Versatile reaction of the potential host system [(Me3Sn) 4Ru(CN) 6]∞ with 4-thiopyridone/4-mercaptopyridine in water

Single crystals of three derivatives of the structurally still incompletely characterized coordination polymer [(Me₃Sn)₄Ru(CN)₆] 1b have been prepared and subjected to crystallographic studies: [1b · 4H₂O]=2b forms stacks of puckered _∞²[Ru{μ-CNSn(Me₃)NC}₂] sheets interlinked by hydrogen bonds in making use of two additional CNSn(Me₃)OH₂ ligands and quasi-zeolitic water. Mild drying of 2b leads to the “missing link” between 1b and 2b, [1b · 2H₂O], 3b. The structure of [1b · 2tp] (tp=4-thiopyridone) consists of a three-dimensional, negatively charged host framework comprising (via Sn-S bonds) one “aromatic” thione linkage and a [Me₃Sn · tp]⁺guest ion involving a more zwitterionic form of tp. Slow uptake of Me₃SnCl from the gas phase by an aqueous solution of K₄[Ru(CN)₆] and tp afforded the novel assembly [1b · 2H₂O · 0.8pms · 0.2pds] (pms/pds=4,4^′-dipyridylmono-/disulfide), the supramolecular architecture of which resembles that of 2b. Bridging pms or pds molecules occupy equivalent interlayer sites, and the pms/pds ratio is likely to vary. At least three further assemblies containing again 1b and either tp or pds/pms have likewise been isolated, however, not as single crystals.     

Tris(triazolyl)borate ligands of intermediate steric bulk for the synthesis of biomimetic structures with hydrogen bonding and solubility in hydrophilic solvents

Tris(triazolyl)borate ligands (Ttz) of intermediate steric bulk were synthesized to investigate their potential for hydrogen bonding and improved solubility in hydrophilic solvents as applied to biomimetic chemistry. The crystal structure of 3-phenyl-5-methyl-1,2,4-triazole (Htz^Ph,Me) revealed hydrogen bonding and π stacking interactions. The new ligand salt, potassium tris(3-phenyl-5-methyl-1,2,4-triazolyl)borate (KTtz^Ph,Me) was synthesized as the first example of a Ttz ligand of intermediate steric bulk. Metathesis between KTtz^Ph,Me and NaCl followed by recrystallization produced [NaTtz^Ph,Me] · 6CH₃OH in which the geometry around the sodium is octahedral with an unusual N₃O₃ donor set; this structure also shows that a hydrogen bonding network is formed by methanol molecules and triazole nitrogens. (Ttz^Ph,Me)ZnCl was synthesized and characterized crystallographically as [(Ttz^Ph,Me)ZnCl] · 0.5CH₃OH in which the zinc is tetrahedral and the triazole rings are within hydrogen bonding distance of CH₃OH. All of these new compounds are methanol soluble to varying degrees and Htz^Ph,Me and KTtz^Ph,Me are soluble in methanol/water mixtures.     

Synthesis and characterization of tris(heteroleptic) diimine complexes of chromium(III)

A preparative procedure of potentially wide applicability is described for the synthesis of previously unreported tris(heteroleptic) [Cr(diimine)₃]³⁺ complexes. The synthetic scheme involves the sequential addition of three different diimine ligands, and employs CrCl₃ · 6H₂O as the initial Cr(III) reagent. The synthesis and characterization of the complexes [Cr(TMP)(phen)(diimine′)]³⁺ are reported (where TMP = 3,4,7,8-tetramethyl-1,10-phenanthroline, phen = 1,10-phenanthroline; and diimine′ is either bpy = 2,2′-bipyridine, Me₂bpy = 4,4′-dimethyl-2,2′-bipyridine, 5-Clphen = 5-chloro-1,10-phenanthroline, or DPPZ = dipyridophenazine). Chiral capillary electrophoresis and electrospray mass spectrometry were essential aids in determining the presence or absence of diimine ligand scrambling. Utilizing emission and electrochemical data obtained on these compounds, the oxidizing power of the lowest lying excited state (²E_g(O_h)) was calculated, and was found to vary in a systematic fashion with diimine ligand type.     

