摘要:
Selective derivatisation of aza macrocyclesAlexander J. Blake,".b Ian A. Fallis,h Robert 0. Gould,h Simon Parsons,h Steven A. Rossh andMartin Schrodera Drpiirtrnent of Clzemistry, The University of Nottinghani, Nottingharn NG7 2RD, UKDeptrrtrnent o j Cliernistry, The University of' Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UKA range of selectively functionalised compounds derived from 1,4,7-triazacyclononane ([9JaneN,), including4,7-bis( 2-h ydroxy-2-methylpropy1)- 1,4,7-triazacyclononane- 1 -carbaldehyde ( H,L' ), 1 -benzyl-4,7-bis(2-hydroxy-2-methylpropy1)- 1,4,7-triazacyclononane ( H,LZ) and 1,4-bis( 2-hydroxy-2-methylpropy1)- 1,4,7-triazacyclononane (H2L3), has been prepared. The structure of HzL3.CHCI, shows a disordered macrocyclicring with the major conformer refining to a site occupancy of 0.663(8), and both disordered rings adopting a[333] conformation.The pendant alcohol arms were not disordered and were found to be hydrogen bonded toa CHCI, solvate molecule with H - O( 1 ) and H O(4) distances of 1.73 and 1.81 A respectively. Thestructure of Na[Cu(H,L')(NCMe)][BF,],[NO,] shows the copper(i1) centre in the [Cu(H,L')(NCMe)lZ +cation bound to two amine donors and two alcohol donors of H,L' and to a MeCN molecule. The Cu-Nbond lengths lie in the range 1.984(3)-2.015(3) A. Both alcohol donors are protonated, with one short Cu-O( 16)bond of 1.963(3) A and one long Cu-O(21) bond of 2.252(3) A. There is also a sixth longer-range interaction ofthe copper(r1) centre with the amide N "(I)] of H,L' at a distance of 2.61 l(5) A, confirmed by the loss ofplanarity of the C(2)-C(9)-N( I)-C( 10)-O( 1 I)-H( 10) amide fragment to give a dihedral angle between theplanes defined by C(2)-C(9)-N( 1 ) and N( 1)-C( 10)-O( 1 1)-H( 10) of 27.1(4)". The structure is completed byinteraction of O( 1 1 ) with a Na 'ion which itself bridges to BF,- counter anions leading to a central infinitecore of [Na(BF4),] - aggregates onto which are attached the [Cu(H2L')(NCMe)l2 + cations.The complex[Cu( H,L2)(OH2)][N0, J 2 shows the six-co-ordinate copper(rr) centre bound to the three amine and twoalcohol donors of H,L2 and to one water molecule. There are four short bonds [to N(7), N(4), O(40) andO(l)] in the range 1.961(5)-2.073(6) 8, and two longer bonds to N(1) and O(70) at 2.308(5) and 2.313(5) Arespectively.The H atoms of the water molecule [O( l)] and one of the pendant arms [0(40)] also makehydrogen-bonding contacts with the nitrate counter ions.The co-ordination chemistry of the facially co-ordinatingtriazamacrocycle 1,4,7-triazacyclononane ([9]aneN,) has beencomprehensively established over the last twenty years.'Further N-functionalisation of [9]aneN, via incorporation ofthree pendant donor groups has afforded a wide range of newhexadentate compounds which can confer remarkable stabilityupon metal However, less work has been reported onselectively functionalised derivatives of [9]aneN, with only oneor two pendant donors. This in part reflects the syntheticdifficulties. Moore and co-workers have reported thepreparation of [9]aneN, with one pendant pyridine (orbipyridine) uitr reaction of an excess of [9]aneN, with 2-methylpyridyl chloride, whilst Spiccia and co-workers havereported a similar compound with two pendant-arm pyridinegroups. They reported an overall yield of 50% by reaction of 2equivalents of 2-methylpyridyl chloride with 1 equivalent of[9]aneK3 under aqueous conditions. Parker and co-workers 'have also reported a derivative of [9]aneN, with one pendantmethylene( methylphosphinic acid) group uia a route where twoof the ring N atoms are protected by a bridging CH, group.We were interested in developing a route which would allowhigh-yield syntheses of mono- and di-functionalised derivativesof [9JaneN,, and which would also allow for the preparation ofcompounds with more than one type of pendant group.Ourapproach has been to expand upon the work initially reportedby Weisman c't which illustrated the suitability oforthoamide derivatives of [9]aneN, as precursors to func-tionalised macrocycles.Results and DiscussionThe preparation of functionalised derivatives of [9]aneN, issummarised in Scheme 1. The starting material was theorthoamide derivative 1,4,7-triazatricyclo[5.2.1 .Os,' 'ldecane1,9 the crystal structure of which has been reported recently. l oReaction of orthoamide I with PhCH,Br in tetrahydrofuran(thf), followed by aqueous hydrolysis, afforded 4-benzyl- 1,4,7-triazacyclononane- I -carbaldehyde 2, where all three N atomsof the ring have been distinguished from each other. The lack offurther reactivity of the cationic intermediate in this reactionhas been rationalised in terms of contributions from amidiniumcanonical forms,' ' as illustrated in Scheme 2.The amide groupof 2 can be hydrolysed in ethanolic KOH solution to affordmonofunctionalised 1 -benzyl- 1,4,7-triazacyclononane 3, theco-ordination chemistry of which has been reported separ-ately.', Reaction