₂(L₃)₂·Cl₂·(OCH₃)₂] (6); and (iii) the alkali metal-mingled seven-coordinated mono-n-butyltin complexes [(C₄H₉Sn)₃L₂Na]⁺·Cl⁻·(CH₃CH₂)₂O (7), [(C₄H₉Sn)₃L₂K]⁺·Cl⁻·CH₂Cl₂ (8). All complexes were characterized by elemental analyses, IR, ¹H, ¹³C, ¹¹⁹Sn NMR and X-ray single crystal diffraction. In these complexes, hydroxamic acids present bidentate coordination modes with the carbonyl O atom and the hydroxyl O atom binding to tin center. In complexes 1-6, each tin atom is coordinated by one hydroxamic acid ligand. However, in complexes 7 and 8, tin atom is surrounded by three hydroxamic acid ligands, and all hydroxyl O atoms of the ligands also bind to the alkali metal center (Na or K). This kind of organotin(IV) framework containing one alkali metal is found for the first time. Furthermore, the supramolecular structures of 1, 3, 4 and 6 have been found to consist of 1D linear molecular chains formed by intermolecular N-H···X or C-H···X (X = O, N or Cl) hydrogen bonds. For complex 2, an interesting macrocyclic tetramer has been built by the intermolecular N-H···O hydrogen bonds. Fascinatingly, two unique symmetric dimeric structures are recognized in complexes 7 and 8, which is individually bridged by intermolecular N-H···Cl and N-H···O hydrogen bonds. In addition, for 8, the dimeric cycles have been further connected into a 1D supramolecular chain.     

Synthesis, characterization and reactivity of the molybdenum(VI) complex [MoCl(NAr)2(CH2CMe2Ph)] (Ar=2,6-Pr2C6H3)

The compounds [MoCl(NAr)₂R] (R=CH₂CMe₂Ph (1) or CH₂CMe₃(2); Ar=2,6-Prⁱ₂C₆H₃) have been prepared from [MoCl₂(NAr)₂(dme)] (dme=1,2-dimethoxyethane) and one equivalent of the respective Grignard reagent RMgCl in diethyl ether. Similarly, the mixed-imido complex [MoCl₂(NAr)(NBu^t)(dme)] affords [MoCl(NAr)(NBu^t)(CH₂CMe₂Ph)] (3). Chloride substitution reactions of 1 with the appropriate lithium reagents afford the compounds [MoCp(NAr)₂(CH₂CMe₂Ph)] (4) (Cp=cyclopentadienyl), [MoInd(NAr)₂(CH₂CMe₂Ph)] (5) (Ind=Indenyl), [Mo(OBu^t)(NAr)₂(CH₂CMe ₂Ph)] (6), [MoMe(NAr)₂(CH₂CMe₂Ph)] (7), [MoMe(PMe₃)(NAr)₂(CH₂CMe ₂Ph)] (8) (formed in the presence of PMe₃) and [Mo(NHAr)(NAr)₂(CH₂CMe₂P h)](9). In the latter case, a by-product {[Mo(NAr)₂(CH₂CMe₂Ph) ]₂(μ-O)}(10) has also been isolated. The crystal structures of 1, 4, 5 and 10 have been determined. All possess distorted tetrahedral metal centres with cis near-linear arylimido ligands; in each case (except 5, for which the evidence is unclear) there are α-agostic interactions present.     

X-ray crystal structures of novel platinum(II) and palladium(II) complexes of dialkyl phosphonated phosphines

Two diethyl phosphonated phosphine ligands of formula Ph₂P(CH₂)₃PO₃Et₂ (ligand L) and Ph₂P(4-C₆H₄PO₃Et₂) (ligand L′) were used to prepare different complexes of platinum(II) (1, cis-PtCl₂L₂; 2, trans-PtCl₂L₂·H₂O; 3A and 3B, cis- and trans-PtCl₂L′₂) and palladium(II) (4, [PdCl₂L]₂; 5, trans-PdCl₂L₂·H₂O; 6, trans-PdCl₂L′₂·CH₂Cl₂). The single-crystal X-ray structure analyses of complexes 1, 2, 4-6 indicate that complexation involved only the phosphine end, whereas the strong polarization of the PO bond was highlighted by the formation of hydrogen bonds with a water molecule in 2 and 5, and with a dichloromethane molecule in 6, with an exceptionally short CH?O hydrogen bond length (C?O separation 3.094(3) Å).     

