C, N and Sn NMR spectral evidence for tin five-coordination in triorganotin(IV) oxinates

The ¹³C and ¹¹⁹Sn NMR spectra of tri(1-butyl)tin(IV) and triphenyltin(IV) oxinates and 1-naphthoxides in neat liquid and deuteriochloroform, pentadeuteriopyridine and hexamethylphosphortriamide solutions, and the ¹⁵N NMR spectra of both the oxinates and 8-methoxyquinoline in deuteriochloroform have been recorded. From the comparison of chemical shifts δ(¹³C), δ(¹⁵N) and δ(¹¹⁹Sn) and coupling constants ⁿJ(¹¹⁹Sn¹³C) of the compounds it is concluded that the triorganotin(IV) oxinates, both as the neat liquid and in solution, form complexes containing five-coordinate tin atoms. In the neat liquid and in deuteriochloroform (a non-coordinating solvent) oxinates form chelate complexes with a cis-trigonal bipyramid arrangement. In coordinating solvents (pentadeuteriopyridine, hexamethylphosphortriamide) these are equilibria involving the formation of small amounts of oxinate complexes with one solvent molecule. These complexes have trans-trigonal bipyramid geometry with butyl or phenyl groups in equatorial plane and the monodentate oxinate group and a solvent molecule in axial positions.     

Direkte und indirekte metallierung von endo-dicylopentadien. Sn- und C-NMR studie stannylierter folgeprodukte

endo-Dicyclopentadiene (1) can be metalated by use of simple procedures with good overall yields. The attack occurs at the various vinyl, rather than at the allyl, positions of 1 as was confirmed by trapping the carbanions with Me₃SnCl. When t-BuLi/TMEDA are used, the 8- and 9-stannyl derivatives (3 and 4) are formed, whereas an excess of n-BuLi/t-BuOK leads to doubly stannylated derivatives with Me₃Sn groups in position 4/8 (6), 4/9 (7), and 3/9 (8) in addition to 3 and 4. Furthermore the latter reaction yields 5,5-bis(trimethylstannyl)cyclopentadiene (5). With stoichiometric amounts of n-BuLi/t-BuOK the formation of 3 and 4 predominates over that of 5–8. 5 is obtained from 1 after deprotonation at the allyl position, followed by an extremely fast retro-Diels-Alder reaction and then by further deprotonation. This follows from two experiments: (1) exo- and endo-5-trimethylstannyl-endo-dicyclopentadiene (11 and 12) which are synthesized from 1 in three steps give cyclopentadienyllithium and 1 when treated with methyllithium at −78°C; (2) cyclopentadiene reacts with an excess of n-BuLi/t-BuOK and Me₃SnCl to give 5. When 12 is heated syn-10-trimethylstannyl-endo-dicyclopentadiene (13) is obtained. The eight stannyl derivatives of 1 are identified mainly from the following NMR parameters: δ(¹¹⁹Sn), δ(¹³C), δ(¹H), ⁿJ(^119/117Sn---¹³C), and ⁶J(¹¹⁹Sn---^119/117Sn). The ¹³C NMR satellite spectrum of 1 yields the isotope shifts ¹Δ¹³(i(¹³C(j)) and ¹J(¹³C---¹³C). The latter lead to the revision of earlier signal assignments.     

混合三烃基锡衍生物的研究(Ⅱ)─一丁基二环己基锡羧酸酯的合成、结构表征及生物活性

合成了21个混合三烃基锡羧酸酯。利用红外光谱、核磁共振谱(¹H,¹³C,¹¹⁹Sn)和质谱表征了化合物的结构。对取代苯甲酸酯化合物,锡原子的化学位移δ(¹¹⁹Sn)与苯环上取代基的Hammett常数有很好的线性关系。化合物的生物活性测定结果表明,它们具有高效杀螨活性。     

1,3,2-Diazastanna-[3]ferrocenophanes bearing alkyn-1-yl groups at tin and their 1,1-organoboration with triethylborane—molecular structure of a novel spirotin compound

