Stereoselectivity in Diphos Addition to Molybdenum Complex with Pyridine‐2‐thionate (pyS) and η3‐Methallyl Coordinated Ligands

The conformational isomers endo‐ and exo‐[Mo{η³‐C₃H₄(CH₃)}(η²‐pyS)(CO)(η²‐diphos)] (diphos: dppm = {bis(diphenylphosphino)methane}, 2 ; dppe = {1,2‐bis(diphenylphosphino)ethane}, 3 ) are prepared by reacting the double‐bridged pyridine‐2‐thionate (pyS) complex [Mo{η³‐C₃H₄(CH₃)}(CO)₂]₂(η¹:η²:μ‐pyS)₂, 1 with diphos in refluxing acetonitrile. Stereoselectivity of the methallyl, C₃H₄(CH₃), ligand improves the formation of the exo‐conformation of 2 and 3 . Orientations and spectroscopy of these complexes are discussed.     

Synthesis,Reactivity, and Crystal Structure of the η2‐Thiocarbamoyl Palladium Complex [Pd(PPh3)2(η2‐SCNMe2)][PF6]

The η¹‐thiocarbamoyl palladium complexes [Pd(PPh₃)(η¹‐SCNMe₂)(η²‐S₂R)] (R = P(OEt)₂, 2 ; CNEt₂, 3 ) and trans‐[Pd(PPh₃)₂(η¹‐SCNMe₂)(η¹‐Spy)], 4 , (pyS: pyridine‐2‐thionate) are prepared by reacting the η²‐thiocarbamoyl palladium complex [Pd(PPh₃)₂(η²‐SCNMe₂)][PF₆], 1 with (EtO)₂PS₂NH₄, Et₂NCS₂Na, and pySK in methanol at room temperature, respectively. Treatment of 1 with dppm (dppm: bis(diphenylphosphino)methane) in dichloromethane at room temperature gives complex [Pd(PPh₃)(η¹‐SCNMe₂)(η²‐dppm)] [PF₆], 5 . All of the complexes are identified by spectroscopic methods and complex 1 is determined by single‐crystal X‐ray diffraction.     

Synthesis and Crystal Structures of the Molybdenum(II) Complexes with the N,N‐dimethylthiocarbamoyl Containing Ligand: Crystal Structures of β [Mo(CO)2{η2‐S2P(OEt)2}(η2‐SCNMe2)(PPh3)] and [Mo(CO)2(η3‐Tp)(η2‐SCNMe2)(PPh3)]

Reactions of the thiocarbamoyl‐molybdenum complex [Mo(CO)₂(η²‐SCNMe₂)(PPh₃)₂Cl] 1 , and ammonium diethyldithiophosphate, NH₄S₂P(OEt)₂, and potassium tris(pyrazoyl‐1‐yl)borate, KTp, in dichloromethane at room temperature yielded the seven coordinated diethyldithiophosphate thiocarbamoyl‐molybdenum complexe [Mo(CO)₂{η²‐S₂P(OEt)₂}(η²‐SCNMe₂)(PPh₃)] β‐3 , and tris(pyrazoyl‐1‐yl)borate thiocabamoyl‐molybdenum complex [Mo(CO)₂(η³‐Tp)(η²‐SCNMe₂)(PPh₃)] 4 , respectively. The geometry around the metal atom of compounds β‐3 and 4 are capped octahedrons. The α‐ and β‐isomers are defined to the dithio‐ligand and one of the carbonyl ligands in the trans position in former and two carbonyl ligands in the trans position in later. The thiocabamoyl and diethyldithiophosphate or tris(pyrazoyl‐1‐yl)borate ligands coordinate to the molybdenum metal center through the carbon and sulfur and two sulfur atoms, or three nitrogen atoms, respectively. Complexes β‐3 and 4 are characterized by X‐ray diffraction analyses.     

