Cleavage of the Fe-Fe Bond of(Me_2SiSiMe_2)[η~5-C_5H_4Fe(CO)_2]_2 with Na/Hg and Molecular Structure of the Ring-Opened Complex

The reaction of the title cyclic complex(1) with sodium amal-gam in THF resulted in the expected cleavage of the Fe--Febond to afford bis-sodium salt (Me_2SiSiMe_2) [η~5-C_5H_4Fe(CO)_2Na]_2 (4). The latter was not isolated and was used di-rectly to react with MeI, PhCH_2Cl, CH_3C(O)Cl, PhC(O)Cl,Cy_3SnCl (Cy=cyclohexyl) or Ph_3SnCl to afford correspondingring-opened derivatives (Me_2SiSiMe_2) [η~5-C_5H_4Fe(CO)_2R]_2[5, R=Me; 6, R=PhCH_2; 7, R=CH_3C(O); 8, R=PhC     

Synthesis and Crystal Structures of Three Ladder Distannoxane Dimers [（PhCH2）2（Cl）SnOSn（X）（CH2Ph）2]2（X=Cl,OMe,OEt）

Three distannoxane dimers[(PhCH2)2(Cl)SnOSn(X)(CH2Ph)2]2(X=Cl,OMe,OEt)were prepared by the hydrolytic reaction of (PhCH2)2SnCl2 with sodium alkoxides.The compounds are assigned tetranuclear distannoxane structures in solid state.which contain the so-called ladder arrangement with a central planar Sn2O2 four-membered ring.The endo-and exo-cyclic Sn atoms are both five-coordinate,and have distorted trigonal bipyramidal geometries.A variety of hydrolyses of(PhCH2)2SnCl2 were performed and these dimers were characterized by IR,^1H NMR spectroscopy and X-ray diffraction analysis.     

Synthesis and Structure of Mixed Distannoxane Dimers [ClR2SnOSnR2′Cl]2

Mixed distannoxane dimers [ClR2SnOSnR2′Cl]2 were synthesized by the reaction of R2SnO(R=Bu,Pr) and R2SnCl2(R=Me,Ph,Cy,Oct). The crystal structures of compound 1 and 5 show they are ladder-type dimers that contain a central planar Sn2O3 four-membered ring. Both endo-and exo-Sn atoms are five-coordinate.     

Theoretical Studies on the M-M Bonding in Complexes [M2Cl4L2] and [M2Cl7L]- （M = Mo, Re; L = Ph2Ppy, （Ph2P）2py）

The structures of complexes [MⅡ2Cl4L2] and [MⅢ2Cl7L]- (M = Mo, Re; L = Ph2Ppy, (Ph2P)2py) were calculated by using density functional theory (DFT) PBE0 method. Based on the optimized geometries, the natural bond orbital (NBO) analyses were carried out to study the nature of Re-Re and Mo-Mo bonds. The conclusions are as follows: the M-M distances in two-Ph2Ppy or (Ph2P)2py complexes [MⅡ2Cl4L2] are shorter than those in mono-Ph2Ppy or (Ph2P)2py complexes [MⅢ2Cl7L]- due to the double bridged N-C-P interactions. For singlet of all complexes, there is ReⅢ-ReⅢ or MoⅡ-MoⅡ quadruply bond in complex [Re2Cl7L]- or [Mo2Cl4L2], while only ReⅡ-ReⅡ or MoⅢ-MoⅢ triply bond in complex [Re2Cl4L2] or [Mo2Cl7L]-. The most stable spin state of 2 and 6, triplet, only contains triple ReⅢ-ReⅢ bond. Because the LPCl → BD*Re-Re delocalizations weaken the Re-Re bond, the distance of ReⅢ-ReⅢ quadruple bonds in [Re2Cl7L]- is slightly longer than that of ReⅡ-ReⅡ triple bonds in [Re2Cl4L2]. Moreover, due to the delocalizations from the lone pair electrons of the remaining P' atom to the M-M antibonding orbitals, the M-M distance in (Ph2P)2py complexes is slightly longer than that in Ph2Ppy complexes.     

