A spirocyclic tetraoxyphosphorane with an apically located chlorine in a trigonal bipyramid and its hydrolysis product

The spirocyclic (chloro)tetraoxyphosphorane CH₂(6-t-Bu-4-Me-C₆H₂O)₂P(Cl)(1,2-O₂C₆Cl₄) (2) and its hydrolysis product CH₂(6-t-Bu-4-Me-C₆H₂O)₂P(O)(OC₆Cl₄-2-OH) (3) have been synthesized and characterized by X-ray crystallography and solution state NMR. Unlike the previously reported spirocyclic chlorophosphoranes where chlorine occupies an equatorial position of a trigonal bipyramid (TBP), in 2 it is apical. The hydrolysis product 3 is a hydrogen bonded dimer. Compound CH₂(6-t-Bu-4-Me-C₆H₂O)₂P(Cl)[1,2-O₂–3,5-(t-Bu)₂C₆H₂] (4) was also synthesized in a manner analogous to that of 2. Attempts to isolate structurally characterizable pentacoordinate compounds by reacting CH₂(6-t-Bu-4-Me-C₆H₂O)₂PX [X=Cl (1), 2,6-Cl₂C₆H₃O (5), cycl-C₆H₁₁NH (6)] with N-chlorodiisopropylamine were not successful, although in some cases a pentacoordinate species was detected; the corresponding oxidized products CH₂(6-t-Bu-4-Me-C₆H₂O)₂P(O)X [X=Cl (7), 2,6-Cl₂C₆H₃O (8), cycl-C₆H₁₁NH (9)] were isolated by this route. Variable temperature (¹H, ³¹P) NMR spectra of 2 have been recorded; at low temperatures, two ³¹P NMR signals of unequal intensity are seen in the pentacoordinate region. A probable intramolecular process involving equatorial–equatorial↔apical–equatorial (for the eight-membered ring) has been invoked to explain the spectral features.     

Chemistry of selected cyclic P(III) compounds possessing a P-Cl bond

The compounds [CH₂(6-t-Bu-4-Me-C₆H₂O)₂]PCl (1), (OCH₂CMe₂CH₂O)-PCl (2), and [ClPN(t-Bu)]₂ (3) have been utilized as precursors in the synthesis of (i) new pentacoordinate phosphorus compounds [e.g. CH₂(6-t-Bu-4-Me-C₆H₂O)₂ P(NRR′)(O₂C₆C1₄), CH₂(6-t-Bu-4-Me-C₆H₂O)₂PX[OC(O-i-Pr)N=N(C(O)O-i-Pr)],(ii) cyclic phosphates and their complexes [e.g. imidazolium⁺CH₂(6-t-Bu-4-Me-C₆H₂O)₂PO₂ ^-.MeOH], (iii) new cycloaddition products [e.g. CH₂(6-t-Bu-4-Me-C₆H₂O)₂PC(CO₂Me)C(CO₂Me)C(O)N, (iv) macrocyclic compounds [e.g. [(t-BuN)P]₂[-OCH₂CMe₂CH₂O-]_h2] and (v) phosphonates [e.g. (OCH₂CMe₂CH₂O)P (O)CH₂C(CN)=CHC₅H₄FeC₅H₅]. The synthetic and structural aspects of these new products are discussed.     

Chelating Phosphorus–An O,C, O-Coordinating Pincer-Type Ligand Coordinating PIII and PV Centres