of 3 with an excess of isobutylene oxidein EtOH at room temperature gives H,L2 in high yield.Alternatively, 2 can be treated with isobutylene oxide prior tohydrolysis of the amide group, which affords the potentiallytetradentate ligand 1 -benzyl-4-( 2-hydroxy-2-met hylpropy1)-1.4,7-triazacyclononane 4.Hydrolysis of orthoamide 1 with dilute HCl(aq) affordsthe previously reported 1,4,7-triazacyclononane- 1 -carbalde-hyde 5.The crystal structure of 5 in both its free base andprotonated forms has been reported separately l 3 along with itsco-ordination chemistry and a range of other amide derivativesof [9]aneN,. Reaction of 5 with an excess of isobutylene oxidein EtOH affords H,L' in high yield. Hydrolysis of the amidegroup of H,L' with ethanolic KOH yields the potentiallypentadentate ligand 1,4-bis(2-hydroxy-2-methylpropyl)- 1,4,7-triazacyclononane H2L3. The 'H and l3C NMK spectra o f 2 , 5and H,L' are complicated by the presence of the formyl amidegroup, the slow period of rotation of which leads to freezing outof conformational isomers in solution at room temperature.J.Clzem. Soc., Dulton Trans., 1996, Pages 4379-4387 437I (ii)Ph416(vii) IH7Scheme 1 Functionalised derivatives of [9]aneN3. Reagents and conditions: ( i ) ( N ) PhCH,Br-thf, ( h ) water, reflux for 3.5 h; (ii) KOH-EtOH,reflux; (iii) isobutylene oxide-EtOH; ( i u ) ( a ) isobutylene oxide-EtOH, ( h ) KOH-EtOH; ( u ) 2.8 mol dm-3 HCl(aq); (ui) ( ( 1 ) PhCH,OCH,CH,Br-diethyl ether, ( b ) water, reflux for 5 h, (c) KOH-EtOH, 72 h; (uii) PdK-H,-MeC0,HPhB i B iScheme 2 Resonance structures of cationic intermediate ( I +PhCH, Br)The NMR spectra of related amide derivatives have beendiscussed.'Compounds H,L', H,L2 and H,L3 described above all havetwo pendant alcohol donor groups, whilst 4 has one pendantalcohol and one benzyl group.We wished to extend this workto the preparation of derivatives of [9]aneN, with only onependant alcohol donor and no other functionality. Our initialapproach was to treat orthoamide 1 with BrCH,CH,OH in thf,which proved to be unsuccessful. We attributed the failure of thisreaction to the elimination of HBr from BrCH,CH,OH underbasic conditions. We therefore decided to protect the alcoholgroup of BrCH,CH,OH prior to reaction with 1 and foundthat an appropriate approach was to prepare a benzyl ether,which would not be susceptible to cleavage under acidic or basicconditions. Thus, reaction of BrCH,CH,OCH,Ph with 1 inEt,O, followed by aqueous hydrolysis and then subsequenthydrolysis of the formyl amide group, afforded 1-(1-benzyloxyethy1)- 1,4,7-triazacycIononane 6 in high yield. Thebenzyl group was then removed by hydrogenolysis with PdjC inglacial acetic acid to yield the potentially tetradentate ligand1,4,7-triazacyclononane-1 -ethanol 7.Czech and Bartsch l 4 havereported that hydrogenolysis of benzyl ethers in the presence ofamines can lead to poor yields and suggest that yields are higherif the reaction is carried out in acetic acid.The general methodology described above can, in principle,be extended to prepare a range of tetra- and penta-dentateligands with a different range of donor atoms. We wereparticularly interested in pentadentate ligands which couldblock off five sites at a metal centre leaving one site free forfurther reactivity. As part of these studies we decided toundertake a single-crystal structure determination of H,L3.Thecrystal structure of [9]aneN, has not been reported previously,in contrast to the wide range of thioether ligands.15 This isperhaps due to its hygroscopic nature and difficulties involvedin preparing single crystals. The structure of the trimethylatedanalogue, 1,4,7-trimethyl- 1,4,7-triazacycIononane, has beenreported as the monohydroperchlorate salt, which shows theprotonated amine donor to be hydrogen bonded to the two freeamine donors. We undertook the structure determination ofH,L3 in order to confirm the conformation of the macrocyclicring of a derivative of [9]aneN, in the solid state.A single crystal of H,L3 was obtained from the slowevaporation of a CHCI, solution of it.Details of the structuresolution and refinement are given in the Experimental section:bonded distances and valence angles are within normal rangesand have been deposited. The determination confirms theexpected structure and shows one molecule of CHCI, perasymmetric unit with long-range hydrogen-bonding contactsbetween CHCI, and both oxygen atoms of the pendant arms[H O( 1 ) 1.73 and H O(4) 1.8 1 A]. The macrocyclic ringwas found to be disordered. with the major conformationdenoted by primes (the minor conformation by double primes)refining to a site occupancy of 0.663(8). No disorder wasapparent in the pendant arms. A view of the major conformer isgiven in Fig. 1. In each of the disordered rings the macrocycleadopts a [333] conformation and can be regarded as 'pre-organised' for complexation to a metal centre.However, thequestion of 'pre-organisation' is complicated by the presence ofthe pendant arms. The actual process of complexation mayinvolve initial co-ordination of the alcohol donors to the metal,followed by the macrocyclic ring donors.The co-ordination chemistry of the pentadentate compoundsH,L' and H,L2 with Cu" is described below. We wished toobserve how the presence of the amide group in H,L' wouldaffect the mode of binding. Amide groups usually bind to metalions through their oxygen atom l 6 since the lone pair on the4380 J. Chern. Soc.., Dalton Trans., 1996, Pages 4379-438P! nFig. 1 View of structure of H,L3 with numbering scheme adC(191optedUFig. 