摘要:
J. CHEM. SOC. DALTON TRANS. 1990 3235Preparation and X-Ray Crystal Structure of a Vanadium(ii1) Complex ofSal icylaldehyde Hydrarone f rom Vanad ium-Schiff Base PrecursorstDavid L. Hughes, G. Jeffery Leigh,* and J. Roger SandersA. F. R. C. Institute of Plant Science Research, Nitrogen Fixation Laboratory, University of Sussex, BrightonBN I 9RQTreatment of [V( NH,NH Ph),(salen)] I, [VO(salen)] [salen = N,N'-ethylenebis(salicylideneiminate)],or a mixture of [VCl,(thf ),I (thf = tetrahydrofuran) and salicylaldehyde with anhydrous hydrazineunder various conditions gives [V(OC,H,CH NNH,),], tris(salicyla1dehyde hydrazonato)vanadium(iii),of which the crystal structure is described.We have been attempting to prepare hydrazine derivatives ofvanadium-containing Schiff-base complexes as models forintermediates in the reduction of N2 by vanadium-basednitrogenase,' and have reported the preparation and struc-ture of a bisbhenylhydrazine) compound of vanadium(m),[V(NH,NHPh),(salen)]I [salen = NJV"'ethylenebis(salicy1-ideneiminate)(2 -)I.The present report gives the results of ourattempts to replace the phenylhydrazine ligands in thiscompound by hydrazine.ResultsTreatment of [V(NH,NHPh),(salen)]I with an excess ofanhydrous hydrazine in methanol at + 20 "C gives a solutionwhich slowly deposits red crystals over a number of days.The magnetic susceptibility of these crystals (2.90 pe) ischaracteristic of a vanadium(1n) compound, and their micro-analysis and i.r. spectra suggest that they contain hydrazine[strong bands characteristic of v(N-H) at 3360,3310, and 3170cm-'1.They are almost insoluble in common organic solventsbut react with non-co-ordinating acids such as HBF,*Et,O togive salicylaldehyde mine (salazine, HOC6H4CH"CHC6-H,OH), consistent with their formulation as a complexcontaining salazine and hydrazine rather than salen(2 -).We subsequently found that red crystals with the sameanalysis and i.r. spectrum are formed when [VO(salen)] issubjected to prolonged heating with an excess of hydrazinein acetonitrile-methanol under reflux, or when [VCl,(thf),](thf = tetrahydrofuran) is treated at 20°C in methanol withsalicylaldehyde, salicylaldehyde hydrazone, or salazine, and anexcess of hydrazine. Similar compounds can be made from[VCl,(thf),] by treatment with 3-methoxysalicylaldehyde or5-bromosalicylaldehyde and an excess of hydrazine.These newsyntheses established that the red crystals do not contain eitherphenylhydrazine (from the original starting material) orethylenediamine (from breaking up of salen ligands).We were unable to rationalise a structure on the basis of thered crystals containing only vanadium, salazine, and hydrazine,so we subjected selected crystals to X-ray analysis that revealedthem to be tris(salicyla1dehyde hydrazonato)vanadium(m).The bands in the 3400-3100 cm-' region of the i.r. spectrum ofthe crystals may thus be assigned to v(N-H) in the hydrazonateligands.Description of the Structure of [V(C7H7N,0),].