[S2], [S3], and [N3] coordination modes of hydrotris(thioxotriazolyl)borato. Zinc, nickel, cobalt, and bismuth complexes

The ligand hydrotris(1,4-dihydro-3-methyl-4-phenyl-5-thioxo-1,2,4-triazolyl)borato (Tr^Ph,Me) was synthetized as natrium salt and the complexes [Zn(Tr^Ph,Me)₂] · 7.5H₂O · 1.5CH₃CN (2a), [Zn(Tr^Ph,Me)₂] · 8DMF (2b), [Co(Tr^Ph,Me)₂] · 8DMF (3a), [Ni(Tr^Ph,Me)₂] · H₂O · 6DMSO (4a), [Bi(Tr^Ph,Me)₂]NO₃ (5), have been isolated and structurally characterized by X-ray diffraction. In the zinc derivatives the ligand adopts different denticity and coordination modes, η² and [S₂] for 2a and η³ and [N₃] for 2b, depending on the crystallization solvent, giving rise to tetrahedral and octahedral geometry, respectively. In the octahedral cobalt and nickel complexes the ligand is η³ and [N₃] coordinated whereas in the bismuth complex the η³ and [S₃] coordination is exhibited.     

Preparation and structure of [Ru2(O2CMe)4]2[Fe(CN)5NO] and magnetically ordered Hx[Ru2(O2CMe)4]3−x[Cr(CN)5NO] possessing interpenetrating lattices

Reaction of [Ru₂(O₂CMe)₄]Cl with K₃[Cr(CN)₅NO] in water forms H_x[Ru^II/III₂(O₂CMe)₄]_3−x-[Cr(CN)₅NO]·zH₂O (x = 0.2) that magnetically orders at 4.0 K and possesses an interpenetrating body centered cubic [a = 13.2509(2) Å] structure with random locations of the bridging nitrosyl ligands, and x/3 vacant cation sites. Similarly, the aqueous reaction of [Ru₂(O₂CMe)₄]Cl with Na₂[Fe(CN)₅NO] forms paramagnetic [Ru₂(O₂CMe)₄]₂[Fe(CN)₅NO]·H₂O, which has a similar tetragonal interpenetrating structure [a = 13.0186(1) Å, c = 13.0699(2) Å] where the NO ligands are presumably nonbridging and 1/3 of the expected cation sites are unoccupied. The presence of uncoordinated NO sites in addition to missing neighboring [Ru₂(O₂CMe)₄]⁺ units, results in significant vacancies (or holes) in the lattice.     

Synthesis and characterization of chromium(III) octaphenylporphyrin complexes with various axial ligands: An insight into porphyrin distortion

Influence of axial ligands, MeCN, H₂O, py, and piperidine (pip), on distortion of (2,3,5,10,12,13,15,20-octaphenylporphinato)chromium(III), [Cr(OPP)]⁺, was investigated by X-ray crystallography and UV-vis and ESR spectroscopies. In crystal structures of [Cr(OPP)(MeCN)(H₂O)]ClO₄ · MeCN and [Cr(OPP)(H₂O)₂]ClO₄ · 3THF, the OPP²⁻ ligand had a planar structure. On the other hand, crystal structures of [Cr(OPP)(pip)₂]ClO₄ · 2CH₂Cl₂ and [Cr(OPP)(py)₂]ClO₄ exhibited a waved structure and a saddle-shaped structure with ruffling, respectively. In the UV-vis spectrum of [Cr(OPP)(py)₂]ClO₄ in CH₂Cl₂, the large red shift of the Soret band was observed. Furthermore, the small D value of 0.10 cm⁻¹ was obtained for [Cr(OPP)(py)₂]ClO₄ from the ESR spectrum in frozen 1,2-dichloroethane solution at 5 K. These results suggest that the OPP²⁻ ligand is distorted both in solid and in solution, and that the axial ligand would exert some effects on the porphyrin distortion.     

