A family of three-dimensional porous coordination polymers with general formula (Kat)2[{M(H2O)n}3{Re6Q8(CN)6}2]·xH2O (Q=S, Se; n=1.5, 2)

The X-ray crystal structures of a series of new compounds (H₃O)₂[{Mn(H₂O)_1.5}₃{Re₆Se₈(CN)₆}₂]·19H₂O (1), (Me₄N)₂[{Co(H₂O)_1.5}₃{Re₆S₈(CN)₆}₂]·13H₂O (2), (Me₄N)₂[{Co(H₂O)_1.5}₃{Re₆Se₈(CN)₆}₂]·3H₂O (3), (Et₄N)₂[{Mn(H₂O)₂}₃{Re₆Se₈(CN)₆}₂]·6.5H₂O (4), (Et₄N)₂[{Ni(H₂O)₂}₃{Re₆S₈(CN)₆}₂]·6.5H₂O (5), and (Et₄N)₂[{Co(H₂O)₂}₃{Re₆S₈(CN)₆}₂]·10H₂O (6) are reported. All six compounds are isostructural crystallizing in cubic space group with four formulae per unit cell. For compounds 1, 3-5 the following parameters were found: (1) a=19.857(2) Å, R1=0.0283; (3 at 150 K) a=19.634(1) Å, R1=0.0572; (4) a=20.060(2) Å, R1=0.0288; (5) a=19.697(2) Å, R1=0.0224. The structures consist three-dimensional cyano-bridged framework formed by cyano cluster anions [Re₆Q₈(CN)₆]⁴⁻, Q=S, Se and transition metal cations, M²⁺=Mn²⁺, Co²⁺, Ni²⁺. Water molecules and large organic cations Me₄N⁺ and Et₄N⁺ are included in cavities of this framework. Porosity of the framework, its ability to accommodate different cations and water molecules by little changes in the structure, as well as distortion of coordination framework under loss of water of crystallization is discussed.     

The influence of organic agents on the resultant crystal structure in the reactions of the [Re4Te4(CN)12] tetrahedral cluster anion with Nd cations

The reaction of the cluster salt K₄[Re₄Te₄(CN)₁₂]·5H₂O with NdCl₃·6H₂O was studied in either an acidic medium (HCl) or in a water solution in the presence of the following organic agents: hexafluoroacetylacetonate, 2,2′-bipyridine or 1,10-phenanthroline (phen). The crystal structures of four new compounds have been solved by single crystal X-ray diffraction analysis: (H)[{Nd(H₂O)₅}{Re₄Te₄(CN)₁₂}]·5.5H₂O (1) (space group P2₁/c, framework structure), K₂[{Nd(H₂O)₇}₂{Re₄Te₄(CN)₁₂}₂]·8H₂O (2) (space group С2/c, isolated structure), K_0.5H_0.5[{Nd(H₂O)₅}{Re₄Te₄(CN)₁₂}]·3H₂O (3) (space group Сmcm, layered structure) and (phenH)[{Nd(H₂O)₂(phen)₂}{Re₄Te₄(CN)₁₂}]·11H₂O (4) (space group С2/c, chain structure). 1,10-Phenanthroline was found to have been incorporated into the structure of compound 4, whilst hexafluoroacetylacetonate and 2,2′-bipyridine did not enter the structures of 2 and 3. It was shown that the structures of compounds 2-4 differ dramatically from that found for compound 1, which was obtained in the absence of the organic agents.     

Syntheses, crystal structures and luminescent properties of two novel lanthanide/4-pya complexes: [Ln(4-pya)3(H2O)2]2 (Ln = Eu, La; 4-pya = trans-4-pyridylacrylate)