2,2-Dichloro-1,3-bis(trimethylsilyl)-1,3,2-diazastanna-[3]ferrocenophane (3) reacts with lithium alkynides LiCCR¹ to give the corresponding di(alkyn-1-yl)tin derivatives 4a (R¹=^tBu) and 4b (R¹=SiMe₃). 1,1-Organoboration of 4 with triethylborane affords the spirotin compounds 5 which contain both a ferrocenophane and a stannacyclopentadiene ring. The crystal structure of 5b was determined by X-ray analysis. The compounds 4 and 5 were characterised in solution by multinuclear magnetic resonance (¹H-, ¹¹B-, ¹³C-, ¹⁵N-, ²⁹Si-, ¹¹⁹Sn-NMR), using pulsed field gradients in HMBC experiments for the ¹H detected ¹⁵N- and ¹¹⁹Sn-NMR signals. The compound 5b was also studied by solid-state ¹³C, ²⁹Si and ¹¹⁹Sn MAS NMR in order to correlate liquid and solid-state NMR data with the structural evidence.     

Organotin compounds : X. Organotin hydride addition to methyl cyclohexene-1-carboxylate and methyl indene-3-carboxylate

Free radical hydrostannation of methyl cyclohexene-1-carboxylate (I) and methyl indene-3-carboxylate (III) with trialkyltin hydrides, R₃SnH (R = Me, n-Bu, Ph) gives the energetically unfavourable cis products, 2-trialkylstannyl cyclohexanecarboxylate (II) and 2-trialkylstannyl indane-1-carboxylate (IV) in high yields, via a trans addition of the tin hydrides. The hydride abstractions by the intermediate trialkylstannylcyclohexanyl (VIII) and trialkylstannylindanyl (IX) intermediate radicals take place stereospecifically, and exclusively from the less hindered ring side. The structures of the isomers II and IV were established by (a) their transformation into the corresponding chlorodialkylstannyl derivatives V and VI, which were shown spectroscopically to have cis stereochemistries by intramolecular complexation of the ester group, and (b) their NMR data. Full ¹H, ¹³C, and ¹¹⁹Sn NMR data are given.     

New phosphabenzenes by [4 + 2] cycloaddition of stannoles to 1-phospha-1-alkynes — determination of signs of coupling constants [J(P, C), J(P, H), J(P, Si), J(Sn, P)]

Stannoles bearing dialkylboryl groups in 3-position react with 1-phospha-1-alkynes P≡C---^tBu (1) and P≡C---CH₂^tBu (2) by [4 + 2] cycloaddition and elimination of stannylene to give phosphabenzenes in high yield. The stannylenes oligomerise to give [R¹₂Sn]_n with n ≥ 7 (R --- Me, Et, -(CH₂)₅₋ or, in the case of R¹ = ^tBu, react with the stannole itself. All phosphabenzenes are characterized by their consistent sets of NMR data. The absolute signs of the coupling constants ⁿJ(³¹P, ¹H), ⁿJ(³¹P, ¹³C), ²J(³¹P, ²⁹Si) and ²J(¹¹⁹Sn, ³¹P) were determined by appropriate ID and 2D NMR experiments.     

Synthesis of bimetallic[Sn,A]-μ-oxoisopropoxyacetate and -μ-oxoisopropoxide and their acetylacetone and benzoylacetone derivatives