The sequence of reactions of the phosphorus-containing aryllithium compound 5-t-Bu-1,3-[(P(O)(O-i-Pr)₂]₂C₆H₂Li (ArLi) with Ph₂PCl, KMnO₄, elemental sulfur and elemental selenium, respectively, gave the aryldiphenylphosphane chalcogenides 5-t-Bu-1,3-[(P(O)(O-i-Pr)₂]₂C₆H₂P(E)Ph₂ ( 1 , E=O; 2 , E=S; 3 , E=Se). Compound 1 partially hydrolysed giving [5-t-Bu-1-{(P(O)(O-i-Pr)₂}-3-{(P(O)(OH)₂}C₆H₂]P(O)Ph₂ ( 4 ). The reaction of ArLi with PhPCl₂ provided the benzoxaphosphaphosphole [1(P), 3(P)-P(O)(O-i-Pr)OPPh-6-t-Bu-4-P(O)(O-i-Pr)₂]C₆H₂P ( 5i ) as a mixture of the two diastereomers. The oxidation of 5i with elemental sulfur gave the benzoxaphosphaphosphole sulfide [1(P), 3(P)-P(O)(O-i-Pr)OP(S)Ph-6-t-Bu-4-P(O)(O-i-Pr)₂]C₆H₂ ( 5 ) as pair of enantiomers P1(R), P3(S)/P1(S), P3(R) of the diastereomer (RS/SR)- 5 ( 5b ). The aryldiphenylphosphane 5-t-Bu-1,3-[(P(O)(O-i-Pr)₂]₂C₆H₂PPh₂ ( 6 ) was obtained from the reaction of the corresponding aryldiphenylphosphane sulfide 2 with either sodium hydride, NaH, or disodium iron tetracarbonyl, Na₂Fe(CO)₄. The oxidation of the aryldiphenylphosphane 6 with elemental iodine and subsequent hydrolysis yielded the aryldiphenyldioxaphosphorane 9-t-Bu-2,6-(OH)-4,4-Ph₂-3,5-O₂-2,6-P₂-4λ⁵-P-[5.3.1.0]-undeca-1(10),7(11),8-triene ( 7 ). Both of its diastereomers, (RR/SS)- 7 ( 7a ) and (RS/SR)- 7 ( 7b ), were separated as their chloroform and i-propanol solvates, 7a ⋅2CHCl₃ and 7b ⋅i-PrOH, respectively. DFT calculations accompanied the experimental work.     

Structural studies of diiron complexes with monophosphine ligands tris(4-chlorophenyl)phosphine or diphenyl-2-pyridylphosphine

Four diiron dithiolate complexes with monophosphine ligands have been prepared and structurally characterized. Reactions of (μ-SCH₂CH₂S-μ)Fe₂(CO)₆ or [μ-SCH(CH₃)CH(CH₃)S-μ]Fe₂(CO)₆ with tris(4-chlorophenyl)phosphine or diphenyl-2-pyridylphosphine in the presence of Me₃NO·2H₂O afforded diiron pentacarbonyl complexes with monophosphine ligands (μ-SCH₂CH₂S-μ)Fe₂(CO)₅[P(4-C₆H₄Cl)₃] (1), (μ-SCH₂CH₂S-μ)Fe₂(CO)₅[Ph₂P(2-C₅H₄N)] (2), [μ-SCH(CH₃)CH(CH₃)S-μ]Fe₂(CO)₅[P(4-C₆H₄Cl)₃] (3), and [μ-SCH(CH₃)CH(CH₃)S-μ]Fe₂(CO)₅[Ph₂P(2-C₅H₄N)] (4) in good yields. Complexes 1–4 were characterized by elemental analysis, ¹H NMR, ³¹P{¹H} NMR and ¹³C{¹H} NMR spectroscopy. Furthermore, the molecular structures of 1–4 were confirmed by X-ray crystallography.     

Synthetic and structural studies of the diiron toluenedithiolate carbonyl complexes with monophosphine ligands

Four diiron toluenedithiolate complexes 2–5 with monophosphine ligands are reported. Treatment of [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₆ (1) with tris(3-chlorophenyl)phosphine, tris(4-chlorophenyl)phosphine, tris(4-methylphenyl)phosphine or 2-(diphenylphosphino)benzaldehyde, and Me₃NO?2H₂O in MeCN resulted in the formation of [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₅[P(3-C₆H₄Cl)₃] (2), [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₅[P(4-C₆H₄Cl)₃] (3), [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₅[P(4-C₆H₄CH₃)₃] (4), and [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₅[Ph₂P(2-C₆H₄CHO)] (5) in 64–82% yields. Complexes 2–5 have been characterized by elemental analysis, IR, ¹H NMR, ³¹P{¹H} NMR, ¹³C{¹H} NMR and further confirmed by single crystal X-ray diffraction analysis. The molecular structures show that 2–5 contain a butterfly diiron toluenedithiolate cluster coordinated by five terminal carbonyls and an apical monophosphine.     