Reactions of Ln₂O₃ and trans-4-pyridylacrylic acid (4-Hpya) in EtOH/H₂O or MeOH/H₂O produced two new lanthanide/4-pya complexes [Ln(4-pya)₃(H₂O)₂]₂ (1: Ln = Eu; 2: Ln = La) in low yields. However, reactions of LnCl₃ · 6H₂O with 4-Hpya/aqueous ammonia in EtOH/H₂O or MeOH/H₂O gave rise to 1 or 2 in higher yields. Both compounds were structurally characterized by elemental analysis, IR spectroscopy and X-ray analysis. Compounds 1 · 2EtOH · 2H₂O and 2 · 2MeOH · 2H₂O were confirmed to possess one-dimensional polymeric chain structures. In the structure of 1, each Eu(III) adopts a monocapped square-antiprism coordination geometry and each dimer [Eu(4-pya)₃(H₂O)₂]₂ within the chain is interconnected by two pairs of different bridging 4-pya ligands. On the other hand, each La(III) of 2 takes a bicapped square-antiprism coordination geometry and each dimer [La(4-pya)₃(H₂O)₂]₂ within the chain is linked by two pairs of tridentate bridging 4-pya ligands. The luminescent properties of 1 and 2 in the solid state were investigated.     

Heteronuclear M(II)-Ln(III) (M = Co, Mn; Ln = La, Pr, Sm, Gd, Dy and Er) coordination polymers: Synthesis, structures and magnetic properties

Thirteen novel 3d-4f heteronuclear coordination polymers based on the pyridine-2,6-dicarboxylic acid (H₂pda) and imidazole ligands, HIm[(pda)₃MLn(Im)₂(H₂O)₂]·3H₂O (Im = imidazole; M = Co, Ln = Pr (1), Gd (2), Dy (3), Er (4); M = Mn, Ln = Pr (5), Sm (6), Gd (7), Dy (8), Er (9)), HIm[(pda)₃CoSm(Im)₂(H₂O)₂]·2H₂O (10), [(Im)₄M(H₂O)₂][(pda)₄La₂(H₂O)₂]·2H₂O (M = Co (11), Mn (12)), and [(pda)₆Co₃Pr₂(H₂O)₆]·6H₂O (13), have been prepared and structurally characterized. X-ray crystallographic analyses revealed that these complexes display four different types of structures. Complexes 1-9 are isostructural, and possess 1-D chain structures constructed by alternately arrayed nine-coordinated Ln(III) (Ln = Pr, Sm, Gd, Dy, Er) and six-coordinated M(II) (M = Mn, Co) ions. Complex 10 exhibits a unique one-dimensional structure, in which two independent chains are parallel viewed down the a-axis and anti-parallel viewed down the c-axis. Complexes 11 and 12 are isostructural and display 1-D homometallic chain structures. Complex 13 is a 3D framework fabricated through PrN₃O₆ and CoO₆ polyhedrons as building blocks. The variable-temperature solid-state dc magnetic susceptibilities of complexes 2, 3, 4, 9 and 13 have been investigated. Antiferromagnetic exchange interactions were determined for these five complexes.     

Hypervalence in germanium compounds containing the tetracylic moiety {S(C6H3S)2O}Ge via O···Ge transannular interactions: A structural study

Treatment of R_nGeCl_4−n with {S(C₆H₃SH)₂O} (1) afforded the stable phenoxathiin-4,6-dithiolate compounds [{S(C₆H₃S)₂O}GeR₂] [n = 2; R = Et (2), Ph (3)] and [{S(C₆H₃S)₂O}GeRCl] [n = 1; R = Et (4), Ph (5)]. Treatment of GeCl₄ with 1 in benzene afforded the dichloro compound [{S(C₆H₃S)₂O}GeCl₂] (8) at 7 °C. Bromo compounds [{S(C₆H₃S)₂O}GeRBr] [R = Et (6), Ph (7)] and [{S(C₆H₃S)₂O}GeBr₂] (9) were synthesized by halogen exchange from the appropriate chloro derivative using KBr/HBr. X-ray structure determinations of diorganyl dithiolate compounds 2 and 3 revealed that germanium atom is contained in a boat–chair-shaped eight-membered central ring and displays a tetrahedral geometry. In contrast, compounds 4–6 display a boat–boat-shaped central ring with a significant intramolecular transannular O···Ge interaction. The geometry of the pentacoordinate Ge atom in these last complexes may be described as distorted trigonal bipyramidal with a 62–65% distortion displacement.     