Synthesis and Crystal Structure of [Nd(η6‐1, 3, 5‐C6H3Me3)‐(AlCl4)3](C6H6) and Structural Comparison of Ln(η6‐arene)‐(AlCl4)3

Reaction of Ndcl₃ with AlCl₃ and mesitylene in benzene gives complex [Nd(η⁶‐1, 3, 5‐C₆H₃Me₃)‐(AlCl₄)₃](C₆H₆) (1) which was characterized by elemental analysis, IR spectra, MS and X‐ray diffractions. The X‐ray determination indicates that 1 has a distorted pentagonal bipyramidal geometry and crystallizes in the monoclinic, space group P2₁/n with a = 0.9586(2), b = 1.1717(5), c = 2.8966(7) nm, β = 90.85 (2)°, V = 3.2529 (6) nm³,D_c= 1.573 g/cm³, Z = 4. A comparison of bond parameters for all the reported Ln (η⁶‐Ar) (AlCl₄)₃ complexes indicates that the bond distance of La? C is shortened with the increasing of methyl group on benzene and with the decreasing of radius of lanthanide ions.     

Synthesis and Nucleophilic Addition Reactions of Tricarbonyl[η5‐2‐(phenylthio)hexadienyl]iron Hexafluorophosphate

3‐Phenylthio‐3‐sulfolene ( 1 ) was readily converted to a C‐5 substituted product 2 , which upon thermolysis and complexation with Fe₂(CO)₉ gave (η⁴‐diene)iron complexes 3a and 3b . Treatment of 3a and 3b with aq. HPF₆ and Ac₂O provided the title compound 5 , which reacted regio‐ and stereospecifically with some nucleophiles to give the addition products 3b and 7 .     

Synthesis,Crystal Structure and Properties of [Mn(hdpa)2(N(CN)2)2] and [Co(hdpa)2(N(CN)2)2] (hdpa = 2, 2'‐Dipyridylamine)

Two new transition metal(II) complexes [M(hdpa)₂(N(CN)₂)₂] (M = Mn ( 1 ), Co ( 2 ); hdpa = 2, 2'‐dipyridylamine) have been prepared and characterized structurally and magnetically. Both compounds crystallize in the monoclinic space group C2/c. 1 and 2 are isotypic with the unit cell parameters a = 8.634(9), b = 13.541(14), c = 21.99(2) Å, β = 94.806(18)°, and V = 2562(5) ų for 1 , a = 8.617(3) Å, b = 13.629(5)Å, c = 21.598(8)Å, β = 94.593(6)°, and V = 2528.4(15)ų for 2 , and Z = 4 for both. According to X‐ray crystallographic studies, each metal(II) ion was six‐coordinated with four nitrogen atoms from two bidentate hdpa ligand and two nitrogen atoms from two N(CN)^— anions to form slightly distorted octahedrons. Adjacent complex molecules are connected by hydrogen bonds or π···π interactions to form three‐dimensional network. The IR and UV spectroscopy were measured and the magnetic behaviors were investigated.     

The First Metal‐Carbon Bond β‐Isomer Paddlewheel Pd24+ Compounds

The first metal‐carbon bond β‐form paddlewheel complexes containing a Pd₂⁴⁺ core, [Pd(η²‐dithio)]₂(μ‐dppa)( μ‐SCNMe₂) (dithio = S₂P(OEt)₂, 2 ; S₂COEt, 3 ; S₂CNC₄H₈, 4 ), were prepared by the reactions of the α‐form paddlewheel‐type Pd₂⁺⁴ dipalladium complex [Pd₂ (μ‐Hdppa)₂(μ‐SCNMe₂)₂][Cl]₂, 1 with various dithio‐ligands, [NH₄][S₂P(OEt)₂], [K][S₂COEt] and [NH₄][S₂CNC₄H₈], in methanol at ambient temperature (Hdppa = bis(diphenylphosphino)amine). Electronic spectra and two X‐ray structures of the Pd₂⁺⁴ species have been determined.     

Synthesis of ferrocene‐containing N‐aryloxo β‐ketoiminate lanthanide complexes and polymerization of ε‐caprolactone

The synthesis, characterization and ε‐caprolactone polymerization behavior of lanthanide amido complexes stabilized by ferrocene‐containing N‐aryloxo functionalized β‐ketoiminate ligand FcCOCH₂C(Me)N(2‐HO‐5‐Bu^t‐C₆H₃) (LH₂, Fc = ferrocenyl) are described. The lanthanide amido complexes [LLnN(SiMe₃)₂(THF)]₂ [Ln = Nd ( 1 ), Sm ( 2 ), Yb ( 3 ), Y ( 4 )] were synthesized in good yields by the amine elimination reactions of LH₂ with Ln[N(SiMe₃)₂]₃(µ‐Cl)Li(THF)₃ in a 1:1 molar ratio in THF. These complexes were characterized by IR spectroscopy and elemental analysis, and ¹H NMR spectroscopy was added for the analysis of complex 4 . The definitive molecular structures of complexes 1 and 3 were determined by X‐ray diffraction studies. Complexes 1 – 4 can initiate the ring‐opening polymerization of ε‐caprolactone with moderate activity. Copyright © 2011 John Wiley & Sons, Ltd.     

