Phosphazene Ring Research Articles

Ab initio Study of Electronic Structure and Properties in Crystalline 1,1,3,3,5,5‐Hexaazidocyclotriphosphazene

AbstractThe banding and electronic structures of crystalline 1,1,3,3,5,5‐hexaazidocyclotriphosphazene (P3N21) have been investigated at DFT‐B3LYP/6‐31G(d) level. Relaxed crystal structure compares well with experimental data. The energy gap is 5.57 eV, indicating that P3N21 is an insulator. The frontier orbital is mainly formed by atomic orbitals of azido group, so it is the most reactive part of the molecule. The intermolecular interaction is strong along the direction that is nearly perpendicular to the phosphazene ring. The distribution of electrostatic potential is quite uneven, so P3N21 has a very high impact sensitivity. The point charge electrostatic potential is very high between the azido groups of the neighboring molecules, which indicates that the crystal lattice in this position may easily be broken and becomes the explosion center when P3N21 is impacted. The overlap populations of P–Nα bonds are much less than those of other bonds, therefore the P–Nα bonds first rupture by external stimuli, which agrees well with the experimental study of mass spectrum.

Phosphazene vs.diazaphospholene PN-bond cleavage in spirocyclic cyclodiphosphazenes

Thermolysis of 2-azido-1,3,2-diazaphospholenes offers access to novel and rare spirocyclic cyclodiphosphazenes. The spectroscopic data and X-ray structure of one representative of the 2-azido-1,3,2-diazaphospholenes reveals an ionic bonding situation explaining sufficiently its rather high thermal stability. The cyclodiphosphazenes were characterised by NMR, mass spectrometry, and X-ray diffractometry. The results of ESI-FT-ICR studies demonstrate the potential of these compounds to undergo reductive elimination at a phosphazene unit via [1,4]-cycloreversion of a lambda5-diazaphospholene ring, as well as symmetrical cleavage of the P2N2-unit. The unexpected inclusion of benzene in the crystal of one of the cyclodiphosphazenes was interpreted in terms of molecular recognition. Chemical reaction studies comprise the proof of double N-protonation at a phosphazene ring, and hydrolytic degradation via selective cleavage of a phosphazene P-N bond.

Conformationally Rigid Chelate Rings in Metal Complexes of Pyridyloxy-Substituted 2,2‘-Dioxybiphenyl-Cyclotetra- and Cyclotriphosphazene Platforms

Divalent metal halides react with pyridyloxy-substituted 2,2'-dioxybiphenyl-cyclotri- and cyclotetraphosphazene ligands to form the complexes, [MLX2] [M=Co or Cu; L=(2,2'-dioxybiphenyl)tetrakis(2-pyridyloxy)cyclotriphosphazene (L1) or (2,2'-dioxybiphenyl)tetrakis(4-methyl-2-pyridyloxy)cyclotriphosphazene (L2); X=Cl or Br], [ZnLCl2] [L=bis(2,2'-dioxybiphenyl)bis(2-pyridyloxy)cyclotriphosphazene (L3) or bis(2,2'-dioxybiphenyl)bis(4-methyl-2-pyridyloxy)cyclotriphosphazene (L4)], [MLCl2] [M=Cu or Hg; L=tris(2,2'-dioxybiphenyl)bis(2-pyridyloxy)cyclotetraphosphazene (L5)] and [Cu2LCl4] (L=trans-bis(2,2'-dioxybiphenyl)tetrakis(2-pyridyloxy)cyclotetraphosphazene (L6)]. Single-crystal X-ray structures show the L2 ligand complexes to have a N3Cl2 five-coordinate, trigonal-bipyramidal donor set with the phosphazene ring and pendant pyridyloxy nitrogens binding to the metal ions. The coordinated L2 ligand in the complex, [CoL2Cl2], slowly hydrolyses in acetonitrile with the loss of a pyridine pendant arm to form a dimetallic species, which has been characterized by crystallography as [{CoL2aCl}]2.4MeCN (L2a=[N3P3(biph)(OPy)3(O)]-, biph=2,2'-dioxybiphenyl, OPy=2-oxopyridine). The ligands, L3, L4, L5, and L6, bind to the metal halides via gem-substituted pyridyloxy nitrogens only. The resulting rigid eight-membered chelate rings all have distorted boat conformations, which force distorted-tetrahedral N2Cl2 coordination environments onto the metal ions. The spectroscopic (ESR and electronic) and magnetic properties of the complexes are reported.

