Methods of distinguishing between cyano-stabilised imino- and methylene-phosphoranes. Crystal structures of adducts from triphenylphosphine and tetracyanoethylene (a heptacyanocyclopentenyliminophosphorane) and from triphenylphosphine and dicyanoacetylene (a hexacyanohexa-1,6-dienediphosphorane)

摘要

1978 1237 Methods of Distinguishing between Cyano-stabilised Imino- and Methyl- ene-phosphoranes. Crystal Structures of Adducts from Triphenylphos- phine and Tetracyanoethylene (a Heptacyanocyclopentenyliminophos-phorane) and from Triphenylphosphine and Dicyanoacetylene (a Hexa- cyanohexa-I ,6-dienediphosphorane) By Peter J. Butterfield and John C. Tebby,rsquo; Department of Chemistry, North Staffordshire Polytechnic, Stoke- on-Trent ST4 2DE Trevor J. King, Department of Chemistry, Nottingham University, University Park, Nottingham NG7 2RD Cyano-stabilised methylene- and imino-phosphoranes may be distinguished by the much faster rate of aikaline hydrolysis of the former and also by the position of the long-wavelength bands in their U.V. spectra, if the anion is delocalised over two or more multiple bonds.The adduct from triphenylphosphine and tetracyanoacetylene has been shown to be 2,3,3,4,4,5,5-heptacyanocyclopentenyliminotriphenylphosphorane. The molecular structure of this adduct (4) and also of (6). 1.2.3.456- hexacyanohexa-2,4-drene-l,6-diylidenebis(triphenylphosphorane), have been determined by X-ray crystallography. We have previously determined the structure of a number Little is known of the relative properties of stabilised of adducts derived from phosphines and electrophilic imino- and methylene-phosphoranes and therefore a acety1enes.l Continuing our interest in this area we have comparative study of model compounds was undertaken. studied the adduct from triphenylphosphine and tetra- Twenty-seven of these were prepared and their chemical cyanoethylene which was originally prepared by Reddy and spectroscopic properties determined.In general, and Weiss.2 the methylenephosphoranes were more basic than their The adduct is derived from one molecule of triphenyl- imino-analogues. However, when the anion was de-phosphine and two molecules of tetracyanoethylene. localised by two or more mesomerically electron-accept- It was originally assigned the five-co-ordinate structure ing groups, both types of compound resisted protonation. (1) on the basis of its i.r. spectrum, its acid hydrolysis Zinc and acetic acid reduced both methylene and imino- to butanetetracarboxylic acid, its assumed conversion to phosphoranes but the products were difficult to identify. an iminoether, and the similarity of its 31P11.m.r.chemical The 31Pn.m.r. chemical shifts were recorded and found to cover a similar range for both series. Protonation of the basic phosphoranes usually produced larger down- field shifts for the imino-compounds but the effect was NC not consistent. The i.r. spectra were recorded. All the NC compounds gave bands in both the v(P=N) region Ph (1 400-1 150 cm-l) and the v(P=C) region (900-800Ph cm-1).5 (11 U.V. spectroscopy provided the best physical method TABLE1 Ph3P=N Long-wavelength U.V. absorption bands ( AInaX,/nni) ofbsol; FN weakly and strongly stabilised methylene- arid iniino- Ph3P=C NC, F=Cbsol; /CN phosphoranes; E,,,. x in parentheses )=c bsol;N=C NC /C,C/ChN IminophosphoranesA,,,.Methylenephosphoranes A,,,,,. NC / bsol; Ph,PNPh 305 Ph,PCHPh 323NC CN gi)lsquo;CN Ph,PNC(CN) C(CN) Ph,PCHC(CN)C(CN) 41 7 (13.4) (26.0)(4) Ph,PNCN 3044:;)Ph,PCHCN(31 shift (Sp 22 p.p.m.) 7 with that of the phosphorane (2),a Adduct (4) Ph,PCPhC(CN)C(CN) (5.741structure which was later shown to be in~orrect.~ Hall Ph,PNC(CN)CHCN 305 (15.6 rsquo; Ph,PC(CN)C(CN)C(CN)2 405) (19.0)and co-workers used an optically active phosphine and found that the activity was retained in the adduct. These workers suggested the adduct was either the ylide (3) or the iminophosphorane (4), preferring the latter (14.3) of distinguishing between the two types of compound. Table 1 shows that within the iminophosphorane series studied the long-wavelength band appears at the same structure wliich was originally considered but dismissed J. B.Hendrickson, C. D. Hall, R. Rees, and J. F. Templeton,by Reddy and Weiss. Positive chcmical shifts, 8p, are downfield of 85 phosphoric acid. N. E. Waite, D. W. Allen, and J. C. Tebby, Phosphorus, 1971. 