Synthesis,Structure, and Magnetic Properties of a Random Bimetallic One‐dimensional CoII‐MnII Coordination Polymer with Mixed Azide‐carboxylate Bridges

The 3d–3d random bimetallic compound [Co_2.28Mn_0.72(N₃)₆(mpc‐3)₂(CH₃OH)₂] ( 1 ) (mpc‐3 = N‐methylpyridinium‐3‐carboxylate) was synthesized by partly substituting the Co^II ions in the homometallic compound by Mn^II. Complex 1 was structurally and magnetically characterized. It consists of one‐dimensional chains with the neighboring metal ions being linked alternatively by [(μ‐EO‐N₃)₂(μ‐COO)] (EO = end‐on) triple bridges and double EO azide bridges. Hydrogen‐bonding interactions and π–π interactions are involved in the formation of a three‐dimensional supramolecular network. Magnetic measurements revealed that complex 1 exhibits slow relaxation, which is similar to the homometallic Co^II parent compound whereas the T_B is lower than that of the Co^II analog.     

Heterodinuclear Ruthenium(II) Complexes of the Bridging Ligand 1,6,7,12‐Tetraazaperylene with Iron(II), Cobalt(II), Nickel(II), as well as Palladium(II) and Platinum(II)

The first heterodinuclear ruthenium(II) complexes of the 1,6,7,12‐tetraazaperylene (tape) bridging ligand with iron(II), cobalt(II), and nickel(II) were synthesized and characterized. The metal coordination sphere in this complexes is filled by the tetradentate N,N′‐dimethyl‐2,11‐diaza[3.3](2,6)‐pyridinophane (L‐N₄Me₂) ligand, yielding complexes of the general formula [(L‐N₄Me₂)Ru(µ‐tape)M(L‐N₄Me₂)](ClO₄)₂(PF₆)₂ with M = Fe {[ 2 ](ClO₄)₂(PF₆)₂}, Co {[ 3 ](ClO₄)₂(PF₆)₂}, and Ni {[ 4 ](ClO₄)₂(PF₆)₂}. Furthermore, the heterodinuclear tape ruthenium(II) complexes with palladium(II)‐ and platinum(II)‐dichloride [(bpy)₂Ru(μ‐tape)PdCl₂](PF₆)₂ {[ 5 ](PF₆)₂} and [(dmbpy)₂Ru(μ‐tape)PtCl₂](PF₆)₂ {[ 6 ](PF₆)₂}, respectively were also prepared. The molecular structures of the complex cations [ 2 ]⁴⁺ and [ 4 ]⁴⁺ were discussed on the basis of the X‐ray structures of [ 2 ](ClO₄)₄ · MeCN and [ 4 ](ClO₄)₄ · MeCN. The electrochemical behavior and the UV/Vis absorption spectra of the heterodinuclear tape ruthenium(II) complexes were explored and compared with the data of the analogous mono‐ and homodinuclear ruthenium(II) complexes of the tape bridging ligand.     

Cyclopentadienyl Ruthenium(II) Complexes with Bridging Alkynylphosphine Ligands: Synthesis and Electrochemical Studies

The reaction of [CpRuCl(PPh₃)₂] (Cp=cyclopentadienyl) and [CpRuCl(dppe)] (dppe=Ph₂PCH₂CH₂PPh₂) with bis‐ and tris‐phosphine ligands 1,4‐(Ph₂PC≡C)₂C₆H₄ ( 1 ) and 1,3,5‐(Ph₂PC≡C)₃C₆H₃ ( 2 ), prepared by Ni‐catalysed cross‐coupling reactions between terminal alkynes and diphenylchlorophosphine, has been investigated. Using metal‐directed self‐assembly methodologies, two linear bimetallic complexes, [{CpRuCl(PPh₃)}₂(μ‐dppab)] ( 3 ) and [{CpRu(dppe)}₂(μ‐dppab)](PF₆)₂ ( 4 ), and the mononuclear complex [CpRuCl(PPh₃)(η¹‐dppab)] ( 6 ), which contains a “dangling arm” ligand, were prepared (dppab=1,4‐bis[(diphenylphosphino)ethynyl]benzene). Moreover, by using the triphosphine 1,3,5‐tris[(diphenylphosphino)ethynyl]benzene (tppab), the trimetallic [{CpRuCl(PPh₃)}₃(μ₃‐tppab)] ( 5 ) species was synthesised, which is the first example of a chiral‐at‐ruthenium complex containing three different stereogenic centres. Besides these open‐chain complexes, the neutral cyclic species [{CpRuCl(μ‐dppab)}₂] ( 7 ) was also obtained under different experimental conditions. The coordination chemistry of such systems towards supramolecular assemblies was tested by reaction of the bimetallic precursor 3 with additional equivalents of ligand 2 . Two rigid macrocycles based on cis coordination of dppab to [CpRu(PPh₃)] were obtained, that is, the dinuclear complex [{CpRu(PPh₃)(μ‐dppab)}₂](PF₆)₂ ( 8 ) and the tetranuclear square [{CpRu(PPh₃)(μ‐dppab)}₄](PF₆)₄ ( 9 ). The solid‐state structures of 7 and 8 have been determined by X‐ray diffraction analysis and show a different arrangement of the two parallel dppab ligands. All compounds were characterised by various methods including ESIMS, electrochemistry and by X‐band ESR spectroscopy in the case of the electrogenerated paramagnetic species.     