3 Alternative view of the cation in Na[Cu(H,L')(NCMe)]-[BF,],[NO,], illustrating the deviation from planarity of the amidegroupc1101OM1View of the cation in Na[Cu(H,L*)(NCMe)][BF,],[NO,] Fig.2with numbering scheme adoptedTable 1 Selected bond lengths (A) and angles (") for Na[Cu-( H , L' )(NCMe)lCBF,I,[N031Cu-N(4, 2.002(3) cu-O( 2 1 ) 2.252(3)Cu-N( 7) 2.0 1 5( 3) Cu-N( 1 a ) 1.984(3)Cu-O( 16) 1.963(3) CU * N( 1 ) 2.61 l ( 5 )N(4)-CLI--N( 7) 86.95( 12) N(7)-Cu-0(21) 77.66( 10)N(4)PCu -0( 16) 82.12( 1 1 ) N( 7)-Cu-N( 1 a) 97.85( 12)N(4)-Cu-0(21) 96.57( 10) O( 16)-Cu-0(21) 103.37( 10)N(~)--CLI- N( l a ) 168.40(12) O( I6)-Cu-N( 1 a ) 92.92( 12)N( 7)-Cu-O( 16) 169.07( 1 1 ) 0(21)-Cu-N( l a ) 94.77( 1 1 )nitrogen atom is delocalised and is not readily available forbinding.'' It was also of interest therefore to see how H,L2would bind to a metal centre to compare with the mode ofbinding of H, L '.Reaction ofCu(N03),*3H,0 with 1 molarequivalent ofH,L'in MeOH followed by addition of NaBF, and recrystallisationfrom MeCN-Et,O afforded blue crystals.The IR spectrum ofthis material indicated the presence of H2L' and both NO3-and BF, counter ions, although the FAB mass spectrumshowed no assignable peaks. The vco amide stretch of H,L' inthis material was observed at 1654 cm which is not shiftedsubstantially from that of free H,L' which occurs at 1656 cm '.Analytical data were confusing, partly due to the presence ofboth NO ~ and BF,- anions as confirmed by IR spectroscopy.This suggested a product with mixed counter ions, such as[Cu( H,L 1)(OH,)][N0,][BF4], although the analytical datadid not agree with any predicted formulae.A single-crystalstructure determination was therefore undertaken.Deep blue prisms of X-ray quality were obtained from thediffusion of diethyl ether into a MeCN solution of the complex.Details of the structure solution and refinement are given in theExperimental section. Selected bond lengths and angles aregiven in Table 1 and a view of the cation in Fig. 2. The cationhas the structure [Cu(H2L')(NCMe)l2 +, with the copper(r1)centre bound to two amine donors and two alcohol donors ofH,L' and also to a co-ordinated MeCN molecule. The Cu-Nbond lengths lie in the range 1.984(3)-2.015(3) A. Both alcoholdonors are protonated, with one short Cu-O(16) bond of1.963(3) 8, and one long Cu-O(21) bond of 2.252(3) A.Thegeometry at the 0 atom of the alcohols IS such that theM-O(H)(C) fragment is planar.In addition to these five bonds, there is also an unusuallonger-range interaction of the metal centre with the amideN-donor "(I)] of H,L' at a distance of 2.611(5) A. Thisis confirmed by the observed loss of planarity of theC(2)-C(9)-N( 1)-C( 10)-O(1 1)-H( 10) amide fragment. Thus,the dihedral angle between the planes defined byC(2)-C(9)-N( 1 ) and N( 1)-C( 10)-O( 1 1)-H( 10) is 27.1(4)",which is illustrated by the view of the cation shown in Fig. 3.The solid-state structure of Na[Cu(H,L')(NCMe)]-[BF,],[NO,] also contains an aggregate of [Na(BF,),]-units which form a polymeric chain structure.Each N C ionmakes five contacts with F atoms (from BF4- ions) in the range2.242(3)-2.424(3) A. In addition, the amide 0 [O( I 1 )] from the[Cu(H2L')(NCMe)l2 cation forms a sixth interaction withthe Na' ion at a distance of 2.321(3) A.The combined effect of the interactions described above is tocreate a supramolecular array of cations and anions whichgenerates a stacked structure in the solid state. The structure iscompleted by nitrate counter ions which do not form anybonding interactions. Fig. 4 shows the structure viewed alongthe h axis and Fig. 5 along the N axis. The ion contacts andgeometries around the Na' ions are given in Table 2, along withthe operations used to generate symmetry-equivalen t atoms.The amide function of H,L' thus interacts with two metalcentres in this structure, namely Cu" and Na'.The interactionof amide 0 atoms with alkali metals is well documented,' 6 - ' 7while interaction of amide N atoms with metal centres usuallyoccurs with concurrent deprotonation of the amide. ''*' Sincethe amide function in H,L' is a tertiary amide, deprotonation isnot possible. As stated previously, the amide function dekiatessignificantly from planarity. However, as the equivalentdihedral angle in an sp3-hybridised donor to a metal centre ( f . g .J . Chem. SOC., Dalton