A New Approach to the Asymmetric Reaction of the Chiron 5－L－Menthyloxy－2（5H）－furanones with Horner－Emmons Reagent

The asymmetric reaction of the chiron 2(5H )-furanones (4a-4c) with the Horner-Emmons reagents (5a-5b) has been investigated. The newly chirai organophosphorus derivatives 6 and 7 were obtained using the phosphoryl-stabilized carbanion as a building block in DMSO under mild conditions. Through the asymmetric introduction, the Horner-Emmons reagent could be transformed to a chiral building block to afford the novel functionalized phosphorus derivatives. The structures of the synthesized compounds 6 and 7 were identified on the basis of their elementary and spectroscopic data, such as IR,^1H NMR, ^13C NMR, MS and X-ray crystallography. These resuits provided a valuable approach to the synthesis of potentially interesting chirai organophosphorus derivatives and probing their biological activities.     

Syntheses and Anti—inflammatory Actiobn of （η—C5H5）2Ti （Cin）2 and （η—C5H5）2Ti（Tzea）2

Two new Complexes(Cp)2Ti(Cin)2and (CP2)Ti(Tzea)2(CP=Cyclopentadienyl η^5-C5H5)have been synthesized in THF by the reaction of HCin(Cincofen,2-phenylquinoline-4-carboxylic acid)or HTzea(5-phenyltetrazolyl-2-ethanoic acid)with(Cp)2TiCl2,and characterized by elemental analyses,IR,1H NMR and 13C NMR,UV spectra,molar conductivity,TGDTA.In the complexes the carboxyl groups are coordinated to Ti(IV)in a monodentate manner,The inhibitory actions of the complexes on mice ear tumefaction caused by croton oil and the rat foot granulation growth produced by cotton wool are higher than those of the corresponding ligands HCin,HTzea and [(Cp)2TiCl2],while their toxicities are lower than those of the free ligands.ηη     

A Facile Solid Phase Synthesis of 2—Alkylthio—4（1H）—quinolones

The resin-bound cyclic malonic acid ester 2 reacted with aryl isothiocyanate and alkyl halides to afford the key intermediate arylthioaminomethylene cyclic malonic ester resin 3.Subsequently,resin 3 proceeded thermal cyclizaiton giving the 2-alkylthio-4(1H)-quinolones in good yields and excellent purties.     

Synthesis and Thermal Rearrangement of Tetramethyldisilane-bridged Bis(cyclopentadienyl) Diiron Complexes with Bis(phosphine)Substitution

Photolysis of [Me2SiSiMe2)[C5H4Fe(CO2)]2with a series of bis(phosphine)ligands Ph2P(CH2)n PPh2(n=1-4) leads to the formation of the corresponding diiron complexes with intramolecular and intermolecular bis(phosphine) substitution.When these complexes were heated in refluxing xylene.only in the complexes with intermolecular bis(phosphine )substitution the thermal rearrangement reaction occurred.     

Synthesis,Crystal Structure of Cis—dioxo—catecholatotungsten（VI） Complex and Its NMR Studies on the Interaction with ATP

Cis-dioxo-catecholatotungsten(VI) complex anion[W^(VI)O2-(OC6H4O)2]^2- was obtained with discrete protonated ethylenediamine (NH2CH2CH2NH3)^ cations by the reaction of tetrabutyl ammonium decatungstate with catechol in the mixed solvent of CH3OH,CH3CN and ethylenediamine,and compared with its molybdenum anaogue [Mo^(V) O2(OC6H4O)2]^3- by crystal structure,UV,EPR,The results of the UV and EPR spectra show that tungsten is less redox active than molybdenum since the molybdenum is reduced from Mo(VI) to Mo(V) but tungsten stays in the original highest oxidized state Mo(VI) when they are crystallized from the solution above.It is worthy to note that [W^(VI)O2(OC6H4O)]^2- shows the same coordination structure as its molybdenum analogue in which the metal center exhibits distorted octahedral coordination geometry with two cis-dioxocatecholate ligands and might have the related coordination structure feature with the cofactor of flavoenzyme because [Mo^(V)O2(OC6H4O)2]^3- presented essentially the same EPR spectra as flavoenzyme.The NMR studies on the interaction of the title complex with ATP reveal that the reduction of W(VI) to W(V) occurs when the title complex is dissolved in D2O and the W(V) is oxidized again when ATP solution is mixed with original solution and the hydrolysis of the catecholato ligand take places at mean time being monitored by ^1H NMR and ^13C NMR spectra.     

