Synthesis and Related Reactions of Iron Vinylidene and Isocyanide Complexes
Date Issued
2005
Date
2005
Author(s)
Yen, Yung-Sheng
DOI
en-US
Abstract
Reaction of (η5-C5R5)(dppe)FeCl (1, R = H; 2, R = Me) with phenylacetylene
affords neutral iron acetylide complexes (η5-C5R5)(dppe)Fe–C≡CPh (3, R = H; 6, R =
Me). Similarly, utilizing the same methodology, complex Cp(dppe)Fe-C≡C-C6H4-C
≡ C-H (5) is prepared from the reaction of
1-ethynyl-4-[2-(triisopropylsilyl)ethynyl]benzene with complex 1 to give complex
Cp(dppe)Fe-C≡C-C6H4-C≡C-TIPS (4) first. Hydrolysis of triisopropyl group of
complex 4 affords the complex 5. Reaction of various alkyl halides with acetylide
complexes 3 and 6 affords a number of cationic vinylidene complexes
[(η5-C5R5)(dppe)Fe=C=C(Ph)CH2R1]＋ (7a, R = H, R1 = CN; 7b, R = H, R1 =
p-C6H4CN; 7c, R = H, R1 = CH=CH2; 7d, R = H, R1 = Ph; 7e, R = H, R1 = p-C6H4CF3;
7f, R = H, R1 = C6F5; 7g, R = H, R1 = CO2Me; 9a, R = Me, R1 = CN; 9b, R = Me, R1
= p-C6H4CN). Similarly, complexes [(Cp)(dppe)Fe=C=C(C6H4C2H)CH2R]＋ (8a, R =
CN; 8b, R = p-C6H4CN) was also prepared by the same synthetic strategy.
Iron cyclopropenyl complexes [Fe]C=C(Ph)CHR ([Fe] = (Cp or Cp*)(dppe)Fe,
10a, R = CN; 10b, R = p-C6H4CN; 10c, R = p-C6H4CF3; 12a, R = CN; 12b, R2 =
p-C6H4CN) are prepared by deprotonation of corresponding vinylidene complexes.
Similarly, cyclopropenyl complexes (Cp)(dppe)FeC=C(C6H4C2H)CHR (11a, R = CN;
11b, R = p-C6H4CN) were also prepared by the same methodology. For the vinylidene
complexes 7c (R = CH=CH2), 7d (R = Ph) and 7f (R = C6F5), the deprotonation
reaction leads to formation of the 1-ferra-2,5-diphosphabicyclo[2.1.1]hexane
complexes (13a, R = CH=CH2; 13b, R = Ph; 13c, R = C6F5). Deprotonation of
vinylidene complex 7g (R = CO2Me) containing an ester group at Cγ affords the
neutral furyl complex Cp(dppe)FeC=C(Ph)CH=C(O)OMe (14). Dinuclear iron
cyclopropenyl complex {[Fe]C=C(CHCN)}2C6H4 (22) ([Fe] = Cp(dppe)Fe) is
prepared by deprotonation of corresponding vinylidene complex
{[Fe]C=C(CH2CN)}2C6H4
2+ (21).
The reaction of TMSN3 with 10a and 10b gives the tetrazolate complexes
Cp(dppe)FeN4CCH(R)CH2CN (15a, R = Ph; 15b, R = C6H4C2H). Treament of 10b
which containing p-cyanophenyl group with TMSN3 affords nitrile complex
[Cp(dppe)FeN≡CCH(Ph)CH2(p-C6H4CN)]N3 (16). In addition, reaction of Cp*
analogous 12a with TMSN3 afforded vinylidene complex 17 which resulted from
hydrolysis the TMS group added to Cγ. Electrophilic addition of TCNQ to 10a and
12a yields the zwitterionic vinylidene complexes
(η5-C5R5)(dppe)Fe=C=C(Ph)CH(CN)(TCNQ) (18a, R =H; 18b, R =Me) which in the
presence of nBu4NOH/MeOH gives the methoxy substituted cyclopropenyl complexes
(η5-C5R5)(dppe)FeC=C(Ph)C(OMe)CN (19a, R =H; 19b, R =Me).
A number of cationic iron isocyanides complexes [Cp(dppe)Fe−C≡NCH2R]+ (24a,
R = Ph; 24b, R = CN; 24c, R = p-C6H4CN; 24d, R = p-C6H4CF3; 24e, R = C6F5; 24f,
R = CH=CH2; 24g, R = CO2CH3) are prepared by alkylation of iron cyano complex
Cp(dppe)Fe-C≡N (23) with corresponding organic halides. Treatment of the cationic
isocyanide complexes with base in acetone affords insertion of carbonyl group to
forms oxzolinyl complexes Cp(dppe)FeCNCH(R)C(Me)2O (26a, R = Ph; 26b, R =
CN; 26c, R = p-C6H4CN; 26d, R = p-C6H4CF3; 26e, R = C6F5; 26f, R = CH=CH2).
The thermally unstable three-membered azirinyl complexes Cp(dppe)FeCNCH(R)
(25b, R = CN, 25c, R = p-C6H4CN) was observed by NMR spectroscopy in the
reaction which in the absence of ketone or aldehyde. Additionally, reaction of
isocyanide complexes with base in the presence of different aldehydes also affords
iron oxazolinyl complexes Cp(dppe)FeCNCH(R1)C(R2)(R3)O (27a, R1 = R2 = Ph, R3
= H; 27b, R1 = CN, R2 = Ph, R3 =H; 27c, R1 = p-C6H4CN, R2 = Ph, R3 = H; 28a, R1 =
Ph, R2 = (CH3)3, R3 = H; 28b, R1 = CN, R2 = (CH3)3, R3 =H).
Treatment of [Ru(=C=C=C(Ph)2)(η5-C5H5)(PPh3)2][PF6] (29) with Grignard
reagent RCH2MgBr in THF yielded the neutral acetylide complex
[Ru]-C≡C-C(Ph)2CH2R ([Ru] = (η5-C5H5)(PPh3)2Ru; 30a, R = CH=CH2; 30b, R =
CMe=CH2; 30c, R = C≡CH, 30d, R = CH2CH=CH2; 30e, R = Ph). Complexes 30a -
30e undergo protonation reactions giving the corresponding vinylidene complexes
{[Ru]=C=CHCPh2CH2R}+ (31a, R = CH=CH2; 31b, R = CMe=CH2; 31c, R = C≡CH;
31d, R = CH2CH=CH2; 31e, R = Ph). Complex 31a in solution transforms to
{[Ru]=C=CHCH2CPh2CH=CH2}+ (32a) via a new metathesis process of the terminal
vinyl group with the C=C of the vinylidene group. Complex 31b undergoes a different
cyclization process yielding 34b containing a η2-cyclic allene ligand which is fully
characterized by single crystal X-ray diffraction analysis. Complex 31c transforms to
{[Ru]=C=CHCH2CPh2C≡CH}+ (32c) which possibly proceeds via a π-coordinated
alkynyl complex. No metathesis or cyclization process was observed on complexes
31d and 31e.
Subjects
鐵金屬
亞乙烯基
異氰基
環丙烯
iron
vinylidene
isocyanide
cyclopropene
Type
thesis
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