Reaktionen des [η2-{P–PtBu2}Pt(PPh3)2] und [η2-{P–PtBu2}Pt(dppe)] mit Metallcarbonylen. Bildung von [η2-{(CO)5M · PPtBu2}Pt(PPh3)2] (M = Cr,W) und [η2-{(CO)5Cr · PPtBu2}Pt(dppe)]

Coordination Chemistry of P-rich Phosphanes and Silylphosphanes. XVI [1] Reactions of [g²-{P–P^tBu₂}Pt(PPh₃)₂] and [g²-{P–P^tBu₂}Pt(dppe)] with Metal Carbonyls. Formation of [g²-{(CO)₅M · PP^tBu₂}Pt(PPh₃)₂] (M = Cr, W) and [g²-{(CO)₅Cr · PP^tBu₂}Pt(dppe)] [η²-{P–P^tBu₂}Pt(PPh₃)₂] 4 reacts with M(CO)₅ · THF (M = Cr, W) by adding the M(CO)₅ group to the phosphinophosphinidene ligand yielding [η²-{(CO)₅Cr · PP^tBu₂}Pt(PPh₃)₂] 1 , or [η²-{(CO)₅W · PP^tBu₂}Pt(PPh₃)₂] 2 , respectively. Similarly, [η²-{P–P^tBu₂}Pt(dppe)] 5 yields [η²-{(CO)₅Cr · PP^tBu₂}Pt(dppe)] 3 . Compounds 1 , 2 and 3 are characterized by their ¹H- and ³¹P-NMR spectra, for 2 and 3 also crystal structure determinations were performed. 2 crystallizes in the monoclinic space group P2₁/n (no. 14) with a = 1422.7(1) pm, b = 1509.3(1) pm, c = 2262.4(2) pm, β = 103.669(9)°. 3 crystallizes in the triclinic space group P1 (no. 2) with a = 1064.55(9) pm, b = 1149.9(1) pm, c = 1693.2(1) pm, α = 88.020(8)°, β = 72.524(7)°, γ = 85.850(8)°.     

Photochemische Reaktionen von Cyclopentadienylbis(ethen)rhodium mit Phenanthren,Acenaphthylen und Triphenylen,sowie ungewöhnlicher H-Austausch zwischen η2-koordinierten Phenanthren- bzw. Acenaphthylen- und η5-Cyclopentadienyl-Liganden

Photochemical Reactions of Cyclopentadienylbis(ethene)rhodium with Phenanthrene, Acenaphthylene, and Triphenylene, and Unusual H Exchange between η²-Coordinated Phenanthrene or Acenaphthylene and η⁵-Cyclopentadienyl Ligands During UV irradiation of [CpRh(C₂H₄)₂] (Cp = η⁵-C₅H₅) in hexane/ether in the presence of phenanthrene one ethene ligand is displaced by coordination of the 9,10 double bond of phenanthrene, and (η⁵-cyclopentadienyl) (η²-ethene)(η²-9,10-phenanthrene)rhodium ( 1 ) is formed. The analogous reaction in hexane in the presence of acenaphthylene occurs with formation of the complexes (η²-1,2-acenaphthylene)(η⁵-cyclopentadienyl)(²-ethene)rhodium 2 and bis(η²-1,2-acenaphthylene)(η⁵-cyclopentadienyl)rhodium 3 in which one and two ethene molecules of [CpRh(C₂H₄)₂], respectively, are substituted by η²-1,2-acenaphthylene. The irradiation of [CpRh(C₂H₄)₂] with triphenylene in hexane yields the compounds [CpRh(η⁴-1,2,3,4-triphenylene)] ( 4 ), [(CpRh)₂(μ-η³: η³-triphenylene)] ( 5 ), and [(CpRh)₃(μ₃-η²: η²: η²-triphenylene)] ( 6 ). Despite the partially very low yields the new complexes could be unequivocally characterized spectroscopically and in the case of 1 and 3 by X-ray structural analysis. The compounds 1 and 2 in solution reveal a novel dynamic behaviour; via an intramolecular C? H activation, exchange occurs between the protons of the η²-coordinated arene and the Cp ligand. The complex 4 in solution is fluxional, too.     