Trans., IY96, Pages 4379-4387 438Fig. 5 View ot NaLCu(H,L’)(NCMe)JLB~,],LNO,J along (I axis.Details as in Fig.4Fig. 4 View ot NaLCu(H,L’)(NCMe)JL~~,J,LNO,J along b axis(NO,- ions omitted for clarity). Key: Cu, magenta; Na, yellow; B,orange; F, turquoise; 0, red; N, blue; C, blackan amine donor) is about 5 5 O , the N atom of the amide groupappears to be midway between sp2 and sp3 hybridised. This canbe viewed as a compromise between donation of the amide N-donor lone pair to the copper(rr) Lewis acid and the stabilitygained from delocalisation of the lone pair onto the 0 atom,thereby optimising interaction with the Na+ ion. Interestingly,Crabtree and co-workers l 9 have reported very recently anexample of N-donor co-ordination of an amide to an iridiumcentre. This complex, like the system described herein,’ uses aconformationally hindered polychelate ligand to control andenforce metal-ligand interactions.Co-ordination of amide 0 atoms to metal centres is normallyaccompanied by a decrease in the vco stretching frequency of ca.30 cm which has not been seen for this structure.This can betaken as further evidence for the amide N atom interacting withthe copper(I1) centrc. The copper-amide interaction shoulddisrupt delocalisation of the amide N lone pair onto the 0atom, which is normally responsible for the lowering of theamide vco stretching frequency. Since the vco stretchingfrequency is not lowered, this suggests that the N atom of theamide is weakly bound to the Cu”. Thus, binding of amide uia0 and N atoms has opposing effects with respect to the vcostretching vibration.Reaction of Cu(N03),.3H20 with 1 molar equivalent of H2L2in ethanol gave a deep blue solution, which upon evaporationafforded a blue microcrystalline solid.This was recrystallisedTable 2 Sodium ion contacts (A) and geometries (”) for Na[Cu-(H,L’ )( NCMe)lCBF,I,CNO,INa-O( 1 I )Na-F(2)Na-F( 7)C( 1 0)-O( 1 1 )-NaB( I )-F(2)-NaB(2)-F( 7)-NaO( 1 1 )-Na-F( 2)O( 1 I )-Na-F( 7)O( 1 I )-Na-F(4’)O( 1 1 )-Na-F( 5”)O( 1 1 )-Na-F( 6”)F(2)-Na-F(7)F(2)-Na-F(4’)F(2)-Na-F( 5”)2.321 (3)2.270( 3)2.257(3)14 1.2(3)1 53.3 3)144.4(3)167.25(11)95.24( 10)92.69( 10)77.36( 9)84.49( 9)94.68( 10)93.80( 10)90.03(9)N a-F( 4‘)Na-F( 5”)Na-F( 6”)F( 2)-Na-F( 6”)F( 7)-Na-F(4’)F( 7)-Na-F( 5”)F( 7)-Na-F( 6“)F(4‘)-Na-F(5”)F( 4‘)-Na-F( 6”)F( 5”)-Na-F( 6”)Na-F(4’)-B( 1’)Na-F( 5”)-B(2’)Na-F( 6”)-B( 2’)2.242( 3)2.424(3)2.353(3)86.93(9)98.15(9)I49.06( 10)93.53(9)1 12.04(9)168.19( 10)56.13 8)132.2(2)96.6(2)99.7(2)Primed atoms are related by the symmetry operation -doubly primed ones by + Y, - j’, 1.+ Y.- j-. z;from hot CH2C12. The FAB mass spectrum of this materialshowed peaks for [Cu(H2L2)It and also for [Cu(H2L2)-(NO,)]’. The compound H2L2 is potentially a pentadentatedonor, through three amine and two alcohol donor atoms. Thesixth co-ordination site of this material could therefore be filledby a water or nitrate ligand, elemental analysis of the samplesuggesting the presence of water. In order to ascertain the co-ordination geometry of the metal centre a single-crystalstructure determination was undertaken.Crystals suitable for X-ray studies were obtained from theevaporation of a solution of the complex in CH2C12.Detailsof the structure solution and refinement are given in theExperimental section. Selected bond lengths and angles aregiven in Table 3 and a view of the cation is shown in Fig. 6. Thecopper(r1) centre is six-co-ordinate, bonding to the three amineand two alcohol donors of H2L2 as well as to a water molecule.There are four short bonds [to N(7), N(4), O(40) and O( l)] intherange 1.961(5)-2.073(6)Aand twolongerbonds[toN( 1)and0(70)] at 2.308(5)and2.3 13(5)A respectively.The H atomsofthewater molecule [O( 1)] and one of the pendant arms [0(40)] are4382 J .Chem. Soc.., Dcxlton Trans., 1996, Pages 4379-438Table 3 Selected bond lengths (A) and angles (") for [Cu-(H,L' )(OH, ~1"0,12cu-O( 1 ) 1.961 (5) Cu-O(40) 2.002( 5 )Cu-N(4) 2.0 1 O(6) Cu-N( 7) 2.073(6)Cu-N( 1 ) 2.308(5) CU-O( 70) 2.3 13( 5 )O( I )-CU-O( 40)0(40)-Cu-N(4)O( 40)-Cu-N( 7)O( 1 )-Cu-N( 1 )N(4)-Cu- N( 1 )O( 1 )-CU-O( 70)N(4)-Cu-O( 70)N( I)-CU-O(70)90.1(2) O( I)-Cu-N(4) 171.6(2)8 1.5(2) O( I)-Cu-N(7) 101.9(2)167.6( 2) N(4)-Cu-N( 7) 86.4(2)84.2( 2) N( 7)-Cu-N( 1 ) 8 1.7(2)98.2(2) 0(40)-C~-N( 1) 99.8(2)87.7( 2) 0(40)-C~-0(70) 103.8(2)9 3 . 