Linking Tribridged Dicopper Complexes with Neutral Dipyridyl Compounds to Coordination Oligomers and Polymers

The stable tribridged dicopper(I) carboxylate complexes [Cu₂(μ‐dppm)₂(μ‐O₂CR)]BF₄ (RCO₂ ⁻ = formate (OFc⁻), m1 ; acetate (OAc⁻), m2 ; benzoate (OBAc⁻), m3 ; o‐toluate (O2TAc⁻), m4 ; p‐toluate (O4TAc⁻), m5 ; 4‐phenylbutyrate (O4PBAc⁻), m6 ; 2‐nitrobenzoate (O2NBAc⁻), m7 ), abbreviated as MM, and neutral dipyridyl compounds (NN; NN = 4,4′‐bipyridine (bpy), 1,2‐bis(4‐pyridyl)ethane (bpa), trans ‐1,2‐bis(4‐pyridyl)ethylene (bpe), 4,4′‐trimethylenedipyridine (tmp)) can form dynamic equilibria in CH₂Cl₂. From the equilibrium mixtures containing MM and NN with MM/NN = 1:1, nine 2:1 oligomers ([( m1 )₂(μ‐bpy)](BF₄)₂ ( o1a (BF₄)₂), [( m3 )₂(μ‐bpe)](BF₄)₂ ( o3c (BF₄)₂), [( m3 )₂(μ‐tmp)](BF₄)₂ ( o3d (BF₄)₂), [( m4 )₂(μ‐bpe)](BF₄)₂ ( o4c (BF₄)₂), [( m5 )₂(μ‐bpy)](BF₄)₂ ( o5a (BF₄)₂), [( m5 )₂(μ‐tmp)](BF₄)₂ ( o5d (BF₄)₂), [( m6 )₂(μ‐bpa)](BF₄)₂ ( o6b (BF₄)₂), [( m7 )₂(μ‐bpy)](BF₄)₂ ( o7a (BF₄)₂), [( m7 )₂(μ‐bpa)](BF₄)₂ ( o7b (BF₄)₂)), one 2:3 oligomer ([{( m2 )(bpy)}₂(μ‐bpy)](BF₄)₂ ( o2a (BF₄)₂)), and five 1:1 polymers ([( m2 )(μ‐bpe)] _n (BF₄ ) _n ( p2c (BF₄ ) _n ), [( m2 )(μ‐tmp)] _n (BF₄ ) _n ( p2d (BF₄ ) _n ), [( m3 )(μ‐bpy)] _n (BF₄ ) _n ( p3a (BF₄ ) _n ), [( m3 )(μ‐tmp)] _n (BF₄ ) _n ( p3d (BF₄ ) _n ), [( m7 )(μ‐tmp)] _n (BF₄ ) _n ( p7d (BF₄ ) _n )) were obtained as single crystals, and their structures were determined by X‐ray crystallography. Both experimental and theoretical results support the presence of two oligomeric species, [{Cu₂(μ‐dppm)₂(μ‐O₂CR)}₂(μ‐NN)]²⁺ and [{Cu₂(μ‐dppm)₂(μ‐O₂CR)(NN)}₂(μ‐NN)]²⁺), in dynamic equilibrium. The oligomers (such as o3d (BF₄)₂) can serve as seeds to induce the formation of soluble coordination polymers as crystals (such as p3d (BF₄)_n ).     