New stable germylenes, stannylenes, and related compounds: 6. Heteroleptic germanium(II) and tin(II) compounds [(SiMe3)2N-E-OCH2CH2NMe2]n (E = Ge, n = 1; Sn, n = 2): synthesis and structure

New stable heteroleptic germanium(II) and tin(II) compounds [(SiMe₃)₂N-E¹⁴-OCH₂CH₂NMe₂]_n (E¹⁴ = Ge, n = 1 (1), Sn, n = 2 (2)) have been synthesized and their crystal structures have been determined by X-ray diffraction analysis. While compound 1 is monomer stabilized by intramolecular Ge ← N coordination, compound 2 is associated to dimer via intermolecular dative Sn ← O interactions.     

Preparation, crystal structures, EPR and reflectance spectra of two new charge-transfer salts, [CpFeCpCH2N(CH3)3]4[XMo12O40] · nCH3CN (n = 0 for X = P or n = 1 for X = Ge)

Two new charge-transfer salts, [CpFeCpCH₂N(CH₃)₃]₄[PMo₁₂O₄₀] · CH₃CN (1) and [CpFeCpCH₂N(CH₃)₃]₄[GeMo₁₂O₄₀] (2), were synthesized by the traditional solution synthetic method and their structures were determined by single-crystal X-ray analysis. Salt 1 belongs to the triclinic space group P1, and salt 2 belongs to the triclinic space group . There exist the complex interactions of the cationic ferrocenyl donor and Keggin polyanion in the solid state. The solid state UV-Vis diffuse reflectance spectra indicate the presence of a charge-transfer band climbing from 450 nm to well beyond 900 nm for 1, a charge-transfer band from 460 to 850 nm with λ_max = 630 nm for 2.The EPR spectra of salts 1 and 2 at 77 K show a signal at g = 2.0048 and 1.9501, respectively, ascribed to the delocalization of one electron in reduced Keggin ion in salt 1 and the Mo^VI in [GeMo₁₂O₄₀]⁴⁻ is partly reduced to Mo^V owing to the charge-transfer transitions taking place between the ferrocenyl donors and the POM acceptors. The two compounds were also characterized by IR spectroscopy and cyclic voltammetry.     

Chiral “P-N-P” ligands, (C20H12O2)PN(R)PY2 [R = CHMe2, Y = C6H5, OC6H5, OC6H4-4-Me, OC6H4-4-OMe or OC6H4-4-Bu] and their allyl palladium complexes

Chiral “P-N-P” ligands, (C₂₀H₁₂O₂)PN(R)PY₂ [R = CHMe₂, Y = C₆H₅ (1), OC₆H₅ (2), OC₆H₄-4-Me (3), OC₆H₄-4-OMe (4) or OC₆H₄-4-^tBu (5)] bearing the axially chiral 1,1′-binaphthyl-2,2′-dioxy moiety have been synthesised. Palladium allyl chemistry of two of these chiral ligands (1 and 2) has been investigated. The structures of isomeric η³-allyl palladium complexes, (R′ = Me or Ph; Y = C₆H₅ or OC₆H₅) have been elucidated by high field two-dimensional NMR spectroscopy. The solid state structure of [Pd(η³-1,3-Ph₂-C₃H₃){κ²-(racemic)-(C₂₀H₁₂O₂)PN(CHMe₂)PPh₂}](PF₆) has been determined by X-ray crystallography. Preliminary investigations show that the diphosphazanes, 1 and 2 function as efficient auxiliary ligands for catalytic allylic alkylation but give rise to only moderate levels of enantiomeric excess.     

Dinitrogen extrusion from diazidophenylborane: Computational analysis of PhBNx (x = 6, 4, 2) isomers

The energies and structures of possible intermediates in the dinitrogen extrusion from diazidophenylborane 4a to give phenylborylene 11a were determined using density functional (B3LYP), multiconfigurational (CASSCF and MRMP2), and coupled cluster (CCSD(T)) computations in conjunction with basis sets of up to cc-pVTZ quality. Formation of 11a and nitrogen from 4a is an exothermic process (−21 kcal mol⁻¹). The triplet electronic ground state of azidophenylborylnitrene 5a (PhBN₄) is only 26 kcal mol⁻¹ higher in energy than 4a and the phenyl shift in 5a to yield N-azidophenyliminoborane 7a is highly exothermic.     