1.139: M. A. Shaw and 13. S. Ward. Tobics in Phosbhorus Chem.Lrsquo;l975; 7, 1. I1 2 G. S. Recldp and C. D. Weiss, J. Org. Cketn., 1963, 28, 1823. J, Org. Chem., 1965, 30, 3312. M. P. Naan, R. L. Powell, and C. D. Hall, J. Chewz. SOC.(B), 1971, 1683. 5 L. C. Thomas, lsquo; Interpretations of the Infrared Spectra of Organophosphorus Compounds,rsquo; Heydon, 1974, p. 87; W. Wei-grabe, H. Bock, and W. Luttke, Chem. Ber., 1966, 97, 3737; W. Wiegrabe and H.Bock, ibzd., 1968, 101, 1414; W. Luttke and K. Wilhelm, Angew. Chem. Internat. Edn., 1965, 4, 875. position (Amx. 304 amp; 1 nm) whereas for the methylene- phosphoranes the band is shifted to longer wavelength as the chromophore is extended. The rates of alkaline hydrolysis of most of the cyano- stabilised imino-and methylene-phosphoranes were determined by following the decrease in the intensity of the U.V. long-wavelength absorption, except for N-cyanoiminotriphenylphosphorane, where the broad nature of the band caused it to overlap that of triphenyl- phosphine oxide. In this case the hydrolysis was followed by the disappearance of the conjugated cyanide band in the i.r. spectrum. The rate constants and half- lives presented in Table 2 show that the iminophos- TABLE2 Rates of hydrolysis of selected cyano-stabilised imino-and methylene-phosphoranes using excess of 0.01M-NaOH at 20 "C Pseudo-first-order rate constant/s-l Half-life/s Ph,PNC(CN) C(CN) Ph,PCHC(CN)C(CN),Ph,PNC (CN) CH (CN) Rdduct (4) Ph,PC(CN)C (CN)C(CN) Ph,PNCN 0.0016 0.22 0.0037 0.0028 0.212 0.0046 417 3.2 186 25 1 3.3 150 Ph,PCH (CN) 0.23 t3 phoranes were hydrolysed much more slowly than the methylenephosphoranes. The iminophosphoranes have half-lives 150 s, whereas the methylenephosphoranes have half-lives of ca.3 s. The adduct from triphenyl- phosphine and tetracyanoethylene was hydrolysed by aqueous alkali with a half-life of 250 s. It was not protonated by perchloric acid and there was a band at A,,, 303 nm in its U.V.absorption spectrum. The lack of protonation of the adduct indicates that if it was a methylenephosphorane it would have an extended conjugated chromophore, such as that in structure (3), 8 FIGURE Perspective drawing of the1 triphenylphosphine-tetracyanoethyleneadduct (4) and would absorb above 400 nm. Thus the data indicates that the adduct is an imino- rather than a methylene-phosphorane. X-Ray crystallographic analysis has established that the adduct has the cyclopentenyliminophosphorane I. Kawamoto, T. Hata, Y. Kishida, and C. Tamura, Tetra-hedron Letters, 1971, 2417; W. Dreissig, H. J. Hecht, and K. Plieth, 2.Krist., 1973, 157, 132. J.C.S. Perkin I structure (4); Figure 1 is a perspective drawing of the molecule. Tables 3 and 4 list bond lengths and angles, I N(4) 2FIGURE Crystallographic numbering system of the triphenylphosphine-tetracyanoethylene adduct (4) and Table 5 a selection of torsion angles.Figure 2 shows the crystallographic numbering system. TABLE3 Bond lengths (A) of adduct (a), with standard deviations in parentheses P(1)-N(1) 1.615(2) C(18)-C (13) 1.397 (4) P(1)-c ( 11 1.792(2) N ( 1 )-C (19) 1.317 (2) W)-C(7) 1.789(2) C(19) -C (20) 1.3 72( 3) P(1)-C( 13) 1.793( 2) C (20)-C( 2 1) 1.524(3)C(l)-C(2) 1.388(3) C(20)-C (24) 1.41 7(3) C( 2)-c (3) 1.389(4) C(24)-N(2) 1.143(3)1.377(4) C( 21)-C( 22) 1.580(3)c(3)-c(4) 1.3 86 (4) C (21)-C (25) 1.478( 3) c(4)-c(5) 1.381(4) C(2 1)-C (26) 1.483 (3) c(5)-c(6)c(6)-C ( 1) 1.396 (3) C( 25)-N( 3) 1.140(3)1.389(3) C (26)-N (4) 1.134(3)CWC (9) c(7)-c(8) 1.393 (3) C (2 2) -C (23) 1.574 (3) C (9) -C (10) 1.3 79 (3) C( 22)-C (27) 1.472(3)C(l0)-C(l1) 1.377(3) C(22)-C (28) 1.481(3)C( 11)-C(12) 1.392(3) C(27)-N(5) 1.138(3)C(12)-C(7) 1.389(3) C(28)-N( 6) 1.129(3)C(13)-C(14) 1.390(3) C(23)-C( 19) 1.560(3)C(14)-C (15) 1.397(4) C (23)-C (29) 1.471(3)C( 15)X (16) 1.372(5) C(23)-C(30) 1.477(3)C(1 6)s (17) 1.3 84 (5) C( 29)-N (7) 1.137 (3) C(17)-C (18) 1.389(4) C(30)-N(8) 1.138(3) This is the first crystallographic study of a cyano- st abilised iminophosphorane although two cyano-st abil- ised methylenephosphoranes have been previously examined.6 The P-N bond length 1.615(2) A in the adduct (4) is typical of other stabilised iminophosphor- anes and the anion delocalisation has the expected effect of lengthening the C(l9)-C(20) and C(24)-N(2) multiple bonds and shortening the N(1)-C( 19) and C(20)-C(24)single bonds.There is also a slight shorten- ing of the C(20)-C(2l) bond 1.524(3) A compared to the remaining. saturated C-C bonds (mean 1.57 A) in the cyclopentene ring. It is interesting to note that the phosphorus atom is only slightly distorted (7.1") from the plane of the NCXCN conjugated system which assists the delocalisation of the negative charge on nitrogen. The P-N-C bond angle (130") is larger than in the less-stabilised iminophosphorane (5);* the contri- 7 T. S. CameronandC. K. Prout, J.Chem. SOC.(C),1969,2285.* M. J. E. Hewlins, J. Chem. SOC.(B),1971, 942. bution of a second plane of d,-p, PN bonding has been discussed in terms of the P-N-C bond angle although TABLE4 Bond angles (") of adduct (4), with standard deviations in parentheses N(1)-P( 1)-C( 1) 109.7(1) N( 1)-P( 1)-C(7) 107.6(1) N( 1)-P( 1)-C( 13) 114.1(1) C(l)-P(l)-C(7) 107.6(1) C(1)-P(1)-C(l3) 111.3(1) C(7)-P(l)-C( 13) 106.2(1) P(1)-c( 1)-c( 2) 119.2(2) P(1)-C( 1)-C(6) 120.4 (2) c(2)-c ( 1)-C (6) 120.0(2) c( 1)-c (2)-c (3) 119.7(2) C (2)-C( 3)-$ (4) 1 19.9(3) c(3)-C(4)-C (4) 120.1(3) C (4)-C (5)-C ( 6) 120.3(2) C( 5)-C( 6)-C (1) 119.6(2) P(l)-C(7)-C(8) 120.9(3)P(l)--C(7)-C(l2) 119.4(2) C(S)-C(7)-C( 12) 119.7( 2) C (7)-C (8)-C (9) 119.8(2) C(8)-C(9)-C(lO) 1 20.3 (2) C(9)-C(10)-C(11) 120.1(2) c(10)-c (1 1)-c( 12) 120.2(2) C( 1 1)-C (12)-C (7) 11 9.9( 2) P(1)-C( 13)-C( 14) 121.3(2) P(1)-C( 13)-c ( 18) 118.3(2) C(14)-C( 13)-C( 18) 120.3 (2) C( 13)-C( 14)-C (1 4) 119.4(3) C( 14)-C ( 15)-C ( 16) 120.1(3) C(15)-C(16)-C(17) 120.9(3) C(16)-C ( 1 7)-C ( 18) 119.8( 3) C( 17)-C ( 18)-C( 13) 119.5(3) P(l)-N{l)-C(l9) 130.0(1) N (1 )-C (19)-C (20) N(l)-C(19)-C(23) C( 20)-C( 19)-C( 23) c( 19)-c (20)-c (21) c(19)-c (20)-c (24) c(21)-c(20)-c (24) c(20)-c (21)-c (22) c(20)-c (21)-c(25)C (20)-C (2 1)-C (26) c(22)-c (2 1)-c(25) C (22)-C (2 1 )-C (26) C (25)-C (2 1 )-C (2 6) c(21)-c(22)-C (23) C( 21)-c(22)-c(27) C (2 1)-C (22)-C (28) C (23)-C (22)-C (2 7) C( 23)-C( 22)-C( 28) C (27) -C (22) -C (28) c(22)-c (23)-c ( 19) C( 22)-C( 23)-C( 29) c(22)-c (23)-c (30) C( 19)-c (23)-c (29) C( 19)-C( 23)-c (30) c(29)-c (3 2)-c (30)C (20)-C (24)-N (2) C(21)-C (25) -N (3) C( 21)--C(25)-N(4) C (22)-C (28)-N (6)C (22)-C (27)-N (5) C (23)-C (30)-N ( 18) C (23)-C (29)-N (7) 137.8( 2) 115.6(2) 106.6(2) 113.9( 1) 128.9( 2) 117.1(2) 101.3(2)110.5(2) 113.5(2) 113.3( 2) 113.1(2) 106.4(2) 102.2(2)11 5.2( 2) 108.8 (2) 111.7 (2) 106.8(2)11 1.5( 2) 101.6(1)1 12.7( 2) 11 1.2(2) 115.5(2) 107.7 (2) 108.0( 2) 174.7(2) 174.0(3) 175.8(3)175.4( 2) 174.4(2) 117.9(2) 175.4(2) steric effects cannot be ignored in this case.The cyclo- pentane ring is close to planarity with the C(22) atom tilted 36" out of the plane.ph3p( k C CN Ph36 bsol;'7 J /NC CN N=C=C SCHEME We consider that the adduct (4)is formed via the X-Ray crystallographic analysis has established that mechanism shown in the Scheme. Although there are the triphenylphosphine-dicyanoacetylene adduct has I"" NCbsol;i:=C' / the 1,6-dimethylenephosphoranestructure (6); Figure 3 CN is a perspective drawing of the molecule looking down Ph3P-C the y axis with, for clarity, only one atom of each bsol;/bsol; phenyl ring shown. Tables 6 and 7 list bond lengths and c=c /bsol; /C=PPh3 angles and Table 8 contains a selection of torsion angles. ph3p=NnBr NC 'CN NC Figure 4 shows the crystallographic numbering system. The most important structural features are the cis-isation of the anion and also delocalisation of the positive charge on phosphorus by back-bonding from nitrogen.This pathway also involves least rearrangement of the reactants. Reaction of phosphorus(II1) atoms