A bulky platinum triamine complex that reacts faster with guanosine 5′-monophosphate than with N-acetylmethionine

A bulky platinum triamine complex, [Pt(Me₅dien)(NO₃)]NO₃ (Me₅dien = N,N,N′,N′,N′′-pentamethyldiethylenetriamine) has been prepared and reacted in D₂O with N-acetylmethionine (N-AcMet) and guanosine 5′-monophosphate (5′-GMP); the reactions have been studied using ¹H NMR spectroscopy. Reaction with 5′-GMP leads to two rotamers of [Pt(Me₅dien)(5′-GMP-N7)]⁺. Reaction with N-AcMet leads to formation of [Pt(Me₅dien)(N-AcMet-S)]⁺. When a sample with equimolar mixtures of [Pt(Me₅dien)(D₂O)]²⁺, 5′-GMP, and N-AcMet was prepared, [Pt(Me₅dien)(5′-GMP-N7)]⁺ was the dominant product observed throughout the reaction. This selectivity is the opposite of that observed for a similar reaction of [Pt(dien)(D₂O)]²⁺ with 5′-GMP and N-AcMet. To our knowledge, this is the first report of a platinum(II) triamine complex that reacts substantially faster with 5′-GMP than with N-AcMet; the effect is most likely due to steric clashes between the methyl groups of the Me₅dien ligand and the N-AcMet.     

Arylazoimidazoliumchloride and chlorometallates: Spectroscopic and structural characterization

Protonation or dialkylation of 2-(arylazo)imidazoles (RaaiH) has generated azoimidazolium motif (RaaiH₂⁺, RaaiR^′H⁺, RaaiR^′₂⁺ where R = H, CH₃ and R^′ = Me, Et, -CH₂Ph). Electrostatic attraction between imdazolium cation and counter ions like Cl⁻, , has generated hydrogen bonded azoimidazolium-chloride/chlorometallated networks. The single crystal X-ray structure of 1-benzyl-2-(phenylazo)imidazolium chloride shows tape like 1-D network of [Cl(H₂O)₄]⁻. Aquated Cl⁻ forms 10 membered supracycle through hydrogen bonding with imidazolium ion. The X-ray structures of [HaaiMe₂ (1,3)]⁺[Me₂NH₂]⁺ [ZnCl₄]²⁻ and [MeaaiH₂⁺·H₂O]₂[PtCl₆]²⁻ show hydrogen bonded chlorometallate chain penetrated into the channel developed by organic motif. Azoimidazolium units are associated through π···π and C-H···π interactions to strengthen the supramolecular geometry.     

New chiral macrocyclic lanthanide complexes derived from (1R,2R)-1,2-diaminocyclohexane and 2,6-diformylpyridine

The new enantiopure complexes [LnL](NO₃)₃ · nH₂O (Ln = Dy⁺³, Ho⁺³, Er⁺³, Lu⁺³) and [LnL]Cl₃ · nH₂O (Ln = Nd⁺³, Sm⁺³, Gd⁺³, Tb⁺³, Dy⁺³, Ho⁺³, Er⁺³, Tm⁺³, Lu⁺³) of the chiral macrocycle L derived from (1R,2R)-1,2-diaminocyclohexane and 2,6-diformylpyridine have been synthesised. The preference of macrocycle L for the heavier lanthanide(III) ions has been established on the basis of competition reaction. The complexes have been characterised by NMR spectroscopy and mass spectrometry. ¹H NMR signals of deuterated water solutions of the Ce⁺³, Nd⁺³ and Eu⁺³ complexes have been assigned on the basis of the COSY and HMQC spectra, and for the remaining lanthanide complexes the signals were assigned on the basis of linewidths analysis. The paramagnetic shifts of the series of lanthanide complexes [LnL](NO₃)₃ · nH₂O and [LnL]Cl₃ · nH₂O have been analysed using both crystal-field dependent and independent methods in order to separate contact and dipolar contributions and establish isostructurality along the series of lanthanide complexes in solution. The data obtained for nitrate derivatives in organic solvent indicate rather irregular deviations from the plots based on those methods, while the plots obtained for water solutions show the characteristic brake in the middle of the lanthanide series, that is interpreted as a result of change of the number of axially coordinated water molecules. The apparent inconsistencies of results obtained on the basis of crystal-field independent method are discussed.     