Synthesis and Crystal Structure of the Diiron Azadithiolate Complex [（μ-SCH_2）_2NPh]Fe_2（CO）5（Ph_2PCH_2PPh_2）

Reaction of [(μ-SCH2)2NPh]Fe2(CO)6 with Ph2PCH2PPh2 in the presence of Me3NO·2H2O gave the title complex [(μ-SCH2)2NPh]Fe2(CO)5(Ph2PCH2PPh2)(1)in 78% yield.The new complex 1 was characterized by elemental analysis,spectroscopy and X-ray crys-tallography.It crystallizes in triclinic,space group P1 with a = 10.832(2),b = 12.003(2),c = 15.579(3),V = 1785.6(6)3,Z = 2,C32H26Fe2NO5PS2,Mr = 819.40,Dc = 1.524 g/cm3,μ(MoKα)= 1.064 mm-1,F(000)= 840,T = 113(2)K,the final R = 0.0543 and wR = 0.1218 for 6203 observed reflections(I > 2σ(I)).The Ph2PCH2PPh2 ligand resides in an axial position of the square-pyramidal coordination sphere of the Fe atom and trans to the benzene ring in order to reduce the steric repulsion between Ph2PCH2PPh2 and the benzene ring.     

Chloro­(μ‐6‐methyl­pyridine‐2‐carboxyl­ato)bis­(6‐methyl­pyridine‐2‐carboxyl­ato)triphenyl­chromium(III)­tin(IV) chloro­triphenyl­tin(IV)

The title compound, [CrSn(C₆H₅)₃(C₇H₆NO₂)₃Cl][Sn(C₆H₅)₃Cl(CH₄O)], was obtained from the reaction of Ph₃SnCl with the complex [Cr(C₇H₆NO₂)₃] in methanol. The structure contains [Ph₃SnCl(MeOH)] (A) and [Ph₃SnClCr(C₇H₆NO₂)₃] (B) mol­ecules. In mol­ecule A, the Sn atom of Ph₃SnCl is coordinated by one methanol mol­ecule. In mol­ecule B, the Sn atom of Ph₃SnCl is coordinated by one carboxyl­ate O atom of [Cr(C₇H₆NO₂)₃]. Mol­ecules A and B are connected through an O—H⋯O hydrogen bond between a carboxyl­ate O atom and the methanol OH group. Weak C—H⋯Cl inter­actions and O—H⋯O hydrogen bonds extend the components of (I) into a two‐dimensional network.     

Organopolysilane oligomers bearing transition-metal moieties: Synthesis, reactivities and molecular structure of [η-Me3SiMe2SiC5H4(CO)Fe(CO)2Fe(CO)-η-C5H4SiMe2SiME3]

Reaction of Me₃SiMe₂SiC₅H₅ (4), prepared from Me₃SiMe₂SiCl and C₅H₅Na, with Fe(CO)₅ in refluxing xylene afforded the title compound (3). The silicon-silicon bond in 3 is exceptionally stable in refluxing xylene and also in succeeding reactions to prepare a series of its derivatives. Thus, 3 reacted with I₂ in either chloroform or benzene, giving [η⁵-Me₃SiMe₂SiC₅H₄Fe(CO)₂I] (6). Compound 3 was reduced by sodium amalgam and reacted subsequently with CH₃I, PhCH₂Cl, CH₃COCl, PhCOCl, Cy₃SnCl (Cy = cyclohexyl) and Ph₃SnCl, producing [η⁵-Me₃SiMe₂SiC₅H₄Fe(CO)₂R][7 : R = CH₃ (a), PhCH₂ (b), CH₃CO (c), PhCO (d), Cy₃Sn (e) and Ph₃Sn (f), respectively]. The molecular structure of 3 has been determined by X-ray diffraction crystallography. It was found that 3 has a trans-configuration with a symmetrical centre located at the middle of the FeFe bond. It is abnormal that the conformation of the disilane part around the SiSi bond is almost eclipsed rather than staggered.     

Syntheses,characterizations, and crystal structures of organotin(IV) chloride complexes with 4,4′‐bipyridine

