Multifold Ring‐Closing Olefin Metatheses in Syntheses of Organometallic Molecules with Unusual Connectivities

Fiedler, Tobias; Gladysz, J. A.

doi:10.1002/9781118711613.ch9

Cited by 16 publications

(15 citation statements)

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“…Multifold ring closing alkene (CC) metatheses can lead to a variety of fascinating molecular architectures, especially in metal coordination spheres. , Over the last 15 years, we have been especially concerned with metathesis/hydrogenation sequences of the type exemplified in Scheme . − These feature educts with trans disposed olefinic phosphine ligands of the formula P((CH 2 ) m CHCH 2 ) 3 , such as the platinum dichloride complexes trans - 1c – e (indices code to the number of atoms between phosphorus and the vinyl group). The major products are almost always derived from 3-fold interligand metatheses, which afford triply trans spanning dibridgehead diphosphine ligands.…”

Section: Introductionmentioning

confidence: 99%

Three-Fold Intramolecular Ring Closing Alkene Metatheses of Square Planar Complexes with cis Phosphorus Donor Ligands P(X(CH₂)_mCH═CH₂)₃ (X = −, m = 5–10; X = O, m = 3–5): Syntheses, Structures, and Thermal Properties of Macrocyclic Dibridgehead Diphosphorus Complexes

et al. 2018

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Reactions of cis-PtCl(P((CH) CH═CH)) and Grubbs' first generation catalyst and then hydrogenations afford cis- PtCl(P((CH) ) P) ( cis-2; n = 2 m + 2 = 12 (b), 14 (c), 16 (d), 18 (e), 20 (f), 22 (g); 6-40%), derived from 3-fold interligand metatheses. The phosphite complexes cis-PtCl(P(O(CH) CH═CH)) are similarly converted to cis- PtCl(P(O(CH) O) P) ( cis-5; n* = 8 (a), 10 (b), 12 (c), 10-20%). The substitution products cis- PtPh(P((CH) ) P) ( cis-6c,d) and cis- PtI(P(O(CH)O) P) are prepared using PhZn and NaI, respectively. Crystal structures of cis-2c,d,f, cis-5a,b, and cis-6c show one methylene bridge that roughly lies in the platinum coordination plane and two that are perpendicular. The thermal behavior of the complexes is examined. When the bridges are sufficiently long, they rapidly exchange via an unusual "triple jump rope" motion over the PtX moieties. NMR data establish Δ H, Δ S, and Δ G/Δ G values of 7.8 kcal/mol, -27.9 eu, and 16.1/18.8 kcal/mol for cis-2d, and a Δ G of ≥19.6 kcal/mol for the shorter bridged cis-2c. While cis-2c,g gradually convert to trans-2c,g at 150-185 °C in haloarenes, trans-2c,g give little reaction under analogous conditions, establishing the stability order trans > cis. Similar metathesis/hydrogenation sequences with octahedral complexes containing two cis phosphine ligands, fac-ReX(CO)(P((CH)CH═CH)) (X = Cl, Br), give fac- ReX(CO)( P(CH) CH)((CH))( P(CH) CH) (19-50%), which are derived from a combination of interligand and intraligand metathesis. The relative stabilities of cis/ trans and other types of isomers are probed by combinations of molecular dynamics and DFT calculations.

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Section: Introductionmentioning

confidence: 99%

Three-Fold Intramolecular Ring Closing Alkene Metatheses of Square Planar Complexes with cis Phosphorus Donor Ligands P(X(CH₂)_mCH═CH₂)₃ (X = −, m = 5–10; X = O, m = 3–5): Syntheses, Structures, and Thermal Properties of Macrocyclic Dibridgehead Diphosphorus Complexes

et al. 2018

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“…The intersection of alkene metathesis and inorganic or organometallic synthesis has proved to be a rich area, allowing targeted approaches to a variety of complex metal-containing molecules. , We evolved initial interests in metallomacrocycle and metallamacrocycle syntheses ( I and II in Scheme ) , into a program involving gyroscope-like complexes of the general type IIIa . − These are distinguished by three methylene chains that span two trans -phosphorus donor atoms and are assembled by alkene metathesis/hydrogenation sequences. Some of the most interesting and intensively studied species have trigonal planar iron carbonyl cores or “rotators” (Fe(CO) 3 , Fe(CO) 2 (NO) + , Fe(CO)(NO)(X)) within the di bridgehead di phosphine “stators”.…”