Two new 4′,4′′-disubstituted dipyrazolylpyridine derivatives, and the structures and spin states of their iron(II) complexes

Reaction of 2 equiv of the sodium salt of ethyl pyrazole-4-carboxylate, with 1 equiv of 2,6-dibromopyridine, in diglyme at 130 °C for 5 days yields 2,6-di[4-(ethylcarboxy)pyrazol-1-yl]pyridine (L¹), with 2-bromo-6-[4-(ethylcarboxy)pyrazol-1-yl]pyridine (L²) as a significant byproduct. Reduction of L¹ with excess NaBH₄ in thf affords 2,6-di[4-(hydroxymethyl)pyrazol-1-yl]pyridine (L³) in low yield. The crystalline complex [Fe(L¹)₂][BF₄]₂ · 2CF₃CH₂OH is low-spin at 150 K, while bulk samples with this formula are approximately 10% high-spin and 90% low-spin at room temperature. This ratio does not vary significantly on cooling from its magnetic susceptibility, suggesting that the material might be contaminated by a second, minor high-spin phase. Single crystals of [Fe(L³)₂][BF₄]₂·1.4CH₃CN have a mixed spin-state population, with the low-spin state predominating at 150 K. The [Fe(L³)₂(BF₄)]⁺ moieties in the lattice associate into 1-D chains through intermolecular O-H?O and O-H?F hydrogen bonding. Bulk samples of [Fe(L³)₂][BF₄]₂ · H₂O are fully low-spin below 200 K, but the magnetic data imply the onset of a gradual thermal spin-transition centred above room temperature. DSC and TGA measurements imply that this transition is centred at 322 K, and involves loss of lattice water. Both complexes undergo spin-crossover in (CD₃)₂CO solution, with transition midpoints near 250 K.     

Gold acyls and imidoyls prepared from anionic Fischer-type carbene complexes

Reaction of [(CO)₅WC(O)Ph]Li or [(CO)₅WC(O)Ph]NBu₄ with Ph₃PAuCl affords acyl complexes of gold. In the latter conversion, both the crystalline products [(CO)₅WCl]NBu₄ (2) and Ph₃PAuC(O)Ph (3) have been isolated and fully characterised. Similarly, imidoyl gold compounds (4-8) result from deprotonated aminocarbene complexes, [(CO)₅MC(NR²)R¹]Li (M = Cr, W; R¹ = Ph, Me; R² = H, Me) and Ph₃PAuCl. Crystal and molecular structure determinations of dinuclear [Ph₃PAuC(NH)Ph] · Cr(CO)₅ (6) show N-coordination of the chromium carbonyl unit that selectively affords a Z-isomer.     

Homoleptic copper(II) and copper(I) complexes of 5,6-dihydro-5,6-epoxy-1,10-phenanthroline. Six-coordinate copper(I) in solution

Reaction of 5,6-dihydro-5,6-epoxy-1,10-phenanthroline (L) with Cu(ClO₄)₂·6H₂O in methanol in 3:1 M ratio at room temperature yields light green [CuL₃](ClO₄)₂·H₂O (1). The X-ray crystal structure of the hemi acetonitrile solvate [CuL₃](ClO₄)₂·0.5CH₃CN has been determined which shows Jahn-Teller distortion in the CuN₆ core present in the cation [CuL₃]²⁺. Complex 1 gives an axial EPR spectrum in acetonitrile-toluene glass with g_|| = 2.262 (A_|| = 169 × 10⁻⁴ cm⁻¹) and g_⊥ = 2.069. The Cu(II/I) potential in 1 in CH₂Cl₂ at a glassy carbon electrode is 0.32 V versus NHE. This potential does not change with the addition of extra L in the medium implicating generation of a six-coordinate copper(I) species [CuL₃]⁺ in solution. B3LYP/LanL2DZ calculations show that the six Cu-N bond distances in [CuL₃]⁺ are 2.33, 2.25, 2.32, 2.25, 2.28 and 2.25 Å while the ideal Cu(I)-N bond length in a symmetric Cu(I)N₆ moiety is estimated as 2.25 Å. Reaction of L with Cu(CH₃CN)₄ClO₄ in dehydrated methanol at room temperature even in 4:1 M proportion yields [CuL₂]ClO₄ (2). Its ¹H NMR spectrum indicates that the metal in [CuL₂]⁺ is tetrahedral. The Cu(II/I) potential in 2 is found to be 0.68 V versus NHE in CH₂Cl₂ at a glassy carbon electrode. In presence of excess L, 2 yields the cyclic voltammogram of 1. From ¹H NMR titration, the free energy of binding of L to [CuL₂]⁺ to produce [CuL₃]⁺ in CD₂Cl₂ at 298 K is estimated as −11.7 (±0.2) kJ mol⁻¹.     