2, 4‐Dimethylpenta‐1, 3‐dien‐ und 2, 4‐Dimethylpentadienyl‐Komplexe des Rhodiums und Iridiums

2, 4‐Dimethylpenta‐1, 3‐diene and 2, 4‐Dimethylpentadienyl Complexes of Rhodium and Iridium The complexes [(η⁴‐C₇H₁₂)RhCl]₂ ( 1 ) (C₇H₁₂ = 2, 4‐dimethylpenta‐1, 3‐diene) and [(η⁴‐C₇H₁₂)₂IrCl] ( 2 ) were obtained by interaction of C₇H₁₂ with [(η²‐C₂H₄)₂RhCl]₂ and [(η²‐cyclooctene)₂IrCl]₂, respectively. The reaction of 1 or 2 with CpTl (Cp = η⁵‐C₅H₅) yields the compounds [CpM(η⁴‐C₇H₁₂)] ( 3a : M = Rh; 3b : M = Ir). The hydride abstraction at the pentadiene ligand of 3a , b with Ph₃CBF₄ proceeds differently depending on the solvent. In acetone or THF the “half‐open” metallocenium complexes [CpM(η⁵‐C₇H₁₁)]BF₄ ( 4a : M = Rh; 4b : M = Ir) are obtained exclusively. In dichloromethane mixtures are produced which additionally contain the species [(η⁵‐C₇H₁₁)M(η⁵‐C₅H₄CPh₃)]BF₄ ( 5a : M = Rh; 5b : M = Ir) formed by electrophilic substitution at the Cp ring, as well as the η³‐2, 4‐dimethylpentenyl compound [(η³‐C₇H₁₃)Rh{η⁵‐C₅H₃(CPh₃)₂}]BF₄ ( 6 ). By interaction of 2, 4‐dimethylpentadienyl potassium with 1 or 2 the complexes [(η⁴‐C₇H₁₂)M(η⁵‐C₇H₁₁)] ( 7a : M = Rh; 7b : M = Ir) are generated which show dynamic behaviour in solution; however, attempts to synthesize the “open” metallocenium cations [(η⁵‐C₇H₁₁)₂M]⁺ by hydride abstraction from 7a , b failed. The new compounds were characterized by elemental analysis and spectroscopically, 4b and 5a also by X‐ray structure analysis.     

Synthesis and Crystal Structure of [(1‐(Phenyltriazenido)‐2‐(phenyltriazeno)benzene)(nitrato)mercury(II)], {Hg[PhN3C6H4N3(H)Ph](NO3)}, a Complex with Weak Metal‐Arene π‐Interactions

The reaction of PhN₃(H)C₆H₄N₃(H)Ph with Hg(NO₃)₂ in THF in the presence of triethylamine yields {Hg[PhN₃C₆H₄N₃(H)Ph](NO₃)} as a yellow powder that can be recrystallized from THF/acetone. The crystals belong to the monoclinic system, space group P2₁ with the cell dimensions a = 9.639(2), b = 5.412(1), c = 19.675(4) Å, β= 97.47(3)°, V = 1017.7 (4) ų, Z = 2. The crystal structure determination (2668 unique reflections with [I>2σ(I)], 262 parameters, R₁ = 0.0393) shows that the structure consists of mononuclear complexes. Hg atoms are linearly coordinated by one N_α atom of the triazenide unit of the planar ligand [Hg‐N(1) = 2.101(8) Å] and an O atom of the NO₃^— ion [Hg‐O(1) = 2.11(1) Å]. Additional weak Hg‐N contacts [Hg‐N(4) = 2.662(9) and Hg‐N(3) = 2.851(9) Å] and an intramolecular hydrogen bond between the triazenide hydrogen and an O atom of the nitrate group are observed [N(6)‐H(6)···O(2) = 2.92(2) Å]. The complexes are stacked to infinite chains by metal‐arene π‐interactions. Each Hg atom is coordinated by the terminal phenyl rings of two neighboring complexes [Hg‐C from 3.40(1) to 4.10(1) Å] in a η² fashion.     

