Taking TiF4 complexes to extremes - The first examples with phosphine co-ligands

Article abstract of DOI:10.1039/c0dt00747a

The first soft donor adducts of TiF₄, [TiF ₄(diphosphine)] (diphosphine = o-C₆H₄(PMe ₂)₂, R₂P(CH₂)₂PR ₂, R = Me or Et) have been prepared from [TiF₄(MeCN) ₂] and the diphosphines in rigorously anhydrous CH₂Cl ₂, as extremely moisture sensitive yellow solids, and characterised by multinuclear NMR (¹H, ³¹P, ¹⁹F), IR and UV/vis spectroscopy. The crystal structure of [TiF₄{Et ₂P(CH₂)₂PEt₂}] has been determined and shows a distorted six-coordinate geometry with disparate Ti-F _transF and Ti-F_transP distances and long Ti-P bonds. Weaker soft donor ligands including Ph₃P, Ph₂P(CH ₂)₂PPh₂, o-C₆H₄(PPh ₂)₂, Ph₂As(CH₂)₂AsPh ₂, o-C₆H₄(AsMe₂)₂ and ⁱPrS(CH₂)₂SⁱPr do not form stable complexes with TiF₄, although surprisingly, fluorotitanate(IV) salts of the previously unknown doubly protonated ligand cations [LH ₂][Ti₄F₁₈] (L = o-C₆H ₄(PPh₂)₂, o-C₆H ₄(AsMe₂)₂ and ⁱPrS(CH ₂)₂SⁱPr) are formed in some cases as minor by-products. The structure of [o-C₆H₄(PPh ₂H)₂][Ti₄F₁₈] shows the first authenticated example of a diprotonated o-phenylene-diphosphine. The synthesis and full spectroscopic characterisation are reported for a range of TiF ₄ adducts with hard N- or O-donor ligands for comparison purposes, along with crystal structures of [TiF₄(thf)₂], [TiF ₄(Ph₃EO)₂]·2CH₂Cl ₂ (E = P or As), and [TiF₄(bipy)]. The Royal Society of Chemistry 2010.