Polypyrazolates of the heavier group 13 and 14 elements: A review

Heavy group 13 and 14 analogs of the poly(pyrazolyl)borates are the subject of this review. Within these, the most extensive research has been performed on the study of polypyrazolylgallates Me₂Ga(R₂pz)₂]⁻ (R = H or Me) and [MeGa(pz)₃]⁻, and their complexes with transition metals. In this review, the common features shared with the boron analogs are presented and contrasted. Other recently reported series of group 13 analogs are the alkali polypyrazolylaluminates Na[(R₂pz)₃] with R = Me, ^tBu; R′ = M. The complexes with one or two pyrazolyl ligands on aluminum display anagostic Al-CH₃?Na interactions, these interactions are persistent even if complexes were obtained from solutions with THF that normally coordinate alkali ions. The polypyrazolylsilane ligands Me₂Si(R₂pz)₂ and MeSi(R₂pz)₃ with R = H, Me are remarkably easy to obtain and isolate, in contrast is the fact that the carbon analogs are much harder to obtain and isolate in reasonable yields. Therefore it is surprising that the chemistry of the former ligands is not as developed as could be anticipated. Nevertheless there are examples of the use of these silanes as ligands with the following transition metals: Cr, Mn, Cu, Zn, Sc and Zr. The heavier group 14 analogs with Ge and Sn display coordination patterns with alkali and alkaline ions that resemble those observed with the borates and aluminates. The formation of cationic bimetallic cages of the type [E₂(R₂pz)₃]⁺ and neutral complexes [E₂(R₂pz)₄] has also been observed that can be consider formal isomers of the alkenes. The use of these compounds as ligands has been recently reported.     

Selective inclusion of DMF molecules within non-covalent cavity

[Me₄P]₄[Cu₄(mnt)₄]·2CH₃CN (1), [Me₄P]₄[Cu₄(mnt)₄]·2CH₃NO₂ (2), [Me₄P]₄[Cu₄(mnt)₄]·2DMF (3) and [Me₄P]₄[Cu₄(mnt)₄]·2C₃H₃N (4) (mnt = maleonitriledithiolate, [S₂C₂(CN)₂]²⁻) clusters are readily synthesized in several solvents like acetonitrile, nitromethane, N,N-dimethylformamide and acrylonitrile to provide respective solvent as guest within the non-covalent cavity of the cluster ion. The guest species is accommodated within non-covalent cavity that is generated by two adjacent {Cu₄(mnt)₄} cores bridging with tetramethylphosphonium cation through hydrogen bonding. These hydrogen bonds are not strong and when mixed solvents were used selective DMF binding takes place to yield only complex 3 over other complexes.     

Neutral and cationic rare-earth metal alkyl complexes that contain bis(2-methoxyethyl)(trimethylsilyl)amine, a neutral [ONO]-type ligand

Neutral tris(trimethylsilylmethyl) complexes [Ln(CH₂SiMe₃)₃(L)] (Ln = Sc (1), Lu (2)) and cationic bis(trimethylsilylmethyl) complexes [Ln(CH₂SiMe₃)₂(L)(THF)]⁺[BPh₄]⁻, (Ln = Sc (3), Lu (4)) that contain bis(2-methoxyethyl)(trimethylsilyl)amine (L = Me₃SiN(CH₂CH₂OMe)₂) as a neutral, tridentate ligand were synthesized and characterized by NMR spectroscopy. X-ray structural analysis was performed for the scandium complex 1 and exhibited a distorted octahedral coordination geometry with a facially arranged ligand at the neutral scandium center. NMR spectroscopy corroborated the coordination of the tertiary amine function of the ligand to the metal. Complexes 3 and 4 expand the still limited range of cationic rare-earth metal alkyl complexes with known neutral, multidentate ligands.     