Bimetallic [Sn^IV,Al^III-μ-oxoisopropoxyacetate (Bu₂Sn(OAc)OAl(OⁱPr)₂] and bimetallic [Sn^IV,Al^III]-μ- oxoisopropoxide [Bu₂SnO₂Al₂(OⁱPr)₄] have been synthesized by thermal condensation of dibutyltin diacetate with aluminium isopropoxide in 1:1 and 1:2 molar ratio, respectively. Reactions of these compounds with acetylacetone and benzoylacetone in these molar ratios yielded compounds of the type [Bu₂Sn(OAc)OAl(OⁱPr)L], [Bu₂Sn(OAc)OAlL₂], [Bu₂SnO₂Al₂(OⁱPr)₃L] and [Bu₂SnO ₂Al₂(OⁱPr)₂L₂] (where L = acetylacetonate or benzoylacetonate anion). The μ-oxo compounds and their derivatives have been characterized by elemental analysis and spectroscopic techniques (IR, ¹H NMR, ¹³C NMR, ²⁷Al NMR and ¹¹⁹Sn NMR).     

Stereochemical non-rigidity of N-(dimethylhalogenosilylmethyl)-N-(1-phenylethyl) acetamides in solutions

The structure and dynamic behavior of (O-Si)-chelate N-(dimethylhalogenosilyl)methyl acetamides of the type MeC(O)N(CH(Ph)Me)CH₂ SiMe₂ X, where X = F, Cl, Br with the OSiC₃X coordination set, were studied by multinuclear (¹H, ¹³C, ¹⁷O, ²⁹Si) and dynamic ¹H NMR spectroscopy. Ligand permutation at silicon was detected. The observed influence of the solvent, nucleofugacity of the X substituent and the external nucleophile on the calculated values of the free energies of activation testify to the dissociative and/or associative mechanisms of the process, but including the stages in which the regular (pseudo-rotation or ‘turnstile’) mechanism takes place. At lower temperatures (up to −90°C) the ¹H, ¹³C, ²⁹Si NMR spectra of N-(dimethylchlorosilyl)methyl acetamide contain the signals of two species of unequal intensity. This effect was explained by an equilibrium between monomers containing the intramolecular O → Si bond and dimers with a hexacoordinate silicon and the bridging chlorine atoms.     

混合三烃基锡衍生物的研究(Ⅲ)──二丁基一环己基锡羧酸酯的合成、结构表征及生物活性

以丁基替换环己基,合成了20种二丁基一环己基锡羧酸酯。利用IR、NMR及元素分析表征了化合物的结构,确定了化合物的质谱裂解机制。对化合物进行了生物活性普筛试验。结果表明,这类化合物同时具有高效杀菌和杀螨活性。     

N, C and Sn NMR and other spectroscopic studies of 8-quinolinol, its O- and N-methyl derivatives, and chelate di- and tri-organotin(IV) complexes

The nature of the 8-quinolinato ligand in various forms has been examined by ¹⁵N, ¹³C and ¹¹⁹Sn NMR spectroscopy, with evidence also from electronic spectroscopy. These forms include 8-quinolinol (HQ), 8-quinolinate, the 8-hydroxyquinolinium ion, O- and N-methyl derivatives, 8-methoxyquinoline (MeQ), the zwitterionic N-methylquinolinium-8-olate and the N-methylquinolinium ion, and the chelating ligand in organotin(IV) complexes. The ¹⁵N shift from MeQ to HQ affords a measure of the intramolecular hydrogen bonding in HQ. The ¹⁵N shifts and ²J(¹⁵N¹H) couplings afford criteria of chelation, and the O- and N-methyl compounds provide useful reference points for its assessment. Evidence for chelation is demonstrated in three groups of compounds, [SnR₂Q₂] (R = Me, Et, Buⁿ, Octⁿ or Ph), [SnR₃Q] (R = Me, Et, Buⁿ or Ph) and [SnR₂ClQ] (R = Me, Et, Buⁿ or Octⁿ), the ¹⁵N and ¹¹⁹Sn shielding increasing from the [SnR₃Q] to the [SnR₂Q₂] compounds.     