Oxidation of Tricarbonyl (η1 η2-but-3-en-1-yl)iron(0)and Tricarbonyl (η3-allyl)iron(0) Anion Complexes with Dioxygen

The addition of reactive carbanions to tricarbonyl(η⁴-1,3-diene)iron(0) complexes proceeded at ?78 °C to give putative tricarbonyl(η¹,η²-but-3-en-1-y1)iron(0) anion complexes and at 25 °C to produce postulated tricarbonyl(η³-allyl)iron(O) anion complexes; trapping of reactive intermediates with dioxygen produced γ,δ-unsaturated acids and allylic alcohols, respectively.     

Synthesis,Reactivity and Crystal Structures of the Palladium(II) Complexes with the Pyrimidine Containing Ligand: Crystal Structures of [Pd(PPh3)(η1‐C4H3N2)(η2‐S2CNC4H8)] and [Pd(PPh3)(η1‐C4H3N2)(η2‐Tp)]

Treatment of Pd(PPh₃)₄ with 5‐bromo‐pyrimidine [C₄H₃N₂Br] in dichloromethane at ambient temperature cause the oxidative addition reaction to produce the palladium complex [Pd(PPh₃)₂(η¹‐C₄H₃N₂)(Br)], 1 , by substituting two triphenylphosphine ligands. In acetonitrile solution of 1 in refluxing temperature for 1 day, it do not undergo displacement of the triphenylphosphine ligand to form the dipalladium complex [Pd(PPh₃)Br]₂{μ,η²‐(η¹‐C₄H₃N₂)}₂, or bromide ligand to form chelating pyrimidine complex [Pd(PPh₃)₂(η²‐C₄H₃N₂)]Br. Complex 1 reacted with bidentate ligand, NH₄S₂CNC₄H₈, and tridentate ligand, KTp {Tp = tris(pyrazoyl‐1‐yl)borate}, to obtain the η²‐dithiocarbamate η¹‐pyrimidine complex [Pd(PPh₃)(η¹‐C₄H₃N₂)(η²‐S₂CNC₄H₈)], 4 and η²‐Tp η¹‐pyrimidine complex [Pd(PPh₃)(η¹‐C₄H₃N₂)(η²‐Tp)], 5 , respectively. Complexes 4 and 5 are characterized by X‐ray diffraction analyses.     

1D Polyoxometalate‐based Inorganic‐Organic Hybrid Derived from ß‐Octamolybdate — Synthesis and Crystal Structure of [CoII(2, 2′‐bipy)2]2[Mo8O26]

A polyoxometalate‐based inorganic–organic hybrid compound [Co^II(2, 2′‐bpy)₂]₂[Mo₈O₂₆] ( 1 ) was synthesized by hydrothermal methods and structurally characterized by IR spectrum, TG analysis and X‐ray diffraction. The compound crystallizes in the monoclinic system, space group P2₁/n, a = 10.0681(2), b = 16.4467(2), c = 15.7838(3) Å, β = 100.046(1)°, V = 2573.52(8) ų, Z = 2. The structure of 1 is built up from β‐[Mo₈O₂₆]^4? subunits covalently linked via [Co^II(2, 2′‐bpy)₂]²⁺ fragments into a infinite 1D {[Co^II(2, 2′‐bpy)₂]₂[Mo₈O₂₆]}_∞ polymer.     