A new tris(2-furyl) substituted pyrazolylborate ligand and its zinc complex chemistry

The new ligand hydrotris(3-(2′-furyl)-5-methylpyrazolyl)borate (Tp^Fu,Me) was prepared by the usual procedure. With zinc salts, it forms the Tp^Fu,MeZn-X complexes (X = Cl, Br, I, NCS, CH₃COO, CF₃COO). With zinc perchlorate, the bis-ligand complex Zn(Tp^Fu,Me)₂ is formed preferrably, but by carefully controlling the reaction conditions, the “enzyme model” Tp^Fu,MeZn-OH could be obtained. The latter models carbonic anhydrase by inserting CO₂ and CS₂ in methanol producing Tp^Fu,MeZn-OCOOMe and Tp^Fu,MeZn-SCSOMe. It models hydrolases by the hydrolytic cleavage of tris(p-nitrophenyl)phosphate and γ-thiobutyrolactone. It does not hydrolyse trifluoroacetamide, but instead deprotonates it, yielding Tp^Fu,MeZn-NHCOCF₃.     

Stereospecific interactions between dinuclear complex cations involving square-planar [Pt(II)(μ-S)2(bpy)] (bpy = 2,2′-bipyridine) frameworks derived from optically active octahedral Co(III) units with d- or l-penicillaminates

The reaction of the octahedral mononuclear complex, trans(N)-[Co(l-pen-N,O,S)₂]⁻ (pen = penicillaminate), with [PtCl₂(bpy)] (bpy = 2,2′-bipyridine) stereoselectively gave an optically active S-bridged dinuclear complex, [Pt(bpy){Co(l-pen)₂}]Cl · 3H₂O (2Cl · 3H₂O), whose structure is enantiomeric to the previously reported [Pt(bpy){Co(d-pen)₂}]Cl · 3H₂O (1Cl · 3H₂O). The mixture of equimolar amounts of 1Cl · 3H₂O and 2Cl · 3H₂O in H₂O crystallizes as [Pt(bpy){Co(d-pen)₂}]_0.5[Pt(bpy){Co(l-pen)₂}]_0.5Cl · 7H₂O (3Cl · 7H₂O), in which the enantiomeric complex cations 1 and 2 are included in the ratio of 1:1. The crystal structures of 2Cl · 3H₂O and 3Cl · 7H₂O were determined by X-ray crystallography, and compared with that of 1Cl · 3H₂O. The structural feature for 2 is essentially consistent with that for 1, except for the absolute configurations around the octahedral Co(III) center. The optically active complex cation 2 exists as a monomer, accompanied by no intermolecular interactions in the π-electronic systems of bpy moieties. In the crystals of 3Cl · 7H₂O, on the other hand, the enantiomeric complex cations, [Pt(bpy){Co(d-pen)₂}]⁺ and [Pt(bpy){Co(l-pen)₂}]⁺, are arranged alternately while overlapping the bpy planes along a axis, and the π electronic system of the bpy framework in [Pt(bpy){Co(d-pen)₂}]⁺ interacts with those in [Pt(bpy){Co(l-pen)₂}]⁺. Differences between the crystal structures of 2Cl · 3H₂O and3Cl · 7H₂O significantly reflect their diffuse reflectance spectra. In aqueous solution, each cation in both 2Cl · 3H₂O and 3Cl · 7H₂O is comparatively put on a free environment without such intermolecular interactions.     