A ferrocenyl-bridged intramolecularly coordinated bis(diorganostannylene): Synthesis, molecular structure and reactivity of [4-t-Bu-2,6-{P(O)(O-i-Pr)2C6H2Sn}C5H4]2Fe

The intramolecularly coordinated heteroleptic stannylene [4-t-Bu-2,6-{P(O)(O-i-Pr)₂}₂C₆H₂]SnCl serves as synthon for the synthesis of the ferrocenyl-bridged bis(diorganostannylene) [4-t-Bu-2,6-{P(O)(O-i-Pr)₂}₂C₆H₂SnC₅H₄]₂Fe (1) which in turn reacts with W(CO)₆ and Cr(CO)₄(C₇H₈) to provide the corresponding transition metal complexes [4-t-Bu-2,6-{P(O)(O-i-Pr)₂}₂C₆H₂Sn{W(CO)₅}C₅H₄]₂Fe (2) and [4-t-Bu-2,6-{P(O)(O-i-Pr)₂}₂C₆H₂SnC₅H₄]₂Fe · Cr(CO)₄ (3), respectively. Reaction of compound 1 with sulphur and atmospheric moisture gave, under partial tin-carbon and oxygen-carbon bond cleavage, a tetranuclear organotin-oxothio cluster 5. All compounds were characterized by ¹H, ¹³C, ³¹P, and ¹¹⁹Sn NMR, and IR spectroscopy, as well as by single-crystal X-ray diffraction analysis. Compounds 1 and 3 were also investigated by Mössbauer spectroscopy. Cyclovoltametric studies reveal the influence of the organostannyl moieties on the redox-behaviour of compounds 1-3 in comparison with unsubstituted ferrocene.     

Synthesis and selected reactions of pentakis ( t -octylisocyanide)cobalt(II) complexes

The ligand 1,1,3,3-tetramethylbutylisocyanide, CNCMe₂CH₂CMe₃, i.e. t-octylisocyanide, with Co(ClO₄)₂ · 6H₂O or Co(BF₄)₂ · 6H₂O in ethanol, produces pentakis(alkylisocyanide)cobalt(II) complexes, [Co(CNC₈H₁₇-t)₅](ClO₄)₂ (1) and [Co(CNC₈H₁₇-t)₅](BF₄)₂ · 2.0H₂O (2). These Co(II) complexes undergo reduction/substitution upon reaction with trialkylphosphine ligands to produce [Co(CNC₈H₁₇-t)₃{P(C₄H₉-n)₃}₂]ClO₄ (3), [Co(CNC₈H₁₇-t)₃{P(C₄H₉-n)₃}₂]BF₄ (4), and [Co(CNC₈H₁₇-t)₃{P(C₃H₇-n)₃}₂]ClO₄ (5). Complex 3 is oxidized with AgClO₄ to produce [Co(CNC₈H₁₇-t)₃{P(C₄H₉-n)₃}₂](ClO₄)₂ (6). Complex 1 yields [Co(CNC₈H₁₇-t)₄py₂](ClO₄)₂ (7) upon dissolving in pyridine. Reactions with triarylphosphine and triphenylarsine ligands were unsatisfactory. The chemistry of 1 and 2 is therefore more similar to that of Co(II) complexes with CNCMe₃ than with CNCHMe₂, other alkylisocyanides, or arylisocyanides, but shows some behavior dissimilar to any known Co(II) complexes of alkylisocyanides or arylisocyanides. Infrared and electronic spectra, magnetic susceptibility, molar conductivities, and cyclic voltammetry are reported and compared with known complexes. ¹H, ¹³C, and ³¹P NMR data were also measured for the diamagnetic complexes 3, 4, and 5.     