The reaction of (μ-H)2Os3(CO)9(PPh3) with ethylene affords the ethylidene complex (μ-H)2Os3(CO)9(PPh3)(μ-CHCH3)

The product isolated from the reaction of (μ-H)₂Os₃(CO)₉(PPh₃) with ethylene is shown to be the ethylidene complex (μ-H)₂Os₃(CO)₉(PPh₃)(μ-CHCH₃) (1) rather than the ethylene complex (μ-H)(H)Os₃(CO)₉(PPh₃)(C₂H₄), as previously claimed. The characterization of 1 is based on a combination of ¹H and ¹³C NMR results. The ¹H NMR data (δ 6.84 (1 H_D), 2.53 (3 H_C), J(CD) = 7.4 Hz) establish the presence of the ethylidene moiety, whereas detailed analysis of the 1-D and 2-D ¹³C NMR spectra of ¹³CO-enriched 1 indicates the relative positions of the ethylidene, hydride, and phosphine ligands on the triosmium framework.     

C CP MAS NMR, FTIR, X-ray diffraction and PM3 studies of some N-(ω-carboxyalkyl)morpholine hydrohalides

N-(ω-carboxyalkyl)morpholine hydrochlorides, OC₄H₈N(CH₂)_nCOOH·HCl, n=1–5, were obtained and analyzed by ¹³C cross polarization (CP) magic angle spinning (MAS) NMR, FTIR and PM3 calculations. The structure of N-(3-carboxypropyl)morpholine hydrochloride (n=3) has been solved by X-ray diffraction method at 100 K and refined to the R=0.031. The crystals are monoclinic, space group P2₁/c, a=14.307(3), b=9.879(2), c=7.166(1) Å, β=93.20(3)°, V=1011.3(3) ų, Z=4. In this compound the nitrogen atom is protonated and two molecules form a centrosymmetric dimer, connected by two N⁺–HCl⁻ (3.095(1) Å) and two O–HCl⁻ (3.003(1) Å) hydrogen bonds. ¹³C CP MAS NMR spectra, contrary to the solution, showed non-equivalence of the ring carbon atoms. The PM3 calculations predict a molecular dimer without proton transfer for an HCl complex, while for an HBr complex an ion pairs with proton transfer, and reproduces correctly the conformation of both dimers but overestimates H-bond distances. Shielding constants calculated from the PM3 geometry of ion pairs gave a linear correlation with the ¹³C chemical shifts in solids.     

Studies on adducts of rhodium(II) tetraacetate and rhodium(II) tetratrifluoroacetate with some amines in CDCl3 solution using H, C and N NMR

¹H, ¹³C and ¹⁵N NMR spectroscopy has been applied for investigation of amine adducts with rhodium(II) tetraacetate dimer and rhodium(II) tetratrifluoroacetate dimer in CDCl₃ solution. Subsequent formation of two adducts, 1:1 and 2:1, was proved by NMR and VIS titration experiments, and by NMR measurements at reduced temperatures, from 233 to 273 K. The adduct formation shift, defined as Δδ=δ_adduct−δ_ligand and characterizing complexation reaction, varies from ca. 0 to +1.6 ppm for ¹H, from ca. −10 to +6 ppm for ¹³C and from −4.4 to −39 ppm for ¹⁵N NMR. Formation of N–Rh bond slows the inversiof on the nitrogen atom and generates, in the case of N-methyl-(1-phenylethyl)-amine, a nitrogenous chiral center in the molecule. VIS spectra of amine-dirhodium salt mixture contain two bands in the 532–597 nm spectral range, assigned to 1:1- and 2:1-adducts.     