Phosphorus−Nitrogen Compounds. 14. Synthesis, Stereogenism, and Structural Investigations of Novel N/O Spirocyclic Phosphazene Derivatives

The reactions of hexachlorocyclotriphosphazatriene, N3P3Cl6, with N/O donor-type N-alkyl-o-hydroxybenzyl- and o-hydroxynaphthylamines result in novel mono- (3a, 4a and 4b), di- (5a and 5b), and tri- (3b, 6a, and 6b) spirocyclic phosphazene derivatives. The tetrakis-pyrrolidinophosphazene, 3b, has been obtained from the reaction of partly substituted compound 3a with the excess pyrrolidine in tetrahydrofuran. The relationship between the endocyclic NPN (alpha) and exocyclic NPO (alpha') bond angles of the analogous spirocyclic phosphazenes with the deltaP shifts of NPO phosphorus atoms have been presented. It was observed that there is a linearity between alpha angles and deltaP shifts, while no linear relationship has been observed for alpha' angles. In addition, we have found the correlation between Delta(P-N) and deltaNPO shifts, which implies a linear relationship. Delta(P-N)=(a-b), where a and b are the average lengths of two adjacent P-N bonds. The structural investigations of all of the compounds have been made by elemental analyses; mass spectrometry; Fourier transform infrared spectroscopy; one-dimensional 1H, 13C, and 31P NMR; distortionless enhancement by polarization transfer; and two-dimensional correlation spectroscopy, heteronuclear shift correlation, and heteronuclear multiple-bond correlation homo- and heteronuclear correlation techniques. The solid-state structures of 3a, 4a, 4b, and 5a have been determined by X-ray crystallographic techniques. The asymmetric units of compounds 3a and 4a contain two independent molecules, and 3a has strong intermolecular N-H...N hydrogen bonds linking three phosphazene rings. The molecular structure of 6a looks like a propeller where the chemical environment of P1 is different from that of P2 and P3. On the other hand, compounds 5a and 5b are expected to exist as cis- or trans-geometric isomers and to be in cis (meso) or trans (racemic) configurations. The crystallographic and preliminary chiral solvating agents results show that both of them are trans (racemic). In addition, 6a and 6b are also expected to exist as cis-trans-trans- and cis-cis-cis-geometric isomers; both of them are found to be in cis-trans-trans geometries. According to the two-dimensional spectroscopic data, the possible conformations of 3a and 4a in CDCl3 are the same with the solid-state structures.

New Approaches to Hybrid Polymers that Contain Phosphazene Rings

New methods are described for the incorporation of cyclophosphazene rings into macromolecules. These include polynorbornenes with cyclophosphazene side units produced by ROMP reactions, polystyrenes linked to phosphazene rings by azide coupling processes, and cyclolinear polymers by ADMET and Heck coupling reactions. These last species are wavelength-emission tailored electroluminescent materials.