Synthesis of Heteroleptic Cerium(IV) Complexes Using a Heptadentate (N4O3) Tripodale Schiff‐base Ligand

The Cerium(IV) complexes [{N[CH₂CH₂N=CH(2‐O‐3,5‐^tBu₂C₆H₂)]₃}CeCl] ( 1 ) and [{N[CH₂CH₂N=CH(2‐O‐3,5‐^tBu₂C₆H₂)]₃}Ce(NO₃)] ( 2 ) were derived from the condensation of tris(2‐aminoethyl)amine and 3,5‐di‐tert‐butylsalicylaldehyde and the appropriate Ce starting material CeCl₃(H₂O)₆ and (NH₄)₂[Ce(NO₃)₆], respectively. Single crystal X‐ray diffraction studies reveal monomeric complexes.     

Reactions of iridium bis(phosphinite) pincer complexes with protic acids

Iridium pincer complexes [C₆H₃-2,6-(OPBu^t ₂)₂]Ir(H)Cl (10) and [4-EtOOCC₆H₂-2,6-(OPBu^t ₂)₂]Ir(H)Cl (11) react with protic acids undergoing metallation of one of the tert-butyl groups to form double cyclometallated products [4-R-C₆H₂-2-(OPBu^t ₂)-6-(OP(Bu^t)CMe₂CH₂)]IrCl (12, R = H; 13, R = COOEt), which are stable in air. Complex 12 reacts with CO and Bu^tNC giving the corresponding 18-electron complexes [C₆H₃-2-(OP-Bu^t ₂)-6-(OP(Bu^t)CMe₂CH₂)]Ir(L)Cl (14, L = CO; 15, L = CNBu^t). The structure of compound 14 was established by X-ray diffraction analysis.     

Two new supramolecular compounds based on Ni(II)-Schiff-base and Keggin-type [PMo12O40]3−

Two polyoxometalate-templated nickel-Schiff-base compounds, {[Ni(L)₂]₂[PMo₁₂O₄₀][Cl] · 1.5DMF · H₂O} _n (1) and {[Ni(L)₂]₂[PMo₁₂O₄₀][Cl] · DMSO · CH₃OH · 0.5H₂O} _n (2) (where L is 1,4-bis(4-imidazolyl)-2,3-diaza-1,3-butadiene), were synthesized in situ from Ni²⁺ and L in H₂O/DMF/CH₃OH or H₂O/DMSO/CH₃OH at room temperature and characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction analysis. The results of the single-crystal X-ray diffractions suggested that both compounds have the same packing of the Ni(II)-Schiff-base cation layer and Keggin anion layer. Thermogravimetric analyses suggested that two supramolecular compounds have similar thermal stabilities based on the same packing of the cation and anion layers.     

Syntheses of (η6-p-cymene)ruthenium(II) piano-stool amine complexes: molecular structure of [(η6-C10H14)RuCl2(H2N-C6H4-p-Cl)]

The dimeric complex [{(η⁶-p-cymene)Ru(μ-Cl)Cl}₂] (1) reacts with S,N-donor Schiff base ligands, para-substituted S-(thiophen-2-ylmethylene)phenylamines in methanol to give mononuclear amine complexes of the type [(η⁶-p-cymene)RuCl₂(NH₂–C₆H₄–p-X)] {X?=?H (2a); X?=?CH₃ (2b); X?=?OCH₃ (2c); X?=?Cl (2d); Br (2e) X?=?NO₂ (2f), respectively} by hydrolysis of the imine group of the ligand after coordination to the metal. The complexes were characterized by analysis and IR and NMR spectroscopy. The molecular structure of [(η⁶-C₁₀H₁₄)RuCl₂(H₂N–C₆H₄–p-Cl)] (2d) was established by a single-crystal X-ray diffraction study.     

