摘要:
366 J.C.S. DaltonCharacterisation of Bis-methylgermanium and Bis-methylsilicon Carbo-di-imides and their Reactivity with Protic ReagentsBy John E. Drake," Raymond T. Hemmings, and Ernest Henderson, Department of Chemistry, University ofWindsor, Windsor, Ontario, N9B 3P4, CanadaBismethylgermanium and bismethylsilicon carbodi-imides have been prepared in high yield by halide metathesisreactions with lead(ii). silver(r), or silicon(tv) species. The new derivatives in the series of general formula(Me,H,_,MN:),C (M = Si or Ge ; n = 1,2, or 3) have been characterised by l H n.m.r., i.r., and Raman spectroscopyas well as mass spectrometry and cleavage reactions. The utility of the germanium carbodi-imides as syntheticintermediates is shown by ready cleavage of the Ge-N bond by Group VI and other protic species leading to theformation of chalcogeno-germanes and related derivatives of the type (Me,H,,,Ge),E ( E = 0, S, Se, or Te) andMe,H,,GeSR (R = Me, But, Ph.MeC(0). or -CH,CH,-). Comparative studies show that in the siliconcarbodi-i mides the Si-N bond is not susceptible to protolysis by the heavier chalcogenols.NUMEROUS studies have demonstrated the utility ofspecies containing the Si-N bond as synthetic inter-mediates in silane and organosilicon chemistry.Studies of the analogous Ge-N species have been con-fined largely to the fully substituted organogermanes.3Several methods for the preparation of fully substi-tuted organornet allic carbodi-imides of the type R,M*NCN-MR, (R = alkyl or aryl; 31 = Si, Ge, or Sn) aredescribed in the l i t e r a t ~ r e .~ ~ Early work by Pump andWannagat showed that bistrimethylsilylcarbodi-imide,(Me,SiN:),C, was formed in a variety of systems such asreaction of Na(R,Si),N with COCl,, Me,SiCl with (LiMe,-SiN),CO, or Me,SiCl with AgCN,. A modification to thesilver salt procedure has recently ap~eared.~ Otherworkers report the formation of the gerrnanium species(Et3GeN:),C and (Ph,GeN:),C in the reactions of thecorresponding oxide or bromide respectively withcyanamide, H,NCN, under forcing conditions.6 We findthat Me,SiCl and Me,GeBr are readily converted into thecarbodi-imides, (Me,SiN:),C and (Me,GeN:),C, by direct1 B. J. hylett, Adv. Iizoyg. Chcm Radiochem., 1969, 12, 249;J. E. Drake and C. Riddle, Qzdavt. Rev., 1970, 24, 263.2 U.Wannagat, Adv. Ino1.g. Cliena. Radiochetn., 1964, 6, 225.3 J. G. A. Luijtcn, F. Kijkens, and G. J. M. Van der KerkAdv. Orgaiaometalltc Chent., 1965, 3, 397; I;. Glockling, ' TheChemistry of Germanium,' Academic Press, London, 1969, p. 94.J. Pump arid ICJ. Wannagat, Annulen, 1962, 652, 21, andAngew. Clcein., 1962, 74, 117; 0. F. Schercr and M. Schmidt, 2.ATatuvforsch., 1965, 20b, 1009.heating with lead(I1) cyanamide. However, these and theforegoing reactions are not suited for the formation ofthe thermally unstable hydridic species and, indeed, noreaction occurs between Me,HSiCI and PbCN, a t roomtemperature in the gas phase. In keeping with the wellknown heavy-metal salt exchange series the meta-thetical reaction of the iodo-silanes and -germanes withlead(I1) cyanamide leads to extremely satisfactory yieldsof the corresponding carbodi-imido-species, (Me,H3 -%-MN:),C (M = Si or Ge; $2 = 0, 1 , 2 , or 3) [equation (l)].2>M-I + PbCN, __+c (>M-N:),C +PbI, (M = Si or Ge) (1)The comparative reactions of the iodides with silver(1)cyanamide give significantly reduced yields with in-creased disproportionation as has been observed in othersystems employing silver-salt