-In thecomplex molecule, three chelating hydrazone ligands surroundthe V atom in a propeller-like arrangement.The pseudo-three-fold symmetry of these ligands is, however, spoilt, since one ofthe ligands is bound in the opposite direction to the other twoFigure. View of a molecule of [V(C,H,N,O),]. The atom names in oneligand are shown; the other ligands are labelled similarly. Hydrogenbonds, intra- and inter-molecular, are indicated with thinner bonds.Roman superscripts denote symmetry relations which are defined inTable 2(Figure). The resulting co-ordination about the vanadium atomhas distorted-octahedral geometry, with the V-0 and V-Ndistances showing rather wide ranges of values. The shortestV-0 distance is opposite the longest V-N distance, a mild transeffect; in the other trans pairs, N(9b) is opposite N(9c), andO(1a) opposes O(1b).The mean dimensions, V-0 1.939(6) andV-N 2.14(3) A, are somewhat longer than those found in anothervanadium(u1) complex [V(NH,NHPh),(salen)]I, where V-0was 1.881(3) and V-N 2.082(5) A;' the effects of hydrogenbonding, both intra- and inter-molecular (see below), may be thecause of the lengthened bonds in the present structure.There are also significant variations in the dimensions inthe hydrazone ligands, probably resulting from inadequacies inthe diffraction data. The mean values from the three ligandsappear normal, e.g. 0(1)-C(2) 1.323(1 l), C(8)-N(9) 1.278(5),N(9)-N(10) 1.410(3) A, C(7)-C(8)-N(9) 126.0(6) and C(8)-The striking feature in this structure is the hydrogen bonding.The two hydrogen atoms of each NH, group were located andN(9)-N(10) 115.9(3)".t Supplementary data available: see Instructions for Authors, J.Chem.SOC., Dalton Trans., 1990, Issue 1 , pp. xix-xxii3236 J. CHEM. SOC. DALTON TRANS. 1990Table 1. Final atomic co-ordinates (fractional x lo4) for [V(C7H7-N20)J with estimated standard deviations (e.s.d.s) in parenthesesX2 203(2)2 678(6)2 115(10)2 866( 11)2 286( 14)952( 14)241 (1 2)792( 1 1)266(7)-89(10)- 800( 8)-391(83)- 1 603(79)1519(6)2 085(9)1646(10)2 173(12)3 115(12)3 543(10)3 053(9)3 501(9)3 223(7)3 592(8)3 728(77)4 455( 107)3 884(5)4 250( 10)5 609( 10)6 006( 10)5 lOl(12)3 751(11)3 292(9)1 844(10)1228(8)- 208( 10)- 775(67)- 492(68)Y3 054(2)4 314(6)5 107(10)5 942( 11)6 804( 12)6 924( 13)6 159(11)5 266(10)4 460( 10)3 665(8)2 922(8)2 691(84)3 496(77)2 108(6)2 240( 10)1 173(11)1291(12)2 461(14)3 521(11)3 434( 10)4 665( 10)4 757(8)6 086(8)5 968(78)6 810(109)2 456(6)1 514(9)1 424( 10)494( 1 1)- 427( 1 1)- 380( 10)585(9)524(10)1 330(7)1 057(11)1 357(66)23 8( 70)Z4 315(2)2 601(6)1 776(11)601(10)- 256( 11)40( 12)1189(11)2 066( 10)3 283(11)4 237(8)5 253(9)6 164(87)5 453(71)6 138(6)7 247(9)8 362( 10)9 566( 1 1)9 686( 11)8 599(10)7 353(10)6 316(11)5 123(9)4 295(9)3 390(78)4 399(95)4 279(6)3 729(9)3 697(8)3 150(10)2 586(9)2 614(9)3 183(8)3 203(9)3 639(7)3 541(9)4 235(65)3 647(62)refined, and all are involved in hydrogen bonds.In each NH,group, H( 10) forms an intramolecular bond which, in each case,connects the chelating ligand with the meridionally co-ordinated group in the complex, e.g. the hydrogen bond N( 10a)-H( 10a) O( 1 b) completes the nearly planar, meridionalarrangement of O(la), N(9a), and O(1b). The three ligands arethus bound tightly together within the molecule.Atom H( 1 1) of each NH, group forms a hydrogen bond withan 0 or N atom of a neighbouring molecule; such bonds areformed in pairs, related by centres of symmetry, resultingin strong intermolecular interactions. Extensive sheets ofhydrogen-bonded molecules are thus formed, corresponding tothe flat, plane, shape of the crystal.Interactions