Conformational Flexibility in 2,2‘-Dioxybiphenyl-chloro-cyclotetraphosphazenes and its Relevance to Polyphosphazene Analogues

The reaction of the cyclotetraphosphazene, [N4P4Cl8], with the difunctional reagent, 2,2'-biphenol, in the presence of potassium carbonate in acetone produced the spiro-substituted derivatives, 2,2'-dioxybiphenylhexachlorocyclotetraphosphazene, bis(2,2'-dioxybiphenyl)tetrachloro-cyclotetraphosphazene, and tris(2,2'-dioxybiphenyl)dichlorocyclotetraphosphazene. Both cis and trans geometrical isomers of the bis compound are observed. Although chromatographic separation of these was unsuccessful, a sample of the trans isomer was obtained by fractional crystallization. The compounds all show non-first-order 31P NMR spectra which were simulated to extract the spectral parameters. Single-crystal X-ray structures of both the trans bis and the tris compounds show that the cyclophosphazene rings exhibit conformational flexibility which gives rise to different crystalline forms being obtained from the same solvent systems. Crystals of trans-bis(2,2'-dioxybiphenyl)tetrachloro-cyclotetraphosphazene were obtained in two different space groups: Pnna (orthorhombic) and P21/n (monoclinic). In the orthorhombic structure, the dominant (72%) conformation of one phosphazene ring is a chair form, and the other (28%) resembles a boat. While for the monoclinic structure, the ring is virtually flat with an oval shape. In both cases the dioxybiphenyl groups are found in R and S configurations in the same molecule and are pi stacked in columns (Pnna) or involved in pi-pi or pi-H interactions (P21/n), thus anchoring the phosphorus atoms of the cyclotetraphosphazenes but still allowing flexibility in the ring conformations. Three crystalline modifications of tris(2,2'-dioxybiphenyl)dichloro-cyclotetraphosphazene were obtained: two in space group P (triclinic), which contained two molecules of dichloromethane in the unit cell, and one solvent-free form in space group P21/n (monoclinic). The cyclophosphazene rings exhibit puckered conformations with the trans-dioxybiphenyl moieties having opposing RS or SR conformations. DFT calculations were carried out on each of the phosphazene ring conformations in trans-bis(2,2'-dioxybiphenyl)tetrachlorocyclotetraphosphazene identified from the X-ray diffraction analysis. It is concluded that intermolecular interactions (i.e., pi-pi or pi-H) between the dioxybiphenyl groups is a factor that modifies the nature of the potential energy surface between the different conformers. The flexibility of the phosphazene ring is supported computationally through the calculated low-energy barriers and experimentally through the highly disordered phosphazene ring conformations observed in the solid state. The results on 2,2'-dioxybiphenyl-substituted cyclotetraphosphazenes provide evidence that microcrystalline domains in their 2,2'-dioxybiphenyl-substituted polyphosphazene analogues will be generated by similar pi-pi and pi-H interactions.

Dimorphism in 4,4,6,6-tetrachloro-2,2-(2,2-dimethylpropane-1,3-dioxy)cyclotriphosphazene and 6,6-dichloro-2,2:4,4-bis(2,2-dimethylpropane-1,3-dioxy)cyclotriphosphazene

A second, polymorphic, form of the previously reported compound 4,4,6,6-tetrachloro-2,2-(2,2-dimethylpropane-1,3-dioxy)cyclotriphosphazene, C(5)H(10)Cl(4)N(3)O(2)P(3), is now reported. The molecular structures of these two compounds are similar, aside from minor conformational differences. However, the compounds crystallize in two different space groups and exhibit quite different crystal structure assemblies. Additionally, 6,6-dichloro-2,2:4,4-bis(2,2-dimethylpropane-1,3-dioxy)cyclotriphosphazene, C(10)H(20)Cl(2)N(3)O(4)P(3), is shown to exhibit two different conformational polymorphs when crystallized from different solvent mixtures. The alpha form crystallizes in the space group Pnma with the molecular structure lying on a mirror plane (symmetry code: x, -y + {1/2}, z), whilst the beta form is in the space group C2/c with the molecular structure lying on a twofold axis (symmetry code: -x, y, -z + {3/2}). The difference between the two molecular structures is in the conformation of the spiro-ring substituents with respect to the phosphazene ring. The resulting crystal structures give rise to differing packing motifs.