Syntheses,structures and luminescent properties of four copper(I) cyanide coordination polymers based on 2-(n-pyridyl)benzimidazole ligands (n = 2, 3, 4)

Four copper(I) cyanide coordination polymers containing 2-(n-pyridyl)benzimidazole ligands, namely [Cu₂(CN)(2-PyBIm)]_n (1), [Cu₂(CN)₂(3-PyHBIm)]_n (2), {[Cu₃(CN)₃(4-PyHBIm)₄] · 2H₂O}_n (3) and [Cu₅(CN)₃(4-PyBIm)₂]_n (4), have been synthesized and characterized by X-ray crystallography. Complex 1 is a one-dimension coordination polymer in which 2-(2-pyridyl)benzimidazole is deprotonated and adopts a bridging tridentate coordination mode. Complex 2 has ladder-like structure in which 2-(3-pyridyl)benzimidazole does not deprotonate and acts as a bidentate bridge. Complex 3 displays a saddle-shaped helical chain constructed through μ₂-cyanide group and the outstretched neutral 2-(4-pyridyl)benzimidazole monodentate ligand. Complex 4 shows two-dimension layer polymeric structure in which deprotonated 2-(4-pyridyl)benzimidazole acts as a tridentate bridging ligand. The cyanide groups in four complexes all act as bidentate bridging ligands. These complexes are thermal stable and display luminescence in the solid states.     

Synthesis, characterization, protonation studies and X-ray crystal structure of ReH5(PPh3)2(PTA) (PTA = 1,3,5-triaza-7-phosphaadamantane)

The novel rhenium pentahydride complex [ReH₅(PPh₃)₂(PTA)] (2) was synthesized by dihydrogen replacement from the reaction of [ReH₇(PPh₃)₂] with PTA in refluxing THF. Variable temperature NMR studies indicate that 2 is a classic polyhydride (T_1(min) = 133 ms). This result agrees with the structure of 2, determined by X-ray crystallography at low temperature. The compound shows high conformational rigidity which allows for the investigation of the various hydride-exchanging processes by NMR methods. Reactions of 2 with equimolecular amounts of either HFIP or HBF₄ · Et₂O at 183 K afford [ReH₅(PPh₃)₂{PTA(H)}]⁺ (3) via protonation of one of the nitrogen atoms on the PTA ligand. When 5 equivalents of HBF₄ · Et₂O are used, additional protonation of one hydride ligand takes place to generate the thermally unstable dication [ReH₄(η²-H₂)(PPh₃)₂{PTA(H)}]²⁺ (4), as confirmed by ¹H NMR and T₁ analysis. IR monitoring of the reaction between 2 and CF₃COOD at low temperature shows the formation of the hydrogen bonded complex [ReH₅(PPh₃)₂{PTA?DOC(O)CF₃}] (5) and of the ionic pair [ReH₅(PPh₃)₂{PTA(D)?OC(O)CF₃}] (6) preceding the proton transfer step leading to 3.     

Chalcogen-capped ruthenium carbonyl clusters derived from diphosphazane mono- and dichalcogenides of the type X2P(E)N(R)PX2 and X2P(E)N(R)P(E)X2 (E = S or Se)