阴离子在构筑吡啶酰胺－铜(II)配位超分子体系中的作用

Three complexes Cu（ppca）2（H2O）2（NO3）2 （1）, Cu2（μ-OH）2（ppca）2（H2O）4）·（ClO4）2 （2） and Cu2（μ-CH3COO）4（ppca）2（3） have been synthesized by the reaction of copper（Ⅱ） salts with N-phenyl-4-pyridinecarboxamide （ppca） and characterized. For anions, in complex 1, NO3^- coordinated with copper（Ⅱ）, in complex 2 perchlorate anion did not take part in coordination, the copper（Ⅱ） cations were connected by μ-OH to form a dinuclear unit, and complex 3 had a dimeric copper（Ⅱ） carboxylate paddle-wheel core. Noncovalent interactions linked these complexes to form supramolecular networks. Different coordinating modes of anions controlled modes of intennolecular interactions, which resulted in different final structures.     

Syntheses,Characterization and X‐ray Structure of the First Silver(I) Complexes with 4‐Amino‐3‐thioxo‐3,4‐dihydro‐1,2,4‐triazin‐5(2H)‐one

Reaction of thiocarbohydrazide with glyoxolic acid monohydrate led to 4‐amino‐3‐thioxo‐3,4‐dihydro‐1,2,4‐triazin‐5(2H)‐one (AHTTO, 1 ). Treatment of 1 with AgNO₃ and PPh₃ gave thecomplexes [(PPh₃)₂Ag₂(μ‐N,S‐AHTTO)₂](NO₃)₂ ( 2 ) and [(PPh₃)₂Ag(AHTTO)]NO₃ · MeOH ( 3 ) was obtained under different conditions. All the compounds have been characterized by elemental analyses, IR spectroscopy and X‐ray diffraction studies.     

1D Coordination Polymers from Zinc(II) and Cadmium(II) Halides and 2,2′‐Dithiobis(pyridine N‐oxide): Isostructurality and Structural Diversity

Group 12 halides and 2,2′‐dithiobis(pyridine N‐oxide) (dtpo) form the crystalline the 1D coordination polymers [ZnX₂(μ‐dtpo‐κ²O:O′)]_n [X = Cl ( 1 ), Br ( 2 ), I ( 3 )], [Cd₃(μ‐Cl)₄Cl₂(μ‐dtpo‐κ²O:O′)₂(CH₃OH)₂]_n ( 4 ), [(CdBr₂)₂(μ₃‐dtpo‐κ³O,O:O′)₂(H₂O)₂]_n ( 5 ), and [(CdI₂)₂(μ‐dtpo‐κ²O:O′)₃]_n ( 6 ) in methanol. The compounds were structurally characterized by single‐crystal X‐ray analysis. Compounds 1 – 3 represent an isomorphous series of single‐stranded coordination polymers, whereas the Cd^II derivatives are structurally diverse. The metal nodes in 4 and 5 are trinuclear and dinuclear cadmium clusters, respectively. In 4 and 5 , the metal nodes are linked into double‐stranded 1D coordination polymers by two dtpo bridging ligands. Compound 6 contains mononuclear CdI₂ units as nodes and can be viewed as an alternating copolymer of CdI₂(μ‐dtpo‐κ²O:O′)₂ and CdI₂(μ‐dtpo‐κ²O:O′) entities. Owing to the disulfide moiety, the dtpo bridging ligand inevitably exhibits an axially chiral angular structure. The dtpo ligand adopts various coordination modes through the pyridine N‐oxide oxygen atoms.     

Umsetzungen von Cp*NbCl4 und Cp*TaCl4 mit Trimethylsilyl‐azid,Me3Si‐N3. Molekülstrukturen der bis(azido)‐oxo‐verbrückten Komplexe [Cp*NbCl(N3)(μ‐N3)]2(μ‐O) und [Cp*TaCl2(μ‐N3)]2(μ‐O) (Cp* = Pentamethylcyclopentadienyl)

