Übergangsmetall‐funktionalisierte Phosphaarsene als Liganden in Pentacarbonylchrom‐Komplexen. Röntgenstrukturanalyse von (η5‐C5Me5)(CO)2Fe–As[Cr(CO)5] = P–C6H2(tBu)3(2,4,6)
Abstract:Die Umsetzung von photochemisch erzeugtem [(Z)-Cycloocten]Cr(CO), mit den hrgangsmetall-substit~erten Phosphaarsenen (q5-C5&R)(C0XPPhs)Fe -As = P-Ar (2% b) ( Phosphaarsene mit organischen Substituenten vom Typ R' -P =As -R2 (1)2-7) sind schon einige Jahre bekannt. Demgegeniiber wurden die ersten durch Obergangsmetallkomplexfragmente funktionalisierten Phosphaarsene 2 (Phosphaarsenylkomplexe) erst kiirzlich von uns vorgestellt ' ).Die Strukturbestimmung von 2 durch Rontgenbeugung scheiterte an geeigneten Krista… Show more
“…X‐ray crystallography on 266 showed two crystallographically independent molecules in the asymmetric unit, and confirms the ligation of the phosphine to the arsenic atom featuring an average As–P bond length of 2.205 Å. This distance is amidst that of As–P single bonds as measured in [Cp* (CO) 2 Fe–P–As Mes*] 2 (2.360 Å av) and genuine As=P‐double bonds in arsaphosphenes [2.124(2) to 2.155(1) Å]. This situation agrees with an ylide‐type As–P‐multiple bond.…”
Section: Reactivity Of 2‐phosphaethynolatesmentioning
2-Phosphaethynolates, particularly the sodium salts, Na(OCP), are exceedingly versatile nucleophiles, which renders these species important as precursors to phosphorus-containing π-conjugated heterocycles. Moreover, the 2-phosphaethynolate anion serves as a potent phosphide transfer reagent giving rise to the first stable phosphinidine among other prod-[a] Centrum für Molekulare Materialien, 2176 Scheme 3. Synthesis of [Na(dme) 2 (PCO)] 2 (2a) from 3by bond metathesis.philicity of carbon monoxide is considerably increased by ligation to the iron center, and where 2b was observed as the only P-containing product. [7] In keeping with this, heating a DMF solution of K 3 P 7 and [18]-crown-6 to 150°C under an atmosphere of CO led to the formation of [K([18]-crown-6)](PCO) 5 in addition to polyphosphides K 2 P 16 and K 3 P 21 . Aqueous work up allowed the isolation of 5 as a colorless solid in 38 % yield (Scheme 4). [9] Scheme 4. Synthesis of 5.
Alkali Earth Metal 2-PhosphaethynolatesAttempts to emulate Becker's protocol for [Li(dme) 2 ](PCO) with alkaline earth metals was largely met with failure. Exposure of M[P(SiMe 3 ) 2 ] 2 to dimethyl carbonate in THF or DME afforded the corresponding magnesium (6), calcium (7), strontium (8) and barium (9) bis(2-phosphaethynolates), which slowly decomposed in the ethereal solvent. Rapid deterioration of the products was observed in hydrocarbon solvents or by removal of coordinating solvent molecules in vacuo.Solely in the case of the calcium derivative 7, where three DME ligands obviously imparted sufficient stability to the crystals full structural characterization was possible. Otherwise, identification of compounds 6-9 was restricted to NMR evidence (Scheme 5). [6d] Notably, combination of Sr[P(SiMe 3 ) 2 ] 2 with an excess of dimethyl carbonate yielded a few crystals of dinuclear 10, as confirmed by X-ray techniques. [6d] Eur. 2187 Scheme 32. Alkylation reactions of dianion 55 with 2-iodopropane and 4,4′,4′′-trimethoxyphenylmethyl chloride. Scheme 33. Preparation of Li(PCS) (58). 2193 Scheme 49. Synthesis of 98 from 99 and P(SiMe 3 ) 3 . Scheme 50. Synthesis of 98 from Na(OCP) or P 7 (SiMe 3 ) 3 . Scheme 51. Proposed mechanism for the formation of phosphaalkene 98′ from 101′ and (PCO) -(R = Me). Scheme 73. Synthesis of 145 {[K] + = [K{18}-crown-6] + }. 2201 Scheme 79. Synthesis of 153a and 154a. Scheme 80. Synthesis of 153b. Scheme 81. Preparation of 155 and 156 by deprotonation of 152c. Eur. J. Inorg. Chem. 2018, 2175-2227 www.eurjic.org Scheme 95. Formation of adducts 192a-e. Scheme 96. Reaction of 168 with N-heterocyclic carbenes 96 and 193b,c.