Syntheses and Structures of trans-bis(Alkenylacetylide) Ruthenium Complexes

A series of ruthenium alkenylacetylide complexes trans-[Ru{C≡CC(=CH₂)R}Cl(dppe)₂] (R=Ph ( 1 a ), ^cC₄H₃S ( 1 b ), 4-MeS-C₆H₄ ( 1 c ), 3,3-dimethyl-2,3-dihydrobenzo[b]thiophene (DMBT) ( 1 d )) or trans-[Ru{C≡C-^cC₆H₉}Cl(dppe)₂] ( 1 e ) were allowed to react with the corresponding propargylic alcohol HC≡CC(Me)R(OH) (R=Ph ( A ), ^cC₄H₃S ( B ), 4-MeS-C₆H₄ ( C ), DMBT ( D ) or HC≡C-^cC₆H₁₀(OH) ( E ) in the presence of TlBF₄ and DBU to presumably give alkenylacetylide/allenylidene intermediates trans-[Ru{C≡CC(=CH₂)R}{C=C=C(Me)}(dppe)₂]PF₆ ([ 2 ]PF₆). These complexes were not isolated but deprotonated to give the isolable bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH₂)R}₂(dppe)₂] (R=Ph ( 3 a ), ^cC₄H₃S ( 3 b ), 4-MeS-C₆H₄ ( 3 c ), DMBT ( 3 d )) and trans-[Ru{C≡C-^cC₆H₉}₂(dppe)₂] ( 3 e ). Analogous reactions of trans-[Ru(CH₃)₂(dmpe)₂], featuring the more electron-donating 1,2-bis(dimethylphosphino)ethane (dmpe) ancillary ligands, with the propargylic alcohols A or C and NH₄PF₆ in methanol allowed isolation of the intermediate mixed alkenylacetylide/allenylidene complexes trans-[Ru{C≡CC(=CH₂)R}{C=C=C(Me)}(dmpe)₂]PF₆ (R=Ph ([ 4 a ]PF₆), 4-MeS-C₆H₄ ([ 4 c ]PF₆). Deprotonation of [ 4 a ]PF₆ or [ 4 c ]PF₆ gave the symmetric bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH₂)R}₂(dmpe)₂] (R=Ph ( 5 a ), 4-MeS-C₆H₄ ( 5 c )), the first of their kind containing the dmpe ancillary ligand sphere. Attempts to isolate bis(allenylidene) complexes [Ru{C=C=C(Me)R}₂(PP)₂]²⁺ (PP=dppe, dmpe) from treatment of the bis(alkenylacetylide) species 3 or 5 with HBF₄ ⋅ Et₂O were ultimately unsuccessful.     

Phosphine free diamino-diol based palladium catalysts and their application in Suzuki-Miyaura cross-coupling reactions

Inexpensive air and moisture stable diamino-diol ligands [(2-OH-C₁₀H₆)CH₂(μ-NC₄H₈N)CH₂(C₁₀H₆-2-OH)] (1) and [(5-^tBuC₆H₃-2-OH)CH₂(μ-NC₄H₈N)CH₂(5-^tBuC₆H₃-2-OH)] (2) were synthesized by reacting corresponding alcohols with formaldehyde and piperazine. Treatment of ligands 1 and 2 with Pd(OAc)₂ in 1:1 molar ratio afforded neutral palladium complexes [Pd{(OC₁₀H₆)CH₂(μ-NC₄H₈N)CH₂(C₁₀H₆O)}] (3) and [Pd{(5-^tBuC₆H₃-2-O)CH₂(μ-NC₄H₈N)CH₂(5-^tBuC₆H₃-2-O)}] (4) in good yield. The palladium complexes 3 and 4 are employed in Suzuki-Miyaura cross-coupling reactions between phenylboronic acid and several aryl chlorides or bromides. They are found to be competent homogeneous catalysts for a variety of substrates to afford the coupled products in good to excellent yields. The crystal structures of compounds 2 and 4 are also reported.     