exchange reactions.8,Alternatively, the germanium carbodi-imides may beobtained from bistrimet hylsilylcarbodi-imide by ex-S.Cradock, Inoyg. Syntlt., 1974, 15, 167.A. Vostokov and Y u . I. Dergunov, Zhiv. obshchci Khinz.,1970,40,1666 and 1971,41,1647.A. G. MacDiarmid, Quart.Rev., 1956, 10, 205; C. Eaborn,' Organosilicon Compounds,' Butterwortlis, London, 1960, p. 147.E. A. V. Ebsworth and M. J. Mays, J . Chem. Soc., 1962,4844;A. G. MacDiarmid, J . Inovg. Nuclcav Chem.., 1956, 2, 88.E. A. V. Ebsworth and hl. J. Mays, J . Clmn. Soc., 1961,4879; Spect~ockim. Acta, 1963, 19, 11271976 367change with the corresponding fluorogermanes.lo Whilethe illustrative example (2) is a high yield reaction it is(Me3SiX)2C -1 2MeH2GeF -+less convenient because thc fluoride must first be pre-pared from heavier halides. Thus the lead cyanamideroute is the preferable one.I t is interesting to compare the reactions of the organo-metallic carbodi-imides to their organic analoguesRNCNK. In the hydrolysis of an organic carbodi-imide l1 the central carbon atom provides the electro-positive centre for nucleophilic attack so that an urearesults with no fission of a C-N bond.By contrast, inthe germanium or silicon derivatives, the metal atomprovides the focus for nucleophilic attack with cleavage(MeH2GeX)2C + 2Me3SiF ( 2 )and arene-thiols [equation (4)] providing convenientsyntheses for the previously reported H3GeSMe l2 andH,GeSPh13 as well as the new hydride derivatives,H,GeSBut, H,GeSC(O)Me, (H,GeSCH,-),, andMe,H3 -,GeSR [equation (4)].(H,GeN),C $- RSII H,GeSR + i(H,NCN), (4)R = Me, But, MeC(O), -CH,CH2-, or Phalso H,Ge EZ Me,H3-,GeComparative experiments indicate that the SiNCNSisystem is more resistant than is the GeNCNGe linkage tonucleophilic attack by the heavier chalcogenols, SH,SeH, and TeH.Proponents of the importance of (9-d)x bonding in the Si-N system,14 relative to Ge-N, wouldno doubt accept this as further evidence of the ' extra 'stability of thc Si-N bond or of the decreased polarity ofTABLE 1Protolysis reactions of (R,X/IN:) ,C species with chalcogenols(R,MN:},C + HzE -z (R&),E + a (HZNCN) 2(1) (11)E = O E = S E = Se E = Te(1) (11) YiclZ (II)= ,- (I) (11) YieG (I) (;I) Y i e S----__A- r-rt,,x (mmol) (mmol) (%) (mmol) (mmol) (76) (mmol) (mmol) (%) (mmol) (mmol) (%)WJ;P 0.75 0.68 DO 1.45 1.38 95 1.42 1.18 83 1.62 1.01 62Ec,HGc 1 4 1 1.16 82 1 5 0 1.32 88 1.52 1.34 88 1.50 1.18 79RIC,GC 1 24 1.0'7 86 0.89 0.74 83 1.55 1.21 78 1.09 0.97 89M c . ,Si 2 40 3.30 96 No reaction KO reaction No reactionH ,(k 9 36 191 08b 0.24 0.22 92 1.25 1.05 84"n I3uScl-I i? r c y o i t ~ t to ri.,:ct x t it!, M:.,SiS:),C (100 OC, 1 h, benzene) t o give Me,SiSeBu (70%), Yu I.Dergunov, I. A. Vostokov,c S. Cradock, E. A. V. Ebswortli, and D. 'CV. 13. Rankin, .tnd V. 7 E;, c l i l i o ~ , % $ ~ w . oha;ic-,", !, I , I , 1972, 42, 371, 380./. L'Lt/,; S f r ( ? , , iO[jP, l(i2S.b Ref. 10.TABLE 2I'rotcJlysis rcaciions o f (I<,MN:),C species with various tliiols( R31IS:) 2C + 2R'SH + 2R,MSR3 + ; (H,NCN)(11 (11')zi := llIc R = But R = 1'11 K = -CHzC112- !< = MeC(0)T------h-.-.-- ~ (-..-.---L.- --) ---A- ~, r---Ap7 CA--h.-..