Subtle role of counteranions in molecular construction: Structures and properties of novel Cu(II) coordination complexes with bis-(1-benzoimidazolymethylene)-(2,5-thiadiazoly)-disulfide

The direct self-assembly of bis-(1-benzoimidazolymethylene)-(2,5-thiadiazoly)-disulfide (L) with CuSO₄, Cu(NO₃)₂ and CuCl₂ affords three novel supramolecular complexes: 1-D ladder-like chain complex {[Cu(SO₄)(L)] · (CH₃OH)}_n (1), dimer complexes {[Cu(L)(CH₃O)]₂(NO₃)₂} · 2H₂O (2) and [Cu(L)(Cl)(N₃)]₂ · 2CH₃OH (3). The nature of the anions is the underlying reason behind the differences in the structures of this series of complexes. Furthermore, utilizing the coordinatively unsaturated complexes 2 and 3 as precursor complexes, two new derivative complexes [Cu(L)(NCS)(CH₃O)]₂ · 2CH₃OH (2A) and [Cu(L)(ClO₄)(N₃)]₂ · 2CH₃OH (3A) are obtained by the addition and exchange reactions of complexes 2 and 3 with anions. X-ray crystallographic analysis shows that the two derivatives retain the skeletons of their precursor complexes, and the anions with the stronger coordination capacity only bind to the active position of precursor complexes. In addition, different from the obvious effects on the structures in the direct self-assembly of the metal and ligand, the change of counteranions has no great impact on the structures in the anion exchange reactions. We also study the catalytic activities of the complexes 2, 2A, 3, and 3A, which have similar skeletons, for the oxidative coupling polymerization of 2,6-dimethylphenol (DMP). And we find that the introductions of different coordination counterions produce significant impacts on the catalytic properties of these complexes.     

Syntheses, structures and properties of silver(I) complexes with flexible 1,3,5-tris(pyridylmethoxyl)benzene ligands

Five new silver(I) complexes [Ag₂(L₂)₂](BF₄)₂·CH₃CN·CH₃OH (1), [Ag(L₂)(CF₃SO₃)] (2), [Ag(L₃)]ClO₄·CH₃OH (3), [Ag₂(L₃)₂](CF₃SO₃)₂·CH₃CN·CH₃OH·H₂O (4) and [Ag(L₃)]PF₆·2CH₃CN (5) [L₂=1,3,5-tris(2-pyridylmethoxyl)benzene, L₃=1,3,5-tris(3-pyridylmethoxyl)benzene] were synthesized and characterized by single crystal X-ray diffraction analyses. In complexes 1-5, ligands L₂ and L₃ show different conformations and act as three-connectors, while the Ag(I) atom serves as three-connecting node to result in the formation of 2D and 3D frameworks. Complexes 1 and 2 with different counteranions have similar 2D network structure with the same (4,8²) topology. Complex 3 has a 3D structure with (10,3)-a topology while complexes 4 and 5 have the same 2D (6,3) topological structure. The results showed that the structure of organic ligands and counteranions play subtle but important role in determining the structure of the complexes. In addition, the photoluminescence and anion-exchange properties of the complexes were investigated in the solid state at room temperature.     

Salen-type nickel(II), palladium(II) and copper(II) complexes having chiral and racemic camphoric diamine components

Chiral and racemic Salen-type Schiff-base ligands (H₂L¹, H₂L² and H₂L³), condensed between D-(+)- and D,L-camphoric diamine (also known as (1R,3S)-1,2,2-trimethylcyclopentane-1,3-diamine) and 2-hydroxybenzaldehyde or 3,5-dibromo-2-hydroxybenzaldehyde with a 1:2 molar ratio, have been synthesized and characterized. A series of new nickel(II), palladium(II) and copper(II) complexes of these chiral and racemic ligands exhibiting different coordination number (4, 5 and 6) have been characterized with the formulae [NiL¹]·CH₃OH (3), [NiL¹]·H₂O (4), [NiL²] (5), [PdL²] (6), [Cu₂(L²)₂(H₂O)] (7) and [NiL³(DMF)(H₂O)] (8). Different solvent molecules in 3 and 4 (methanol and water molecules) as well as different apical ligands in 7 and 8 (water and DMF molecules) are involved in different O–H···O hydrogen bonding interactions to further stabilize the structures. UV–Vis (UV–Vis), circular dichroism (CD) spectra and thermogravimetric (TG) analyses for the metal complexes have also been carried out.     