between sheetsare at normal van der Waals distances.Discussion and ConclusionsIn the presence of hydrazine there is an equilibrium betweenaldehydes, RCHO, and their hydrazones, RCHNNH,, andazines, RCHNNCHR. It was found that if a 1 : 1 stoicheiometricratio of hydrazine to aldehyde, or a 2: 1 stoicheiometric ratio ofhydrazine to V(salen) complex, was used in the preparationsdescribed here, salazine rather than salicylaldehyde hydrazonewas produced; similarly, salazine rather than salicylaldehydehydrazone was produced by acid decomposition of tris(salicy1-aldehyde hydrazonato)vanadium(IIr). Therefore a large excessof hydrazine, which produces a cation to balance halide ionsderived from [V(NH,NHPh),(salen)]I or [VCl,(thf),], wasused in the preparations. It was found that salazine does notligate to vanadium when treated with VOSO, or [VCl,(thf),] inthe absence of hydrazine.The results show that hydrazine under sufficiently vigorousconditions is able to break up Schiff bases such as H,salen (evenwhen co-ordinated) by substituting an =NNH, or =N-N=group for the central =NCH2CH2N= group.Reactions of Schiff-base compounds of vanadium and presumably of other metalswith hydrazine may therefore give products in which thequadridentate Schiff-base ligand (which is usually consideredinert and able to immobilise four co-ordination positions on themetal atom) is broken up. This effect is in addition to any effectof hydrazine and substituted hydrazines on the oxidation stateof the metal.ExperimentalReactions were carried out under dinitrogen in dried solvents;microanalyses were performed by Mr.C. J. Macdonald of thisLaboratory. Magnetic moments were determined by the Fara-day technique, with susceptibilities corrected using appropriatePascal constants. Salicylaldehyde hydrazone and azine andring-substituted analogues were made by mixing appropriatequantities of hydrazine and salicylaldehyde or substitutedsalicylaldehydes in boiling methanol or ethanol and allowing tocool to room temperature. The complexes [V(NH,NHPh),-(salen)]I,, [VO(~alen)],~ and [VC13(thf),14 were made asdescribed elsewhere.Tris(saZicy1aldehyde hydrazonato)uanadium(III).-(a) Thecomplex [V(NH,NHPh),(salen)]I (2.64 g, 4 mmol) wasstirred in methanol (80 cm3) at 2OoC and hydrazine (0.64 g,20 mmol) added.The suspension quickly dissolved giving aclear red solution that was filtered and set aside for 2 d. Thered crystals (0.6 g, 1.3 mmol) that had formed were filtered off,washed with methanol and diethyl ether, and dried in U ~ C U O(Found: C, 55.4; H, 4.8; N, 18.1. C,,H2,N,O,V requires C, 55.3;H, 4.6; N, 18.4%).(b) The complex [VO(salen)] (1.33 g, 4 mmol) was heatedunder reflux in MeCN (100 cm3) and MeOH (25 cm3) withhydrazine (1.6 g, 50 mmol) for 48 h, then cooled to give redcrystals (0.3 g, 0.7 mmol) (Found: C, 54.7; H, 4.6; N, 18.2%).(c) The complex [VCl,(thf),] (1.80 g, 5 mmol) was dissolvedin methanol giving a green solution. Salicylaldehyde (1.83 g, 15mmol) was added followed immediately by hydrazine (0.96 g, 30mmol).The suspension dissolved giving a red solution fromwhich 0.6 g (1.3 mmol) of crystals precipitated over 3 d (Found:C, 55.0; H, 4.7; N, 18.4%), peff.