Reactions of Cyclohexyl Isocyanide with η5‐Substituted Cyclo‐pentadienyl MoMo Triply Bonded Complexes. Crystal Structure of [Mo(CO)2(η5‐C5H4CO2CH3)]2(μ‐η2‐CNC6H11)

Reactions of one or two equiv. of cyclohexyl isocyanide in THF at room temperature with Mo?Mo triply bonded complexes [Mo(CO)₂(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) gave the isocyanide coordinated Mo? Mo singly bonded complexes with functionally substituted cyclopentadienyl ligands, [Mo(CO)₂(η⁵‐C₅H₄R)]₂(μ‐η²‐CNC₆H₁₁) ( 1a , R=COCH₃; 1b , R=CO₂CH₃) and [Mo(CO)₂(η⁵‐C₅H₄R)(CNC₆H₁₁)]₂ ( 2a , R=COCH₃; 2b , R=CO₂CH₃), respectively. Complexes 1a , 1b and 2a , 2b could be more conveniently prepared by thermal decarbonylation of Mo? Mo singly bonded complexes [Mo(CO)₃(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) in toluene at reflux, followed by treatment of the resulting Mo?Mo triply bonded complexes [Mo(CO)₂(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) in situ with cyclohexyl isocyanide. While 1a , 1b and 2a , 2b were characterized by elemental analysis and spectroscopy, 1b was further characterized by X‐ray crystallography.     

Chloro(η6‐p‐cymene)(phosphoramidite)ruthenium(II), a 16‐Electron Fragment Stabilized by an η2‐Aryl–Metal Interaction,and Its Use in Asymmetric Cyclopropanation

Chloride abstraction from the half‐sandwich complexes [RuCl₂(η⁶‐p‐cymene)(P*‐κP)] ( 2a : P* = (S_a,R,R)‐ 1a = (1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl bis[(1R)‐1‐phenylethyl)]phosphoramidite; 2b : P* = (S_a,R,R)‐ 1b = (1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl bis[(1R)‐(1‐(1‐naphthalen‐1‐yl)ethyl]phosphoramidite) with (Et₃O)[PF₆] or Tl[PF₆] gives the cationic, 18‐electron complexes dichloro(η⁶‐p‐cymene){(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl {(1R)‐1‐[(1,2‐η)‐phenyl]ethyl}[(1R)‐1‐phenylethyl]phosphoramidite‐κP}ruthenium(II) hexafluorophosphate ( 3a ) and [Ru(S)]‐dichloro(η⁶‐p‐cymene){(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl {(1R)‐1‐[(1,2‐η)‐naphthalen‐1‐yl]ethyl}[(1R)‐1‐(naphthalen‐1‐yl)ethyl]phosphoramidite‐κP)ruthenium(II) hexafluorophosphate ( 3b ), which feature the η²‐coordination of one aryl substituent of the phosphoramidite ligand, as indicated by ¹H‐, ¹³C‐, and ³¹P‐NMR spectroscopy and confirmed by an X‐ray study of 3b . Additionally, the dissociation of p‐cymene from 2a and 3a gives dichloro{(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl [(1R)‐(1‐(η⁶‐phenyl)ethyl][(1R)‐1‐phenylethyl]phosphoramidite‐κP)ruthenium(II) ( 4a ) and di‐μ‐chlorobis{(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl [(1R)‐1‐(η⁶‐phenyl)ethyl][(1R)‐1‐phenylethyl]phosphoramidite‐κP}diruthenium(II) bis(hexafluorophosphate) ( 5a ), respectively, in which one phenyl group of the N‐substituents is η⁶‐coordinated to the Ru‐center. Complexes 3a and 3b catalyze the asymmetric cyclopropanation of α‐methylstyrene with ethyl diazoacetate with up to 86 and 87% ee for the cis‐ and the trans‐isomers, respectively.     

Synthesis and Structure of Low‐valent η4‐Cinnamaldehyde Cobalt Complexes

Three η⁴‐(C=C–C=O) coordination cobalt(I) complexes 1 – 3 were synthesized by the reactions of cinnamaldehyde, p‐fluorocinnamaldehyde, and p‐chlorocinnamaldehyde with CoMe(PMe₃)₄. Complex 4 as η²‐(C=C) coordination was prepared by the reaction of chalcone with Co(PMe₃)₄. The structures of complexes 1 – 4 were confirmed by single‐crystal X‐ray diffraction. Although the reactions didn't undergo C–H bond activation and decarbonylation, the formation of complexes 1 – 4 deepens our understanding of the reactions between α,β‐unsaturated aldehyde or ketone with low‐valent central cobalt atom.     