--- 7(1) (TI) Yicld (I) (11) IYeld (I) (11) Yield (I) (11) Yield (I) (11) Yieldli,BI (mniol) (mmol) (7;) (nimol) (minol) (:&) (mmol) (mmol) ( 9 ; ) (mmol) (mmol) ( O h ) (minol) (mmol) (yo)H,Ge 0.45 0.72 81 1.41 3.53 90 0.60 0.98 80 0.86 0.42 49 1.05 1.64 78MeH,Ck 1.42 2.15 75 1.25 2.13 85 1.41 2.20 78 1.40 1.15 82 1.30 2.31 89Me,HGc 1.42 2.38 84 0.96 1.49 7Y 1.12 1.77 79 1.02 0.70 68 1.12 1.95 87Me,Si No reaction 3.00 1.56 39 2.70 1.83 34 No reaction 1.90 1.59 42Me,Ge 1.08 1.69 78 1.50 2.60 87 0.99 1.41 71 0.w 0.83 83 0.99 1.53 77of the AI-K bond and formation of (H,NCN),, and thegerinyl or silyl chalcogenide.Rapid and non-reversible reactions occur with weakacid donors (Tables 1 and 2).With hydrogen chal-cogenides, H2E, protolytic cleavage leads to the corres-ponding gerniyl-Group VI derivatives and dicyanodi-amicle [equation (3)].c.g.(MeH,GeN:),C + H2E __t(MeH,Ge),E 4- $(H,NCN), (3)(E = 0, S, Se, or Te)Cleavage also occurs with a wide variety of alkane-lo s. Cradock ancl E. A. V. Ebsworth, J . Chem. SOC. ( A ) , 1968,l1 F. Kurzev and K. Daurachi-Zadeh, C h m . Rev., 1967, 67,l2 J . 1'. IVang and C. H. Van Dyke, Clicin. Comns., 1967, 612.1423.107.the bond making the silicon atom less open to nucleo-philic attack. Unfortunately, supportive thermo-chemical data, particularly for germyl derivatives, isscant and inconsistent. It seems unlikely that the sup-posed relative weakness of the Ge-N bond could com-pletely account for the quantitative cleavage of Ge-N toform Ge-0, -S, -Se, and -Te bonds. However, the readycleavage of Si-N by H20 and ROH is probably associatedwith the formation of the strong 5-0 bond.15More important than these speculations is that we havel3 C.Glidewell ancl D. W. H. Rankin, J . Chem SOC. ( A ) , 1969,753.l4 E. A. V. Ebsworth in ' Organomctallic Compounds of theGroup IV Elements,' ed. ,4. G. XacDiarmid, Dekkc-r, New York,1968, vol. 1, part 1.l5 T. Tanaka, J . Iyzovg. Nucleav Chriiz., 19G0, 13, 225; A. E.Beezer and C. T. Mortimer, J . Chenz. SOC. ( A ) , 1966, 514J.C.S. Daltonestablished that the Ge-N linkage in germanium carbodi-imides makes them excellent and versatile intermediatesfor the formation of other Ge-M bonds, a property we areutilising in current researches.EXPERIMENTALManipulations ancl spectroscopic measurements were asdescribed previously.16 Silyl and germyl halides wereprepared by standard methods,l7-lg and their puritycstablished spectroscopically.Ag,CN, Was obtained fromAgNO, and CaCN, in basic solution.20 Hydrogen sulphide,selenide, and telluride were prepared by hydrolysis ofaluminum chalcogenides.21 Other materials were reagentgrade of commercial origin.Preparation of the Carbodi-imides, (Me,H3-,MN:),C (M =Si or Ge; n = 0, 1, 2, or 3). (i) Reactions of Me,H,_,MXwith PbCN, and Ag,Cln;,. The gaseous iodo-silane or-germane (ca. 5 mmol) was passed at 25 "C over the an-hydrous cyanaiiiide (ca. 25 g) held in a column on glass wool.Exothermic reactions ensued and after two or three double-passes the lH 1i.m.r. spectra of the colourless, sparinglyvolatile, material showed no iodide resonances.Afterfractional conclensation a t -23 "C the yields of the silyl-and germyl-carbodi-imides were frequently in the region of00% in the PbCN, reactions with little evidence for dispro-portionation : e.g. GeH,I (0.50 mmol) gave (H,GeN:),C(0.21 mmol, 84%; v.p. ca. 0.6 mmHg a t 0 "C; m.p. 10 "C, 6GeH 4.94 p.p.1n.) and SiH,I (2.89 mmol) gave (H,SiN:),C(1.25mmol,870/,; v.p. 18mmHgatO°C,6SiH4.45p.p.m.).Vsing Ag,CN, yields of only 40-60% could be realised withconsiderable formation of involatile residues (shown tocontain polymeric H,hTCN) and parent hydrides. Thecorresponding hydrido-chlorides or-bromides showed little orno reactivity in the gas phase. However, the high thermalstability of Me,SiCl ( 1 1.20 mmol) and Me,GeBr ( 1 1.30 mmol)permitted direct heating (ca.100 "C, 5 11) with the cyanamidesalt (ca. 20 g) in a sealed ampoule when again satisfactoryconversion into (Me,SiN:)& (5.03 mmol, 90%) and (Me,-GeN:),C (5.08 mmol, 90%) occurred.