3 2) N( 7)-Cu-O( 70) 74.0( 2)155.7(2)Fig. 6nunibering scheme adoptedVien o f the structure of [Cu(H,L2)(OH2)][N0,], with thefound to make hydrogen-bonding contacts with the nitratecounter ions.Three such contacts are made, H(40). . O(92) at1.85, H( 121) - O(91) at 1.92 and H(l b) - - O(82) at 1.75 A,which can be observed in Fig. 6. Such association between thenitrate ions and the cation in solution may help to explain theunexpected solubility of this material in CH2Cl,.Fig. 7 illustrates the packing for [Cu(H2L2)(OH2)][N031,.The aromatic benzyl groups of H2L2 are seen to lie above eachother in the solid state with a vertical separation of 3.334(5) 8,and a centroid-centroid distance of 3.658(5) A, which may beindicative o f a n--n stacking interaction. However, care must betaken to distinguish x-n stacking forces from simple crystal-packing forces. Much work has been devoted recently to thedevelopment of molecular receptors which utilise aromatic n-nstacking (in conjunction with hydrogen bonding) to bindmolecule^ such as nucleotide bases and phenols.2oAs mentioned earlier. H,L' and H2L2 have similiar donorarrays, thc difference being the functional group attached toN ( 1 ). which is a formyl group in H2L' and a benzyl group inH,L'. Comparison of the Cu-N(I) bond lengths in the twostructures shows a substantial difference, with a Cu-N( 1 )distance ot'2.308(5) A in [Cu(H,L2)(OH,)I2+ and 2.61 l(5) 8, in[Cu(H,I.' )(NCMe)]' + . This substantiates further the idea thatthe interaction of the amide with the copper(i1) centre in[Cu( H2L1 )(NCMe)l2' is not as strong as a copper(i1)-amineinteraction.Fig. 7 View of the packing for [Cu(H2L2)(OH,)][NO,1,Experiment a1All solvents were dried and purified using standardprocedures.2 1 Tetrahydrofuran ('HPLC-grade', Fisons) wasdistilled from sodium-benzophenone. Dimethylformarnideused for macrocycle cyclisation reactions was always takenfrom a fresh bottle. Standard chemicals were used as com-mercially supplied. The PhCH2Br (BDH) was distilled on ashortway distillation apparatus then stored at - 20 "C prior touse. Infrared spectra were recorded as KBr discs or thin filmsbetween CsI plates on a Perkin-Elmer 1600 Series Fourier-transform spectrometer, fast atom bombardment ( FAB) andelectron ionisation (EI) mass spectra on a Kratos MS 50TCspectrometer, with FAB spectra in a 3-nitrobenzyl alcoholmatrix. Elemental analyses were performed by the University ofEdinburgh Chemistry Department microanalytical service.Proton NMR spectra were recorded on Bruker WP80.WI'200and AC250 spectrometers, operating at 80.13. 200.13 and250.13 MHz respectively, 13C NMR spectra on Bruker WI'200and AC250 spectrometers, operating at 50.32 and 63.89 MHzrespectively. 1,4,7-Triazacyclononane was prepared 'by astandard literature procedure.2' The preparation of 1.4.7-TriazatricycloC5.2. I .04. "ldecane 1 from 1,4,7-triazacyclonon-ane was carried out according to the method reported byAtkins.'Syntheses4-Benzyl-l,4,7-triazacyclononane-l-carbaldehgde 2. This com-pound was prepared according to the method of Weisman etul. 1,4,7-Triazatricyclo[5.2.1 .04*'0]decane 1 (0.50 g. 0.0036mol) and benzyl bromide (0.615 g, 0.0036 mol) were stirredtogether in thf (2 cm3) for 1 h to yield a thick paste (the reactiontime of 24 h quoted by Weisman was found to be unnecessary).Diethyl ether (10 cm3) was then added and the solution filteredto give a white solid which was dissolved in water (10 cm3) andrefluxed for 3.5 h.The solution was adjusted to pH 12 withNaOH solution (5 mol dm 3, and the product extracted withCHCI, ( 5 x 50 cm3). The combined extracts were dried(MgSO,) and the solvent removed under reduced pressure togive the product as a yellow oil, which was stored as a standardsolution in ethanol at -20 "C (0.80 g, 89.91:;). KMR (CDCI,):'H(200.13MHz),62.35-3.25(12H,m,NCH2,ring),3.49(2H,s, NCH2Ph), 7.13 (5 H, br s, aryl H), 7.79 and 7.93 ( 1 H, s,NCHO, from alternative isomers); 13C (50.32 MHz), 6 45.93,46.03, 46.37, 47.13, 47.33, 48.19, 49.39, 51.45. 52.12.54.73,J . Clwrn. Soc., Dulton Trans., 1996, Pages 4379-4387 43856.51 (NCH,, ring, from alternative isomers, assuming onecoincidence), 6 1.54 (NCH,Ph, assuming both isomers coinci-dent), 126.33, 126.53, 127.59, 127.70, 128.26 (aromatic CH,assuming one coincidence), 138.04 (aromatic quaternary,assuming both isomers coincident), 163.01 and 163.17 (NCHO,from alternative isomers) (Found: C, 67.4; H, 9.10; N, 16.9.C14H21N30 requires C, 68.0; H, 8.55; N, 17.0%).l-Benzyl-l,4,7-triazacyclononane 3. Compound 2 (0.3 g,0.0012 mol) was added to a solution of potassium hydroxide(1.48 g, 0.026 mol) in EtOH (10 cm3) and the mixture refluxedfor 24 h.The solvent was removed in uacuo and the residuetaken up in water ( 5 cm3). The solution was extracted withCHCI, ( 5 x 25 cm3), the combined extracts were dried(MgSO,) and the solvent was removed under reduced pressureto give a yellow oil. This was distilled on a shortway bulb-to-bulb distillation apparatus to give the product as a clear viscousoil which was stored as a standard solution in ethanol at6 2.46-2.59 (12 H, m, NCH, ring), 3.53 (2 H, s, NCfI,Ph)and 7.14 ( 5 H, m, aryl H); 13C (50.32 MHz), 6 45.77, 45.96,52.08 (NCH,, ring), 60.97 (NCH,Ph), 126.37, 127.65, 128.32(aromatic CH) and 139.08 (aromatic quaternary). EI massspectrum: mi. 219 ( M ' ) .