The Nitrogen‐Assisted Triphenylphosphine Displacement of 3‐Hydroxypyridine and 3‐Aminopyridine Ligands in Palladium(II) Complexes: Crystal Structures of [Pd(PPh3)Br]2{μ,η2‐C5H3N(OH)}2 and [Pd(PPh3)Br]2{μ,η2‐C5H3N(NH2)}2

Treatment of Pd(PPh₃₎₄ with 2‐bromo‐3‐hydroxypyridine [C₅H₃N(OH)Br] and 3‐amino‐2‐bromopyridine [C₅H₃N(NH₂)Br] in dichloromethane at ambient temperature cause the oxidative addition reaction to produce the palladium complex [Pd(PPh₃₎₂{η¹‐C₅H₃N(OH)}(Br)], 2 and [Pd(PPh₃₎₂{η¹‐C₅H₃N(NH₂)}(Br)], 3 , by substituting two triphenylphosphine ligands, respectively. In dichloromethane solution of complexes 2 and 3 at ambient temperature for 3 days, it undergo displacement of the triphenylphosphine ligand to form the dipalladium complexes [Pd(PPh₃)Br]₂{μ,η²‐C₅H₃N(OH)}₂, 4 and [Pd(PPh₃)Br]₂{μ,η²‐C₅H₃N(NH₂)}₂, 5 , in which the two 3‐hydroxypyridine and 3‐aminopyridine ligands coordinated through carbon to one metal center and bridging the other metal through nitrogen atom, respectively. Complexes 4 and 5 are characterized by X‐ray diffraction analyses.     

Zum Einfluß der PR3‐Liganden auf Bildung und Eigenschaften der Phosphinophosphiniden‐Komplexe [{η2‐tBu2P–P}Pt(PR3)2] und [{η2‐tBu2P1–P2}Pt(P3R3)(P4R′3)]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes XXI The Influence of the PR₃ Ligands on Formation and Properties of the Phosphinophosphinidene Complexes [{η²‐^tBu₂P–P}Pt(PR₃)₂] and [{η²‐^tBu₂P¹–P²}Pt(P³R₃)(P⁴R′₃)] (R₃P)₂PtCl₂ and C₂H₄ yield the compounds [{η²‐C₂H₄}Pt(PR₃)₂] (PR₃ = PMe₃, PEt₃, PPhEt₂, PPh₂Et, PPh₂Me, PPh₂ⁱPr, PPh₂^tBu and P(p‐Tol)₃); which react with ^tBu₂P–P=PMe^tBu₂ to give the phosphinophosphinidene complexes [{η²‐^tBu₂P–P}Pt(PMe₃)₂], [{η²‐^tBu₂P–P}Pt(PEt₃)₂], [{η²‐^tBu₂P–P}Pt(PPhEt₂)₂], [{η²‐^tBu₂P–P}Pt(PPh₂Et)₂], [{η²‐^tBu₂P–P}Pt(PPh₂Me)₂], [{η²‐^tBu₂P–P}Pt(PPh₂ⁱPr], [{η²‐^tBu₂P–P}Pt(PPh₂^tBu)₂] and [{η²‐^tBu₂P–P}Pt(P(p‐Tol)₃)₂]. [{η²‐^tBu₂P–P}Pt(PPh₃)₂] reacts with PMe₃ and PEt₃ as well as with ^tBu₂PMe, PⁱPr₃ and P(c‐Hex)₃ by substituting one PPh₃ ligand to give [{η²‐^tBu₂P¹–P²}Pt(P³Me₃)(P⁴Ph₃)], [{η²‐^tBu₂P¹–P²}Pt(P³Ph₃)(P⁴Me₃)], [{η²‐^tBu₂P¹–P²}Pt(P³Et₃)(P⁴Ph₃)], [{η²‐^tBu₂P¹–P²}Pt(P³Me^tBu₂)(P⁴Ph₃)], [{η²‐^tBu₂P¹–P²}Pt(P³ⁱPr₃)(P⁴Ph₃)] and [{η²‐^tBu₂P¹–P²}Pt(P³(c‐Hex)₃)(P⁴Ph₃)]. With ^tBu₂PMe, [{η²‐^tBu₂P–P}Pt(P(p‐Tol)₃)₂] forms [{η²‐^tBu₂P¹–P²}Pt(P³Me^tBu₂)(P⁴(p‐Tol)₃)]. The NMR data of the compounds are given and discussed with respect to the influence of the PR₃ ligands.