Reactivity studies of a four-coordinate methyl chloro aluminium aminophenolate complex with B(C6F5)3

The X-ray characterized four-coordinate aminophenolate aluminium complex {6-(CH₂NMe₂)-2-CPh₃-4-Me-C₆H₂O}Al(Me)(Cl) (1), which is readily available by reaction of the corresponding aminophenolate Li salt with MeAlCl₂, slowly reacts with B(C₆F₅)₃ to yield a 1/1 mixture of the Al methyl cation {6-(CH₂NMe₂)-2-CPh₃-4-Me-C₆H₂O}Al(Me)(THF)⁺ (2, as salt) and the Al dichloro derivative {6-(CH₂NMe₂)-2-CPh₃-4-Me-C₆H₂O}AlCl₂ (3). This reaction most likely proceeds via a Me⁻ abstraction/ligand exchange sequence.     

Decavanadates with complex cations: synthesis and structure of (NH4)2[M(H2O)5(NH3CH2CH2COO)]2V10O28·nH2O (M?=?ZnII, n?=?4; M?=?MnII, n?=?2)

Decavanadates with complex cations, (NH₄)₂[Zn(H₂O)₅(NH₃CH₂CH₂COO)]₂V₁₀O₂₈·4H₂O (4) and (NH₄)₂[Mn(H₂O)₅(NH₃CH₂CH₂COO)]₂V₁₀O₂₈·2H₂O (5), have been prepared and characterized by elemental analysis, i.r., Raman, UV–vis. and ⁵¹V-n.m.r. spectroscopies and by thermal analysis. The X-ray structure determination revealed, both in 4 and 5, the presence of complex cations with hexacoordinated central atoms and monodentate β-alanine ligands, and decavanadate V₁₀O₂₈ ⁶⁻ anions. The differences in the structural arrangement in 4 and 5 are probably a consequence of the different ionic radii of Zn²⁺ and Mn²⁺ (high spin).     

Phosphine-substituted diiron 1,2-dithiolate complexes as the models for the active site of [FeFe]-hydrogenases

Abstract

In this article, five diiron 1,2-dithiolate complexes containing phosphine ligands are reported. Treatment of complex [Fe₂(CO)₆(μ-SCH₂CH₂S)] (1) with the phosphine ligands tris(4-methylphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(3-chlorophenyl)phosphine, tris(3-methylphenyl)phosphine, or 2-(diphenylphosphino)biphenyl in the presence of Me₃NO·2H₂O as the decarbonylating agent afforded the target products [Fe₂(CO)₅(L)(μ-SCH₂CH₂S)] [L?=?P(4-C₆H₄CH₃)₃, 2; P(4-C₆H₄OCH₃)₃, 3; P(3-C₆H₄Cl)₃, 4; P(3-C₆H₄CH₃)₃, 5; Ph₂P(2-C₆H₄Ph), 6] in 80–93% yields. Complexes 2–6 have been characterized by elemental analysis, spectroscopy, and X-ray crystallography. Additionally, the electrochemical properties were studied by cyclic voltammetry.     

Even and odd: uranium(IV) complexes with two,four, and six salicylaldiminate ligands with an unusual κ1-coordination mode

We report the synthesis and structural determination of three uranium(IV) complexes bearing two, four, and six salicylaldiminate ligands. Reaction of UI₄(1,4-dioxane)₂ with two, four, and six equivalents of K[OC₆H₄C(H)=N(2,6-ⁱPr₂C₆H₃)], 1, yielded [(2,6-ⁱPr₂C₆H₃)N=C(H)C₆H₄O-κ²(O,N)]₂UI₂(NCCH₃), 2, [(2,6-ⁱPr₂C₆H₃)N=C(H)C₆H₄O-κ¹(O)]₂[(2,6-ⁱPr₂C₆H₃)N=C(H)C₆H₄O-κ²(O,N)]₂U(THF), 3, and {[2,6-ⁱPr₂C₆H₃)N=C(H)C₆H₄O-κ¹(O)]₆U}^2?, 4. While 2 shows normal κ²-coordination through both oxygen and nitrogen donors, 3 has two salicylaldiminate ligands bound only through oxygen and 4 has all six ligands bound only through oxygen. This is an exceedingly rare example of a chelating ligand not completing its chelation in f-element chemistry. In addition, 4 is the first report of a homoleptic octahedral actinide complex with a Schiff base ligand.     