-20°C (0.251 g, 95.1%). NMR (CDCI,): 'H (200.13 MHz),1 -Benzyl-4,7-bis( 2-hydroxy-2-methylpropy1)- 1,4,7-triazacy-clononane (HzL2).Compound 3 (0.420 g, 0.0019 mol) andisobutylene oxide (0.552 g, 0.0076 mol) were dissolved in EtOH( 5 cm3) in a round-bottomed flask (10 cm3). The flask wassealed with a greased stopper and then left for 10 d at 20 "C.Removal of the solvent and excess of isobutylene oxide irz uacuoafforded the product as a pale yellow oil. No furtherpurification was necessary, as the NMR spectra showed nostarting materials to be present and confirmed the acceptablepurity of the product (0.695 g, essentially quantitative). NMR(CDCI,): 'H (80.13 MHz), 6 1.08 (12 H, s, CH,), 2.43 (4 H, s,CH, arm), 2.72 (8 H, m, CH, ring), 2.88 (4 H, s, CH, ring), 3.60(2 H, s, NCH,Ph), 4.45 (2 H, br s, OH) and 7.21-7.25 ( 5 H.m,aryl H); 13C (50.32 MHz), 6 27.77 (CH,), 57.52, 59.14, 59.78(CH,, ring), 62.55 (CH,, arm), 69.56 [C(CH,),OH], 126.46,127.79, 128.60 (aromatic CH) and 139.37 (aromatic quaternary)(Found: C, 69.0; H, 10.9; N, 10.3. C2,H,,N,02 requires C,69.4; H, 10.3; N, 11.6%). EI mass spectrum: mi- 363 ( M ' ) .1 -Benzyl-4-( 2-hydrox y-2-methylpropy1)- 1,4,7-triazacyclonon-ane 4. Compound 2 (0.30 g, 0.0012 mol) and isobutylene oxide(0.250 g, 0.0026 mol) were dissolved in ethanol ( 5 cm3) in a wellsealed flask and left for 10 d at 20 "C. The solvent and excessof oxirane were removed in uacuo and the remaining oilredissolved in ethanol. Potassium hydroxide (1.7 g, 0.030 mol)was added to the flask and the mixture was refluxed for 30 h.The ethanol was removed under reduced pressure and theresidue taken up in water ( 5 cm').The solution was extractedwith CHCI, ( 5 x 25 cm3), the combined extracts were dried(MgSO,) and the solvent was removed under reduced pressureto give the product as a pale yellow oil, which was stored as astandard solution in EtOH at -20 "C (0.308 g, 88.3%). NMR(CDCI,): 'H (80.13 MHz), 6 1.15 (6 H, s, CH,), 2.55-2.77 (14H, m, NCH, ring and arm), 3.68 (2 H, s, NCH,Ph), 4.41 (1 H, s,OH) and 7.25 ( 5 H, s, aryl H); 13C (50.32 MHz), 6 27.98 (CH,),45.18, 47.35, 49.41, 54.06, 54.88 (NCH, ring, assuming onecoincidence), 62.08 (NCH,Ph), 69.29 (NCH, arm), 69.96[C(CH,),OH], 126.98, 128.08, 129.30 (aromatic CH) and138.42 (aromatic quaternary). El mass spectrum: nz/z 291( M + 1.1,4,7-Triazacyclononane-l-carbaldehyde 5.This was preparedaccording to the method of Weisman et ul.8 1,4,7-Triazatricy-cl0[5.2.1.0~~'~]decane 1 ( 5 g, 0.036 rnol) was stirred in HCI (20cm3, 2.8 rnol dm ,) at room temperature for 8 h. The solutionwas then cooled to 0 "C and adjusted to pH 12 with NaOHsolution ( 5 rnol dm ,). The product was extracted immediatelywith CHCI, (5 x 50 cm3), the combined extracts were dried(MgSO,) and the solvent was removed under reduced pressureto give a clear, viscous oil which crystallised upon standing.Recrystallisation from CHC1,-hexane gave white needles (2.6 1g, 44.6%). NMR (CDCI,): 'H (200.13 MHz), 6 2.01 (2 H, s,NH), 2.65-2.77 (4 H, m, CH,), 2.98-3.10 (4 H, m, CH,), 3.31-3.44 (4 H, m, CH,) and 8.1 1 (1 H, s, NCHO); ' (50.32 MHz),6 46.58, 48.14, 48.62, 49.20, 49.73, 52.59 (CH,) and 163.79(NCHO) (Found: C, 54.4; H, 10.1; N, 26.4.C,Hl,N30 requiresC, 53.5; H, 9.60; N, 26.7%). IR (KBr disc): 3321s (NH), 2879s(CH), 1656vs (CO), 1450s, 1 161 s, 97 1 m and 762s cm '. EI massspectrum: m/z 157 ( M ' ) .4,7-Bis(2-hydroxy-2-methylpropyl)-l,4,7-triazacyclononane-I-carbaldehyde (H,L'). Compound 5 (0.60 g, 0.0038 mol) andisobutylene oxide (1.20 g, 0.016 mol) were dissolved in EtOH ( 5cm3) in a round-bottomed flask (10 cm3). The flask was sealedwith a greased stopper and then left for 10 d. Removal of thesolvent and excess of oxirane in uacuo afforded the product as apale yellow oil. No further purification was necessary, as theNMR spectra showed no starting materials and no otherproducts to be present (1.14 g, quantitative). NMR (CDC1,):'H (200.13 MHz), 6 1.1 1 (6 H, s, CH,), 1.13 (6 H, s, CH,), 2.51(4 H, s, CH,, arm), 2.65 (4 H, s, CH,, ring), 2.93 (4 H, m, CH,,ring),3.47(4H,m,CH2,ring),4.51(2H,brs,OH)and8.10(lH, s, NCHO); ' (distortionless enhancements of polarisationtransfer, DEPT, 3x/4,50.32 MHz), 6 27.85, 28.09 (CH,), 50.06,52.66, 56.76, 58.60, 58.80, 59.04 (CH,, ring), 70.27 and 71.73(CH,, arm) (Found: C, 59.0; H, 9.75; N, 14.9.C15H31N303requires C, 59.8; H, 10.4; N, 13.9%). EI mass spectrum: m/r 302( M + ) . IR spectrum: vco 1656 cm '.1,4-Bis(2-hydroxy-2-methylpropyl)-l,4,7-triazacyclononane(H,L'). Compound H2L' (0.450 g, 0.0013 mol) was added toKOH (1.48 g, 0.026 mol) in EtOH (10 cm3) and this mixture wasrefluxed for 24 h.The solvent was then removed in uacuo andthe residue taken up in water ( 5 cm3). The solution wasextracted with CHCI, ( 5 x 25 cm3), the combined extractswere dried (MgSO,) and the solvent was removed underreduced pressure to give the product as a pale yellow oil, whichwas stored at -20 "C (0.350 g, 96.4%). NMR (CDCI,): 'H(200.13 MHz), 6 1.15 (1.2 H, s, CH,), 2.54 (4 H, s. CH,, arm),2.73-2.83 (12 H, m, CH,, ring) and 3.50 (2 H, br s, OH); 13C(50.32 MHz), 6 28.17 (CH,), 48.51, 56.91, 57.23 (CH,, ring),70.05 (CH,, arm) and 70.81 [C(CH,),OH] (Found: C, 59.4; H,11.9; N, 14.9. C14H31N302 requires C, 61.5; H, 11.4; N,15.4%). EI mass spectrum: rFz/z 274 (A4+).2-Benzyloxyethyl bromide.Tribromophosphine ( 1.55 g,0.0057 mol) and pyridine (0.5 cm3) were added to freshlydistilled benzene (3 cm3) at 6 "C under N,. 