Synthesis characterization and X-ray crystal structures of cis-1,4-diaminocyclohexane-platinum(II) nucleobase adducts

Platinum complexes of the type [Pt(cis-1,4-DACH)(L)₂]X, where cis-1,4-DACH = cis-1,4-diaminocyclohexane; L = adenine (ade) (1), hypoxanthine (hyp) (2), 9-methylguanine (9-megua) (3), cytosine (cyt) (4), or 1-methylcytosine (1-mecyt) (5); and X = SO₄ or Cl₂ groups, were synthesized and characterized by elemental analysis and by ¹H, ¹³C, and ¹⁹⁵Pt nuclear magnetic resonance spectroscopy. The crystals of [Pt(cis-1,4-DACH)(9-megua)₂]SO₄[9-megua-H]₂SO₄ (3) and [Pt(cis-1,4-DACH)(1-mecyt)₂]Cl₂ · 6H₂O (5) were also subjected to single-crystal X-ray diffraction. The base/PtN4 coordination plane dihedral angles were 74.55° and 85.61° in complex 3 and 78.12° and 81.80° in complex 5. The platinum had distorted square planar geometry in both complexes; the two adjacent corners were occupied by the two nitrogen atoms of cis-1,4-DACH, and the other two corners were occupied by the two N7 atoms of 9-megua in complex 3 and the two N3 atoms of 1-mecyt in complex 5. The cis-1,4-DACH, which has a unique twist-boat configuration, formed a seven-member chelating ring with platinum, which led to considerable strain during bidentate cis-1,4-DACH binding. Cations of both complexes 3 and 5 adopted C₂ molecular symmetry. These adducts were the models for the intrastand cross-links that were relevant to the binding of the Pt(II) antitumor drugs to DNA.     

Cationic methyl complexes of rhodium(III): synthesis, structure, and some reactions

Cationic methyl complex of rhodium(III), trans-[Rh(Acac)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄] (1) is prepared by interaction of trans-[Rh(Acac)(PPh₃)₂(CH₃)I] with AgBPh₄ in acetonitrile. Cationic methyl complexes of rhodium(III), cis-[Rh(Acac)(PPh₃)₂ (CH₃)(CH₃CN)][BPh₄] (2) and cis-[Rh(BA)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄] (3) (Acac, BA are acetylacetonate and benzoylacetonate, respectively), are obtained by CH₃I oxidative addition to rhodium(I) complexes [Rh(Acac)(PPh₃)₂] and [Rh(BA)(PPh₃)₂] in acetonitrile in the presence of NaBPh₄. Complexes 2 and 3 react readily with NH₃ at room temperature to form cis-[Rh(Acac)(PPh₃)₂(CH₃)(NH₃)][BPh₄] (4) and cis-[Rh(BA)(PPh₃)₂(CH₃)(NH₃)][BPh₄] (5), respectively. Complexes 1-5 were characterized by elemental analysis, ¹H and ³¹P{¹H} NMR spectra. Complexes 1, 2, 3 and 4 were characterized by X-ray diffraction analysis. Complexes 2 and 3 in solutions (CH₂Cl₂, CHCl₃) are presented as mixtures of cis-(PPh₃)₂ isomers involved into a fluxional process. Complex 2 on heating in acetonitrile is converted into trans-isomer 1. In parallel with that isomerization, reductive elimination of methyl group with formation of [CH₃PPh₃][BPh₄] takes place. Replacement of CH₃CN in complexes 1 and 2 by anion I⁻ yields in both cases the neutral complex trans-[Rh(Acac)(PPh₃)₂(CH₃)I]. Strong trans influence of CH₃ ligand manifests itself in the elongation (in solid) and labilization (in solution) of rhodium-acetonitrile nitrogen bond.     

Structural diversity in Cu(II), Cd(II) and Hg(II) coordination complexes with the rigid N,N′-bis(2/3-aryl)-1,4-benzenedicarboxamide ligand