Comparison of calculated DFT/B3LYP and experimental C and O NMR chemical shifts, ab initio HF/6-31G* optimised structures, and single crystal X-ray structures of some substituted methyl 5β-cholan-24-oates

Single crystal X-ray structures (monoclinic space group P2₁) for methyl 3-oxo-5β-cholan-24-oate and methyl 3,12-dioxo-5β-cholan-24-oate have been solved and compared with HF/6-31G* optimised structures. In the crystalline packings the side chains are connected with weak OC(sp³)HO-type of interactions between C25–H and C24–O–C25 and the keto ends with weak C(sp³)HO=C-type of interactions between C4–H and O=C3. The orientations of the side chains, which steric configurations are of great importance to the biological activity of the molecules, are compared with the experimental structure of methyl 3-hydroxy-5β-cholan-24-oate. Probable reasons for the observed differences are discussed. In addition, ¹³C and ¹⁷O NMR chemical shifts of methyl 3-oxo-5β-cholan-24-oate and methyl 3,12-dioxo-5β-cholan-24-oate as well as the epimeric methyl 3-hydroxy-5β-cholan-24-oate and methyl 3β-hydroxy-5β-cholan-24-oate have been calculated (DFT/B3LYP/6-311G*) and compared with the experimental values by linear regression analyses. In general, the correspondence between the theoretical and experimental parameters is good or excellent.     

Nuclear shielding calculations on the primary structure of the gellan polysaccharide

Ab initio, GIAO and IGLO, nuclear shielding calculations are performed on each of the four pyranose ring residues of the tetrasaccharide repeating unit in a single chain of the gellan polysaccharide, [→ 3)- -Glcp-(1 → 4)-β- -GlcpA-(1 → 4)-β- -Glcp-(1 → 4)-- -Rhap(1 _n. The results provide an insight into the effects of the changing primary molecular electronic structure on the calculated ¹³C, ¹⁷O and ¹H shieldings. In particular, the observed trends in the calculated isotropic (σⁱ) shielding values are rationalised withi the framework of the localised molecular orbital shielding contributions and Mulliken population analyses (MPA).     

Novel rearrangements of fused zwitterionic heterocyclic systems

(E)-2-Chlorodimethylstannyl-3-diethylboryl-2-pentene (1) reacts with the C-lithiated azoles 2 (derived from thiazole (2a), 4-methylthiazole (2b), 1,4-dimethylimidazole (2c), benzoxazole (2d) and benzthiazole (2e)) to eliminate LiCl, giving first mixtures containing compounds with either a coordinative N--- bond (3) or the zwitterionic isomer with an Sn---N bond (4), or both, and in some cases a rearranged product (5) with a 1,2,5-azastannaborole unit is also present. The zwitterionic compounds 4 tend to rearrange into the heterocycles 5 in which the heteroaromatic system is no longer present and two new C---C bonds, a new B---C and a new B---N bond are formed. The reactions were monitored by multinuclear NMR (¹H, ¹¹B, ¹³C, ¹⁴N and ¹¹⁹Sn NMR) which also served for the characterization of the final products. In the case of 5e, the molecular structure was determined by single-crystal X-ray analysis (monoclinic; space group P2₁/n; A=11.691(2), B=12.396(2), C=13.149(2) Å; β=93.41(2)°).     

桥连双(酮亚胺)和双(二酮亚胺)及其铝配合物的合成与催化活性

通过桥连双β-二酮类化合物与取代苯胺反应, 合成了5个新的桥连双(β-单酮亚胺)化合物(1~5)和2个新的桥连双(β-二酮亚胺)化合物(6,7), 它们与三甲基铝反应, 得到了相应的3个双(β-酮亚胺基)二铝配合物(8~10)和2个双(β-二酮亚胺基)二铝配合物(11,12). 采用核磁共振、 红外光谱和质谱等对这些化合物进行了表征, 通过X射线单晶衍射分析证实了铝配合物的结构, 并考察了这些铝配合物在ε-己内酯开环聚合反应中的催化活性.     