with electronegative atoms is well established l1 and tri-phenylphosphine has been shown to attack the nitrogen atoms of diazo compounds when a stabilised ion is produced.12 We have previously studied a similar cyano-stabilised adduct formed in the reaction of triphenylphosphine TABLE5 Selected torsion angles (") of adduct (4) N(l)-euro;'(l)-C(l)-C(2) 21.2 C(lS)-C(13)-euro;'(1)-N(l) 55.3 N( l)-P(l)-C(7)-C( 12) 61.4 P(1)-N( 1)-C( 19)-C(20) 7.1 P(l)-N(l)-C(l9)-C(33) 176.1 X(1)-C(19)-C(20)-C(24) 11.3 N ( 1 )-C ( 19)-C (20)-C (2 1) 171.5 C(23)-C( 19)-C( 2O)-C( 2 1) 11.5 c( 1 9)-C( 20)-c (2 1)-c (22) 12.7 c(23)-C (22)-C ( 2 1)-c(20) --30.8 C(19)-c (23)-C (22)-C (21) 37.5 C( 22)-C (23)--C( 19)-N( 1) 151.3 c(q-c(23)-C (1 9)-c (20) -30.9 and dicyanoacetylene. The adduct was assigned the 1,6-dimethylenephosplioranestructure (6) on the basis of i.r., n.m.r., and mass spectral data.13 It has a strong U.V. absorption at 485 nm (E 21 800) which, from the foregoing study, is also in accordance with the methylenephosphorane structure (6).A crystallo-graphic study was undertaken in order to confirm the structure and determine the stereochemistry of this novel structure. NCbsol; //c NCyc) 'C-CN)/CN Adduc't (4) many examples of similar reactions proceeding by attack at the ethylenic carbon,1deg; the attack at nitrogen gives an intermediate in which there is extensive delocal- G.W. .4damson and J. C. J. Bart, Chem. Comnz., 1969, 1036; A. W. Schlueter and R. A. Jacobsen, J. Chem. SOC.(A), 1968, 2317. L. I-Iorner and K. Klupfel, Annalen, 1955, 591, 69; F. Ramirez, J. 1;. Pilot, and C. P. Smith, Tetrahedron, 1968,24, 3735. 11 H. Hoffmann and H. J. Diehr, Angew. Ch~m.IntPrnat. Edn., 1964, 3, 737. geometry about the P-y carbon-carbon bonds C(20)-C(21),and the cisoid conformation of the molecule as a whole which originates from the stereochemistry about the C(21)-C(21)* bond. This central bond 1.476(5) A is not significantly longer than that normal for a con- jugated system (1.46 A), and the attached atoms are l2 B. H.Freeman, D. Lloyd, and M. C. Singer, Tetrahedron, 1974, 30, 211; A. W. Johnson, ' Ylid Chemistry,' Academic Press, 1966. 13 M. A. Shaw, J. C. Tebby, K. S. Ward, and D. H. Williams, J. Chem. SOC.(C), 1968, 1609. only 61" from a planar cisoid conformation. Although the suggested mechanism of formation of the diphos- phorane (6) involves the cis-addition of dicyanoacetylene 3FIGURE Perspective drawing of the 1,6-~li1nethylenepl1osphorane(6) I I N(2) FIGURE Crystallographic numbering system of the4 1,6-dirnethylenephosphorane(6) to a dimer of the 1 : 1 phosphine-acetylene inter-niediate,13 as shown in (7), the stereochemistry is probably governed by other factors. NC (7) EXPERIMENTAL Tetracyanoethylene (m.p.200 "C, sealed tube) was purified by sublimation. 1.r. spectra were recorded on a Perkin-Elmer 457 spectrometer, and U.V. spectra on a Perkin-Elmer 402 instrument. Proton n.m.r. spectra were measured on a JEOL MH 100 spectrometer. 2,3,3,4,4,5,5-He~tacyanocycEopentenyliminotriphenyE-9hosfihorane (4) .-This was prepared from triphenyl-phosphine (5.8 g, 22 mmol) and tetracyanoethylene (5.2 g, 40 mmol) according to the method of Reddy and Weiss., Recrystallisation gave buff crystals (8.8 g, 80y0), m.p. 164-165 "C (lit.,, 168-170 "C) (Found: C, 69.4; H, 3.5; N, 21.4. C,,HI5N,P requires C, 69.5; H, 3.4; N, 21.6); J.C.S. Perkin I vmak (KBr disc) 3 OSOw, 2 245w, 2 198s, 1.580~~1 437s, 1 385s, 1 115s, 997s, 905s, 81Os, 790s, 750s, 745s, and 728s cm-'; A,,, (CH,Cl,) x 238 (12.30), 268 (8.10), 277 (7.40), and 303 (5.74) nm.Reduction of the Adduct (4).