Reactions of Cp*NbCl₄ and Cp*TaCl₄ with Trimethylsilyl‐azide, Me₃Si‐N₃. Molecular Structures of the Bis(azido)‐Oxo‐Bridged Complexes [Cp*NbCl(N₃)(μ‐N₃)]₂(μ‐O) and [Cp*TaCl₂(μ‐N₃)]₂(μ‐O) (Cp* = Pentamethylcyclopentadienyl) The chloro ligands in Cp*TaCl₄ (1c) can be stepwise substituted for azido ligands by reactions with trimethylsilyl azide, Me₃Si‐N₃ (A) , to generate the complete series of the bis(azido)‐bridged dimers [Cp*TaCl_3‐n(N₃)_n(μ‐N₃)]₂ ( n = 0 (2c) , n = 1 (3c) , n = 2 (4c) and n = 3 (5c) ). If the solvent CH₂Cl₂ contains traces of water, an additional oxo bridge is incorporated to give [Cp*‐TaCl₂(μ‐N₃)]₂(μ‐O) (6c) or [Cp*TaCl(N₃)(μ‐N₃)]₂(μ‐O) (7c) , respectively. Both 6c and 7c are also formed in stoichiometric reactions from [Cp*TaCl₂(μ‐OH)]₂(μ‐O) (8c) and A . Analogous reactions of Cp*NbCl₄ (1b) with A were used to prepare the azide‐rich dinuclear products [Cp*NbCl_3‐n(N₃)_n(μ‐N₃)]₂ (n = 2 (4b) , and n = 3 (5b) ), and [Cp*NbCl(N₃)(μ‐N₃)]₂(μ‐O) (7b) . The mononuclear complex Cp*Ta(N₃)Me₃ (10c) is obtained from Cp*Ta(Cl)Me₃ and A . All azido complexes were characterised by their IR as well as their ¹H and ¹³C NMR spectra; X‐ray crystal structure analyses are available for 6c and 7b .     

Titanium(IV) and Zirconium(IV) Sulfato Complexes Containing the Kläui Tripodal Ligand: Molecular Models of Sulfated Metal Oxide Surfaces

Treatment of titanyl sulfate in about 60 mM sulfuric acid with NaL_OEt (L_OEt^?=[(η⁵‐C₅H₅)Co{P(O)(OEt)₂}₃]^?) afforded the μ‐sulfato complex [(L_OEtTi)₂(μ‐O)₂(μ‐SO₄)] ( 2 ). In more concentrated sulfuric acid (>1 M ), the same reaction yielded the di‐μ‐sulfato complex [(L_OEtTi)₂(μ‐O)(μ‐SO₄)₂] ( 3 ). Reaction of 2 with HOTf (OTf=triflate, CF₃SO₃) gave the tris(triflato) complex [L_OEtTi(OTf)₃] ( 4 ), whereas treatment of 2 with Ag(OTf) in CH₂Cl₂ afforded the sulfato‐capped trinuclear complex [{(L_OEt)₃Ti₃(μ‐O)₃}(μ₃‐SO₄){Ag(OTf)}][OTf] ( 5 ), in which the Ag(OTf) moiety binds to a μ‐oxo group in the Ti₃(μ‐O)₃ core. Reaction of 2 in H₂O with Ba(NO₃)₂ afforded the tetranuclear complex (L_OEt)₄Ti₄(μ‐O)₆ ( 6 ). Treatment of 2 with [{Rh(cod)Cl}₂] (cod=1,5‐cyclooctadiene), [Re(CO)₅Cl], and [Ru(tBu₂bpy)(PPh₃)₂Cl₂] (tBu₂bpy=4,4′‐di‐tert‐butyl‐2,2′‐dipyridyl) in the presence of Ag(OTf) afforded the heterometallic complexes [(L_OEt)₂Ti₂(O)₂(SO₄){Rh(cod)}₂][OTf]₂ ( 7 ), [(L_OEt)₂Ti(O)₂(SO₄){Re(CO)₃}][OTf] ( 8 ), and [{(L_OEt)₂Ti₂(μ‐O)}(μ₃‐SO₄)(μ‐O)₂{Ru(PPh₃)(tBu₂bpy)}][OTf]₂ ( 9 ), respectively. Complex 9 is paramagnetic with a measured magnetic moment of about 2.4 μ_B. Treatment of zirconyl nitrate with NaL_OEt in 3.5 M sulfuric acid afforded [(L_OEt)₂Zr(NO₃)][L_OEtZr(SO₄)(NO₃)] ( 10 ). Reaction of ZrCl₄ in 1.8 M sulfuric acid with NaL_OEt in the presence Na₂SO₄ gave the μ‐sulfato‐bridged complex [L_OEtZr(SO₄)(H₂O)]₂(μ‐SO₄) ( 11 ). Treatment of 11 with triflic acid afforded [(L_OEt)₂Zr][OTf]₂ ( 12 ), whereas reaction of 11 with Ag(OTf) afforded a mixture of 12 and trinuclear [{L_OEtZr(SO₄)(H₂O)}₃(μ₃‐SO₄)][OTf] ( 13 ). The Zr^IV triflato complex [L_OEtZr(OTf)₃] ( 14 ) was prepared by reaction of L_OEtZrF₃ with Me₃SiOTf. Complexes 4 and 14 can catalyze the Diels–Alder reaction of 1,3‐cyclohexadiene with acrolein in good selectivity. Complexes 2 – 5 , 9 – 11 , and 13 have been characterized by X‐ray crystallography.     