Synthesis of new N-substituted imidazolyl and 1H-1,2,4-triazolyl derivatives of (η-arene)(η-cyclopentadienyl)iron(II) salts

A series of new imidazolyl and 1H-1,2,4-triazolyl derivatives of (η⁶-arene)(η⁵cyclopentadienyl)iron(II) salts have been prepared by reaction of the corresponding chloroarene complexes with the sodium salts of the heterocycles. Good yields of N-substituted products were obtained in all cases under very mild conditions. In contrast to substitution by primary and secondary amines, both chlorines were displaced from [(η⁵-1,2-dichlorobenzene)(η⁵-Cp)Fe][PF₆], indicating electron withdrawal by the imidazolyl and triazolyl groups. Detailed ¹H and ¹³C NMR analysis confirmed this point. NOE difference spectra were used for ¹³C assignments, and evidence for conformational isomers in the 1,2-disubstituted complexes is presented.     

Some further studies of estertin compounds. crystal structures of [NEt4][MeO2CCH2CH2Sn(dmio)2] (dmio = 1,3-dithiole-2-one-4,5-dithiolato) and (MeO2CCH2CH2)2SnX2[X2 = I2, (NCS)2 or Cl, Br]

Estertn compounds, (MeO₂CCH₂CH₂)₂SnX₂ [X₂ = I₂ (2); X₂ = Br₂ (9); X₂ = Cl, Br (4)) or X₂ = (NCS)₂ (3)] have been obtained by halide exchange reactions of (MeO₂CCH₂CH₂)₂SnCl₂. Crystal structure determinations of 2–4 revealed chelating MeO₂CCH₂CH₂ units with distorted octahedral geometries at tin. The Sn---O bond lengths in the isothiocyanato complex, 3, are shorter [2.390(11) to 2.498(12), mean 2.439 Å], with the chelate bite angles, C---Sn---O, larger [74.3(7) to 78.2(6), mean 76.0°] than those in the halide analogues 2 and 4 [Sn---O = 2.519(2) to 2.541(8), mean 2.530 Å; C---Sn---O 72.8(3) to 73.9(4), mean 73.3°]. ¹H, ¹³C and ¹¹⁹Sn NMR and IR spectra of 2–4 and 9 were determined in CDCl₃ solution: the NMR spectra of (MeO₂CCH₂CH₂)₂SnX₂ show the following trends: (i) both δ¹H and δ¹³C, increase and (ii) both ²J (Sn---H) and ¹J(Sn---C) decrease in the sequence X₂ = (NCS)₂, Cl₂, ClBr, Br₂ and I₂. The MeO₂CCH₂CH₂ and dmio groups (dmio = 1,3-dithiole-2-one-4,5-dithiolato) are all chelating groups in (MeO₂CCH₂CH₂)₂Sn(dmio) (5). As shown by X-ray crystallography, the tin atom in the anion of solid [Q][MeO₂CCH₂CH₂Sn(dmio)₂] 6 (Q = NEt₄) forms 5 strong bonds [to C and the 4 thiolato S atoms, Sn---S 2.459(2) to 2.559(2) Å], arranged in a near trigonal bipyramidal array. There is an additional Intramolecular but weaker, interaction with the carbonyl oxygen atom [Sn---O = 3.111(5) Å]; v(C=O) = 1714 cm⁻¹ in solid 6 (Q = NEt₄). NMR spectra of 5 and 6 are also reported.     

Molecular motion and phase transition in perovskite-type (CH3)nNH4−nSnCl3 (n=1–4) studied by proton NMR spin–lattice relaxation

Powder X-ray diffraction, ¹¹⁹Sn NMR spectra, and ¹H NMR spin–lattice relaxation times, T₁, were measured for (CH₃)_nNH_4−nSnCl₃ (n=1–4). From the Rietveld analysis, it is shown that all four compounds crystallize into deformed perovskite-type structures at room temperature. The temperature dependence of ¹H T₁ was analyzed in terms of the CH₃ reorientation and other motions of the whole cation. Except for the phase transition in CH₃NH₃SnCl₃, which is from monoclinic to rhombohedral at 331 K, ¹H T₁ was continuously changed at other phase transitions in this compound as well as in the n=2–4 compounds, suggesting that the transitions are not caused by the change of the motional state of the cation but by an instability of the [SnCl₃]_nⁿ⁻ perovskite lattice.