Crystal Structure of cis-ansa-2,4-Dichloro-2,4-[2,2'-methylenebis(4-nitrophenoxy)]-6,6-dipyrrolidinocyclo-2.LAMBDA.5,4.LAMBDA.5,6.LAMBDA.5-triphosphazatriene

The title compound, C21H24Cl2N7O6P3, consists of a non-planar trimeric phosphazene ring and a bulky 2,2′-methylenebis(4-nitrophenoxy) side group, two cis-Cl atoms and two geminal pyrrolidine rings. In the 2,2′-methylenebis(4-nitrophenoxy) side group, the phenyl rings are almost perpendicular to each other. Two ansa-P atoms are expected to be stereogenics (meso). It belongs to the space group P bca with cell parameters a = 11.467(5), b = 28.542(7), c = 16.553(2)A.

Polyphosphazenes with Pyridylalkylamino Groups: Synthesis, Thermal Properties, Ion Uptake and -Selectivity

Three series of polyphosphazenes with 25, 50, 75 and 100% of pendent 2-, 3-, or 4-pyridylmethylamino groups and in case of the co-polymers additional phenoxy groups were synthesized and characterized. The physical properties of the materials depend on the type of pyridine derivative, the amount of functional groups, and their arrangement (geminal or non-geminal) on the polymer chain. Characterization was performed by NMR, GPC and elemental analyses. Thermal studies show two degradation pathways: (1) depolymerization under formation of phosphazene rings for species with P(OPh)2 and P(OPh)(NHCH2C5H4N) units and (2) chain cleavage for polymers with high amounts of P(NHCH2C5H4N)2 groups. Ion uptake and -selectivity of the new materials were also investigated. 2-Pyridylalkylamino derivatives show increasing capacity and selectivity for copper in the presence of nickel or cobalt as the amount of functional groups increases whereas capacities and selectivities of the 3- and 4-pridylmethlyamino substituted polymers are surprisingly low and decrease even with increasing functionalization within the series of the 4-pyridylmethylamino polyphosphazenes.

Cyclophosphazenes tethered together via N-ring centres with ortho-, meta- and para-xylylene linkers

Hexakis (organoamino) cyclotriphosphazenes (RNH) 6P 3N 3 {R = i-Bu ( 1), R = i-Pr ( 2)} react with ortho-, meta- and para-derivatives of α,α′-dibromo xylene in 2:1 ratio to form salts of compositions [{(RNH) 6P 3N 3} 2xyl]Br 2, {R = i-Bu, o-xyl ( 3); R = i-Pr, m-xyl ( 4); R = i-Pr, p-xyl ( 5)}. These contain dications consisting of two phosphazene rings, which are tethered together via ring N centres by a xylylene unit. X-ray structure analyses show that the substitution pattern at the xylylene bridge controls the orientation and distance between the two tethered phosphazene rings. The solid state structures exhibit dense networks of hydrogen bonds linking dications and anions. Direct N–H⋯N bonds between dications are observed in the crystal structure of 3.

Copper complexes with 1,10-phenanthrolines tethered to a cyclotriphosphazene platform