Two bicyclic dinuclear complexes generated from 3,3′‐[1,3,4‐thiadiazole‐2,5‐diyldi(thiomethylene)]dibenzoic acid (L) and dimethylformamide (DMF): [Cu(L)(DMF)]2 and [Zn(L)(DMF)]2

A new 1,3,4‐thiadiazole bridging ligand, namely 3,3′‐[1,3,4‐thiadiazole‐2,5‐diyldi(thiomethylene)]dibenzoic acid (L), has been used to create the novel isomorphous complexes bis{μ‐3,3′‐[1,3,4‐thiadiazole‐2,5‐diyldi(thiomethylene)]dibenzoato}bis[(N,N‐dimethylformamide)copper(II)], [Cu₂(C₁₈H₁₂N₂O₄S₃)₂(C₃H₇NO)₂], (I), and bis{μ‐3,3′‐[1,3,4‐thiadiazole‐2,5‐diyldi(thiomethylene)]dibenzoato}bis[(N,N‐dimethylformamide)zinc(II)], [Zn₂(C₁₈H₁₂N₂O₄S₃)₂(C₃H₇NO)₂], (II). Both exist as centrosymmetric bicyclic dimers constructed through the syn–syn bidentate bridging mode of the carboxylate groups. The two rings share a metal–metal bond and each of the metal atoms possesses a square‐pyramidal geometry capped by the dimethylformamide molecule. The 1,3,4‐thiadiazole rings play a critical role in the formation of a π–π stacking system that expands the dimensionality of the structure from zero to one. The thermogravimetric analysis of (I) indicates decomposition of the coordinated ligands on heating. Compared with the fluorescence of L in the solid state, the fluorescence intensity of (II) is relatively enhanced with a slight redshift, while that of (I) is quenched.     

Synthesis,Crystal Structure and Magnetic Behaviour of the new Tetrameric Gadolinium Carboxylate [Gd4(OH)4(CF3COO)8(H2O)4] · 2.5 H2O

The novel tetrameric gadolinium(III) compound [Gd₄(OH)₄(CF₃COO)₈(H₂O)₄] · 2.5 H₂O was synthesized and structurally characterized by X‐ray crystallography. The Gd³⁺ ions are bridged by hydroxide ions and carboxylate groups to tetramers with Gd³⁺‐Gd³⁺ distances between 384.2(2) and 388.1(2) pm. The compound crystallizes in the monoclinic space group C2/c (Z = 4). The magnetic behaviour of [Gd₄(OH)₄(CF₃COO)₈(H₂O)₄] · 2.5 H₂O was investigated in the temperature range of 2 to 300 K. The magnetic data of this compound indicate antiferromagnetic interactions (J_ex = ?0.0197 cm^?1).     

A coordinatively flexible hexadentate ligand gives structurally isomeric complexes M2(L)X3 (M = Cu,Zn; X = Br,Cl)