-The adduct (4) (5.2 g, 10 mmol) in chloroform (150 ml) was heated under reflux with TABLE 6 Bond lengths (A) of the 1,6-diphosphorane (6), with standard deviations in parentheses 1.802(3) C(13)-C (14) 1.387 (6) '(')-'P(1)-c ((')7) 1.805 (4) C(14)-C (15) 1.388(6)P(l)-C(13) 1.779(4) C(15)-C ( 1 6) 1.3 75 (6) P(1)-C ( 19) 1.7 6 1(4) C( 16)-C (17) 1.377( 7) ( (2) 1.3 76 (5) C(17)-C( 18) 1.365( 6) 1.376(6) C(18)-C( 13) 1.395(4)1.354(8) C(19)-C( 20) 1.423(5) C (20) -C (2 1) 1.373(5)C(21)-C(21r) * 1.476(5) C(19)-C( 22) 1.417(5) C (20)-C (23) 1.42 7 (6) C (21)-C( 24) 1.421(5) C (9)-C (1 0) 1.384( 9) C( 22)-N( 1) 1.153(5) C( 10)-C (1 1) 1.358(8) C(23)-N(2) 1.136(7) C(11)-C( 12) 1.398(8) C(24)-N(3) 1.158(6)C(12)-C (7) 1.384( 6) * C(21I) is at 1 -x, y, 0.5 -z TABLE7 Bond angles (") of the 1,6-diphospho1ane (6), with standard deviations in parentheses C(l)-C(l)-C(7) 106.3(2) P(1)-C( 13)-c (14) 121.2(3)C(1)-P(1)-C (13) 110.3( 2) P(l)-C(13)-C(lS) 118.6(3) C( 1)-P( 1)-C (19) 111.3 (2) c( 14)-C( 13)-c (1 8) 120.3( 4) C (7)-P( 1)-C{ 13) 109.6(2) C(13)-C( 14)-C( 15) 11 9.7 (3) c(7)-P( 1)-c(1 9) 110.q2) C( 14)-C ( 15)-C ( 16) 119.0(4)C( 13)-P( 1)-C ( 19) 108.4 (2) C (1 5)-C ( 16)-C( 17) 12 1.4( 5)P(1)-C( 1)-C(2) 119.7(3) C(16)-C ( 17)-C ( 18) 120.1 (4) P(1)-C ( 1)-C (6) 120.5 (3) C, (17)-C ( 18)-C( 13) 119.5(4)C (2)-C (1 )-C (6) 11 9.8 (3) P(1)-c( 19)-c (20) 126.6(3)C(l)-C(2)-C(3) 118.8(4) P(1)-c (19)-c (22) 113.4(3)C(2)-C (3)-C( 4) 12 1.5 (5) C( 2O)-C ( 19)-c (22) 118.3(3)C.(3)-C(4)-C(5) 119.4(4) C( 19)-c (20)-C (21) 125.6(3)C (4)-C (5)-C (6) 1 20.7 (5) c( 19)-c (20)-c (23) 119.5(3) C (5)-C (6)-C (1) 119.7 (4) c(2 1) -c (20)-c (23) 114.9(3)P(1)-C ( 7)-C (8) 120.7 (3) C (20)-C (2 1)-C (24) 12 1.2(3) P(1)-C (7) -C (12) 119.4(3) c(20)-c (2 1)-C( 211) 124.5(3) C (8)-C (7)-C ( 12) 119.9( 4) C( 24)-c (21)-c(211) 11443) C (7)-C (8)-C (9) 119.9(5) C(19)-C (22)-N ( 1) 176.0( 3) C(8)-euro;(9)-C(lO) 119.9(5) C (20)-C (23) -N (2) 176.3 (4) C (9)-C (10)-C (1 1) 120.4(5) C (21) -C (24)-N (3) 174.7(5) C(1 0)-C (11)-C (12) 120.5 (6) C(10)-C ( 12)-C (7) 119.4 (4) TABLE8 Selected torsion angles (") of the 1,6-diphosphorane(6) c(2)-c (1)-P(1)-c(19) -158.1 C (8)-C (7) -P( 1)-C (19) -118.8 c(14)-c ( 13)-P (1)-c ( 1 9) -124.0 c( 1)-P( 1)-c(1 9)-c (20) -91.4 c(7)-P ( 1)-c( 19)-c (20) 150.5 c(13)-P( 1 )-c(19)-c (20) 30.1 P(1)-C( 19)-C( 20)-c (2 1) -171.8 c( 19)-c (20)-C.( 2 1)-c(211) 7.3 C( 20)-c (2 1)-c(2 lI)-C (201)* 61.0 * C(201) is at 1 -x, y, 0.5 -z.zinc powder (4 g) and acetic acid (5 ml) for 30 min. The reduced product precipitated from the filtered solution by addition of diethyl ether. Recrystallisation from aqueous alcohol gave N-1-( 2-aminomethyl) hexacyanocyclopentane- aminotriphenylphosphonium acetate (4.0 g 70y0), m.p. OC278-280 (Found: C, 67.4; H, 4.35; N, 20.1. C32H25-N,O,P requires C, 67.7; H, 4.4; N, 19.7); vmaX.(KBr disc) 3 500m, 3 350br,m, 3 050m, 2 WOW, 2 250m, 1 740s, 1978 1670s, 1580s, 1445s, 1125s, 950ms, 850m, 765m, and 750s cm-1; .c(CF,CO,H) 2.2-2.5 (15 H, br,s), 4.6 (1 H, dd, ,JpNCH 15.0, 3JHCCH 7.0 Hz), 5.1 (1 H, m), 6.8 (3 H, s), and 7.7 (2 H, br,m). N-Tricyanovinyliminotraphenylp1iosphorane.-Tetra-cyanoethylene (2.5 g, 20 mmol) in dry benzene (100 ml) was added dropwise to a stirred solution of iminotriphenyl- phosphorane l4 (5.4 g, 20 mmol) in dry benzene to give a buff-coloured solid (2.5 g). After Soxhlet extraction with benzene colourless crystals were obtained (1.5 g, 56y0), m.p. 198-200 "C (lit.,15 192-194 "C) (Found: C, 72.6; H, 3.85; N, 14.45. Calc. for C,,H,,N,P: C, 73.0; HI 3.95; N, 14.8); vmax.(KBr disc) 3 OBOw, 2 225s, 2 215s, 2 190m, 1 575br,m, 1 500br,ni, 1 435s, 1 3955, 1 250s, 1 113s, 1 OOOni, 877s, 760ms, and 732s cm-l; A,,,. (CH,Cl,) (E~~,~. lo-",x 233 (18.5), 268 (7.90), 276 (7.02), and 303 (13.40) nm. Reduction of N-Tricyanovinyliminotriphenylp?hosphorane. -This was reduced as described for the adduct (4) and prepared as a colourless solid, m.p. 285-5287 "C (Found: C, 69.85; H, 6.65; N, 12.65; C,amp;amp;,N4021' requires (1, 67.8; H, 6.46; N, 12.5y0); vmax. (KBr disc) 3 450br,ni, 3 320m, 3 060w, 2 92Ow, 2 860w, 2 250w, 1 675s, 1 585s, 1440s, 1 120s, 950ms, 845m, 760m, and 750s cm-l; .c(CF,-C0,H) 2.3-2.6 (15 H, br, s), 4.7 (1 H, br, dd, 3JpNCH ca. 15.0, 3JHccE ca. 9.0 Hz), 5.15 (1 H, br,ni), 6.85 (3 H, s), and 7.75 (4 H, br,m).TetracyanoallylidenetriPheny1phosphorane.-This was pre- pared by the method of Trippett,16 m.p. 239-240 "C (1it.,l6 239-240 "C); vmax. (KBr disc) 3 050w, 2 230w, 2 210s, 2 195m, 2 182s, 1463s, 14353, 1364ms, 1 133m, 1 103s, 996mw, 810s, 752s, and 720s cm-l; Amx. (CH,Cl,) (E,~~. X 10-3) 230 (44.60), 268 (6.25), 276 (4.35), 401 (6.3), and 405 (19.0) nm. Reduction of Tetracyanoallylidenetriphenylp?