Full text of DOI:10.1039/c0dt00747a

Electronic Supplementary Information for Dalton Transactions
This journal is © The Royal Society of Chemistry 2010
Electronic Supplementary Information
Taking TiF4 complexes to extremes – the first examples with
phosphine co-ligands
Marek Jura, William Levason, Edmund Petts, Gillian Reid, Michael Webster and
Wenjian Zhang
Synthesis of N- and O-donor ligand complexes
Experimental
[TiF4(2,2’-bipy)]: [TiF4(thf)2] (0.265 g, 1.0 mmol) was dissolved in CH2Cl2 (5 mL) and a
solution of 2,2’-bipyridyl (0.155 g, 1.0 mmol) in CH2Cl2 (5 mL) added via a syringe. The
solution was stirred for 30 min, concentrated to ~5 mL and refrigerated overnight. The white
solid which deposited was filtered off and dried in vacuo. Yield: 0.13 g, 46%. Required for
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C10H8F4N2Ti (280.1): C, 42.9; H, 2.9; N, 10.0. Found: C, 42.6; H, 2.7; N, 9.8%. H NMR
(CD2Cl2): δ 7.65 (m) [2H], 8.15 (m) [4H], 8.65 (t) [2H]. 19F{1H} NMR (CH2Cl2) 293 K:
2
207.7 (s) [2F], 140.3 (s) [2F]; 223 K: 204.3 (t) [2F], 136.9 (t) [2F] JFF = 35 Hz. IR
(Nujol/cm−1): 664, 622, 592, 560 ν(TiF). UV/vis (diffuse reflectance) Emax/cm−1: 38700,
30700(sh). Small colourless crystals were grown by refrigerating (260 K) the filtrate, and also
by vapour diffusion of diethyl ether into a CH2Cl2 solution of the complex. The following
complexes were made similarly.
[TiF4(1,10-phen)]: White powder. Yield: 56%. Required for C12H8F4N2Ti (304.1): C, 47.4;
H, 2.7; N, 9.2. Found: C, 47.6; H, 2.5; N, 9.6%. 1H NMR (CD2Cl2): δ 7.63 (m) [2H], 7.85 (s)
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[2H], 8.25 (dd) [2H], 9.19 (t) [2H]. F{1H} NMR (CH2Cl2) 293 K: 210.4 (s) [2F], 141.6 (s)
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[2F]; 243 K: 208.2 (t) [2F], 140.1 (t) [2F] JFF = 33 Hz. IR (Nujol/cm−1): 645, 618, 569 TiF.
UV/vis (diffuse reflectance) Emax/cm−1: 38600, 33000(sh).
Cis-[TiF4(py)2]: White powder. Yield: 60%. Required for C10H10F4N2Ti (282.1): C, 42.6; H,
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3.6; N, 9.9. Found: C, 43.4; H, 3.7; N, 10.1%. H NMR (CD2Cl2): δ 7.45 (s) [2H], 7.90 (s)
[H], 8.93 (s) [2H]. 19F{1H}NMR (CH2Cl2) 293 K: 218.3 (s) [2F], 150.8 (s) [2F]; 243 K: 213.8
2
(t) [2F], 151.6 (t) [2F] JFF = 28 Hz. IR (Nujol/cm−1): 654, 638, 631, 570 ν(TiF). UV/vis
(diffuse reflectance) Emax/cm−1: 38600, 33000(sh).
[TiF4{Me2N(CH2)2NMe2}]: The reaction solution was filtered and then reduced to dryness in
vacuo and the white residue washed with diethyl ether. Yield: 75%. Required for
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C6H16F4N2Ti (240.1): C, 30.0; H, 6.7; N, 11.7. Found: C, 30.1; H, 7.0; N, 11.3%. H NMR
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(CD2Cl2): δ 2.71 (s) [3H], 2.80 (s) [H]. F{1H} NMR (CH2Cl2) 293 K: 199.1 (t) [2F], 145.2
2
(t) [2F] JFF = 37 Hz. IR (Nujol/cm−1): 630, 604(br) ν(TiF). UV/vis (diffuse reflectance)
Emax/cm−1: 45500, 35700(sh).
Cis-[TiF4(pyNO)2]: White powder. Yield: 75%. Required for C10H10F4N2O2Ti (314.1): C,
38.2; H, 3.2; N, 8.9. Found: C, 38.0; H, 2.6; N, 8.7%. 1H NMR (CD2Cl2): δ 7.40 (s) [2H], 8.23
(br) [3H]. 19F{1H} NMR (CH2Cl2) 293 K: 170.7 (s) [2F], 136.9 (s) [2F]; 223 K: 162.4 (t)
2
[2F], 134.2 (t) [2F] JFF = 35 Hz. IR (Nujol/cm−1): 1223, 1208 ν(NO), 630, 580(br) ν(TiF).
UV/vis (diffuse reflectance) Emax/cm−1: 45500, 40000, 33000(sh).
Cis-[TiF4(Ph3PO)2]: Colourless crystals. Yield: 56%. Required for C36H30F4O2P2Ti (680.5):
1
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C, 63.6; H, 4.4. Found: C, 62.9; H, 3.9%. H NMR (CD2Cl2): δ 7.3−7.7 (m). F{1H} NMR
(CH2Cl2) 293 K: 200.7 (s) [2F], 140.7 (s) [2F]; 243 K: 195.7 (t) [2F], 137.9 (t) [2F] 2JFF = 38
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31
Hz. P{1H} NMR (CH2Cl2) 293 K: 40.2 (s); 200 K: 41.7 (s). IR (Nujol/cm−1): 1152, 1067
ν(PO), 640, 620, 596 ν(TiF). UV/vis (diffuse reflectance) Emax/cm−1: 43100, 38500. Crystals
were obtained directly from the reaction filtrate after isolating the bulk material.
Cis-[TiF4(Me3PO)2]: Colourless powder. Yield: 73%. Required for C6H18F4O2P2Ti (308.0):
1
C, 23.4; H, 5.9. Found: C, 22.6; H, 6.2%. H NMR (CD2Cl2): δ 2.15 (s). 19F{1H} NMR
(CH2Cl2) 293 K: 188.2 (s) [2F], 127.4 (s) [2F]; 243 K: 179.5 (t) [2F], 127.5 (t) [2F] 2JFF = 38
Hz. 31P{1H} NMR (CH2Cl2) 293 K: 63.1 (s). IR (Nujol/cm−1): 1155(m), 1075(br) ν(PO),
640(sh), 620, 580 ν(TiF). UV/vis (diffuse reflectance) Emax/cm−1: 44100, 38600.
Cis-[TiF4(Ph3AsO)2]:
Colourless
crystals.
Yield:
59%.
Required
for
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C36H30As2F4O2Ti·CH2Cl2 (853.3): C, 52.1; H, 3.8. Found: C, 51.7; H, 3.7%. H NMR
(CD2Cl2): δ 7.3−7.7 (m). 19F{1H} NMR (CH2Cl2) 293 K: 160.8 (t) [2F], 121.2 (t) [2F] 2JFF
=
35 Hz. IR (Nujol/cm−1): 845(br) ν(AsO), 640(sh), 616, 595, 570 ν(TiF). UV/vis (diffuse
reflectance) Emax/cm−1: 45500, 36400. Crystals were grown by vapour diffusion of diethyl
ether into a CH2Cl2 solution of the complex.
[TiF4{Ph2P(O)CH2P(O)Ph2}]: Colourless crystals. Yield: 48%. Required for
1
C25H22F4O2P2Ti (540.3): C, 55.6; H, 4.1. Found: C, 55.2; H, 4.2%. H NMR (CD2Cl2): δ
7.3−7.7 (m), 5.2 (s,br). 19F{1H} NMR (CH2Cl2) 293 K: 218.8 (t) [2F], 135.7 (t) [2F] 2JFF = 35
31
Hz. P{1H} NMR (CH2Cl2) 293 K: 40.1 (s). IR (Nujol/cm−1): 1156, 1100 ν(PO), 657, 639,
622, 600(sh) ν(TiF). UV/vis (diffuse reflectance) Emax/cm−1: 45000, 39100, 36400(sh).
3