The organotin(IV) chlorides R_nSnCl_4−n (n = 3, R = Ph, PhCH₂, n−Bu; and n =2, R = n−Bu, Ph, PhCH₂) react with 4,4′‐bipyridine (4′4‐bpy) to give [(Ph₃SnCl)₂(4,4′‐bpy)_1.5(C₆H₆)_0.5] ( 1 ), [(PhCH₂)₃‐ SnCl]₂ (4,4′‐bpy) ( 2 ), [(n−Bu)₃SnCl]₂(4,4′‐bpy) ( 3 ), [(n−Bu)₂SnCl₂(4,4′‐bpy)] ( 4 ), [Ph₂SnCl₂(4,4′‐bpy)] ( 5 ), and [(PhCH₂)₂SnCl₂(4,4′‐bpy)] ( 6 ). The new complexes have been characterized by elemental analyses, IR, ¹H, ¹³C, ¹¹⁹Sn NMR spectroscopy. The structures of ( 1 ), ( 2 ), ( 4 ), and ( 6 ) have been determined by X‐ray crystallography. Crystal structures of ( 1 ) and ( 2 ) show that the coordination number of tin is five. In complex ( 1 ), two different molecules exist: one is a binuclear molecule bridged by 4,4′‐bpy and another is a mononuclear one, only one N of 4,4′‐bpy coordinate to tin. Complex ( 2 ) contains an infinite 1‐D polymeric binuclear chain by weak Sn…Cl intermolecular interactions with neighboring molecules. In the complexes ( 4 ) and ( 6 ), the tin is six‐coordinate, and the 4,4′‐bpy moieties bridge adjacent dialkyltin(IV)dichloride molecules to form a linear chain. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:338–346, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20016     

Synthesis,properties and crystal structural characterization of diorganotin(IV) derivatives of 2‐mercapto‐6‐nitrobenzothiazole

The diorganotin(IV) dichlorides R₂SnCl₂ (R: Ph, PhCH₂ or n‐Bu) react with 2‐mercapto‐6‐nitrobenzothiazole (MNBT) in benzene to give [Ph₂SnCl(MNBT)] ( 1 ), [(PhCH₂)₂Sn(MNBT)₂] ( 2 ) and [(n‐Bu)₂Sn(MNBT)₂] ( 3 ). The three complexes have been characterized by elemental analysis and IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopies. X‐ray studies of the crystal structures of 1 , 2 and 3 show the following. The tin environment for complex 1 is distorted cis‐trigonal bipyramid with chlorine and nitrogen atoms in apical positions. The structure of complex 2 is a distorted octahedron with two benzyl groups in the axial sites. The geometry at the tin atom of complex 3 is that of an irregular octahedron. Interestingly, intra‐molecular non‐bonded Cl…S interactions and S…S interaction were recognized in the crystallographic structures of 1 and 3 respectively. As a result, complex 1 is a polymer and complex 3 is a dimer. Copyright © 2003 John Wiley & Sons, Ltd.     

Coordination chemistry of organometallic polydentate ligand Reactive chemistry of the tridentate ligand trans‐Fe(Ph2PQu‐P)2‐(CO)3 [PhzPQu=2‐diphenyl‐phosphino‐4‐methylquinoline] and molecular structure of [Fe(CO)3(μ‐Ph2PQu)2HgI]+ [HgI3]

Reaction of a new type of bidentate ligand PhPQu [PhPQu = 2‐diphenylphosphino‐4‐methylquinoline] with Fe(CO)₅ in butanol gave trans‐Fe(FpPQu‐P)(CO)₃ (1). Compound 1, which can act as a neutral tridentate organometallic ligand, was reacted with I B, II B metal compounds and a rhodium complex to give six binuclear complexes with Fe? M bonds, Fe(CO)₃ (μ‐Ph₂PQu)MX_n (2–7) [M= Zn(II), Cd(II), Hg(II), Cu(I), Ag(I), Rh(I)], and an ion‐pair complex [Fe(CO)₃ (μ‐Ph₂PQu)₂HgI][HgI₃]^? (8). The structure of 8 was determined by X‐ray crystallography. Complex 8 crystallizes in the space group P‐1 with a = 1.0758(3), b = 1.6210(4), c=1.7155(4)nm; a=75.60(2), β=71.81(2), γ=81.78(2)° and Z = 2 and its structure was refined to give agreement factors of R=0.050 and R_w = 0.057. The Fe‐Hg bond distance is 0.2536nm.     