Polypyridyl multidentate ligands based on ethylenediamine backbones are important metal‐binding agents with applications in biomimetics and homogeneous catalysis. The seemingly hexadentate tpena ligand [systematic name: N,N,N′‐tris(pyridin‐2‐ylmethyl)ethylenediamine‐N′‐acetate] reacts with zinc chloride and zinc bromide to form trichlorido[μ‐N,N,N′‐tris(pyridin‐2‐ylmethyl)ethylenediamine‐N′‐acetato]dizinc(II), [Zn₂(C₂₂H₂₄N₅O₂)Cl₃], and tribromido[μ‐N,N,N′‐tris(pyridin‐2‐ylmethyl)ethylenediamine‐N′‐acetato]dizinc(II), [Zn₂Br₃(C₂₂H₂₄N₅O₂)]. One Zn^II ion shows the anticipated N₅O coordination in an irregular six‐coordinate site and is linked by an anti carboxylate bridge to a tetrahedral ZnX₃ (X = Cl or Br) unit. In contrast, the Cu^II ions in aquatribromido[μ‐N,N,N′‐tris(pyridin‐2‐ylmethyl)ethylenediamine‐N′‐acetato]dicopper(II)–tribromido[μ‐N,N,N′‐tris(pyridin‐2‐ylmethyl)ethylenediamine‐N′‐acetato]dicopper(II)–water (1/1/6.5) [Cu₂Br₃(C₂₂H₂₄N₅O₂)][Cu₂Br₃(C₂₂H₂₄N₅O₂)(H₂O)]·6.5H₂O, occupy two tpena‐chelated sites, one a trigonal bipyramidal N₃Cl₂ site and the other a square‐planar N₂OCl site. In all three cases, electrospray ionization mass spectra were dominated by a misleading ion assignable to [M(tpena)]⁺ (M = Zn²⁺ and Cu²⁺).     

Cobalt(II) Tri‐tert‐butoxysilanethiolates with Bidentate Spacer Ligands

A new series of Co^II tri‐tert‐butoxysilanethiolate complexes with bidentate N,N′‐ligands (L) such as pyrazine, quinoxaline and 4,4′‐bipy was obtained: for pyrazine and quinoxaline the complexes are binuclear {[Co{SSi(tBuO)₃}₂]₂(μ‐L)} with metal atoms linked by an adequate heterocyclic base L. The use of 4,4′‐bipy resulted in a coordination polymer [Co{μ‐SSi(tBuO)₃}{SSi(tBuO)₃}(μ‐4,4′‐bipy)]_n and two polymorphic forms of {[Co{SSi(tBuO)₃}₂]₂(μ‐4,4′‐bipy)}. Pyridyl rings in one polymorph form a torsion angle of 0.57°, whereas a rotation about the linking C–C bond of 4,4′‐bipy in second polymorph is significant and results in a torsion angle of 72.4°. Complexes were analysed and characterised using elemental analysis, solid state IR and UV/Vis spectroscopy, and single‐crystal X‐ray analysis.     

Pentamethylcyclopentadienyl Halfsandwich Complexes of Vanadium and Tantalum with Amido‐, Imido‐ Nitrido‐ and Azido Ligands

Lithium bis(trimethylsilyl)amide, LiN(SiMe₃)₂, reacts with Cp*V(O)Cl₂ and Cp*TaCl₄ to give trimethylsilylimido complexes such as [Cp*V(NSiMe₃)(μ‐NSiMe₃)]₂ ( 7 ) and Cp*Ta(Cl)(NSiMe₃)[N(SiMe₃)₂] ( 19 ), respectively. Substitution of the chloro ligand in 19 by anionic groups leads to complexes with 3 different N‐containing ligands, Cp*Ta(X)(NSiMe₃)[N(SiMe₃)₂] (X = N₃ ( 20 ) or NPEt₃ ( 21 )). Complex 7 is air‐ and moisture‐sensitive, and several derivatives containing oxo and trimethylsiloxy ligands have been identified. Trimethylsilyl azide, Me₃Si‐N₃, is able to replace the oxygen‐containing ligands for azido ligands. The two complete series of bis(azido)‐bridged complexes, [Cp*VCl_n(N₃)_2‐n(μ‐N₃)]₂ (n = 2, 1, 0) and [Cp*TaCl_n(N₃)_3‐n(μ‐N₃)]₂(n = 3, 2, 1, 0), are accessible from the reactions of Cp*VCl₃ and Cp*TaCl₄, respectively, with trimethylsilyl azide. A bis(nitrido)‐bridged azido‐vanadium complex, [Cp*V(N₃)(μ‐N)]₂ ( 18 ), has also been obtained and structurally characterized.     