The syntheses and structures of a series of metal complexes, namely Cu₂Cl₄(L¹)(DMSO)₂·2DMSO (L¹ = N,N′-bis(2-pyridinyl)-1,4-benzenedicarboxamide), 1; {[Cu(L²)_1.5(DMF)₂][ClO₄]₂·3DMF}_∞ (L² = N,N′-bis(3-pyridinyl)-1,4-benzenedicarboxamide), 2; {[Cd(NO₃)₂(L³)]·2DMF}_∞ (L³ = N,N′-bis-(2-pyrimidinyl)-1,4-benzenedicarboxamide), 3; {[HgBr₂(L³)]·H₂O}_∞, 4, and {[Na(L³)₂][Hg₂X₅]·2DMF}_∞ (X = Br, 5; I, 6) are reported. All the complexes have been characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. Complex 1 is dinuclear and the molecules are interlinked through S?S interactions. In 2, the Cu(II) ions are linked through the L² ligands to form 1-D ladder-like chains with 60-membered metallocycles, whereas complexes 3 and 4 form 1-D zigzag chains. In complexes 5 and 6, the Na(I) ions are linked by the L³ ligands to form 2-D layer structures in which the [Hg₂X₅]⁻ anions are in the cavities. The L² ligand acts only as a bridging ligand, while L¹ and L³ show both chelating and bridging bonding modes. The L¹ ligand in 1 adopts a trans-anti conformation and the L² ligand in 2 adopts both the cis-syn and trans-anti conformations, whereas the L³ ligands in 3–6 adopt the trans conformation.     

Syntheses and structures of Ag(I) complexes containing 1,4-bis(4,5-dihydro-2-oxazolyl)benzene

The reactions of the polydentate ligand 1,4-bis(4,5-dihydro-2-oxazolyl)benzene (L) with AgX (X = CH₃COO⁻, ClO₄⁻ and CF₃SO₃⁻) afforded the complexes [Ag₂(L)(CH₃COO)₂]_∞ (1), [Ag₂(L)₃(ClO₄)₂]_∞ (2), and [Ag(L)(CF₃SO₃)]_∞ (3), whereas the reaction of L with Ag₂SO₄ in MeOH/H₂O system afforded {[Ag₂(L)₃(H₂O)₃][SO₄] · 9H₂O}_∞ (4). The EA and IR have been recorded and all the complexes have been structurally characterized by X-ray crystallography, confirming that complexes 1–4 are two-dimensional coordination polymeric frameworks. The bidentate L ligands in complexes 3 and 4 adopt both the syn and anti conformation and those in 1 and 2 adopt the anti conformation only. The anions CH₃CO₂⁻ in complex 1 bridge the Ag(I) atoms in η¹, η², μ₃-coordination mode forming a 1-D zig-zag –[Ag(CH₃COO)]_n– chains, while the anions ClO₄⁻, CF₃SO₃⁻ and SO₄²⁻ in complexes 2–4 are not coordinated to the Ag(I) atoms, but all of them play an important roles in linking cationic 2-D frameworks into 3-D supramolecular structures.     

Synthesis, spectral characterization and crystal structure of copper(II) complexes of 2-benzoylpyridine-N(4)-phenylsemicarbazone

An interesting series of nine new copper(II) complexes [Cu₂L₂(OAc)₂]·H₂O (1), [CuLNCS]·½H₂O (2), [CuLNO₃]·½H₂O (3), [Cu(HL)Cl₂]·H₂O (4), [Cu₂(HL)₂(SO₄)₂]·4H₂O (5), [CuLClO₄]·½H₂O (6), [CuLBr]·2H₂O (7), [CuL₂]·H₂O (8) and [CuLN₃]·CH₃OH (9) of 2-benzoylpyridine-N(4)-phenyl semicarbazone (HL) have been synthesized and physico-chemically characterized. The tridentate character of the semicarbazone is inferred from IR spectra. Based on the EPR studies, spin Hamiltonian and bonding parameters have been calculated. The g values, calculated for all the complexes in frozen DMF, indicate the presence of the unpaired electron in the d_x²-y² orbital. The structure of the compound, [Cu₂L₂(OAc)₂] (1a) has been resolved using single crystal X-ray diffraction studies. The crystal structure revealed monoclinic space group P2₁/n. The coordination geometry about the copper(II) in 1a is distorted square pyramidal with one pyridine nitrogen atom, the imino nitrogen, enolate oxygen and acetate oxygen in the basal plane, an acetate oxygen form adjacent moiety occupies the apical position, serving as a bridge to form a centrosymmetric dimeric structure.     