Reactions of Ru₃(CO)₁₂ with diphosphazane monoselenides Ph₂PN(R)P(Se)Ph₂ [R = (S)-∗CHMePh (L⁴), R = CHMe₂ (L⁵)] yield mainly the selenium bicapped tetraruthenium clusters [Ru₄(μ₄-Se)₂(μ-CO)(CO)₈{μ-P,P-Ph₂PN(R)PPh₂}] (1, 3). The selenium monocapped triruthenium cluster [Ru₃(μ₃-Se)(μ_sb-CO)(CO)₇{κ²-P,P-Ph₂PN((S)-∗CHMePh)PPh₂}] (2) is obtained only in the case of L⁴. An analogous reaction of the diphosphazane monosulfide (PhO)₂PN(Me)P(S)(OPh)₂ (L⁶) that bears a strong π-acceptor phosphorus shows a different reactivity pattern to yield the triruthenium clusters, [Ru₃(μ₃-S)(μ₃-CO)(CO)₇{μ-P,P-(PhO)₂PN(Me)P(OPh)₂}] (9) (single sulfur transfer product) and [Ru₃(μ₃-S)₂(CO)₅{κ²-P,P-(PhO)₂PN(Me)P(OPh)₂}{μ-P,P-(PhO)₂PN(Me)P(OPh)₂}] (10) (double sulfur transfer product). The reactions of diphosphazane dichalcogenides with Ru₃(CO)₁₂ yield the chalcogen bicapped tetraruthenium clusters [Ru₄(μ₄-E)₂(μ-CO)(CO)₈{μ-P,P-Ph₂PN(R)PPh₂}] [R = (S)-∗CHMePh, E = S (6); R = CHMe₂, E = S (7); R = CHMe₂, E = Se (3)]. Such a tetraruthenium cluster [Ru₄(μ₄-S)₂(μ- CO)(CO)₈{μ-P,P-(PhO)₂PN(Me)P(OPh)₂}] (11) is also obtained in small quantities during crystallization of cluster 9. The dynamic behavior of cluster 10 in solution is probed by NMR studies. The structural data for clusters 7, 9, 10 and 11 are compared and discussed.     

Steric and electronic effects in stabilizing allyl-palladium complexes of “P-N-P” ligands, X2PN(Me)PX2 (X = OC6H5 or OC6H3Me2-2,6)

The chemistry of η³-allyl palladium complexes of the diphosphazane ligands, X₂PN(Me)PX₂ [X = OC₆H₅ (1) or OC₆H₃Me₂-2,6 (2)] has been investigated.The reactions of the phenoxy derivative, (PhO)₂PN(Me)P(OPh)₂ with [Pd(η³-1,3-R′,R″-C₃H₃)(μ-Cl)]₂ (R′ = R″ = H or Me; R′ = H, R″ = Me) give exclusively the palladium dimer, [Pd₂{μ-(PhO)₂PN(Me)P(OPh)₂}₂Cl₂] (3); however, the analogous reaction with [Pd(η³-1,3-R′,R″-C₃H₃)(μ-Cl)]₂ (R′ = R″ = Ph) gives the palladium dimer and the allyl palladium complex [Pd(η³-1,3-R′,R″-C₃H₃)(1)](PF₆) (R′ = R″ = Ph) (4). On the other hand, the 2,6-dimethylphenoxy substituted derivative 2 reacts with (allyl) palladium chloro dimers to give stable allyl palladium complexes, [Pd(η³-1,3-R′,R″-C₃H₃)(2)](PF₆) [R′ = R″ = H (5), Me (7) or Ph (8); R′ = H, R″ = Me (6)].Detailed NMR studies reveal that the complexes 6 and 7 exist as a mixture of isomers in solution; the relatively less favourable isomer, anti-[Pd(η³-1-Me-C₃H₄)(2)](PF₆) (6b) and syn/anti-[Pd(η³-1,3-Me₂-C₃H₃)(2)](PF₆) (7b) are present to the extent of 25% and 40%, respectively. This result can be explained on the basis of the steric congestion around the donor phosphorus atoms in 2. The structures of four complexes (4, 5, 7a and 8) have been determined by X-ray crystallography; only one isomer is observed in the solid state in each case.     