Reduktive Dimerisierung von NO an Dirutheniumkomplexen und Bildung eines tridentaten 2, 2‐Bis(diphenylphosphanyl)ethanolato‐Liganden

The reaction of the trans‐hyponitrito complex [Ru₂(CO)₄(μ‐η²‐ONNO)(μ‐H)(μ‐PtBu₂)(μ‐dppen)] ( 1 , dppen = Ph₂PC(=CH₂)PPh₂) with tetrafluorido boric acid afforded the new complex salt [Ru₂(CO)₄(μ‐η²‐ONNOH)(μ‐H)(μ‐PtBu₂)(μ‐dppen)]BF₄ ( 2 ) containing the monoprotonate hyponitrous acid as the ligand in the cationic complex. Complex 1 showed a nucleophilic reactivity towards the trimethyloxonium cation resulting in the monoester derivative of the hyponitrous acid [Ru₂(CO)₄(μ‐η²‐ONNOMe)(μ‐H)(μ‐PtBu₂)(μ‐dppen)]BF₄ ( 3 ). During heating of compound 2 in ethanol under reflux for a short time nitrous oxide was liberated affording unexpectedly a new tridentate 2, 2‐bis(diphenylphosphanyl)ethanolato ligand formed by an intramolecular attack of an intermediate hydroxido ligand towards the unsaturated carbon carbon double bond in the bridging dppen ligand. Thus the complex salt [Ru₂(CO)₄{μ‐η³‐OCH₂CH(PPh₂)₂}(μ‐H)(μ‐PtBu₂)]BF₄ ( 4 ) was formed in good yields. The new compounds 2 , 3 , and 4 were characterized by spectroscopic means as well as their molecular structures were determined in the crystal.     

Neue Azidokomplexe des Tantals(V). Synthese und Molekülstruktur der Zweikernverbindungen [Cp*TaCl(N3)(μ‐N3)]2(μ‐O) und [Cp*Ta(N3)3(μ‐N3)]2 (Cp* = Pentamethylcyclopentadienyl)

New Azido Complexes of Tantalum(V). Synthesis and Molecular Structure of the Dinuclear Compounds [Cp*TaCl(N₃)(μ‐N₃)]₂(μ‐O) and [Cp*Ta(N₃)₃(μ‐N₃)]₂ (Cp* = Pentamethylcyclopentadienyl) The reaction of Cp*TaCl₄ ( 1 ) with an excess of trimethylsilyl azide (Me₃Si–N₃) leads to azide‐rich dinuclear complexes which contain both terminal and bridging azido ligands. The oxo complex [Cp*TaCl(N₃)(μ‐N₃)]₂(μ‐O) ( 4 ) was formed in dichloromethane in the presence of traces of water, whereas [Cp*Ta(N₃)₃(μ‐N₃)]₂ ( 5 ) was obtained from boiling toluene after several days. According to the X‐ray structure determinations the Ta…Ta distance in 4 (314,5 pm) is considerably shorter than in 5 (382,2 pm).     

Dinuclear cobalt(II) complexes with double phosphate ester bridges and tetradentate ligands having anisole or quinoline appendages

Phosphate esters provide a rigid and stable polymeric backbone in nucleic acids. Metal complexes with phosphate ester groups have been synthesized as structural and spectroscopic models of phosphate‐containing enzymes. Dinucleating ligands are used extensively to synthesize model complexes since they provide the support required to stabilize such complexes. The crystal structures of two dinuclear Co^II complexes, namely bis(μ‐diphenyl phosphato‐κ²O :O ′)bis({2‐methoxy‐N ,N‐bis[(pyridin‐2‐yl)methyl]aniline‐κ⁴N ,N ′,N ′′,O }cobalt(II)) bis(perchlorate), [Co(C₁₂H₁₀O₄P)₂(C₁₉H₁₉N₃O)₂](ClO₄)₂, and bis(μ‐diphenyl phosphato‐κ²O :O ′)bis({N ,N‐bis[(pyridin‐2‐yl)methyl]quinolin‐8‐amine‐κ⁴N ,N ′,N ′′,O }cobalt(II)) bis(perchlorate), [Co(C₁₂H₁₀O₄P)₂(C₂₁H₁₈N₄)₂](ClO₄)₂, with tetradentate 2‐methoxy‐N ,N‐bis[(pyridin‐2‐yl)methyl]aniline (L ¹) and N ,N‐bis[(pyridin‐2‐yl)methyl]quinolin‐8‐amine (L ²) ligands are reported. The complexes have similar structures, with distorted octahedral geometries around the metal centres. Both are centrosymmetric (Z ′ = 0.5), with the Co^II centres doubly bridged by diphenyl phosphate ester groups. A number of aromatic–aromatic interactions are present and differ between the two complexes as the anisole group in L ¹ is replaced by a quinoline group in L ². A detailed study of these interactions is presented.     

