Synthesis of Mono‐, Bis‐ and Tris(pentafluoroethyl)tin Derivatives, (C₂F₅)_4−nSnX_n (X=Ph, Me, Cl, Br, Cp; n=1–3)

Abstract

For (pentafluoroethyl)phenylstannanes, (C F ) SnPh (n=1-3), and dimethylbis(pentafluoroethyl)stannane, (C F ) SnMe , a high yield synthesis was developed by the use of LiC F as a C F transfer reagent. The treatment of these products with gaseous hydrogen chloride or hydrogen bromide afforded (C F ) SnX (X=Cl, Br; n=1-3) in good yields. The (pentafluoroethyl)stannanes were fully characterized by H, C, F and Sn NMR, IR spectroscopy and mass spectrometry. The treatment of the (pentafluoroethyl)tin halides (C F ) SnX with 1,10-phenanthroline (phen) led to the formation of the corresponding octahedrally coordinated complexes [(C F ) SnX (phen)], the structures of which were elucidated by X-ray diffraction analyses. The bromostannane (C F ) SnBr reacted with sodium cyclopentadienide to give the (η -cyclopentadienyl)tris(pentafluoroethyl)stannane, (C F ) SnCp, for which single-crystal X-ray diffraction analysis could be performed. The coupling constants J( Sn, C) and J( Sn, F) of all new stannanes are strongly correlated and sensitive to the substitution pattern at the tin atom. For both coupling constants a negative sign could be assigned.

Tris(pentafluoroethyl)stannane: Tin Hydride Chemistry with an Electron‐Deficient Stannane

“…We recently published the synthesis of novel pentafluoroethyltin compounds through the treatment of phenyl-protected tin chlorides, Ph 4Àn SnCl n (n = 1-3), with pentafluoroethyllithium, LiC 2 F 5 . [16] The latter is generated in situ through the combination of gaseous pentafluoroethane, HC 2 F 5 ,w ith nBuLi and, unlike homologous LiCF 3 ,i ss table up to À40 8C. [18] Subsequent cleavage of the phenylg roups with gaseousH Br leads to the formation of the correspondingbromostannanes, Br n Sn(C 2 F 5 ) 4Àn (n = 1-3).…”

“…In previouse xperiments,t he 19 FNMR spectra of the possible products ISn(C 2 F 5 ) 3 ,B rSn(C 2 F 5 ) 3 ,and ClSn(C 2 F 5 ) 3 exhibit resonances for the CF 2 group with markedly different 2 J(F, 119 Sn) coupling constants ( 2 J(F,Sn) = 422 Hz for ISn(C 2 F 5 ) 3 , 2 J(F,Sn) = 447 Hz for BrSn(C 2 F 5 ) 3 ,a nd 2 J(F,Sn) = 461 Hz for ClSn(C 2 F 5 ) 3 ). [16] In the 1 HNMR spectrum, the terminal halomethyl groups give rise to distinct signals at d = 3.50 ppm for CH 2 Cl, d = 3.37 ppm for CH 2 Br,a nd d = 3.15 ppm forC H 2 I( Figure 6). If two equivalents of HSn(C 2 F 5 ) 3 were added to this 1:1:1m ixture, complete conversion was observed, with ISn(C 2 F 5 ) 3 as the exclusive organotin species.…”

“…However,d ebromination with at hird equivalent of HSn(C 2 F 5 ) 3 turnedo ut to be impossible in the presence of ISn(C 2 F 5 ) 3 because of the competing formation of the symmetrical distannane (F 5 C 2 ) 3 SnSn(C 2 F 5 ) 3 .C ompared with tri-n-butyltin halides, tris(pentafluoroethyl)tin halides, XSn(C 2 F 5 ) 3 (X = Cl, Br, I), have much higher vapor pressures (7 to 25 mbar) and are thus conveniently removed under reduced pressure at room temperature. [16] Again, it should be highlighted that there is no need for ar adical initiator,s uch as azobisisobutyronitrile (AIBN). Clearly,p erfluoroalkyl substituents activate the SnÀH functionality sufficiently to undergo addition and substitution reactions.…”

“…The compound was isolated and, similar to its homologues BrSn(C 2 F 5 ) 3 and ClSn(C 2 F 5 ) 3 ,i tf ormed ac rystalline complex with 1,10-phenanthroline (phen;S cheme 6). [16] Ac rystal suitable for XRD was grown from as olution in dichloromethane ( Figure 7).…”

“…205 8C( dec);I R (ATR): ñ = 2962 (w), 2924 (w), 2854 (w), 1528 (w), 1435 (w), 1297 (w), 1260 (m), 1201 (m), 1071 (s), 1017 (s), 914 (m), 868 (m), 846 (m), 796 (s), 721 (m), 646 (w), 598 (w), 585 (w), 531 (w), 422 cm À1 (m); 1 HNMR ([D 3 ]acetonitrile, 298 K): d = 9.98/9.44 (2 d, 3 J(H,H) = 5.1 Hz, 3 J(H,H) = 5.1 Hz, 2H;H 2/H9), 9.07/9.03 (2 dd, 3 J(H,H) = 8.3 Hz, (H,H) = 1.5 Hz, 3 J(H,H) = 8.3 Hz, 4 J(H,H) = 1.5 Hz, 2H;H 4/H7), 8.34 (s, 2H;H 5/H6), 8.29 ppm (dd, 3 J(H,H) = 8.3 Hz, 3 J(H,H) = 5.2 Hz, 2H; H3/H8); 13 C{ 1 H} NMR ([D 3 ]acetonitrile, 298 K): d = 149.6/149.5 (s, t, 4 J(C,F) = 7Hz; C2/C9), 143.4/143.3 (2 s; C4/C7), 138.0/137.1 (2 s; C11/ C12), 130.2/130.1 (2 s; C4a/C6a), 128.0/127.8 (2 s; C5/C6), 126.3/ 125.7 ppm (2 s; C3/C8); 13 C{ 19 F} NMR ([D 3 ]acetonitrile, 298 K): d = 127.7 (s, 1 J(C,Sn) = 384/402 Hz;C F 2 ), 124.0 (s, 1 J(C,Sn) = 1144/ 1197 Hz;C F 2 ), 120.6 (s;C F 3 ), 120.1 ppm (s, 2 J(C,Sn) = 140 Hz;C F 3 ); 19 FNMR ([D 3 ]acetonitrile, 298 K): d = À80.2 (m, 3F;C F 3 ), À81.8 (m, 6F;C F 3 ), À112.1 (m, 2 J(F,Sn) = 305 Hz, 2F;C F 2 ), À118.6 ppm (m, (F,Sn) = 516 Hz, 4F;C F 2 ); 119 Sn{ 19 F} NMR ([D 3 ]acetonitrile, 298 K): d = À585.3 ppm (s);M S( EI, 70 eV,p os. ): m/z (%): 484.7(8) [ISn(C 2 F 5 ) 2 ] + ,3 84.7(26) [ISnF(C 2 F 5 )] + ,2 84.7 (3) [ISnF 2 ] + ,2 46.7(16) [SnI] + ,180.0 (100) [phen] · + ,154.0 (16), 138.8(15) [SnF] + .…”