~osphorane.-This was reduced by the method described for the adduct (4). The product was a colourless solid, m.p. 262-265 "C (Found: C, 68.9; H, 6.75; N, 12.05. C,,H3,N40,P requires C, 68.1; H, 6.94; N, 11.78); v,,~~.(KBr disc) 3 315br,m, 3 295br,m, 3 040w, 3 OOOw, 2 930w, 2 220w, 1 680br,m, 1550br,s, 1440s, 1055s, 1028s, 950s, WOW, and 750nib.v cm-l; r(CF,CO,H) 2.25-2.55 (15H, br, s),4.5 (1 H, br,m), 5.25 (1 H, br,m), 6.75 (3 H, s), and 7.65 (6 H, br,m).N-Cyanoiminotriphenylphosphorane.-This was prepared from iminotriphenylphosphorane l4 and cyanogen bromide by the method of ref. 17 and recrystallised from benzene, m.p. 194-196 "C (lit.,l8 195 "C). 2,3,3'-Tricyanovinylbenzylidenetriphenylphosphorane.-Benzylidenetriphenylphosphorane l9 ( 1.75 g, 5 mmol) in dry tetrahydrofuran (50 ml) was added dropwise to a solution of tetracyanoethylene (0.65 g, 5 mmol) in dry benzene (400 ml) with stirring. Recrystallisation of the precipitate from ethanol-light petroleum gave yellow crystals (1.9 g, 86y0), m.p. 248-250 "C (Found: C, 79.4; H, 4.35; N, 9.40.C,,H,,N,P requires C, 79.5; H, 4.42; N, 9.28); vmx, (KBr disc) 3 060w, 2 238w, 2 ZOOS, 2 180s, 1 587m, 1 500s, 1474s, 1440s, 1 360ms, 1 193w, 1 163w, 1 lOOs, 1063m, 1OOOms, 903m, 815s, 750w, 745s, and 725s cm-l; A,,,. (CH,CI,) x 236 (15.0). 265 (6.l), 269 (8.8),297 (5.1), and 415 (15.6) nm. l4 L. Birkofer and A. Ritter, Angew. Chem. Internat. Edn., 1965, 4, 417. l5 R. Partosand I(.Ratts, J. Amer. Chem. Soc., 1966, 89, 4996; N. Zhmurova and R. S. Yurchenko, Zhur. obshchei. Khim., 1968, 38, 592. l8 S. Trippett, J. Chem. Soc., 1962, 4733. l7 A. Schmidpeter and D. Ebeling, Chem. Ber., 1968,101, 2602. 2-Cyanovinyliminotriphenyl~hos~horane.-Methyltri-phenylphosphonium bromide 2O (4.5 g, 12 mmol) suspended in dry ether under nitrogen was treated with butyl-lithium (6 ml of 15 solution in hexane) (0.8 g, 15 mmol) with stirring.After 30 niin cyanogen was added at room temperature until the yellow colour of methylenetriphenyl- phosphorane was removed. The buff-coloured precipitate was filtered off under nitrogen and dried in vacuo to give a hygroscopic buff -coloured powder, m .p.210-2 14"C (Found: C, 77.1; H, 4.85; N, 8.85. C,,H,,N,P requires C, 76.7; H, 5.18; N, 8.53); v,,~~,. (KBr disc) 3 040w, 2 960w, 2 9OOw, 2 195s, 1 590~7, 1480ni, 1 438s, 1 340s, 1 llOs, 1 005m, 91Oms, 760m, 745m, and 720s cm-l. Cynnomethylivninotripheny1pIzosplzorane.-Chloroaceto-nitrile (0.75 g, 10 mniol) was added to a solution of imino-triphenylphosphorane l4(2.8g, 10 mmol) in dry tetrahydro- furan under nitrogen and the solution stirred for 1 h.The precipitated conjugate acid of compound (11) was collected, dried, and dissolved in dry acetonitrile. Butyl-lithium (5 ml of a 15 solution in hexane) (0.7 g, 12 mmol) was added with stirring under nitrogen. After 1 h the solution was filtered under nitrogen and the acetonitrile solvent removed by rotary evaporation to give the product as colourless crystals (2.2 g, 68y0), m.p. 286-287 "C (sealed tube); vmx. (KBr disc under nitrogen) 3 060w, 2 930w, 2 240w, 1 580m, 1480m, 1 4354 1 295s, 1 115s, 1 OOOnis, 850m, 845m, and 750s cm-l; .c(CF,CO,D) 2.3-2.5 (15 H, m) and 5.1 (2 H, d, J 16.0 Hz). The compound was too unstable for us to obtain reproducible elemental analyses. Alkaline Hydrolysis of Imino- and Methylene-phosphoranes. -A stock solution of each compound listed in Table 4 (1 x 10-3~ in ethanol-water, 19 : 1) was prepared.The optical density of the long-wavelength absorption was calibrated directly with solutions of known concentration. Equal volumes of the stock solution and sodium hydroxide solution (0.01~ in 95 ethanol) were mixed and the decrease in intensity of the long-wavelength absorption recorded by a driven chart at this fixed wavelength. The times taken for the absorption curve to reach the intensities of the successive half-concentrations were plotted against log, of each con- centration. Linear plots were obtained and the half-lives were calculated from the slope (A) by use of the equation kd = 0.693/k.The rate constant and half-lives are given in Table 4. A lkaline Hydrolysis of N-CyanoiminotriphenylpI~os-p1zorane.