Cobalt(II) and cadmium(II) square grids supported with 4,4′‐bipyrazole and accommodating 3‐carboxyadamantane‐1‐carboxylate

In poly[[bis(μ‐4,4′‐bi‐1H‐pyrazole‐κ²N²:N^2′)bis(3‐carboxyadamantane‐1‐carboxylato‐κO¹)cobalt(II)] dihydrate], {[Co(C₁₂H₁₅O₄)₂(C₆H₆N₄)₂]·2H₂O}_n, (I), the Co²⁺ cation lies on an inversion centre and the 4,4′‐bipyrazole (4,4′‐bpz) ligands are also situated across centres of inversion. In its non‐isomorphous cadmium analogue, {[Cd(C₁₂H₁₅O₄)₂(C₆H₆N₄)₂]·2H₂O}_n, (II), the Cd²⁺ cation lies on a twofold axis. In both compounds, the metal cations adopt an octahedral coordination, with four pyrazole N atoms in the equatorial plane [Co—N = 2.156 (2) and 2.162 (2) Å; Cd—N = 2.298 (2) and 2.321 (2) Å] and two axial carboxylate O atoms [Co—O = 2.1547 (18) Å and Cd—O = 2.347 (2) Å]. In both structures, interligand hydrogen bonding [N...O = 2.682 (3)–2.819 (3) Å] is essential for stabilization of the MN₄O₂ environment with its unusually high (for bulky adamantanecarboxylates) number of coordinated N‐donor co‐ligands. The compounds adopt two‐dimensional coordination connectivities and exist as square‐grid [M(4,4′‐bpz)₂]_n networks accommodating monodentate carboxylate ligands. The interlayer linkage is provided by hydrogen bonds from the carboxylic acid groups via the solvent water molecules [O...O = 2.565 (3) and 2.616 (3) Å] to the carboxylate groups in the next layer [O...O = 2.717 (3)–2.841 (3) Å], thereby extending the structures in the third dimension.     

Two New Cadmium(II) Compounds based on Distinct Second Building Subunits: Solvothermal Syntheses,Crystal Structures,and Luminescent Properties

Two cadmium(II) coordination polymers, namely [Cd₃(bpt)₂(DMA)₂]_n ( 1 ) and [Cd₂(bpt)(btz)(DMF)]_n ( 2 ) (H₃bpt = biphenyl‐3,4′,5‐tricarboxylic acid, Hbtz = 1H‐benzotriazole, DMA = N,N‐dimethylacetamide; DMF = N,N‐dimethylformamide), were solvothermally synthesized and structurally characterized by single‐crystal X‐ray diffraction. Compound 1 displays a 3D framework based on trinuclear {Cd₃(COO)₄} subunits and can be simplified into a (4,8)‐connected topological network by viewing bpt^3– ligands and trinuclear {Cd₃(COO)₄} units as 4‐, 8‐connected nodes, respectively. Compound 2 also displays a 3D framework but based on 1D chain subunits controlled by carboxylate groups and btz^– ligands. In addition, the thermal stabilities and luminescent properties of compounds 1 and 2 were also investigated.     

Structure and Magnetism of two Polynuclear Complexes Containing both Macrocyclic and Azido Ligands

The two complexes of formula [Cu₂(CuL)₂(μ‐N₃)₄] · 2CH₃OH ( 1 ) and [Cu₂(NiL)₂(μ‐N₃)₄] · 2CH₃OH ( 2 ) (CuL and NiL, H₂L = 2,3‐dioxo‐5,6,14,15‐dibenzo‐1,4,8,12‐tetraazacyclo‐pentadeca‐7,13‐dien), were synthesized and structurally determined. The magnetic susceptibility data of 1 and 2 were analyzed. For complex 1 , magnetic measurements show alternating ferromagnetic and antiferromagnetic exchange couplings J₁ = 23.67 cm^–1, J₂ = –189.11 cm^–1, zJ’ = –0.62 cm^–1. For complex 2 , the doubly bridged asymmetric EO promotes a ferromagnetic interaction between Cu^II and Cu^II ions(J = 40.764 cm^–1).