N-Functionalization of the Tetrahedrane Fe2(CO)6(/z-SNH) Max Herberhold*, Uw e Bertholdt, Wolfgang M ilius, Bernd Wrackmeyer Laboratorium für Anorganische Chemie, Universität Bayreuth, D-95440 Bayreuth Dedicated to Prof. Dr. Lothar Beyer on the occasion of his 60th birthday Z. Naturforsch. 51 b, 1283-1289 (1996); received March 27, 1996 Azadiferrathia, Tetrahedrane, Cluster Anion, Element-Nitrogen Bonds, NMR Spectra The azadiferrathia tetrahedrane, Fe 2(CO)6(£/-SNH) (1), was deprotonated to give the anion [Fe2(CO)6(/J-SN)]_ (2) which reacts with halides of phosphorus, arsenic, silicon, germanium, tin and boron by formation of element-nitrosen bonds. The new compounds were characterized by their IR. NMR('H, mB, i3C, i5N, 29Si,3 P, m Sn)and mass spectra. The molecular structure of [Fe2(CO)6(A/-SN-SiMe2CH 2-)]2 (11) was determined by X-ray structure analysis (space group Pi; triclinic; a = 799.8(2), b = 958.5(2), c = 1035.7(2) pm, a = 86.30(2)°, (3 = 81.27(2)°, 7 = 69.90(2)°). Introduction Results and Discussion The reaction of carbonyliron complexes with Syntheses bis(trimethylsilyl)sulfurdiimide, The reactions of the anion 2 with various element Me3Si(NSN)SiMe3, followed by chromatography halides are summarized in Scheme 1. Apparently, on silica, leads to the azadiferrathia tetrahedrane any triorganosilyl, -germyl or -stannyl chloride can 1 [1]. The corresponding anion 2 is formed by be used to prepare complexes of the type 3-5. The deprotonation using sodium [2], "BuLi in hex­ reactions of 2 with bis(chlorosilyl) compounds, as ane or DBU (l,8-diazabicyclo[5.4.0]undec-7-ene) shown in Scheme 2, afford the new compounds 9 [3] [eq. (1)]. It was already shown that 2 reacts - 11, of which 11 was studied by X-ray diffraction with Me^'BuSiCl to give the N-silylated complex (vide infra). Fe2(CO)6(//-SN-SiMe2'Bu) [2], and that N-organo- It appears that the reaction of 2 with arsenic chlo­ substituted derivatives Fe 2(CO)6(/u-SN-R) are ac­ rides is also straightforward, and the products 6a and cessible from the reaction of 2 with carbenium or 6b are isolated in moderate to good yields. In con­ trialkyl oxonium cations [3], These successful trans­ trast, 'BU2PCI does not react with 2. If the reaction formations of 2 prompted us to start a systematic of 2 with either 'PnPCl or Cy 2PCl is monitored by study of the N-functionalization of 1. Here we de­ IR spectroscopy , the presence of the desired prod­ scribe the new complexes which contain group 15 ucts can be observed for about 5 - 1 0 min at -78°C, (phosphanyl, arsanyl), group 14 (silyl, germyl. stan- but thereafter decomposition into unidentified com­ nyl) and group 13 (boryl) substituents at the nitrogen pounds takes place, as is also apparent from the atom. 11P NMR spectra of reaction solutions. However, it turns out that 2 reacts with cyclic diaminophospho- rus halides bearing bulky substituents ('Bu groups) (i) at the nitrogen atoms to give reasonably stable prod­ / -N»7 V © N ------S x A N S ucts (7a, 7b). Compounds 7c and 7d with the less / > < S \ -------- 5Ü--------- / X \ \ bulky N'Pr groups had to be characterized at low (OC)3Fe —---------Fe(CO)3 -C4H10, -Li (OC^Fe -----------Fe(CO>3 temperature. \ DBU f 2 The boron-substituted tetrahedranes 8 can be readily isolated if at least one dialkylamino group is linked to boron. All attempts to obtain dialkyl- boryl derivatives failed. Although 2 reacts with the 9-BBN derivatives 9-chloro- and 9-methoxy- * Reprint requests to Prof. Dr. M. Herberhold. borabicyclo[3.3.1 jnonane, it was not possible so 0939-5075/96/0900-1283 $ 06.00 © 1996 Verlag der Zeitschrift für Naturforschung. All rights reserved. 1284 M. Herberhold et al. ■ N-Functionalization of the Tetrahedrane Fe 2 (CO)6 (//-SNH) M RR' R,R'M 3a Si Me Me \ 3b Si Me H N ------S 3c Si Me ‘Bu /,X\ 3d Si Me SiM e, (OC )3Fe ______ _ Fe( CO)3 3e Si 'Bu H 3 f Si Ph ’Bu 3. 4. 