The synthesis of two ligands, L 1 and L 2, each containing two 2-oxy-1,10-phenanthroline moieties attached to the same phosphorus atom of a substituted cyclotriphosphazene ring via an oxy-bridge, but differing in substitution on the biphenyl capping groups, is described. The single-crystal X-ray structure of L 1 · 2CH 2Cl 2 shows an ordered structure in the lattice with channels, containing dichloromethane molecules, running parallel to the a-axis. The reactions of L 1 and L 2 with [Cu(MeCN) 4](PF 6) afford the dimetallic copper(I) derivatives, [(CuL 1) 2] (PF 6) 2 · CH 2Cl 2 and [(CuL 2) 2](PF 6) 2. The single-crystal X-ray structure of the former complex shows that the L 1 ligands of the cation [(CuL 1) 2] 2+ act as a bridges coordinating to the two copper(I) centres in a helical fashion. The copper atoms have distorted tetrahedral geometries with the interligand dihedral angle being 85°. With copper(II) chloride and copper(II) perchlorate, the monomeric copper(II) complexes, [CuL 1Cl]Cl · 2CH 2Cl 2, [CuL 2Cl]Cl · CH 2Cl 2, [CuL 1(OMe)]PF 6 · 2H 2O, [CuL 2(OMe)]PF 6 · 2H 2O, [CuL 1(OH 2)](ClO 4) 2 and [CuL 2(OH 2)](ClO 4) 2 · H 2O are obtained. The single-crystal X-ray structure of [CuL 1Cl]Cl · 2CH 2Cl 2 shows the copper to be in a square-base pyramidal distorted trigonal-bipyramidal (SBPDTB) environment ( τ = 0.57) with L 1 acting as a κ 4N donor, coordinating via the four nitrogen atoms of the two tethered 1,10-phenanthrolines. In CH 3CN, this complex undergoes hydrolysis via the presence of adventitious water losing one oxyphenanthroline arm to form the centrosymmetric dimetallic species, [(CuL 3Cl) 2] · 4CH 3CN · 3H 2O (L 3 = [N 3P 3(biph) 2(ophen)O] − where biph = 2,2′-dioxybiphenyl and O replaces an oxyphenanthroline and is attached to the phosphorus of the phosphazene ring). The two monomeric units, which are linked by bridging chlorine atoms, have a distorted square-based pyramidal geometry about the copper with the basal plane made by the ‘ON 2Cl’ ligand set. Spectroscopic (mass spectral, electronic and ESR) and magnetic moment data for the complexes are discussed.

Structural investigations of phosphorus–nitrogen compounds. 7. Relationships between physical properties, electron densities, reaction mechanisms and hydrogen-bonding motifs of N3P3Cl(6 − n)(NHBu t ) n derivatives

A series of compounds of the N3P3Cl(6 - n)(NHBu(t))n family (where n = 0, 1, 2, 4 and 6) are presented, and their molecular parameters are related to trends in physical properties, which provides insight into a potential reaction mechanism for nucleophilic substitution. The crystal structures of N3P3Cl5(NHBu(t)) and N3P3Cl2(NHBu(t))4 have been determined at 120 K, and those of N3P3Cl6 and N3P3Cl4(NHBu(t))2 have been redetermined at 120 K. These are compared with the known structure of N3P3(NHBu(t))6 studied at 150 K. Trends in molecular parameters [phosphazene ring, P-Cl and P-N(HBu(t)) distances, PCl2 angles, and endo- and exocyclic phosphazene ring parameters] across the series are observed. Hydrogen-bonding motifs are identified, characterized and compared. Both the molecular and the hydrogen-bonding parameters are related to the electron distribution in bonds and the derived basicities of the cyclophosphazene series of compounds. These findings provide evidence for a proposed mechanism for nucleophilic substitution at a phosphorus site bearing a PCl(NHBu(t)) group.

Divalent cobalt, nickel and zinc halide complexes with multimodal ligands based on the cyclotriphosphazene platform: A structural study