Organtin complexes of 2,5‐dithiobiurea (H2dtbu): The crystal structures of (Ph3Sn)2(dtbu) and [(n‐Bu)2SnCl]2(dtbu)

A series of organotin(IV) complexes of two types, [R₃Sn]₂(dtbu) (R = PhCH₂ 1 , Ph 2 , n‐Bu 3 , H₂dtbu = 2,5‐dithiobiurea), [R₂SnCl]₂(dtbu) (R = PhCH₂ 4 , Ph 5 , n‐Bu 6 ) have been synthesized and characterized by elemental analysis, IR, and NMR (¹H, ¹¹⁹Sn) spectroscopy. The structures of 2 and 6 have been determined by X‐ray crystallography. Crystal structures show that both complexes 2 and 6 are the symmetric dinuclear unit. Interestingly, supramolecular structures show that complex 2 has formed a linear chain through N H⋅⋅⋅S hydrogen bonding and 6 has formed a two‐dimensional network in perfect bc plane connected through N H⋅⋅⋅Cl hydrogen bonding and nonbonded S⋅⋅⋅S interactions. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:435–442, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20456     

Oxorhenium(V) Complexes with 1,3,4‐Triphenyl‐1,2,4‐triazol‐5‐ylidene

Reactions of the oxorhenium(V) complexes [ReOX₃(PPh₃)₂] (X = Cl, Br) with the N‐heterocyclic carbene (NHC) 1,3,4‐triphenyl‐1,2,4‐triazol‐5‐ylidene (L^Ph) under mild conditions and in the presence of MeOH or water give [ReOX₂(Y)(PPh₃)(L^Ph)] complexes (X = Cl, Br; Y = OMe, OH). Attempted reactions of the carbene precursor 5‐methoxy‐1,3,4‐triphenyl‐4,5‐dihydro‐1H‐1,2,4‐triazole ( 1 ) with [ReOCl₃(PPh₃)₂] or [NBu₄][ReOCl₄] in boiling xylene resulted in protonation of the intermediately formed carbene and decomposition products such as [HL^Ph][ReOCl₄(OPPh₃)], [HL^Ph][ReOCl₄(OH₂)] or [HL^Ph][ReO₄] were isolated. The neutral [ReOX₂(Y)(PPh₃)(HL^Ph)] complexes are purple, airstable solids. The bulky NHC ligands coordinate monodentate and in cis‐position to PPh₃. The relatively long Re–C bond lengths of approximate 2.1Å indicate metal‐carbon single bonds.     

(6‐Oxido‐2‐oxo‐1,2‐dihydropyrimidine‐5‐carboxylato‐κ2O5,O6)bis[2‐(2‐pyridyl)‐1H‐benzimidazole‐κ2N2,N3]manganese(II) monohydrate

In the title compound, [Mn(C₅H₂N₂O₄)(C₁₂H₉N₃)₂]·H₂O, the Mn^II centre is surrounded by three bidentate chelating ligands, namely, one 6‐oxido‐2‐oxo‐1,2‐dihydropyrimidine‐5‐carboxylate (or uracil‐5‐carboxylate, Huca²⁻) ligand [Mn—O = 2.136 (2) and 2.156 (3) Å] and two 2‐(2‐pyridyl)‐1H‐benzimidazole (Hpybim) ligands [Mn—N = 2.213 (3)–2.331 (3) Å], and it displays a severely distorted octahedral geometry, with cis angles ranging from 73.05 (10) to 105.77 (10)°. Intermolecular N—H...O hydrogen bonds both between the Hpybim and the Huca²⁻ ligands and between the Huca²⁻ ligands link the molecules into infinite chains. The lattice water molecule acts as a hydrogen‐bond donor to form double O...H—O—H...O hydrogen bonds with the Huca²⁻ O atoms, crosslinking the chains to afford an infinite two‐dimensional sheet; a third hydrogen bond (N—H...O) formed by the water molecule as a hydrogen‐bond acceptor and a Hpybim N atom further links these sheets to yield a three‐dimensional supramolecular framework. Possible partial π–π stacking interactions involving the Hpybim rings are also observed in the crystal structure.     