Assisted self-association of dicyanoaurate, [Au(CN)2], and dicyanoargentate, [Ag(CN)2], through hydrogen bonding to metal ammonia complexes

The salts - yellow [Cr(NH₃)₆][Ag(CN)₂]₃ · 2H₂O, red [Co(NH₃)₆][Ag(CN)₂]₃ · 2H₂O, red [Co(NH₃)₆][Au(CN)₂]₃ · 2H₂O, pale yellow [Ru(NH₃)₆][Ag(CN)₂]₃ · 2H₂O, yellow K[Cr(NH₃)₆]₂[Au(CN)₂]₇ · 4H₂O, and colorless [(μ²-NH₂)₂Pt₂(NH₃)₁₀][Au(CN)₂]₆ · 5.5{OS(CH₃)₂} · 0.5H₂O - have been prepared by evaporation of aqueous solutions of potassium dicyanoargenate or potassium dicyanoaurate and salts of the appropriate cations. Hydrogen bonding between the cations and the cyano groups of the anions facilitates the formation of structures with strong metallophilic interactions between the anions. Thus, the [Au(CN)₂]⁻ or [Ag(CN)₂]⁻ ions self-associate into linear trimers in the isostructural set of crystals, [Cr(NH₃)₆][Ag(CN)₂]₃ · 2H₂O (Ag?Ag distance; 3.1610(4) Å), [Co(NH₃)₆][Ag(CN)₂]₃ · 2H₂O (Ag?Ag distance; 3.1557(2) Å), [Co(NH₃)₆][Au(CN)₂]₃ · 2H₂O (Au?Au distance; 3.0939(4) Å), and [Ru(NH₃)₆][Ag(CN)₂]₃ · 2H₂O (Ag?Ag distance; 3.1584(5) Å). Crystalline [(μ²-NH₂)₂Pt₂(NH₃)₁₀][Au(CN)₂]₆ · 5.5{OS(CH₃)₂} · 0.5H₂O also contains nearly linear trimers of the dicyanoaurate ion. Yellow crystals of K[Cr(NH₃)₆]₂[Au(CN)₂]₇ · 4H₂O contain a centrosymmetric, bent chain of seven dicyanoaurate ions with Au?Au separations of 3.1806(3), 3.2584(4), and 3.1294(4) Å.     

Lanthanide(III) complexes with phosphoryl containing 1,8-naphthyridine: Crystal structures and vibrational spectra

The complexes of 2-[2-(diphenylphosphoryl)prop-2-yl]-1,8-naphthyridine (L) with lanthanide nitrates Ln(NO₃)₃ (Ln = Nd, Eu, Lu) were investigated to elucidate the coordination ability of a novel type of potentially tridentate ligands - phosphorylalkyl substituted naphthyridines. The X-ray crystal structures of [NdL₃]³⁺ · 3(NO₃)⁻ · MeCN (1), [EuL₃]³⁺ · 3(NO₃)⁻ · [Eu(NO₃)₃ · 4H₂O] · MeCN (2), and [LuL₃]³⁺ · 3(NO₃)⁻ · [Lu(NO₃)₃ · 3H₂O] · 2 MeCN · 0.5 H₂O (3) are reported together with their IR and Raman spectra. All the compounds studied contain isostructural [LnL₃]³⁺ cations and three NO₃⁻ counterions. Coordination of each L appears to be O,N,N tridentate-cyclic and coordination number of Ln is nine. Vibrational spectra of 1-3 are also compared with that of free ligand and model compounds.     

Hydrolytic stability of SnCl4 and GaCl3 in the formation of [cis-SnCl4(H2O)2] · 18-crown-6 · 2H2O and [[2,2,2]cryptand + 2H][GaCl4]2

The combination of anhydrous SnCl₄ with 18-crown-6 in aqueous conditions results in formation of the non-hydrolysed product [cis-SnCl₄(H₂O)₂] · 18-crown-6 · 2H₂O. The X-ray crystal structure shows extensive intermolecular hydrogen bonding involving the cis-octahedral SnCl₄(H₂O)₂ units, the uncoordinated water molecules and the crown ether. Similarly, [2,2,2]cryptand reacts with an aqueous solution formed by adding anhydrous GaCl₃ to slightly acidic water, affording [[2,2,2]cryptand + 2H⁺][GaCl₄]₂.