(ii) Reactio9t of Me,H,- ,GeF with bis (trimethyZsiZy1)-cnrbodi-imide. Typically (Me,SiN:),C (0.597 g, 3.21 mmol)was distilled into a reaction vessel (10 ml) held at - 196 "Ccontaining a slight excess of MeH,GeF (0.833 g, 7.67 mmol).Thc mixture was allowed t o react (room temp., 15 min) andthen vacuum fractionated. A pure sample of (MeH,GeN:),C(0.636 g, 2.90 mmol; 90.3%) was retained in a trap a t-23 "C; traces of (Me,SiN:),C (ca. 0.3 mmol) in a trap at-45 "C; small amounts of MeH,GeF (ca. 1.8 mmol;identified by i.r.and n.ni.r. spectra 17) in a trap at -95 "C;and Me,SiF (cn. 5.8 mmol; identified by i.r.22 and n.m.r.23spectra) in a - 196 "C following trap. By similar pro-cedures Me,HGeF (8.80 mmol) and Me,GeF (9.12 mmol)reacted with (Me,SiX:),C (ca. 4 mmol) to give (Me,HGeN:),Cl 6 J. E. Drake and R. T. Hemmings, Canad. J . Chem., 1973,51,302.17 J. E. Drake, K . T. Hemmings, and C. Riddle, J. Chem. SOC.( A ) , 1970, 3359; G. K. Barker, J . E. Drake, R. T. Hemmings, andB. Rapp, J . Chen?. SOC. ( A ) , 1971, 3291; Spectrochim. Actn, 1972,28A, 1113.18 G. K. Barker, J. E. Drake, and R. T. Hemmings, Canad. J.Chem., 1974, 52, 2622.19 H. J. EmelCus and L. E. Smythe, J . Chem. SOC., 1958, 609;E. A. V. Ebsworth, M'. Onyszchuk, and N. Sheppard, ibid.,1958, 1453; H. J .EmelCus, A. G. Maddock, and C. Reid,ibid., 1941, 1353; J . W. Anderson, G. K. Barker, J. E. Drake,ancl I<. T. Hemmings, SyNth. Inorg. Metnlorg. Chem., 1973, 3, 125.(3.44 mmol, 89.4%) and (&Ie,GeN:),C (3.35 mmol; 88.9%)respectively.Characterisation of the Carbodi-imides.-(i) lH N.3n.r.spectra. All the carbodi-imides give first-order spectra(Table 3) consistent with free rotation about the C-M bonds.The chemical shifts (6 p.p.m.) of M-H resonances in the(Me,H,-,MN:),C species are comparable to those of relatedcompounds containing an M-N bond, viz. (H,Ge),N 4.9;H,Ge-N, 5.1; -NCO 5.05, -NCS 5.18; (H,Si),N 4.44;H,Si-N, 4.49; -NCO 4.42, -NCS 4.46 ~ 3 . ~ ~ 9 , ~ Markeddilution shifts (e.g. ca. 0.5 p.p.m. from neat liquid t o 5%CCl, solution) suggest association.This is supported byline-broadening in the more concentrated solutions.Broadening as a result of interactions involving the 14Nquadrupole should be concentration independent.(ii) The vibrational spectra of (Me,H,-,MN:),C (M = Si orGe). These spectra are displayed in Tables 3-5. Prin-TABLE 3The IH n.m.r. parameters * of (Me,H,-,MN:),C (M =Si or Ge) and (Me,,H,-,Ge),E (E = 0, S, Se, or Te) speciesCompound 6(Me) 6(MH) [JHHyicl [ JaH[(hSeH,SiN :) ,C 6 0.36 4.61 3.75 126.5(Me,HSiN:) ,C b 0.26 4.74 3.30 123.4(Me,SiN:) ,C c 0.14 118.6(MeH,GeN:),C 0.58 4.99 3.00 129.6(Me,HGeN:),C 0.51 5.18 2.63 129.0(Me,GeN:) ,C 0.43 128.1(MeH,Ge) ,O 0.69 5.28 2.91 129.1(Me,HGe) ,O 0.40 6.40 2.43 128.2(Me,Ge),O 0.29 126.9(MeH,Ge),S 0.66 4.87 3.30 129.4(iMe,HGe) ,S 0.64 4.93 2.81 129.0(Me,Ge),S 0.51 127.6(MeH,Ge) ,Se 0.77 4.65 3.88 129.6(Me,HGe) ,Se 0.69 4.73 2.96 127.5(Me,Ge) ,Se d 0.58 127.1(MeH,Ge) ,Te 0.93 4.12 3.53 132.6(Me,HGe),Te e 0.80 4.65 3.37 131.7(Me,Ge) ,Te f 0.71 129.1* The spectra were recorded at ambient temperature in CC1,solution (ca.5% v/v). Chemical shifts (6 f0.02 p.p.m.) are inp.p.m. to low field of Me,Si as internal standard. Deviationsfor coupling constants are J(HH) f0.06 Hz, J(13CH) f 0 . 