-Standard solutions were used to relate directly concentrations with the intensity of the i.r. absorption band at 2 180 cm-l. The hydrolysis was performed in an infrasil cell and the decrease in intensity of the v(CN) 2 180 cm-l band recorded by driven chart at this fixed wavelength. The rate constant and the half-life were calculated as already described. X-Ruy Crystallographic Analysis of the Triphenylphos-phine-Tetracyanoethylene Adduct (4) .-Cell parameters were first determined from oscillation and Weissenberg photo- graphs and then by least squares from the setting angles of 14 reflections on a Hilger and Watts four-circle diffracto- meter.M. E. Hermes and F. D. Marsh, J. Amer. Chem. Soc., 1964,86, 4506. 19 S. 0. Grim, A. W. Yankowsky, S. A. Bruno, W. J. Bailey, E. F. Davidoff, and T. J. Marks, J. Chem. and Eng. Data, 1970,15, 497. 2O V. Mark, C. Dungan, M. Crutchfield, and J. Van Wazer, Topics in Phosphorus Chem., 1967, 5, 227. 1242 J.C.S. Perkin I TABLE9 U = 2 605.7 ,,Do = 1.322 g ~m-~,= 4, D, = 1.33 g Fractional co-ordinates (x lo4)of the adduct (a), with ern-,, F(000)= 1064. Space group Y2,/c from systematic standard deviations in parentheses absences. Cu-K, radiation (nickel filter), A = 1.5418 A; xla Ylb zlc p(Cu-K,) = 12.24 cm-l. 7 267(0) 4 013(0) 3 473(0) 6 651(1) 4 232(1) 4 545(2) TABLE11 6 741(2) 5 102(2) 5 054(2)6 283(2) 5 265(2) 5 904(2) 31P n.m.r.chemical shifts data for alkyl-and amino-5 742(2) 4 566(2) 6 239(2) phosphonium salts, methylene-and imino-phos-5 647(2) 3 698(2) 5 728( 2) phoranes6 106(2) 3 522(2) 4 890(2) 7 727(1) 2 836( 1) 3 626(2) Ph,kH,Br-22.7 a 20.37 514(2) 2 169(2) 2 826(2) Ph,PCH, 7 887(2) 1260(2) 2 962(2) Ph,kH,Ph Br-d 23.58 462(2) 1019(2) 3 890(2) Ph,PCHPh 7.1 f I8 670(2) 1676(2) 4 687(2) 8 307(2) 2 589(2) 4 559(2) Ph,PCH,COPh C1-I 26.5 6 498(2) 4 031(1) 2 227(2) Ph,PCHCOPh i 21.0 5 556(2) 3 840(2) 2 157(2) Ph,GCH,CO,Et Cl-f 21.5 4 996(2) 3 787(2) 1 163(3) Ph,PCHCO,Et 9 18.0 5 376(2) 3 927(2) 267(2)6 313(2) 4 125(2) 330(2) Ph,lkH,CN C1-g 24.5 6 881(2) 4 174(2) 1312(2) Ph,PCHCN I 22.5 8 173(1) 5 59531) 3 155(2) Ph,PCHC(CN) C(CN) ,l 23.5 7 567(1) 6 257(1) 2 651(2) Ph,kH(CN), C1- n 29.08 042(1) 7 104(1) 2 232(2) Ph,PC(CN), n 21.29 076(1) 6 736(1) 2 336(2) Ph,PC(CN)COCO,Me P 24.59 157(1) 6 058( 1) 3 322(2) Ph,PC(Ph)C(CN) :C(CN) ,P 22.06 584(2) 6 271(2) 2 512(2)7 612(2) 7 316(2) 1131(2) Ph,$NH, C1-b 36.0 7 977(2) 7 986( 1) 2 844(2) Ph,PNH b -2.0 9 795( 1) 7 479(1) 2 488(2) Ph36NHPh C1- 34.09 154(1) 6 132(1) 1412(2) Ph,PNPh 2.09 941(2) 5 394(2) 3 387(2) 9 271(1) 6 604(2) 4 317(2) Ph,$NHCOPh C1-h 25.5 8 134(1) 4 735( 1) 3 545( 1) Ph,PNCOPh h 21.5 5 794(1) 6 355(2) 2 386(2) Ph,$NHCO,Et C1-23.0 7 205(2) 7 477(2) 311(2) Ph,PNCO,Et 20.0 7 870(2) 8 660(2) 3 289(2) 10 371(2) 8 025(2) 2 686(2) Ph,$NHCN Br-38.0 9 199(2) 5 622(2) 744(2) Ph,PNCN (9) 27.0 10 586(2) 4 931(2) 3 455(2) Ph,PNC(CN):C(CN), m 24.5 9 329(2) 7 020(2) 5 084(2) Ph,PNC(CN):CH(CN) 0 21.0 Ph,PNC(CN) :CH, 14.0 TABLE10 Ph,$NHCH,CN C1-36.0 co-ordinates ( x lo4) of the 3,6-diphosphorane Ph,PNCH,CN 23.0 (6), with standard deviations in parentheses a Ref.19. Ref. 13. c S. 0. Grim, W. McFarlane, and Atom xla Ylb zlc T. J. Marks, Chem. Comm., 1967, 1191; T A. Albright and W) 3 397(1) 4 779(1) 1839(1) E. E. Schweizer, J. Org. Chem., 1976, 41, 1168. d F. Ramirez, C(1) 2 520(2) 4 507(3) 1122(2) 0.P. Madan, and C. P.Smith, Tetrahedron, 1966,22,567. * W. c(2) 2 074(3) 5 354(3) 764(2) Wiegrabe and H. Bock, Chem. Ber., 1968, 7, 661. fRef. 18. (73) 1394(3) 5 129(5) 234(3) S. Trippett and D. Walker, J.Chem.Soc., 1959, 3874.H. H. C(4) 1163(3) 4 lOO(5) 50(3) Wassermann and R. C. Koch, Chem. Ind., 1956, 1014. G. C(5) 1611(3) 3 267(4) 395(3) Aksnes, Acta. Chem. Scand., 1961,15, 692. 