2-Benzyloxyethanol(2.5 g, 0.0165 mol) was then added dropwise over 5 min. Thereaction mixture was allowed to warm to room temperature andstirred for 48 h, which gave rise to an orange precipitate.Benzene (20 cm3) was added, the solution was washed with HCI(0.5 rnol), NaHCO, ( 1 .O mol) and water. Chloroform (20 cm3)was added, the solution was dried over MgSO,, concentrated invac'uu and distilled on a shortway bulb-to-bulb distillationapparatus. Thin-layer chromatography and NMR spectroscopyshowed this to be a 4: I mixture of the required product andbenzyl bromide. This mixture was purified by flash columnchromatography on silica (hexane-diethyl ether, 10: 1 ) to givethe final product as a clear oil (1.68 g, 47.473; R, = 0.35(hexane-diethyl ether, 10: 1 on silica).NMR (CDCI,): 'H(250.13 MHz), 6 3.50 (2 H, t, OCH,CH,Br), 3.79 (2 H, t,OCH,CH,Br), 4.59 (2 H, s, PhCH,O) and 7.35 ( 5 H, m, aryl H);13C (62.89 MHz), 6 30.32 (OCH,CH,Br), 69.78 (OCH,CH,-Br), 72.95 (PhCH,O), 127.58, 127.68, 128.3 1 (aromatic CH)4384 J. Chenz. Soc., Dalton Trans., 1996, Pages 4379-438and 137.56 (aromatic quaternary). EI mass spectrum: m/z 215(M+ ).1-( l-Benzyloxyethyl)-l,4,7-triazacyclononane 6. Compound 1(0.50 g, 0.0036 mol) and 2-benzyloxyethyl bromide (0.773 g,0.0036 mol) were stirred in freshly distilled ether (10 cm3) for 5d. The solvent was then removed in uucuo and the residue wasrefluxed in water (15 cm3) for 5 h.The water was removed invacuo, potassium hydroxide (1.6 g, 0.028 mol) in EtOH (10 cm3)was added and the mixture was refluxed for 3 d. The solvent wasremoved in vacuo, water (5 cm3) added, and the solution wasextracted with CHCl, (5 x 25 cm3). The organic layer wasdried (MgSO,) and the solvent removed to yield the product asa pale yellow oil (0.610 g, 64.4%). NMR (CDCl,): 'H (250.13MHz), 6 2.63 (8 H, dt, J = 2.82, NCH,CH,N), 2.70 (4 H, S,NCH,CH,N), 2.77 (2 H, t, J = 5.78, NCH,CH,O), 3.29 (2 H,br s, NH), 3.49 (2 H, t, J = 5.78 Hz, NCH,CH,O), 4.45 (2 H, s,PhCH,O) and 7.24 (5 H, m, aryl H); I3C (62.89 MHz), 6 45.92,46.04, 52.77 (NCH,, ring), 55.84 (NCH,CH,O), 68.58(NCH,CH,O), 72.90 (PhCH,O), 127.34, 127.46, 128.1 1(aromatic CH) and 137.95 (aromatic quaternary).EI massspectrum: mjz 263 (M').1,4,7-Triazacyclononane-l-ethanol 7. Compound 6 (0.50 g,0.0019 mol) was added to a suspension of Pd on charcoal (5%,1.20 g) in glacial acetic acid (150 cm3). Hydrogen gas wasvigorously bubbled through this solution for 5 min and thenslowly passed over the solution for 78 h.', The Pd/C wasfiltered off (glass microfibre filter-paper), washed with glacialacetic acid and the filtrate concentrated in vacuo. Potassiumhydroxide solution was added to the residue to pH 14, toluenewas added and the mixture transferred to a round-bottomedflask fitted with a Dean and Stark trap. The solution wasrefluxed for 24 h to remove water and the toluene was filteredand concentrated in uucuo to yield the product as a pale yellowoil (0.293 g, 89.1%).NMR (CDCl,): 'H (250.13 MHz), 6 2.44(14 H, m, NCH, ring and NCH,CH,OH) and 3.32 (2 H, t, J =5.5 Hz, NCH,CH,OH); 13C (62.89 MHz), 6 45.80,46.15,52.06(NCH, ring), 58.07 (NCH,CH,OH) and 59.40 (NCH, CH,OH).EI mass spectrum: m/z 173 (Mf).Compound H, L1(0.050 g, 0.00016 mol) and Cu(NO3),-3H,O (0.038 g, 0.00016mol) were each dissolved in MeOH ( 5 cm3) and the twosolutions were mixed. This gave a change from pale to intenseblue. Upon standing for several days the solution evaporated toyield a blue glass. This was dissolved in the minimum volume ofwater, and NaBF, (0.040 g, 0.00036 mol) added. No precipitateformed upon standing, whereupon the water was removed inuacuo and the residue recrystallised by diffusion of Et20 into aMeCN solution of the product to afford blue crystals (0.035 g,33.1%) (Found: C, 29.9; H, 6.01; N, 10.5.C,,H,,B,CuF,-N,NaO, requires C, 30.7; H, 5.15; N, 10.5%). IR (KBr disc):2977m, 1654s, 1474m, 1383s and 1028m cm '. FAB massspectrum: no assignable peaks.[Cu(H,L2)(0H2)] [NO,],. Compound H2L2 (0.180 g,0.0005 mol) and Cu(NO3),-3H,O (0.108 g, 0.00045 mol) wereeach dissolved in EtOH (3 cm3) and the solutions mixed to givea deep blue solution. Evaporation over several days affordedblue crystals, which were recrystallised from hot CH2C12 (0.209g, 81.6%) (Found: C, 44.4; H, 6.05; N, 12.2. C2,H,,CuN,0,requires C, 44.3; H, 6.85; N, 12.3%). FAB mass spectrum:m/z 425 [Cu(H,L2)], 488 [Cu(H2L2)(N03)] and 550Na [ Cu(H,L')(NCMe)] [ BF,] , [ NO,].CC~(H2L2)(N03)2l*CrystallographyCrystal data and details of the structure determinations appearTable 4 Summary of crystal dataFormulaA4Crystal sizelmmCrystal appearanceCrystal systemSpace groupalAblAC I API"UjANo.reflections usedDJg cm-3ZT/Kp( Mo-Ka)/mm-'F( 000)hkl RangesUnique reflectionsReflections usedAbsorption