Section: Introductionmentioning

confidence: 99%

Partially Shielded Fe(CO)₃ Rotors: Syntheses, Structures, and Dynamic Properties of Complexes with Doubly trans Spanning Diphosphines, trans-Fe(CO)₃(PhP((CH₂)_n)₂PPh)

et al. 2017

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Reactions of Fe(CO) 3 (η 4 -benzylideneacetone) and PhP((CH 2 ) m CHCH 2 ) 2 (m = a, 4; b, 5; c, 6) give trans-Fe(CO) 3 (PhP((CH 2 ) m CHCH 2 ) 2 ) 2 (2a−c, 28−70%), which are treated with Grubbs' catalyst (15 mol %; refluxing CH 2 Cl 2 ). NMR analyses of the crude interligand metathesis products trans-Fe(CO) 3 (PhP((CH 2 ) m CHCH(CH 2 ) m ) 2 PPh) (3a−c, 30−31%) suggest Z/E CC mixtures and/or byproducts from intraligand metathesis or oligomers. Subsequent hydrogenations (5 bar/cat. Rh(Cl)(PPh 3 ) 3 or PtO 2 ) afford trans-Fe(CO) 3 (PhP((CH 2 ) n ) 2 PPh) (4a−c, 69−77%; n = 2m + 2, synperiplanar phenyl groups), which density functional theory calculations show to be more stable than isomers derived from other metathesis modes. Crystallizations give (E,E)-3a and 4b, the X-ray structures of which are determined and analyzed. Variable-temperature 13 C{ 1 H} NMR experiments show that rotation of the Fe(CO) 3 moiety in 4b is rapid on the NMR time scale (RT to 0 °C; ΔG ⧧ 273 K ≤ 12.8 kcal/mol), but that in 4a is not (RT to 105 °C; ΔG ⧧ 378 K ≥ 17.9 kcal/mol). These data indicate rotational barriers lower than those in analogues in which three methylene chains connect the phosphorus atoms, trans-Fe(CO) 3 (P((CH 2 ) n ) 3 P).

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“…As preserved in historic video footage, Steve Jobs unveiled the iPhone 4 against the backdrop of a classical mechanical gyroscope (the actual in-phone gyroscope that controls the screen orientation and other functions has an advanced generation design). In view of their many technological applications and the ever-increasing emphasis in consumer, industrial, or military devices on miniaturization, several groups have undertaken long-term quests for molecular gyroscopes. − All of these involve assemblies consisting of a “rotator” and “stator”, the former being akin to the flywheel of the classical gyroscope.…”

Section: Introductionmentioning

confidence: 99%

“…Our research group has undertaken extensive investigations of dibridgehead diphosphine complexes of the type I (Scheme ). ,− These are accessed in surprisingly high yields via 3-fold intramolecular ring-closing metatheses of bis(phosphine) complexes of the formula trans -ML y (P((CH 2 ) m CHCH 2 ) 3 ) 2 . Both the lengths of the methylene chains that connect the two phosphorus atoms and the sizes of the ancillary ligands (L y ) are easily varied.…”

Section: Introductionmentioning

confidence: 99%

Syntheses, Reactivity, Structures, and Dynamic Properties of Gyroscope-like Iron Carbonyl Complexes Based on Dibridgehead Diarsine Cages

et al. 2016

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Reactions of BrMg(CH2) m CHCH2 (m = 4, a; 5, b; 6, c) and AsCl3 (0.30 equiv) give the arsines As((CH2) m CHCH2)3 (58–70%), which when added to iron tricarbonyl sources yield trans-Fe(CO)3(As((CH2) m CHCH2)3)2 (66–70%). Reactions with Grubbs’ catalyst (18 mol %, CH2Cl2, reflux) and then hydrogenations (ClRh(PPh3)3/60–80 °C) afford gyroscope-like complexes trans- Fe(CO)3(As((CH2) n )3 As) (4a–c, n = 2m + 2; 41–59%/two steps) of idealized D 3h symmetry. Additions of NO+BF4 – give the isoelectronic and isosteric cations [Fe(CO)2(NO)(As((CH2) n )3 As)]+BF4 – (5a–c + BF4 –; 81–98%), and [H(OEt2)2]+BArf – (BArf = B(3,5-C6H3(CF3)2)4) gives the hydride complexes mer,trans-[Fe(CO)3(H)(As((CH2) n )3 As)]+BArf – (6a–c + BArf –; 98–99%). Crystal structures of 4a–c and 5b +BF4 – are determined. That of 4c suggests enough van der Waals clearance for the Fe(CO)3 moiety to rotate within the As(CH2)14As linkages; that of 4a shows rotation to be blocked by the shorter As(CH2)10As linkages. The rotator dynamics in these complexes are probed by VT NMR. At ambient temperature in solution, 5a +BF4 – and 6a +BArf – give two sets of P(CH2) n/2 13C NMR signals (2:1), while 5b,c +BF4 – and 6b,c +BArf – give only one. At lower temperatures the signals of 5b +BF4 – and 6b +BArf – decoalesce. The data give ΔH ⧧/ΔS ⧧ values (kcal/mol and eu) of 7.7/–22.1 and 5.4/–22.7 for Fe(CO)2(NO)+ and Fe(CO)3(H)+ rotation. These barriers are distinctly lower than in diphosphine analogues, consistent with the longer iron–arsenic vs −phosphorus bonds increasing the interior dimensions of the diarsine cage.