Reactions at the Boron‐Carbon Double Bond of Methyl(methylidene)boranes

The addition of Lewis bases L to the methyl(methylidene)boranes MeB=CA₂(A = SiMe₃) and MeB=CAA′ (A′ = SiMe₂Cl) gives the adducts MeB(L)=CA₂ ( 1a , b ; L = trimethylpyridine, PMe₃) and MeB(L)=CAA′ ( 1c , d ; L = di‐ and trimethylpyridine), respectively. Alcohols and amines HX are added to the BC double bond to give boranes MeB(X)—CHA₂ ( 8a — c ; X = OiPr, OtBu, NiPr₂); MeB=CAA′ and HNMe₂ react in the ratio 1:2, yielding MeB(X)—CHA(SiMe₂X) ( 2d ; X = NMe₂). From MeB=CA₂ and BH₃, the five‐membered ring [—CA₂—BH—CA₂—BMe(Hm)₂BMe—] ( 2e ; 2:1) or the six‐membered ring [—CA₂—BH(H_μ)₂BMe—CA₂—BH(H_μ)₂BMe—] ( 2f ; 1:1) are formed, both containing double hydrogen bridges; the product 2f crystallizes in the space group P1¯. The metallocene trihydrides [Cp₂MH₃] add to the BC double bond under formation of a double hydrogen bridge to give [Me(A₂CH)B(H_μ)₂MCp₂] ( 2g , h ; M = Nb, Ta). MeB=CA₂ can be chloroborated, ‐stannated, and ‐phosphated with E—Cl to yield the boryldisilylmethanes MeB(Cl)—CA₂—E ( 2i — l ; E = EtClB, tBuClB, Me₂ClSn, Cl₂P). The alkyloboration and ‐alumination with E—R leads to the boryldisilylmethanes MeBR—SiA₂—E ( 2m — o ; E—R = Me₂B—Me, Et₂B—Et, Cl₂Al—Et) and the bromination to MeB(Br)—CA₂Br. (2+2) Cycloadditions are achieved, when MeB=CA₂ is reacted with unsaturated molecules a=b, yielding four‐membered rings [—BMe—CA₂—b—a—] [ 4a — d ; a=b = fluorenone, bis(methoxycarbonyl)ethyne (reacting at both of the C=O bonds), phenylisocyanate (reacting at the C=O bond), N‐isopropylacetoneimine], or with triple bond systems RC≡Z, yielding four‐membered rings [—BMe—CA₂—Z=CR—] ( 4e — g ; RC≡Z = PhC≡CPh, AC≡CCl, tBuC≡P). With a series of six molecules with an element‐oxygen double bond, a primary (2+2) cycloaddition is followed by a metathetical splitting of the transient four‐membered rings 4h — m . One of the metathesis products is MeB≡O, which is identified as boroxene (MeBO)₃, the other component is an alkene RR′C=CA₂ [starting from MeB=CA₂ and PhCHO, PhC(Me)O] or an alkene RR′C=CAA′ (starting from MeB=CAA′ and PhCHO, tBuCHO) or the methylidene phosphorane Ph₃P=CA₂ (starting from MeB=CA₂ and Ph₃PO) or the dicarbadicobaltatetrahedrane [(CA)₂{Co(CO)₃}₂] {starting from MeB=CA₂ and [Co₂(CO)₈]}. The (2+3) cyclodaddition of MeB=CA₂ to the azide X₂PN₃ (X = NiPr₂) as 1, 3‐dipole gives the five‐membered ring [=BMe—CA₂—N=N—NX=] ( 5a ) and to RN₃ the rings [=BMe—CA=N—NA—NR=] ( 5′b , c ; R = iBu, A; formed from the cycloadducts 5b , c by migration of A); analogously, [=BMe—CA′=N—NA—NA=] ( 5′d ) is formed from MeB=CAA′ and AN₃. Finally, the nitrone O—NMe=CHPh and MeB=CA₂ or MeB=CAA′ give the corresponding (2+3) cycloadducts 5e , f , respectively. All of the products were characterized by their ¹H, ¹¹B, and ¹³C NMR spectra.     

5‐n‐Butylpyridine‐2‐carboxylate–copper(II) and –iron(III) complexes

In trans‐bis(5‐n‐butyl­pyridine‐2‐carboxyl­ato‐κ²N,O)­bis­(methanol‐κO)copper(II), [Cu(C₁₀H₁₂NO₂)₂(CH₄O)₂], the Cu atom lies on a centre of symmetry and has a distorted octahedral coordination. The Cu—O(methanol) bond length in the axial direction is 2.596 (3) Å, which is much longer than the Cu—­O(carboxylate) and Cu—N distances in the equatorial plane [1.952 (2) and 1.977 (2) Å, respectively]. In mer‐tris(5‐n‐bu­tyl­pyridine‐2‐carboxyl­ato‐κ²N,O)­iron(III), [Fe(C₁₀H₁₂NO₂)₃], the Fe atom also has a distorted octahedral geometry, with Fe—O and Fe—N bond‐length ranges of 1.949 (4)–1.970 (4) and 2.116 (5)–2.161 (5) Å, respectively. Both crystals are stabilized by stacking interactions of the 5‐n‐butyl­pyridine‐2‐carboxyl­ate ligand, although hydrogen bonds also contribute to the stabilization of the copper(II) complex.