Aminobis(phenolate)s of imidomolybdenum(VI) and -tungsten(VI)

The reactions of trans-[MoO(ONO^Me)Cl₂] 1 (ONO^Me = methylamino-N,N-bis(2-methylene-4,6-dimethylphenolate) dianion) and trans-[MoO(ONO^tBu)Cl₂] 2 (ONO^tBu = methylamino-N,N-bis(2-methylene-4-methyl-6-tert-butylphenolate) dianion) with PhNCO afforded new imido molybdenum complexes trans-[Mo(NPh)(ONO^Me)Cl₂] 3 and trans-[Mo(NPh)(ONO^tBu)Cl₂] 4, respectively. As analogous oxotungsten starting materials did not show similar reactivity, corresponding imido tungsten complexes were prepared by the reaction between [W(NPh)Cl₄] with aminobis(phenol)s. These reactions yielded cis- and trans-isomers of dichloro complexes [W(NPh)(ONO^Me)Cl₂] 5 and [W(NPh)(ONO^tBu)Cl₂] 6, respectively. The molecular structures of 4, cis-6 and trans-6 were verified by X-ray crystallography. Organosubstituted imido tungsten(VI) complex cis-[W(NPh)(ONO^tBu)Me₂] 7 was prepared by the transmetallation reaction of 6 (either cis or trans isomer) with methyl magnesium iodide.     

Syntheses,structures and luminescent properties of four d-metal coordination polymers based on the 2,4,5-tri(4-pyridyl)-imidazole ligand

Four d¹⁰-metal coordination polymers based on the 2,4,5-tri(4-pyridyl)-imidazole ligand (Htpim), {[Zn₂(Htpim)₄Cl₄] · 8H₂O}_n (1), {[Cd(tpim)₂(H₂O)₂] · 4CH₃OH}_n (2), {[Cu₂(Htpim)(PPh₃)₂I₂] · CH₃CN}_n (3) and {[Ag(Htpim)](NO₃) · CH₂Cl₂}_n (4), have been synthesized and characterized by elemental analyses, IR, thermogravimetric and X-ray structural analyses. Both complexes 1 and 2 show one dimensional ribbon-like structures. Via intermolecular hydrogen bonds, a 2D supramolecular network and 3D framework are formed for 1 and 2, respectively. Complex 3 shows a 1D zigzag chain with a CuI₂Cu rhomboid dimer. Complex 4 shows a 1D ladder-like polymer with two different metallacycles. The luminescent properties of all the complexes have been studied in the solid state.     

Ligand behaviour of P-functionally substituted organotin halides: palladium(II) and platinum(II) complexes with Ph2PCH2CH2SnCl3

The P-functional organotin chloride Ph₂PCH₂CH₂SnCl₃ reacts with [(COD)MCl₂] and trans-[(Et₂S)₂MCl₂] (M=Pd, Pt) in molar ratio 1:1 to the zwitterionic complexes [(COD)M⁺(Cl)(PPh₂CH₂CH₂Sn⁻Cl₄)] (1: M=Pd; 2: M=Pt) and trans-[(Et₂S)₂M⁺(Cl)(PPh₂CH₂CH₂Sn⁻Cl₄)] (3: M=Pd; 4: M=Pt). The same reaction with [(COD)Pd(Cl)Me] yields under transfer of the methyl group from palladium to tin the complex [(COD)M⁺(Cl)(PPh₂CH₂CH₂Sn⁻MeCl₃)] (5) which changes in acetone into the dimeric adduct [Cl₂Pd(PPh₂CH₂CH₂SnMeCl₂·2Me₂CO)]₂ (6). In molar ratio 2:1 Ph₂PCH₂CH₂SnCl₃ reacts with [(COD)MCl₂] to the complexes [Cl₂Pd(PPh₂CH₂CH₂SnCl₃)₂] (7: M=Pd, mixture of cis/trans isomer; 8: M=Pt, cis isomer). In a subsequent reaction 8 is transformed in acetone into the 16-membered heterocyclic complex cis-[Cl₂Pt(PPh₂CH₂CH₂)₂SnCl₂]₂ (9). trans-[(Et₂S)₂PtCl₂] and Ph₂PCH₂CH₂SnCl₃ in molar ratio 1:2 yields the zwitterionic complex [(Et₂S)M⁺(Cl)(PPh₂CH₂CH₂SnCl₃)(PPh₂CH₂CH₂Sn⁻Cl₄)] (10). The results of crystal structure analyses of 1, 3, 6, 9 and of the adduct of the trans-isomer of 7 with acetone (7a) are reported. ³¹P- and ¹¹⁹Sn-NMR data of the complexes are discussed.     