5 4 Ge Me Me 5a Sn Me Me A 5b Sn Et Et tßu,As \ R,RMC1 N ------S -er / X } , R R (OC)3F e _ ______Fe(C O )3 ^ \ t B u , A s C l ( PCI ( p 6a -er \ © N ------S R R N ------S / > v -CI /X\' (O C ),F c _ ------- _F e(C O )3 (OC)3Fe _____ _ Fe(CO)3 r °, f ASCI. As k Ö \ R f \ N ------S 7a ‘Bu (C H ,), ‘Bu (C H ,), A X s > RRBCI 7b (OC)3F c __ ____ _F e(C O )3 'Pr (C H ,), -er 7c 7d ‘Pr (S iM e,), 6b RR'B RR N ------S 8a N'Pr, N'Pr, / X c 8b N(Bu)CH:CH:NBu (OC)3Fe ______ _F e(C O )3 8c N M e2 Fe Scheine 1 ^ SiMe,SiMe2v^ sr > N ' ' n —- s / / W / x \ \ (OC)3Ft------------Fe(CO)3 (OC)3Fe-------------Fe(CO)3 9 CISiMe2SiMe2Cl -2CI" ° Nc > s 2 / ^ \N (OC)3Fe—--------- Fe(CO)3 ClSiMe2OSiMe2Cl ClSiMe2CH2CH2SiMe2Cl -2 C r -2 CI' ^ SiMe,OSiMe,^ ^ SiMe2CH2CH2SiMe^ S -—- N N ----- S S----- N ----- S // X \ / X o / / V \ / X \ - (OC)3Fe------------Fe( CO )3 (OC )3Fe - ---------- Fe(CO)3 (OC)3Fe------------Fe(CO)3 (OC)3Fe------------Fe(CO)3 10 11 Scheine 2 M. Herberhold et al. • N-Functionalization of the Tetrahedrane Fe 2 (CO)6 (//,-SN H ) 1285 Table I. I5N, 2ySi and 31P NMR data of the tetrahedranes spectra (see Experimental part). In the IR spectra the 3 and 7 (chemical shifts [ppm], coupling constants [Hz], z/(CO) absorptions appear as a characteristic pattern solvent: CaD^, 25°C). of five or six bands indicating a Fe 2(CO)6 unit of b'5 N <$29Si 1 y(29si, I5n ) Cs or lower symmetry [5]. In the mass spectra, the molecular ions are detected together with fragments 3a -359.2 35.5 5.6 generated by stepwise loss of CO. 3b -370|al 22.1 3c -371.0 35.6 5.6 The nature of the element-nitrogen bonds in 3 - 3d -362.1 -19.7 (SiMe->), 3.9 11 is of particular interest. In the cases of 3 and 32.1 (SiMei) 7, LiN NMR spectra were measured (Table I), in 3e -374,0 30.8 addition to 29Si or 11P NMR spectra (cf. Figures 1 3f [d] 9.8 and 2), and chemical shifts <5ll9Sn and 6n B were <515N ^31P '7(3IP,I5N) determined for compounds 5 and 8. 7a|b| -292.0 (cycle), 137.5 59.6 (cycle). The magnitude of the coupling constants -292.2 (Fe.SN) 99.6 (Fe-iSN) l'7(29Si,15N)l is small, similar to '7(29Si,l5N) in 2,5- 7b|b| -296.6 (Fe2SN), 119.6 94.0 (FeiSN), dihydro-1,2,5-azoniasilaboratoles 16,7], in which -300.3 (cycle) 72.0 (cycle) an ammonium-type nitrogen atom is present. The 7c [d] 136.1 intensities of the 29Si satellites in the l5N NMR 7d|c| 168.1 [d] spectra of 3 are somewhat higher than expected. [a]: <5(14N); [b]: -20°C; [c]: <$(29Si) = -4.6ppm, 27(31 P,29Si) It is therefore assumed that 57Fe satellites over­ = 11.7Hz; [d]: not measured. lap with the 29Si satellites. The coupling constants 'y(57Fe,l5N) are in the same order of magnitude far to isolate well-defined products. The n B NMR (« 6 Hz [2]) as *y(29Si,15N). In the case of 7, as in spectra of reaction solutions indicate the formation other phosphorus-nitrogen compounds [8], the mag­ of (9-BBN)tO (b 11 B = 58.0 [4]) which suggests an nitude and the sign (usually positive; reduced cou­ unexpected course of these reactions. pling constant 1 K(31 P,I5N) < 0) of the coupling con­ stants 17(3IP,15N) are dominated by the phosphorus Spectroscopic results atom, in particular by the influence of the lone pair of electrons [9]. Therefore, the '/ ( 3IP,15N) values All compounds 3 -1 1 were characterized by IR, of 7 are rather similar to those measured for deriva­ 'H and l3C NMR. and in most cases by El mass tives in which the azadiferrathia tetrahedrane unit is replaced by the Me2N group [10]. The neighbour- S(,5N) -290 -300 Fig. 1. 30.4 MHz l3N NMR spectrum of 6(15N) Fe2(CO)6(//-SN-SiMe2?Bu) (3c) (saturated in CaD^, 25°C), measured by using the refocused INEPT pulse Fig. 2. 30.4 MHz 15N{1H} NMR spectrum of sequence (based on 37(lsNSiC'H) « 1.5 Hz). 2ySi satel­ Fe2(CO)6[/i-SN-P(NCBu)CH2)->CH'>] (7b) (1 g in C7DS, lites are marked with arrows. -20°C. 1286 M. Herberhold et al. ■ N-Functionalization of the Tetrahedrane Fe 2 (CO)6 (^ -S N H ) Table II. Selected bond lengths |pm] and angles [°J in 0(4) [Fe2(CO)6(//-SN-SiMe2CH2‘'-)]2 (11). S-N 169.2(3) Fe( 1)- S - Fe(2) 69.4( 1) Fe( 1) - Fe(2) 250.6(1) Fe( 1) - S - N 58.4( 1) Fe( 1) - N 194.8(3) Fe(2) - S - N 58.0(1) Fe(2)- N 194.4(2) Fe( 1) - Fe(2) - S 55.1(1) Fe(1)- S 219.8(1) Fe(2) - Fe( 1)- S 55.5( 1) Fe(2)- S 220.7(1) N - Fe( 1) - S 47.7(1) N -S i 178.5(3) Fe(l) - N -Si 134.3(1) F e (l)-C (l) 179.5(4) Fe(2) - N -Si 138.9(2) Fe(1)-C(2) 179.3(3) S - N - Si 129.1(1) Fe(1)-C(3) 180.8(3) C(8) - Si - C(9) 112.7(1) Fig.