(293 K) = 2.90 pB. Salicylalde-hyde hydrazone (15 mmol) or salazine (7.5 mmol) was also usedin place of salicylaldehyde, the product being identified by its i.r.spectrum.Also made by method (c) were tris(3-rnethoxysalicylaldehydehydrazonato)uanadium(rrI) (Found: C, 52.2; H, 5.1; N, 14.9.C2,H2,N,06V requires C, 52.8; H, 4.9; N, 15.4%), peff. = 2.95pB, and tris(5-bromosalicylaldehyde hydrazonato)uanadiurn(IiI)(Found: C, 36.3; H, 2.7; N, 12.0. C2,H,8Br3N60,V requires C,36.4; H, 2.6; N, 12.073, peff. = 2.85 pB.In the latter case thereaction mixture was heated under reflux overnight because ofthe relative insolubility of 5-bromosalicylaldehyde.Reaction of Tris(salicyla1dehyde hydrazonato)uanadium(Ilr)with Acid.-The complex [V(C7H,N,0)3] (0.46 g, 1.0 mmol)was stirred in methanol (50 cm3) and HBF,-Et,O (0.5 g, 3.3mmol) added. The suspension turned yellow; after 1 h it waswarmed to 60 "C giving a yellow solution that gave crystals ofsalazine (0.15 g, 0.6 mmol) on coolingJ. CHEM. SOC. DALTON TRANS. 1990 3237Table 2. Molecular dimensions (bond lengths in A, angles in ") in[V( C7H 7N20)3] with e.s.d.s in parenthesesReaction of H,salen with Hydrazine.-The compoundH,salen (0.53 g, 2 mmol) and hydrazine (0.32 g, 10 mmol) werestirred in methanol for 3 d; HBF,*Et,O (2 g, excess) was added,precipitating salazine.(a) About the vanadium atomV-O(la) 1.935(6) V-N(9a) 2.18 1( 7)V-O( 1 b) 1.950(6) V-N(9b) 2.154(7)V-O(lC) 1.931(6) V-N(9c) 2.082(7)O( la)-V-N(9a)O( 1 a)-V-O( 1 b)N(9a)-V-O( 1 b)O( 1 a)-V-N(9b)N(9a)-V-N(9b)O( 1 a)-V-O( 1 c)N(9a)-V-O( lc)O( 1 b)-V-N(9b)83.6(3) O( 1 b)-V-O( lc) 96.5(2)166.5(3) N(9b)-V-O( Ic) 90.3(3)85.8( 3) O( 1 a)-V-N(9c) 96.4( 3)86.9(3) N(9a)-V-N(9c) 88.1(3)93.3(3) O( 1 b)-V-N(9c) 9 1.4( 3)94.7(3) O( 1 c)-V-N(~C) 88.4(3)85.6(3) N(Bb)-V-N(9c) 176.6(3)175.9(3)(6) Bond lengths in the ligands a, b, and ca1.30 1 ( 10)1.40 1 (1 2)1.4O3( 12)1.373( 13)1.398(15)1.347( 13)1.387( 12)1.474(12)1.27 1 (1 0)1.415(9)1.06(9)1.14(8)(c) Angles in the ligands a, b, and caV-O(l)-C(2) 138.7(6)O(1 )-C(2)-C(3) 120.8( 10)O(1 )-C(2)-C(7) 122.3( 10)C(3)-C(2tC(7) 116.7( 10)C(2)-C(3tC(4) 120.9( 1 1)C(3)-C(4tC(5) 12 1.3( 12)C(4)-C( 5 1-c (6) 1 18.1( 1 1)C(5>-C(6tC(7) 121.9( 11)C(2)-C(7tC(6) 120.9( 1 1)C(2)-C(7)-C(8) 121.7(9)C(6)-c(7bC(8) 117.3(10)C(7)-C(8W(9) 126.4(9)V-N(9tC( 8) 127.0(7)V-N(9)-N( 10) 116.4(6)C(8)-N(9tN( 10) 115.6(8)N(9)-N( 10)-H( 10) 11 l(5)N(9)-N( 10)-H( 1 1) 1 15(4)H(lO)-N(lOtH(ll) 1 W6)b1.327(9)1.389( 1 1)1.395( 12)1.368(13)1.365( 13)1.422( 1 1)1.275(10)1.4O6(9)0.98(8)1.400( 12)1.440( 12)1.02( 10)b130.0(6)118.7(9)122.6(9)118.7(9)120.6( 10)12 1.3( 10)118.6(10)122.0( 10)118.9(9)12439)1 16.2(9)124.9(9)125.1 (7)1 18.4(6)116.5(8)107(5)122(6)105(7)(6) Hydrogen bonding dimensionsN * * * N / O H***N/Odistance distanceN(lOa)-H(lOa)* O(1b) 2.787(10) 2.14(8)N(lOa)-H(lla)-.. N(1Ob') 3.251(11) 2.16(8)N(lOb)-H(lOb)-..O(1a) 2.821(11) 2.11(8)N(lOc)-H(l&) N(l0a) 3.020(13) 2.11(7)Roman superscripts denote the symmetry operations: Iz; I1 1 - x, 1 - y . 1 - 2; 111 -x, --y, 1 - z.N(l0b)-H(l1b) . - - O(1c") 3.205(10) 2.29(10)N(l&)-H(ll~)*.- O(1b"') 3.137(12) 2.34(7)C1.338(9)1.386(11)1.409(11)1.339( 12)1.388(12)1.365(11)1.412( 1 1)1.436( 12)1.289( 10)1.409( 10)1.04(7)0.80(6)C132.0(6)119.8(9)122.2(8)1 18.0(9)122.7(9)1 17.8(9)119.2(9)123.8(9)1 17.0(9)126.7(9)125.3(7)118.8(6)1 15.7(8)1 16(4)107(5)107(7)12 1.1( 10)12 1.1 (10)N-H * N/Oangle117(6)159(6)127(6)148(8)145(5)174(6)-x, 1 - y , 1 -Crystal Structure Analysis of [V(C7H7N20)3] .