9 G. Aksnes, ibid., C(6) 2 289(3) 3 460(4) 936(2) 1961, 15, 438. kH. R. Kricheldorf, Synthesis, 1972, 12, 605. (77) 3 840(2) 5 958(3) 1543(2) 1 E. Zbiral, Monatsh., 1965, 96, 1967. Ref. 14. * L. Horner (78) 3 958(3) 6 892(3) 1971(2) and H. Oediger, Chem. Ber., 1958, 91, 37. E. Ciganek, J.O lsquo;(9) 4 299(3) 7 789(4) 1735(3) Org. Chem., 1970, 35, 3631. p E. Ciganek, J. Org. Chem., 1970, 4 545(3) 7 740(4) 1086(3) 35, 1725. c(lo) 4 406(3) 6 842(5) 653(3)C(11) 4 045(3) 5 938(4) 873(2) Reflections were measured out to 8 6 75rdquo; by the W-28 lsquo;(12) 3 159(2) 5 055(3) 2 694(2) scan mode.4 223 planes having a net count 230 were C(14)c(13) 2 387(2) 5 075(3) 2 742(2) deemed observed. Lorentz polarisation but not absorption 2 222(3) 5 261(4) 3 423(2) lsquo;(15) 2 831(3) 5 456(4) 4 034(2) corrections were made. The structure was solved routinely lsquo;(16) 3 598(3) 5 443(4) 3 987(2) by direct methods by use of MULTAN 21 and was refined lsquo;(17) 3 768(2) 5 237(3) 3 324(2) without difficulty by block-diagonal least-squares. In the lsquo;(18) 4 044(2) 3 670(3) 1 970(2) later stages a weighting scheme of the form w = 1 forlsquo;(19) 4 075(2) 2 801(3) 2 478(2) c(20) 4 641(2) 2 012(3) 2 636(2) F, A and w = (A/F,)2when F, A, the value of A was c(21)C(22) 4 423(2) 3 538(3) 1389(2) 20.0. Hydrogen atoms were included in calculated posi- 3 474(2) 2 698(3) 2 864(2) tions but were not refined.At convergence the conven- c(23) 4 552(2) 1082(3) 3 055(2) c(24) 4 690(2) 3 444(3) 887(2) tional R was 4.7.N(1) 2 993(2) 2 558(3) 3 161(3) Table 9 shows the fractional co-ordinates of the atoms. ldquo;2) N(3) 4 528(2) 289(3) 3 380(3) With the exception of MULTAN all calculations were made Crystal data. C,,H,,N,P, M = 518.5. Monoclinic, a = 21 G. Germain, P. Main, and M. M. Wolfson, Acta Cryst., 1971,14.594(3), b = 14.112(2), c = 12.833(3) A, p = 99.63(2)rdquo;, A27, 368. 1978 by use of the ' X-Ray '70 ' program system.22 Observed and calculated structure factors and thermal parameters for both compounds (4) and (6) are available in Supple- mentary Publication No. SUP 22217 (28 pp., 1 microfiche).* X-Ray Crystallographic Analysis of the Damethylene-phosphorana (6).-Cell parameters were determined as before from the setting angles of 23 reflections.Crystal data. C,,H,,N,P,, M = 752.7. Monoclinic, a = 17.628(2), b = 12.365(2),c = 18.616(3) A, p = 104.57(2)", U = 3 927.2 Hi3, D, = 1273 g cm-,, Z = 4, D, = 1.26 g ern-,, F(000) = 1560. Space group Cs/c from systematic absences. Mo-A', radiation (graphite monochromator) 1 = 0.710 69 A; p(Mo-Ka) = 1.14 cm-'. The preliminary photographs had shown that the crystal was not single, but no better sample was obtainable and it proved possible to collect data from one of the component crystals with no obvious interference from the other com- ponents. Reflections were scanned (w-28 mode) out to 0 25".3 485 observable reflections were measured of which 2 041 having a net count 30 were deemed observed. Lorentz polarisation but not absorption corrections were applied. * For details of Supplementary Publications see J.C.S. Perkin I, 1977, Index issue. The structure was solved by use of the centrosymmetric direct methods program SHELX, which revealed the mole- cule lying on the two-fold axis at x = 0.5, z = 0.25. Refine-ment proceeded normally. In the final stages hydrogen atoms were included in calculated positions with U 0.05. The final weighting scheme was of the form w = 1/(1 + (F -B)/A)2 with B = A = 25.0. The refinement with non-hydrogen atoms treated anisotropically was in three blocks, and the final R value was 6.1. The perspective drawing was obtained by use of the PLUTO program.23 Table 10 displays the fractional co-ordinates of the atoms. For both structures intramolecular contacts were greater than the sum of van der Waals radii. 31PN.un.r.Analysis.-The spectra of the alkyl- arid amino- phosphonium salts and their corresponding methylene- and imino-phosphoranes (usually in chloroform solution) were determined on a Perkin-Elmer R10 spectrometer operating at 24.6 MHz. The 3LPchemical shifts are given in Table 11. 7/1091 Received, 23rd June, 19771 22 1970 Revision of ' X-Ray 67,' eds. J. M. Stewart, F. A. Kundall, and J. C. Baldwin, University of Maryland Technical Report TR 6758, 1967. 23 Cambridge Data Centre Program ' PLUTO,' W. D. S. Motherwell, personal communication.