Functionalized cyclodiphosphazanes cis-[BuNP(OR)]2 (R=C6H4OMe-o, CH2CH2OMe, CH2CH2SMe, CH2CH2NMe2) as neutral 2e, 4e or 8e donor ligands

Cyclodiphosphazanes having donor functionalities such as cis-[^tBuNP(OR)]₂ (R = C₆H₄OMe-o (2); R = CH₂CH₂OMe (3); R = CH₂CH₂SMe (4); R = CH₂CH₂NMe₂ (5)) were obtained in good yield by reacting cis-[^tBuNPCl]₂ (1) with corresponding nucleophiles. The reactions of 2-5 with [RuCl₂(η⁶-cymene)]₂, [MCl(COD)]₂ (M = Rh, Ir), [PdCl₂(PEt₃)]₂ and [MCl₂(COD)] (M=Pd, Pt) result in the formation of exclusively monocoordinated mononuclear complexes of the type cis-[{^tBuNP(OR)}₂ML_n-κP] irrespective of the reaction stoichiometry and the reaction conditions. In contrast, 2-5 react with [RhCl(CO)₂]₂, [PdCl(η³-C₃H₅)]₂, CuX (X=Cl, Br, I) to give homobinuclear complexes. Interestingly, CuX produces both mono and binuclear complexes depending on the stoichiometry of the reactants and the reaction conditions. The mononuclear complexes on treatment with appropriate metal reagents furnish heterometallic complexes.     

Preparation,NMR studies and crystal structure of mononuclear and dinuclear Pd(II) and Pt(II) complexes that contain 1,2-bis[3-(3,5-dimethyl-1-pyrazolyl)-2-thiapropyl]benzene

The reaction between 1,2-bis[3-(3,5-dimethyl-1-pyrazolyl)-2-thiapropyl]benzene (bddf) and [MCl₂(CH₃CN)₂] (M = Pd(II), Pt(II)) in a 1:1 M/L ratio in CH₂Cl₂ or acetonitrile solution, respectively, gave the complexes trans-[MCl₂(bddf)] (M = Pd(II) (1), Pt(II) (4)), and in a 2:1 M/L ratio led to [M₂Cl₄(bddf)] (M = Pd(II) (2), Pt(II) (5)). Treatment of 1 and 4 with AgBF₄ and NaBPh₄, respectively, gave the compounds [Pd(bddf)](BF₄)₂ (3) and [Pt(bddf)](BPh₄)₂ (6). When complexes 3 and 6 were heated under reflux in a solution of Et₄NBr in CH₂Cl₂/CH₃OH (1:1) for 24 h, analogous complexes to 1 and 4 with bromides instead of chlorides bonded to the metallic centre were obtained. These complexes were characterised by elemental analyses, conductivity measurements, infrared, ¹H, ¹H{¹⁹⁵Pt}, ¹³C{¹H}, ¹⁹⁵Pt{¹H} NMR, HSQC and NOESY spectroscopies. The X-ray crystal structure of the complex [Pd(bddf)](BF₄)₂ · H₂O has been determined. The metal atom is tetracoordinated by the two azine nitrogen atoms of the pyrazole rings and two thioether groups.     

Diorganotin(IV) complexes with 2-benzoylpyridine and 2-acetylpyrazine N(4)-phenylthiosemicarbazones: Synthesis, crystal structures and biological activities

Four diorganotin(IV) complexes [(Me)₂Sn(L¹)(CH₃COO)]·CH₃CH₂OH (1), [(Ph)₂Sn(L¹)(CH₃COO)]·CH₃CH₂OH (2), [(Me)₂Sn(L²)Cl] (3) and [(Ph)₂Sn(L²)(CH₃COO)] (4) where HL¹ = 2-benzoylpyridine N(4)-phenylthiosemicarbazone and HL² = 2-acetylpyrazine N(4)-phenylthiosemicarbazone have been synthesized and characterized by elemental analysis, IR MS, ¹H NMR and single-crystal X-ray diffraction studies. Schiff bases in their deprotonated forms coordinate to tin(IV) via pyridine/pyrazine nitrogen atom and the nitrogen atom and sulfur atoms of the thiosemicarbazone moiety. The tin atom is seven-coordinated in 1, 2 and 4 containing one acetato group, respectively, and six-coordinated in 3 containing one chloride ion. Biological studies, carried out in vitro against selected bacteria and K562 leukaemia cells, respectively, have shown that different substituted groups attached at the thiosemicarbazone moieties and different diorganotin(IV) groups showed distinctive differences in the biological property.