The Hydride‐Ion Affinity of Borenium Cations and Their Propensity to Activate H2 in Frustrated Lewis Pairs

A range of frustrated Lewis pairs (FLPs) containing borenium cations have been synthesised. The catechol (Cat)‐ligated borenium cation [CatB(PtBu₃)]⁺ has a lower hydride‐ion affinity (HIA) than B(C₆F₅)₃. This resulted in H₂ activation being energetically unfavourable in a FLP with the strong base PtBu₃. However, ligand disproportionation of CatBH(PtBu₃) at 100 °C enabled trapping of H₂ activation products. DFT calculations at the M06‐2X/6‐311G(d,p)/PCM (CH₂Cl₂) level revealed that replacing catechol with chlorides significantly increases the chloride‐ion affinity (CIA) and HIA. Dichloro–borenium cations, [Cl₂B(amine)]⁺, were calculated to have considerably greater HIA than B(C₆F₅)₃. Control reactions confirmed that the HIA calculations can be used to successfully predict hydride‐transfer reactivity between borenium cations and neutral boranes. The borenium cations [Y(Cl)B(2,6‐lutidine)]⁺ (Y=Cl or Ph) form FLPs with P(mesityl)₃ that undergo slow deprotonation of an ortho‐methyl of lutidine at 20 °C to form the four‐membered boracycles [(CH₂{NC₅H₃Me})B(Cl)Y] and [HPMes₃]⁺. When equimolar [Y(Cl)B(2,6‐lutidine)]⁺/P(mesityl)₃ was heated under H₂ (4 atm), heterolytic cleavage of dihydrogen was competitive with boracycle formation.     

The reactions of non-gem-hexanedioxytetrachlorocyclotriphosphazene with 2-(2-hydroxyethyl)thiophene,benzyl alcohol and 1,1,3,3-tetramethylguanidine. Spectroscopic studies of the derived products

Abstract

Reactions of non-gem-hexanedioxytetrachlorocyclotriphosphazene (1) with monofunctional nucleophilic reagents, 2-(2-hydroxyethyl)thiophene (2), benzyl alcohol (3) and 1,1,3,3-tetramethylguanidine (4) were investigated. The reactions, using an excess of NaH, in THF solutions, under refluxing conditions and with 1:2?mole ratios allow the synthesis of the following novel cyclotriphosphazene derivatives: 2,4-dichloro-2,4-(hexane-1,6-dioxy)-6,6-[2-(2-ethoxy)hiophene]-cyclotriphosphazatriene, N₃P₃Cl₂[O(CH₂)₆O-(C₆H₈OS)₂] (5); 2,4-(hexane-1,6-dioxy)-2,4,6,6-[2-(2-ethoxy) thiophene]-cyclotriphosphazatriene, N₃P₃[O(CH₂)₆O-(C₆H₈OS)₄] (6); 2,4-dichloro-2,4-(hexane-1,6-dioxy)-6,6-(methoxybenzene)-cyclotriphosphazatriene, N₃P₃Cl₂[O(CH₂)₆O-(C₆H₅CH₂O)₂] (7); 2,4-(hexane-1,6-dioxy)-2,4,6,6-(methoxybenzene)-cyclotriphosphazatriene, N₃P₃[O(CH₂)₆O-(C₆H₅CH₂O)₄] (8); and 2,4-dichloro-2,4-(hexane-1,6-dioxy)-6,6-(1,1,3,3-tetramethyguanidine)-cyclotriphosphazatriene, N₃P₃Cl₂[O(CH₂)₆O-HN-CN₂(CH₃)₄] (9). The structures of the synthesized compounds (5–9) have been characterized by elemental analysis, TLC-MS, ¹H, ¹³C and ³¹P {+¹H} and {?¹H} NMR spectral data.