The reaction of hexakis(2-pyridyloxy)cyclotriphosphazene (L) and hexakis(4-methyl-2-pyridyloxy)cyclotriphosphazene (MeL) with the dihalides of cobalt(II), nickel(II) and zinc(II) afford the complexes [CoLX 2], [Co(MeL)X 2], [(CoLX)CoX 3], [{Co(MeL)X}CoX 3], [CoLX]PF 6 (X = Cl or Br), [NiLCl]PF 6, [NiLCl 2] (a green and a red isomer) and [(ZnCl 2) 2L]. Single crystal X-ray structures on a selection of the complexes show that L and MeL are versatile multimodal ligands, which exhibit a variety of coordination modes. [Co(MeL)Br 2] and the red isomer of [NiLCl 2] have the metal atom in a distorted trigonal bipyramidal environment ( τ = 0.83 and 0.78, respectively) with the ligand acting as a κ 3 N donor coordinating via the nitrogen atoms from two non-geminal pyridyloxy pendant arms, a nitrogen atom in the phosphazene ring and two halide ions. For the cobalt complex the pyridyloxy groups are cisoid and for the nickel complex they are transoid. The dimetallic complexes, [{Co(MeL)X}CoX 3] (X = Cl or Br) are zwitterionic with one cobalt atom in a rhombic coordination sphere with the ligand acting as κ 5 N donor binding to the metal through the nitrogen atoms of four pyridyloxy pendant arms, phosphazene nitrogen atom and a halide ion. The second cobalt atom is in a distorted tetrahedral site with the ligand acting as a κ 1 N donor via one pyridyloxy nitrogen, the remaining ligands being three halide ions. The dimetallic zinc complex, [(ZnCl 2) 2L], contains two ZnCl 2 units in distorted trigonal bipyramidal ( τ = 0.82) and tetrahedral coordination environments. In the five-coordinate site, L acts in a κ 3 N non-geminal transoid fashion as observed for the red nickel complex [NiLCl 2]. In the other site, L acts as a κ 2 N geminal bidentate via two pyridyloxy arms, with two chloride ions completing the coordination sphere. The cationic cobalt complexes, [MLBr]PF 6 (M = Co or Ni) both contain the metal atom in a rhombic environment similar to that found in the dimetallic [{Co(MeL)X}CoX 3] species. The green isomer of [NiLCl 2] contains a six coordinate ‘NiN 4Cl 2’ distorted octahedral coordination sphere with L behaving as a κ 4 N donor via the nitrogen atoms from three pyridyloxy pendant arms and one nitrogen in the cyclophosphazene ring; two halide ions complete the coordination sphere. In all the complexes the phosphazene ring atoms remain virtually coplanar as a consequence of the flexibility of the phenoxy-hinge, which links the pyridine pendant donors to the cyclophosphazene platform. The formation of the resulting six-membered chelate rings enhances the binding of the phosphazene nitrogen to metal bond which, in each of the five- or six-coordinate metal binding sites, is always shorter than the pyridyloxy nitrogen to metal bonds [2.023(6)–2.1075(18) cf. 2.157(4)–2.397(3) Å].

Control of the conjugation length and solubility in electroluminescent polymers

AbstractA new type of cyclolinear polymer, poly(phenylene vinylene‐alt‐cyclotriphosphazene), was synthesized through Heck‐type coupling reactions to produce π‐conjugated macromolecules with excellent solubility and precise electronic control of the band‐gap energy. This synthesis method is capable of producing well‐defined alternating polymers. The method is highly adaptable and can be readily used for other chromophore systems. The resulting polymers were also capable of accommodating a wide variety of substituents on the cyclophosphazene rings with minimal effect on the electronic properties. The band gap and electron affinities of the polymer were varied through the manipulation of the π‐conjugated unit located between the insulating phosphazene rings. Each chromophore matched the intended conjugation length consistently throughout the macromolecules. The polymers were good film formers because of the chosen substituents on the phosphazene rings. The absorbance of the polymers indicated minimal spectral shift from the monomer absorbance. This suggested an effective insulation of each chromophore unit from its neighbors by the phosphazene rings. Solution photoluminescence efficiencies were found to be up to 44.1%. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 69–76, 2006

Lewis Acid Adducts of [PCl2N]3.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Lewis Acid Adducts of [PCl2N]3

Reaction of aluminum trichloride or gallium trichloride with the extremely weak base hexachlorotriphosphazene gives adducts in which the group 13 element is bound to a phosphazene nitrogen atom. In solution, the adducts exhibit fluxional behavior. The phosphazene ring of the adducts is distorted into a slight chair conformation.