Group 12 metal aryl selenolates. Crystal and molecular structure of [2-(Et2NCH2)C6H4]2Se2 and [2-(Me2NCH2)C6H4Se]2M (M = Zn, Cd)

Diorganodiselenide [2-(Et₂NCH₂)C₆H₄]₂Se₂ (1) was obtained by hydrolysis/oxidation of the corresponding [2-(Et₂NCH₂)C₆H₄]SeLi derivative. The treatment of [2-(Et₂NCH₂)C₆H₄]₂Se₂ with elemental sodium in THF resulted in [2-(Et₂NCH₂)C₆H₄]SeNa (2). Reactions between alkali metal selenolates [2-(R₂NCH₂)C₆H₄]SeM′ (R = Me, Et; M′ = Li, Na) and MCl₂ (M = Zn, Cd) in a 2:1 molar ratio resulted in the [2-(R₂NCH₂)C₆H₄Se]₂M species [R = Me, M = Zn (3), Cd (4); R = Et, M = Zn (5), Cd (6)]. The new compounds were characterized by multinuclear NMR (¹H, ¹³C, ⁷⁷Se, ¹¹³Cd) and mass spectrometry. The crystal and molecular structures of 1, 3 and 4 revealed monomeric species stabilized by N → Se (for 1) and N → M (for 3 and 4) intramolecular interactions.     

Two types of coordination polymers based on cluster anions [Re4Q4(CN)12] (Q = S, Se) and cations of rare-earth metals Ln: Syntheses and crystal structures

The reactions of aqueous solutions of the tetrahedral cluster anions [Re₄Q₄(CN)₁₂]⁴⁻ (Q = S, Se) with lanthanide chlorides resulted in the crystallization of the formed compounds into two main structural types [{Ln(H₂O)₄(H₂O)_2/3Cl_1/3}₃{Re₄Q₄(CN)₁₂}₂]·2H₂O (Ln = La-Gd, Q = S, Se) and K_0.5(H)_0.5[{Ln(H₂O)₄}{Re₄S₄(CN)₁₂}]·nH₂O or (H)[{Ln(H₂O)₄}{Re₄Se₄(CN)₁₂}]·nH₂O (Ln = Tb-Lu). Compounds of the first type crystallize in the hexagonal crystal system (space group Р6₃/m) and they have a three-dimensional polymeric structure; compounds of the second type crystallize in the orthorhombic crystal system (space group Cmcm) and they have a two-dimensional crystal structure due to the polymeric anion {[{Ln(H₂O)₄}{Re₄Q₄(CN)₁₂}]⁻}_∞∞.     

Syntheses, crystal structures and DFT studies of [Me3EM(CO)5] (E = Sb, Bi; M = Cr, W), cis-[(Me3Sb)2Mo(CO)4], and [Bu3BiFe(CO)4]

Syntheses of [Me₃SbM(CO)₅] [M = Cr (1), W (2)], [Me₃BiM(CO)₅] [M = Cr (3), W (4)], cis-[(Me₃Sb)₂Mo(CO)₄] (5), [^tBu₃BiFe(CO)₄] (6), crystal structures of 1-6 and DFT studies of 1-4 are reported.     

Synthesis, characterisation of two hexa-iron clusters with {Fe2S2(CO)x} (x = 5 or 6) fragments and investigation into their inter-conversion

Reaction of a trithiol ligand, 2-(mercaptomethyl)-2-methylpropane-1,3-dithiol (H₃L), with tri-iron dodecacarbonyl in toluene produces two hexa-iron clusters (1 and 2). The two clusters are characterised crystallographically and spectroscopically. NMR spectroscopy reveals that the cluster 2 exists in two conformations in equilibrium 2_anti ⇔ 2_syn and the equilibrium constant K_eq = 0.55 under CO atmosphere. In the cluster 2, the central {Fe₂S₂(CO)₆} sub-unit is flanked by two identical {Fe₂S₂(CO)₆} satellite sub-units through thiolate linkages whereas one of the thiolate linkages can further form Fe-S bond with the proximal Fe atom in one of the two satellite sub-units to produce the cluster 1 by expelling one CO. This conversion can be entirely reversed by continuously purging CO through the solution of the cluster 1. As suggested by DFT calculations, the conversion features a key step, the rotation of the Fe_prox(CO)₃ to expose a vacant site for exogenic ligand binding (the S atom from the central sub-unit in this case) with concomitant switch for one of the three CO ligands in the unit of Fe_prox(CO)₃ from terminal to bridging orientation. The conversion from the clusters 1-2 involving one CO uptake is much faster than its reverse process since the latter is an endergonic process characterised by large reaction barriers, as revealed by the DFT calculations.     