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Multifold Ring‐Closing Olefin Metatheses in Syntheses of Organometallic Molecules with Unusual Connectivities

Cited by 16 publications

References 53 publications

Three-Fold Intramolecular Ring Closing Alkene Metatheses of Square Planar Complexes with cis Phosphorus Donor Ligands P(X(CH₂)_mCH═CH₂)₃ (X = −, m = 5–10; X = O, m = 3–5): Syntheses, Structures, and Thermal Properties of Macrocyclic Dibridgehead Diphosphorus Complexes

Three-Fold Intramolecular Ring Closing Alkene Metatheses of Square Planar Complexes with cis Phosphorus Donor Ligands P(X(CH₂)_mCH═CH₂)₃ (X = −, m = 5–10; X = O, m = 3–5): Syntheses, Structures, and Thermal Properties of Macrocyclic Dibridgehead Diphosphorus Complexes

Partially Shielded Fe(CO)₃ Rotors: Syntheses, Structures, and Dynamic Properties of Complexes with Doubly trans Spanning Diphosphines, trans-Fe(CO)₃(PhP((CH₂)_n)₂PPh)

Syntheses, Reactivity, Structures, and Dynamic Properties of Gyroscope-like Iron Carbonyl Complexes Based on Dibridgehead Diarsine Cages

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Multifold Ring‐Closing Olefin Metatheses in Syntheses of Organometallic Molecules with Unusual Connectivities

Cited by 16 publications

References 53 publications

Three-Fold Intramolecular Ring Closing Alkene Metatheses of Square Planar Complexes with cis Phosphorus Donor Ligands P(X(CH2)mCH═CH2)3 (X = −, m = 5–10; X = O, m = 3–5): Syntheses, Structures, and Thermal Properties of Macrocyclic Dibridgehead Diphosphorus Complexes

Three-Fold Intramolecular Ring Closing Alkene Metatheses of Square Planar Complexes with cis Phosphorus Donor Ligands P(X(CH2)mCH═CH2)3 (X = −, m = 5–10; X = O, m = 3–5): Syntheses, Structures, and Thermal Properties of Macrocyclic Dibridgehead Diphosphorus Complexes

Partially Shielded Fe(CO)3 Rotors: Syntheses, Structures, and Dynamic Properties of Complexes with Doubly trans Spanning Diphosphines, trans-Fe(CO)3(PhP((CH2)n)2PPh)

Syntheses, Reactivity, Structures, and Dynamic Properties of Gyroscope-like Iron Carbonyl Complexes Based on Dibridgehead Diarsine Cages

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Three-Fold Intramolecular Ring Closing Alkene Metatheses of Square Planar Complexes with cis Phosphorus Donor Ligands P(X(CH₂)_mCH═CH₂)₃ (X = −, m = 5–10; X = O, m = 3–5): Syntheses, Structures, and Thermal Properties of Macrocyclic Dibridgehead Diphosphorus Complexes

Three-Fold Intramolecular Ring Closing Alkene Metatheses of Square Planar Complexes with cis Phosphorus Donor Ligands P(X(CH₂)_mCH═CH₂)₃ (X = −, m = 5–10; X = O, m = 3–5): Syntheses, Structures, and Thermal Properties of Macrocyclic Dibridgehead Diphosphorus Complexes

Partially Shielded Fe(CO)₃ Rotors: Syntheses, Structures, and Dynamic Properties of Complexes with Doubly trans Spanning Diphosphines, trans-Fe(CO)₃(PhP((CH₂)_n)₂PPh)