“…X‐ray crystallography on 266 showed two crystallographically independent molecules in the asymmetric unit, and confirms the ligation of the phosphine to the arsenic atom featuring an average As–P bond length of 2.205 Å. This distance is amidst that of As–P single bonds as measured in [Cp* (CO) 2 Fe–P–As Mes*] 2 (2.360 Å av) and genuine As=P‐double bonds in arsaphosphenes [2.124(2) to 2.155(1) Å]. This situation agrees with an ylide‐type As–P‐multiple bond.…”
Section: Reactivity Of 2‐phosphaethynolatesmentioning
2-Phosphaethynolates, particularly the sodium salts, Na(OCP), are exceedingly versatile nucleophiles, which renders these species important as precursors to phosphorus-containing π-conjugated heterocycles. Moreover, the 2-phosphaethynolate anion serves as a potent phosphide transfer reagent giving rise to the first stable phosphinidine among other prod-[a] Centrum für Molekulare Materialien, 2176 Scheme 3. Synthesis of [Na(dme) 2 (PCO)] 2 (2a) from 3by bond metathesis.philicity of carbon monoxide is considerably increased by ligation to the iron center, and where 2b was observed as the only P-containing product. [7] In keeping with this, heating a DMF solution of K 3 P 7 and [18]-crown-6 to 150°C under an atmosphere of CO led to the formation of [K([18]-crown-6)](PCO) 5 in addition to polyphosphides K 2 P 16 and K 3 P 21 . Aqueous work up allowed the isolation of 5 as a colorless solid in 38 % yield (Scheme 4). [9] Scheme 4. Synthesis of 5.
Alkali Earth Metal 2-PhosphaethynolatesAttempts to emulate Becker's protocol for [Li(dme) 2 ](PCO) with alkaline earth metals was largely met with failure. Exposure of M[P(SiMe 3 ) 2 ] 2 to dimethyl carbonate in THF or DME afforded the corresponding magnesium (6), calcium (7), strontium (8) and barium (9) bis(2-phosphaethynolates), which slowly decomposed in the ethereal solvent. Rapid deterioration of the products was observed in hydrocarbon solvents or by removal of coordinating solvent molecules in vacuo.Solely in the case of the calcium derivative 7, where three DME ligands obviously imparted sufficient stability to the crystals full structural characterization was possible. Otherwise, identification of compounds 6-9 was restricted to NMR evidence (Scheme 5). [6d] Notably, combination of Sr[P(SiMe 3 ) 2 ] 2 with an excess of dimethyl carbonate yielded a few crystals of dinuclear 10, as confirmed by X-ray techniques. [6d] Eur. 2187 Scheme 32. Alkylation reactions of dianion 55 with 2-iodopropane and 4,4′,4′′-trimethoxyphenylmethyl chloride. Scheme 33. Preparation of Li(PCS) (58). 2193 Scheme 49. Synthesis of 98 from 99 and P(SiMe 3 ) 3 . Scheme 50. Synthesis of 98 from Na(OCP) or P 7 (SiMe 3 ) 3 . Scheme 51. Proposed mechanism for the formation of phosphaalkene 98′ from 101′ and (PCO) -(R = Me). Scheme 73. Synthesis of 145 {[K] + = [K{18}-crown-6] + }. 2201 Scheme 79. Synthesis of 153a and 154a. Scheme 80. Synthesis of 153b. Scheme 81. Preparation of 155 and 156 by deprotonation of 152c. Eur. J. Inorg. Chem. 2018, 2175-2227 www.eurjic.org Scheme 95. Formation of adducts 192a-e. Scheme 96. Reaction of 168 with N-heterocyclic carbenes 96 and 193b,c.
“…The calculated value for an As−C single bond is 1.96 Å . The Fe−As bond (2.3711(9) Å) is slightly shortened as compared to the ones in (η 5 -C 5 Me 5 )(CO) 2 FeAs[Cr(CO) 5 ]PMes* (2.389(1) Å) and in (η 5 -C 5 H 5 )(CO) 2 FeAsC(OSiMe 3 )( t Bu) (2.407(1) Å) 1 Molecular structure of 13a .
Reaction of
(η5-C5Me5)(CO)2FeP(SiMe3)2
(4a) with carbon disulfide afforded the
unstable
metallophosphaalkene
(η5-C5Me5)(CO)2Fe−PC[SSiMe3]2
(5a), which decomposed to the
doubly metalated 1,3,4-thiadiphosphole 8a by extrusion of
bis(trimethylsilyl)sulfide. The
transient metallophosphaalkene 5a was intercepted as the
isolable [(CO)5Cr]-adduct 6a by
treatment with
[(Z)-cyclooctene]Cr(CO)5.
Similarly, the metallodisilylarsanes
(η5-C5Me5)(CO)2M−As(SiMe3)2 (M = Fe,
Ru) (11a,b) were converted to stable metalloarsaalkenes
12a,b
by exposure to CS2. Pentacarbonylchromium complexes
13a,b were accessible by reaction
with [(Z)-cyclooctene]Cr(CO)5.
The X-ray structure analysis of 13a revealed the
molecule
as the first η1-arsaalkene complex.
“…[17] Due to the π-interaction with a metal atom, the As-P distance within the 2-phospha-1-arsaallyl ligand in 4a [2.2507(7) Å] is longer than the unsupported As=P double bonds in the structurally characterized compounds {(Me 3 Si) 2 CH}As=P(2,4,6-tBu 3 C 6 H 2 ) [2.124 Å] [18] or [Cp*-(CO) 2 FeAs{Cr(CO) 5 }=P(2,4,6-tBu 3 C 6 H 2 )] [2.155(1) Å]. [19] The bond length P(1)-C(13) in 4a [1.791(2) Å]−as is also found in VI (M = Mo) [1.7875(12) Å]−is elongated with respect to a localized and unsupported P=C double bond (1.65-1.72 Å), [20] but is clearly shorter than a P-C single bond (av. 1.85 Å).…”
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