2 Hz.C JgiHgem, 6.9 Hz.Compare with 6(Me,Ge),E (CC1,solution) of 0.31(0) ; 0.53(S) ;0.66(Se) p.p.m. in H. Schmidbaur and I. Ruidisch, Inorg.Chem., 1964, 8, 699. 6 Recorded in cyclohexane (5% vlv).f Agrees with approximate value of 6 0.74 p.p.ni.(C6H,solution) in H. Schumann, K. Mohtachemi, H. J . Kroth, and U.Frank, Chem. Ber., 1973, 106, 2049; JxTeViC 6.5 Hz.a J(,%iH), 218 Hz. 6 J(,%iH), 217 Hz.cipal features can be assigned by comparison with thespectra of related but simpler m ~ l e c ~ l e ~ . ~ ~ ~ ~ ~ 16-18 The N=C=N asymmetric stretch is placed in the i.r. spectra at ca.2 250 cm-l for the silanes and 2 150 cm-l for the germanes.Not surprisingly, in view of the effective, local centro-2O L. Kowak, Przemyzl Chem., 1958, 13, 688.G. R. Waitkins and R. Shutt, Inorg. Synth., 1946, 2, 183;J . E. Drake and C. Riddle, ibid., 1972, 13, 14; A. Tiam and S.Aubanel, Compt. rend. Trav. Faculte'. Sci. Marseille, 1942, 1, 97.22 H. Kriegsman, 2. anorg.Chem., 1958,294,113.23 E. A. V. Ebsworth and S. G. Fankiss, Trans. Faraday Soc.,1963, 59, 1518.24 S. Cradock and E. A. V. Ebsworth, J . Chew. SOC. ( A ) , 1968,1420; K. M. Mackay and S. R. Stobart, Spectrochim. Acta, 1970,26A, 373; E. A. V. Ebsworth and M. J. Mays, J . Chem. SOC., 1962,3450; ibid., 1964, 4844; E. A. V. Ebsworth and J. J . Turner,J. Phys. Chem., 1963,67, 805.D. W. H. Rankin, J . Chern. Soc. ( A ) , 1969, 1926; 31. JIassoland J. SatgC, Bull. SOC. chim. France, 1966, 27371976 369TABLE 4The i.r. and Raman spectra (cm-') of the bismethylgertnaniutn carbodi-imidcs *(MeH,GeN :) ,C (Me,HGeN:) ,C (Me,GeN:) ,Ch - - A - - &-----, FTentative assignment 1.r. (gas)2 997m2 928w CH, stretch {(a)N=C=N stretch (a) 2 149sGe-H stretch 2 086sN=C=N stretch (s)1 405vwCH,def.{I") 1 259w882m GeH,def (sc)845m802s( s )9GeH,,GeH def. 728mRaman (liq)2 992m, dpN.O.2 083vs, p1 418m, p1 249m, p877m, p2 919vs, p:a. 840sh731111, dpSkeletal bend 675m 675m, dpGeC stretch {[::;) 612m 611vs, pGeH, rock 474w 478m, dpG ~ N stretch {:{Skeletal mode; -i[ 194m, dp545m398w? 421s, p227m, p1.r. (liq)2 990m2 916w2 142vs2 073vs1 417w1 249111832s816scn. 760sh712m661m619s593m530s425w?Raman (liq)2 991ni, dp2 918vs, pN . O .2 063vs, p1412m, p1 248111, p850w, dp705m, p636m, dp603111, dp579x5, pca. 500sh420s, p225m184s, dp1.r. (liq)2 995m2 918m2 130vs1408m1252m825sca. 75Osh670m617s572m527s* Spectra recorded at room temperature.m = medium, s = strong, w = weak, v = very, sh = shoulder, p = polarised, dp = depolarised.0 Gas.b CH,(a) is expected in this region. Polarisation spectrum.Tentative assignmentCH, (stretch (('INC-N stretch (a)Si-H stretch(s)S=C=N stretch ( 5 ) aCH, defSiH,,SiH defSkeletal bendSic stretch {(a"/SiH, rocksin- stretch { g;Skeletal modas[I(3')TABLE 6The i.r. and Raman spectra (an-') of the bismethylsilicon carbodi-imides * t(MeH,SiX) %C (Me,HSiN:),Ch A r 7 I -7 7 1.r. (gas) Raman (liq) 1.r. (gas) Raman (liq) 1.r. (liq)2 972111 2 968m, dp 2 967m 2 981m 2 972m, dp2 924w 2 911vs, p 2 911w 2 906vs, p 2 903w2 258vs N.O. 2 241vs N.o.2 176vs 2 170vs, p 2 149vs 2 147vs, p1 566111 1 552mN.o.1 504m N . O . 