TY - JOUR
T1 - Phase and redox shifted four iron/four sulfur clusters
T2 - fluorous analogs of metalloenzyme cofactors
AU - Zhang, Cheng Pan
AU - Xi, Zhenxing
AU - Mueller, Kory M.
AU - Holliday, Bradley J.
AU - Bazzi, Hassan S.
AU - Gladysz, John A.
N1 - Publisher Copyright:
© The Royal Society of Chemistry.
PY - 2015/7/30
Y1 - 2015/7/30
N2 - Reactions of (1) [Q]2[Fe4S4(SC(CH3)3)4] and the fluorous thiols HS(CH2)nRf8 (n = 2, 3; Rf8 = (CF2)7CF3)), or (2) [Na]2[Fe4S4(S(CH2)nRf8)4] (n = 2, 3) and [PhCH2P((CH2)3Rf6)3][Br] or [PPN][Cl] (PPN = Ph3P⋯N⋯PPh3), give the title compounds [Q]2[Fe4S4(S(CH2)nRf8)4], comprised of a fluorous dianion and in some cases fluorous cations, with (1) Q/n = Ph4P/2 (4, 67%), Ph4P/3 (5, 67%), Me4N/3 (69%), and Ph3P(CH2)2Rf6/2 (73%) or (2) PhCH2P((CH2)3Rf6)3/2 (14, 39%), PhCH2P((CH2)3Rf6)3/3 (15, 63%), and PPN/2 (36%). The educt [Ph3P(CH2)2Rf6]2[Fe4S4(SC(CH3)3)4] is in turn prepared from FeCl3, HSC(CH3)3/CH3ONa, and [Ph3P(CH2)2Rf6][I], and the educts [Na]2[Fe4S4(S(CH2)nRf8)4] from [Na]2[Fe4S4(SC(CH3)3)4] and HS(CH2)nRf8. The SCH21H and 13C NMR signals of these paramagnetic salts appear 8.7-10.3 and 32.3-34.9 ppm downfield from those of the corresponding thiols, but the chemical shifts of other signals are nearly normal. The UV-visible spectra show bands similar to those of non-fluorous analogs (290-298 nm and 406-415 nm; ε = 25 700 and 19 200 M-1 cm-1 for 5). The singly fluorous salts are soluble in organic solvents of moderate polarity, but not in fluorous solvents. The doubly fluorous salts 14, 15 are soluble in all fluorous solvents assayed, with partition coefficients of >99.65: <0.35 (CF3C6F11/toluene) and 93.2-93.1: 6.9-6.8 (FC-72/THF). Cyclic voltammograms carried out using a platinum working microelectrode show that 4 is 0.08 V thermodynamically easier to reduce than 5.
AB - Reactions of (1) [Q]2[Fe4S4(SC(CH3)3)4] and the fluorous thiols HS(CH2)nRf8 (n = 2, 3; Rf8 = (CF2)7CF3)), or (2) [Na]2[Fe4S4(S(CH2)nRf8)4] (n = 2, 3) and [PhCH2P((CH2)3Rf6)3][Br] or [PPN][Cl] (PPN = Ph3P⋯N⋯PPh3), give the title compounds [Q]2[Fe4S4(S(CH2)nRf8)4], comprised of a fluorous dianion and in some cases fluorous cations, with (1) Q/n = Ph4P/2 (4, 67%), Ph4P/3 (5, 67%), Me4N/3 (69%), and Ph3P(CH2)2Rf6/2 (73%) or (2) PhCH2P((CH2)3Rf6)3/2 (14, 39%), PhCH2P((CH2)3Rf6)3/3 (15, 63%), and PPN/2 (36%). The educt [Ph3P(CH2)2Rf6]2[Fe4S4(SC(CH3)3)4] is in turn prepared from FeCl3, HSC(CH3)3/CH3ONa, and [Ph3P(CH2)2Rf6][I], and the educts [Na]2[Fe4S4(S(CH2)nRf8)4] from [Na]2[Fe4S4(SC(CH3)3)4] and HS(CH2)nRf8. The SCH21H and 13C NMR signals of these paramagnetic salts appear 8.7-10.3 and 32.3-34.9 ppm downfield from those of the corresponding thiols, but the chemical shifts of other signals are nearly normal. The UV-visible spectra show bands similar to those of non-fluorous analogs (290-298 nm and 406-415 nm; ε = 25 700 and 19 200 M-1 cm-1 for 5). The singly fluorous salts are soluble in organic solvents of moderate polarity, but not in fluorous solvents. The doubly fluorous salts 14, 15 are soluble in all fluorous solvents assayed, with partition coefficients of >99.65: <0.35 (CF3C6F11/toluene) and 93.2-93.1: 6.9-6.8 (FC-72/THF). Cyclic voltammograms carried out using a platinum working microelectrode show that 4 is 0.08 V thermodynamically easier to reduce than 5.
UR - http://www.scopus.com/inward/record.url?scp=84947596649&partnerID=8YFLogxK
U2 - 10.1039/c5dt01959a
DO - 10.1039/c5dt01959a
M3 - Article
AN - SCOPUS:84947596649
SN - 1477-9226
VL - 44
SP - 19615
EP - 19624
JO - Dalton Transactions
JF - Dalton Transactions
IS - 45
ER -