correctionsParameters refinedx in weighting schememeasured at k OF(maximum, minimum)w-l = OZ(F) + X Px, y in w1 = o2(FOz) + (xp)' + yp,P = :[max(FOZ,O) + 2FC2]R, R' (SHELX 76)R, W R (SHELXL 93)SMinimum, maximum residuesin final AF synthesisle k3C14H31N30z.CHC13404.80.80 x 0.56 x 0.12Colourless plateOrthorhombicPna211.813(6)1 1.300(6)15.23 l(9)2033.13225-271.2841500.4684018581638None21 70-14, S 1 3 , - 18 to 0--0.004 64, 1.650.047,O.1041.1 1$0.30, -0.30C1 ,H34B,CuF,N,Na0,664.520.58 x 0.42 x 0.17Deep blue prismMonoclinic9.637(2)30.814(12)10.104(2)114.43(22)27322530-321.61541500.9091364- 10 to 9,o-33,o-1034493239u, Scans0.789, 0.703376p2 1 la0.000 0350.0342, 0.04491.037-+0.45, -0.42c2 1 H39CuN509569.1 10.40 x 0.15 x 0.12Deep blue lathMonoclinic17.863(5)30.685(8)109.37( 3)52303423-321.44682600.890240833663314u, Scans0.867. 0.794363Qic10.1 14(3)- 19 to 18, a-10, O--M-0.050, 78.3-0.0607, 0.1601.073+0.88, -0.96Common parameters: Stoe Stadi-4 four-circle diffractometer with Oxford Cryosystems low-temperature device;23 Mo-Ka radiation, h = 0.7 10 73 A;0-28 scans using on-line profile fitting,24 28,,, = 45".Except where stated otherwise, non-H atoms were refined anisotropically and H atoms wereintroduced at calculated positions. Phenyl rings, where present, were refined as idealised hexagons.J. Chem. SOC., Dalton Trans., 1996, Pages 43794387 438in Table 4 and only special features of the analyses are notedhere.H,L3CHCl,. The structure was solved by direct methodsusing SHELXS 8625 and refined on F2 using SHELXL 93.26Substantial disorder in the macrocyclic ring was modelled byallowing isotropic refinement of two interpenetrant rings withconstrained values of C-C and C-N bonds which converged at1.515(7) and 1.472(3) 8, respectively.The major and minorconformers were found to have occupancies of 0.663(8) and0.337(8) respectively. Affected non-H atoms were refinedisotropically while other non-H atoms were refined withanisotropic thermal parameters, H atoms bound to N and 0atoms were refined positionally and other H atoms wereincluded in calculated positions. Molecular plots weregenerated using SHELXTL-PC.27Na[Cu(H,L')(NCMe)] [BF4],[NO3]. Deep blue prisms ofdiffraction quality were obtained by diffusion of ether into anacetonitrile solution of the complex. A correction for crystaldecay (3%) was applied during data processing.The Cu atom was located from a Patterson synthesis, and thestructure was then developed using iterative rounds of least-squares refinement and Fourier-difference synthesis usingSHELX 76.28 All non-H atoms were refined with anisotropicthermal parameters and all H atoms were fixed in calculatedpositions except H(16) and H(21) which were located andallowed to ride at a fixed distance of 0.96 A.During refinementthe CH, group of the MeCN molecule was found to bedisordered by rotation around the C-C-N axis. This wasmodelled using two distinct, equally occupied orientations withrestrained C-H and H 0 H distances. Molecular plots weregenerated using SHELXTL-PC 27 and CAMERON.29[Cu(H,L2)(OH,)] [NO,],. Deep blue laths suitable fordiffraction studies were obtained from evaporation of asolution of the complex in CH2C12.A correction for crystaldecay (4%) was applied as part of the data reduction procedure.The structure was solved by direct methods using SIR 92,'and refined using CRYSTALS.,l During refinement one of thenitrate ions was found to be disordered due to tilting of the 0,plane about the N atom. This was modelled by restraining the Nand 0 atoms to lie on a plane and refining two distinctorientations of the 0 atoms. All non-H atoms were refined withanisotropic thermal parameters and all H atoms were fixed incalculated positions, except those on the water molecule. Thesewere located and then allowed to refine with restraints on theO-H distances and H-O-H angle. The final cycles of leastsquares were performed against F2 using SHELXL 93.26Molecular plots were generated using SHELXTL-PC.27Atomic coordinates, thermal parameters and bond lengthsand angles have been deposited at the Cambridge Crystallo-graphic Data Centre (CCDC). See Instructions for Authors,J. Chem. SOC., Dalton Trans., 1996, Issue 1. Any request to theCCDC for this material should quote the full literature citationand the reference number 186/203.AcknowledgementsWe thank the University of Edinburgh for a studentship (toS. A. R.), and the EPSRC and The Royal Society for support.References1 P. Chaudhuri and K. Wieghardt, Prog. Inorg. Chem., 1987,35,329;K. Wieghardt, Pure Appl. Chem., 1988,60,509.2 P. V. Bernhardt and G. A. Lawrance, Coord. Chem. Rev., 1990,104,297; J. L. Sessler, J.Hugdahl, H. Kurosaki and Y. Sasaki, J. Coord.Chem., 1988,18,93; S. G. Taylor, M. R. Snow and T. W. Hambley,Aust. J. Chem., 1983, 36, 2359; K. Wieghardt, W. Schmidt,W. Herrmann and H. J. Kuppers, Inorg. 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ISSN:1477-9226
DOI:10.1039/DT9960004379
出版商:RSC
年代:1996
数据来源: RSC