1518m N.o.1481m1419vw 1418w, dp 1 429w cn. 1420w, br 1406w1 381w1267m 1257m, p 1262ms 1259m, p 1253s837s838s 843w 736s2 205s964s 963m, p9 15vs 929w, dp 906s 907w, dpca. 87Osh 868w, dp 884vs 883wca. 730m 726m, dp 627m 632m686w 707~s) p 750111587m N.o. 584w N.o. 58lm739s 702m, dp 698m760s 761vs, p 674vs, p 640w512w 515m, dp789vs 775s 772w? 7 60s493s, p 484s, p 480w273m 279m232111, p 246m199s dp* See footnote to Table 4.a See text.N.o. = not observed.Raman (liq)2 985m, dp2 915vs, pN.O.1 409m, p1 250m, p833vw763vw663sh615m, dp576vs, pca. 480sh430s, p240sh189sl63ms(Me,SiN:),CRaman (liq) '2 966m, dp2 904vs, pN.o.1514m1453m1416m, dp1 262m, p845w, br760w, dpN.O.699111, dp645vs, p480s, p2831.7, dp208s, p195shsymmetry of the carbodi-imide structure 26 this mode isabsent in the Raman effect.27 The N=C=N symmetricstretch is a polarised mediuni-intensity band a t ca.1 409-1 418 cm-l in the Raman spectra of the germanes. In thesilanes, a more complex pattern appears at 1 500-1 570cm-l which seems to be a characteristic feature of silyl-carbodi-imides and so is assigned as the N=C=N symmetriczB J . D. Murdoch and D. W. H. Rankin, J.C.S. Chem. Coinin.,19'iJ. 748.stretch. In (H,SiN:),C, the feature was attributed toFermi resonance with the overtone of the i.r.-active SiH,deformation node.^ In (MeH,SiN:),C it is reasonable toassume that there is Fermi resonance between the N=C=Nsymmetric stretch and the overtone (2 x 761 cm-l).For27 M. Davies and W. J. Jones, Trans. Faraday SOC., 1958, 54,1454; L. Kahovec and K. W. F. Kohlrausch, Z . phys. Chem.,1937, B37, 421 ; G. D. Meakins and R. J . Moss, J . Chenz. Soc.,1957, 993370 J.C.S. Daltonthe other species, the rationale for the complex band-patternis less obvious, but could involve the overtone of the Si-Nasymmetric stretch, which is expected in the region 760-790 cm-l [788 cm-l in (H,SiN:),Cg]. For the germaniumseries, the assignmcnt of the Ge-N asymmetric stretch to astrong i.r. band in the region 527-545 cm-1 [547 cm-1 in(H,GeW:),C] lo is clear as are the assignments of the Ge-Cstretching modes (ca. 576-619 cm-l) 1’ and the GeH, andGeH deformation modes. The M-N symmetric stretchesappear in the Raman spectra as strong polarised bands inthe regions of 480-493 cm-l for the silanes [496 cni-l in(H,SiN:),C] and of 420-430 cm-1 for the germanes [a10cm-l in (H,GeN:),CJ .lo(iii) Mass spectra.In all cases the molecular ion,viz., (hfe,H,_,,MN:),C’, is detected and provides con-firmation of the molecular species. The low normalisedabundancc (i.e. cn. 1 to 20) of this ion is a commonfeature in the spectra of organo-silanes and -ger-m a n e ~ . ~ * ~ ~ ~ Ions arising from H and Me stripping appearto be most abundant although significant ion current in thegermanes is carried by rearranged ions such as Ge,N+ orGeS2+ and ions from N-C bond cleavage, i.e. Me,H,-,GeN+.This is in general agreement with the observations in thespectrum of (H,GeN:),C but we have been unable to detections of the type MN,C+ reported in the same study.1°(iv) Chemical characterisntiovl (i.e.ana2ysis for Me,H3-,nl-groz+s). This was achieved by protolytic cleavage of the M-Nlinkage with an excess of gaseous hydrogen halides leadingto the isolation of stoicheiometric quantities of familiarhalogeno-silanes and -germanes, Me,H3-,MX (X = C1, Br,or I), which were identified spectroscopically.~7~~~~ 3093l Theextensive protolysis reactions with chalcogenols (see nextsection and Table 1) also provide indirect evidence for thestoicheionietric/monomeric nature of the carbodi-imides.Reactions of the Carbodi-inzides with Selected Protic Re-agents.