Syntheses and study on nickel and copper complexes with 1,3,5-benzenetricarboxylic acid. Crystal and molecular structure of [Cu3(mdpta)3(btc)](ClO4)3 · 4H2O

Nickel and copper complexes containing 1,3,5-benzenetricarboxylic acid, with a combination of selected N-donor ligands and Schiff bases, of the composition Ni₃(bimz)₆(btc)₂ · 12H₂O (1), Ni₃(btz)₉(btc)₂ · 12H₂O (2), Ni₂(L₁)(btc) · 7H₂O (3), Ni₃(L₂)₂(Hbtc) · 9H₂O (4), Ni₂(L₃)(btc) · 4H₂O (5), Cu₂(L₄)(btc) · 7H₂O (6), [Cu₃(pmdien)₃(btc)](ClO₄)₃ · 6H₂O (7) and [Cu₃(mdpta)₃(btc)](ClO₄)₃ · 4H₂O (8); H₃btc = 1,3,5-benzenetricarboxylic acid, bimz = benzimidazole, btz = 1,2,3-benztriazole, L₁ = 2-[(phenylimino)methyl]phenol, L₂ = N,N′-bis-(salicylidene)propylenediamine, L₃ = 2-{[(2-nitrophenyl)methylene]amino}phenol, L₄ = 2-[(4-methoxy-phenylimino)methyl]phenol, pmdien = N,N,N′,N″,N″-pentamethyldiethylenetriamine, mdpta = N,N-bis-(3-aminopropyl)methylamine, have been synthesized. The complexes have been studied by elemental analysis, IR, UV–Vis spectroscopies, magnetochemical and conductivity measurements and selected compounds also by thermal analysis. The crystal and molecular structure of complex 8 was solved. The complex is trinuclear with btc³⁻-bridge. The coordination polyhedron around each copper atom can be described as a distorted square with a CuON₃ chromophore formed by one oxygen atom of carboxylate and three nitrogen atoms of mdpta. The magnetic properties of 8 have been studied in the 1.8–300 K temperature range revealing a very weak antiferromagnetic exchange interaction with J = −0.56 cm⁻¹ for g = 2.13(9). The antimicrobial activities against selected strains of bacteria were evaluated. It was found that only complex 5 is able to inhibit the growth of Staphylococcus strains.     

Pentabenzylcyclopentadienyl molybdenum and tungsten hydrides: Syntheses, structures and electrochemistry of [MHCp(CO)2(L)] (L = CO, PMe3, PPh3)

Complexes [MHCp^Bz(CO)₂(PR₃)] (R = CH₃, M = Mo (1); M = W (2); R = Ph, M = Mo (3); Cp^Bz = C₅(CH₂Ph)₅) were prepared by thermal decarbonylation of the corresponding [MHCp^Bz(CO)₃] in the presence of trimethyl- or triphenyl-phosphine. In solution the NMR spectra of all compounds show the presence of cis and trans isomers that interconvert at room temperature. In the solid state the molecular structures obtained for compounds 1 and 2 correspond to the trans isomers, while for 3 the cis isomer is present.The electrochemistry of [MoHCp^Bz(CO)₂(PMe₃)] (1), [MoHCp^Bz(CO)₃] (5), [WHCp^Bz(CO)₃] (6), [WCp^Bz(CO)₃]₂ (7), and [MCp^Bz(CO)₃(CH₃CN)]BF₄ (8), is described. The cleavage of M-H bonds takes place upon oxidation or reduction. Cations [MCp^Bz(CO)₂L(CH₃CN)]⁺ form in solvent-assisted M-H bond breaking upon oxidation of [MHCp^Bz(CO)₂L] (L = PMe₃, CO). Reduction of [MHCp^Bz(CO)₃] gives [MCp^Bz(CO)₃]⁻ and H₂. The presence of one PMe₃ ligand lowers the reduction potential and precludes the observation of reduction waves.