-Crystaldata. C21H21N603V, M = 456.4, triclinic, space group P i(no.2), a = 10.019(1), b = 10.283(1), c = 10.424(1) A, a =77.828(7), p = 87.434(8), y = 104.183(9)", U = 1012.6 A3,Z = 2, D, = 1.497 g ~ m - ~ , F(O00) = 472, p(Mo-K,) = 5.1cm-l, h(Mo-&) = 0.710 69 A.Crystals are deep red, thin laths; all are twinned, each by apairing of two laths along their long, thin, sides. One such pairwas sliced in half along the twinning plane giving a singlesliver, 0.17 x 0.05 x 0.01 mm; this was mounted on a glassfibre with epoxy resin. After preliminary photographicexamination, the crystal was transferred to an Enraf-NoniusCAD4 diffractometer (with monochromated radiation) fordetermination of accurate cell dimensions (from the settings of25 reflections, with 8 in the range 6-9", each centred in fourorientations) and measurement of diffraction intensities (toOm,,.= 20"). During processing, intensities were corrected forLorentz-polarisation effects and to eliminate negative intensities(by Bayesian statistical methods). There was no deteriorationof the crystal during the data collection, and no absorptioncorrection was applied.1 879 Independent reflections (of which 1052 had I > 20~)were entered into the SHELX program system.' An electron-density map based on the V atom (located from the Pattersonmap) showed the whole structure clearly.During therefinement process, by full-matrix least-squares methods,hydrogen atoms of C-H groups were included in idealisedpositions, and the N-H hydrogen atoms, all located indifference maps, were refined independently. All the non-hydrogen atoms were allowed anisotropic thermal parameters.Refinement reached convergence with R = 0.081, R, = 0.053'for 1503 reflections (those with I > (J,) weighted w = oF-,. Thisrather high value for R probably results from the overall weakdiffraction intensities measured from the small crystal used.There were no features of significance in the final difference map.Scattering-factor curves for neutral atoms were taken fromref. 6. Computer programs, in addition to SHELX, have beenlisted in Table 4 of ref. 7 and were run on the MicroVAX I1computer in this Laboratory. Final atomic co-ordinates are inTable 1 and selected molecular dimensions in Table 2.Additional material available from the Cambridge Crystallo-graphic Data Centre comprises H-atom co-ordinates, thermalparameters, and remaining bond lengths and angles.References1 R. L. Robson, R. R. Eady, T. H. Richardson, R. W. Miller, M.2 A. Hills, D. L. Hughes, G. J. Leigh, and J. R. Sanders, J. Chem. SOC.,3 M. Mazzanti, S. Gambarotta, C. Floriani, A. Chiesi-Villa, and C.4 G. W. A. Fowles, P. T. Greene, and T. E. Lester, J. Znorg. Nucl. Chem.,5 G. M. Sheldrick, SHELX 76, Program for crystal structure6 'International Tables for X-Ray Crystallography,' Kynoch Press,7 S. N. Anderson, R. L. Richards, and D. L. Hughes, J. Chem. Soc.,Received 23rd April 1990; Paper 0/01792BHawkins, and J. R. Postgate, Nature (London), 1986,322,388.Dalton Trans., in the press.Guastini, Inorg. Chem., 1986,25,2308.1967,29,2365.determination, University of Cambridge, 1976.Birmingham, 1974, vol. 4, pp. 99 and 149.Dalton Trans., 1986,245
ISSN:1477-9226
DOI:10.1039/DT9900003235
出版商:RSC
年代:1990
数据来源: RSC