-(i) Reactions of (lI,MN:),C (R = H or Me) withH,O (E =r 0, S, Sc, or Te).A general procedure wasfollowed for all tlie volatile protic reagents. The carbodi-h i d e (ca. 1-2 mmol) was distilled into a greaseless reactionvessel (150 id) with a bulb which could be immersed in alow-temperature bath and a side arm which could be sealed.An excess of the H,E species was distilled into the vesselwith the bulb head a t -196 “C. The mixture was allowedto attain room temperature, with quenching as the reactionbecame too vigorous (particularly for the thermally unstableH2Te). After typically 60 min, vacuum fractionation of theproducts was carried out. For the H,S, H,Se, and H,Tereactions examination of the products invoIatile a t - 45 “Cshowed no resonances attributable to unchanged carbodi-imide whilst the excess of H,E, volatile at this temperature,was identified in a - 196 “C trap.For the H,O reactionsthe excess of H,O was retained in a - 23 “C trap and spectro-scopically pure oxides were collected in a - 196 “C trap.An amorphous white material remaining in the reactionvessel was subsequently characterised by i.r. spectroscopy 32as polymeric H,NCN. Details of the reactions are given inTable 1 and the 1H 1i.m.r. parameters of tlie new methyl-germanium chalcogenides are collected in Table 3. General2* I;. Glocklingand J. R. C. Light, J . Ckem. SOC. ( A ) , 1968, 717;D. U. Chambers, F. Glockling, and J. R. C. Light, Quavt. Rev.,1968, 22, 317.29 G. P. Van der Kelen, 0. Volders, H. Van Onclielcn, and 2.Eeckhaut, Z.anovg. Cheni., 1965, 338, 106.30 A. L. Smith, J . Chem. Phys., 1953,21, 1997; J . R. DurigandC. W. Hawley, ibid., 1973, 58, 237; ibid., 1973,59, 1; H . Burger,Spect~~ocliiaiz. Acta, 1968, 2M, 2015.features in the Raman spectra of (Me,HGe),E characteristicof Me,H,-,Ge- and Ge-E-Ge moieties appear as follows(cm-l): Ge-E stretching (2 bands) a t 486m,p and 792s (j.r.)[O] ; ca. 38Ovs,p and 409s (i.r.) [S] ; 273vs,p and 282 s (i.r.)[Se]; 228vs,p [Te]; Ge-C stretching (2 bands) at cn.585vs,p and ca. 610m,dp; Ge-H stretching at ca. 2 040-2 080vs,p; CH, stretching (2 bands) at GU. 2 915 vs,p and2 985 m,dp; CH, def. (2 bands) a t cn. 1240m,p and 1414w,dp; Ge-E-Ge def. a t 169m,p [O]; 95m,p [S]; 76n1,p[Se], 2nd 63m,p [Te].Analysis for the Me,H,_,&Ge- groups was carried out bycleavage of the germanium-chalcogen bond with an excessof gaseous HI, which produced stoicheiometric quantities ofH,E and the familiar iodogermanes, Me,,H3-,Gel, which wereidentified spectroscopically.17~ l8 The 70 eV mass spectra ofthe (Me,H,-,Ge),E species further support the forniulationof the chalcogenides as well as providing molecular-weightconfirmation and support for the n priori assignment ofn.m.r.and vibrational spectra.Further preliminary experiments 33 also show that thecorresponding germyl chalcogenols Me,H3 - ,GeEH (E =S, Se, or Te) are formed rapidly a t room temperature whenthe chalcogenides are treated with an excess of H,E insealed tubes.A nexactly similar procedure to that described above was(ii) Xeactiom of (R,MN:),C species with R’SH species.TABLE 61H N.m.r.parameters * of Me,,H3-,,MSR species pre-MeH,GeSMe’Me,HGeSMe’Me,GeSMe’H,GeSCMe,’MeH,GeSCMe,’Me,HGeSCMe,’Me,GeSCMe,’ CMe,SiSCMe,’MeH,GeSPh’Me,HGeSPh’Me,GeSPh’Me,SiSPh’(H,GeSCH’,-)(MeH,GeSCH,’-) ,(Me,HGeSCH,’-)(Me,GeSCH,’-)H,GeSC( 0)Me’MeH,GeSC( 0)Me’Me,HGeSC( 0)Me’Me,GeSC(O)Me’Me,SiSC(O) Me’pared in this study t6 6(Me) (GeWb 1 JHR”’~~ IJCHi0.65 4.77 3.52 130.70.56 4.86 3.24 129.50.51 125.70.64 4.90 3.75 134.90.55 5.02 3.06 130.30.50 127.50.05 119.20.50 5.01 3.67 135.10.47 5.17 3.36 132.30.40 N . O .0.25 123.00.71 4.89 3.53 133.80.61 5.04 3.45 132.70.50 N.o.0.78 4.92 3.42 133.80.68 5.03 3.18 131.70.60 128.10.39 120.84.354.744.628 (CH’) I JOH’ 12.11 143.42.04 142.81.97 141.01.42 125.51.49 132.91.42 129.61.40 126.31.42 128.67.437.387.167.152.86 N.o.2.79 N.o.2.72 N.o.2.60 N.o.2.49 127.22.47 136.02.41 132.02.35 128.82.54 131.1* See footnote to Table 3.a Compare with values of 6(H,GeSR): 4.71 (R -= Ph), C.Glidewell and D.W. H. Rankin J . Chent. SOC. ( A ) , 1960, 783(CBH1,) ; 4.48 (R = Me), J . T. Wang and C. H. Van Dyke, Inorg.Chem., 1968, 7, 1319. b See K. A. Hooton and A. L. Allred,Inorg. Chem., 1965, 4, 671. C E. W. Abel, D. A. Annitage, aidD. B. Brady, J . 0f~ganoi.tzetallic Chewz.., 1966, 5, 130.N.o. = not observed.followed for the volatile MeSH a i d ButSH.The thio-gerinanes could be transferred in a pure state to the side armafter pumTing off the excess of thiol at -45 “C. ReactionE. A. V. Ebsworth, M. Onyszchuk, and N. Sheppard, J .Chem. SOC., 1958, 1453.32 J. I<. Tyler, L. F. Thomas, and J . Sheridan, J . Opt. SOC.Afrzev., 1962, 52, 581.33 J. E. Drake, B. Glavinchevsky, R. T. Hemmings, and H E.Henderson, Canad. J . Chem., t o be published1976 371times of the order of 60 min at room temperature gaveessentially quantitative conversion. The less-volatilespecies, PhSH, HSCH,CH2SH, and MeC(O)SH, were handledvolumetrically and syringed into the reaction vessel anddegassed thoroughly before distilling in the carbodi-imides.For thcsc reactions it was found advantageous to use adeficit of the thiol (see Table 2).Unchanged (R,MN:),Cspecies were pumped from the reaction vessel leavinginvolatile oily sulphides which could be transferred to theside arm and sealed for subsequent spectroscopic analysis(Table ti). The amorphous white material adhering to theu,alls of the reaction vessel was again shown to be (H,NCN),.The very low reactivity of (Me,SiN:),C towards the thiolswas evident even when the mixtures were held at highertemperatures (ca. 60-100 “C) . Preliminary experimentsshow that, as expected, (Me,SiN:),C reacts rapidly with themore acidic alcohols R’OH, leading to Me,SiOR’ specieswhich together with analogous derivatives of the hydrido-silanes and -germanes are currently under study and will beyresentcd at a later date. Thus Me,SiOMe’ (88%; S(Me)0.07 and S(Me’) 3.37 p.p.m], Me,SiOPh [go%; 6(Me) 0.2534 S . Craclock, J . Chem. SOC. ( A ) , 1968, 1426.36 D. F. Van De Vondel, E. V. Van den Berghe, and G. I”.\.‘an clcr Kelen, J . Organometallic Chew., 1970, 23, 106.p.p.m], Me,Si(OCH,), [SO%; 6(Me) 0.08 and 6(CH2) 3.57p.p.m.1 and Me,SiOC(O)Me’ [92% ; 6(Me) 0.26, 6(Me’) and1.991 were obtained from (Me,SiN:),C with MeOH, PhOH,HOCH,CH,OH, and HOC(0)Me respectively.The lH n.m.r. parameters of the new Me,H,-,GeSR’species are presented in Table 6. The i.r. and Ramanspectra show features characteristic of both Me,H3- .Ge- and-SR’ moities but we have not attempted any detailedanalysis at this stage. By comparison with thc spectra ofH,GeSMe 34 and H,GeSPh l3 and other thiogermanes theGe-S stretching frequency has been assigned as follows inthe Raman spectra of the liquids: viz. 386-396 cin-1 (R =Me) ; 450-451 c1n-l (R = But) ; 378-381 cm‘-l (R = Ph) ;393-398 cm-l (R = -CH,CH,-); 288-293 cin-l [R =MeC(O)]. The Ge-H stretching frequency appears sur-prisingly low in the range 2 040-2 088 cm-1 for all spccies.The mass spectra of the more volatile Me,H,-,GeSMe havealso been obtained and show the expected molecular ions inlow abundance consistent with their formulation.We thank the National Research Council of Canada forfinancial support.[5/946 Received, 19th M q ) , 1975
ISSN:1477-9226
DOI:10.1039/DT9760000366
出版商:RSC
年代:1976
数据来源: RSC