Phosphorus-nitrogen compounds: New spiro-cyclic phosphazene derivatives. Structure of 4′,4′,6′,6′-tetrachloro-3,4-dihydro-3-(3-methylpyridin-2-yl) spiro-[1,3,2-benzoxazaphosphinine-2,2′-(2λ 5,4λ 5,6λ 5-cyclotriphosphazene)]. Part XII

The condensation reactions of { N-[(2-hydroxyphenylmethyl)amino]-methylpyridines (5–8) with trimer, N 3P 3Cl 6, have been afforded partially substituted novel spiro-cyclic phosphazene derivatives ( 9– 12) ( Scheme 1). Compounds ( 9– 12) have been characterized by elemental analyses, FTIR, 1H–, 13C–, 31P-NMR, HETCOR, and MS. The structure of the spiro-cyclic phosphazene ( 9) has been examined crystallographically. It crystallizes in the P2 1/n space group with a=10.7906(10) Å, b=8.5625(17) Å, c=21.187(5) Å, β=91.298(12)°, V=1957.1(6) Å 3, Z=4 and D x =1.660 g cm −3. The structure consists of a non-planar phosphazene ring with a bulky methylpyridinyl and a benzo-fused spiro-cyclic side group. The six-membered spiro-cyclic ring has a twist-boat conformation.

7,11-(Butane-1,4-diyldioxydi-o-phenylenedimethylene)-6,6-dichloro-4,4-bis(pyrrolidin-1-yl)-2λ5,4λ5,6λ5-triphosphaza-1,3,5,7,11-pentaazaspiro[5.5]undeca-1,3,5-triene

The title compound, C29H42Cl2N7O2P3, is a phosphazene derivative with a bulky substituent attached through a spiro junction with two pyrrolidine rings. The six-membered C3N2P ring has a chair conformation, while the phosphazene ring has a slight envelope conformation. The two N atoms in the C3N2P ring are likely to be stereogenic.

4′,4′,6′,6′-Tetrachloro-3-(4,6-dimethylpyridin-2-yl)-3,4-dihydrospiro[1,3,2-benzoxazaphosphinine-2,2′-(2λ5,4λ5,6λ5-cyclotriphosphazene)

The title compound, C14H14Cl4N5OP3, is a phosphazene derivative with a bulky substituent attached through a spiro junction. The C3NPO ring at the spiro junction has a twist–boat conformation, while the phosphazene ring has a flattened-boat conformation. The Pspiro atom is likely to be stereogenic.

Phosphorus–nitrogen compounds: Novel fully substituted spiro-cyclophosphazenic lariat (PNP-pivot) ether derivatives. Structures of 4,4,6,6-tetrapyrrolidino-2,2-[3-oxa-1,5-pentane dioxy bis(2-phenylamino)]cyclo-2 λ5,4 λ5,6 λ5-triphosphazene and 4,4,6,6-tetrapyrrolidino-2,2-[1,2-xylylene dioxy bis(2-phenylamino)]cyclo-2 λ5,4 λ5,6 λ5-triphosphazene. Part XI

The condensation reaction of partly substituted spiro-cyclophosphazenic lariat (PNP-pivot) ethers, N 3P 3[( o-NHPhO) 2R]Cl 4 ( 5– 8), where R=–CH 2CH 2–, –CH 2CH 2CH 2–, –CH 2CH 2OCH 2CH 2–, and –CH 2PhCH 2–, with pyrrolidine have been afforded fully substituted pyrrolidino phosphazene derivatives ( 9– 12) (Scheme). There are the first examples of the spiro-cyclophosphazenic lariat (PNP-pivot) ether ligands with N 2O x -( x=2, 3) donor type containing 11–14 membered macrocycles. The solid state structures of ( 11 and 12) have been determined by X-ray diffraction techniques. Evidently, in the macrocyclic ring of the compound ( 11), there are two three-centered (bifurcate) N–H⋯O/N–H⋯N hydrogen bonds, while compound ( 12) has two intramolecular N–H⋯O bonds. The relative radii of macrocyclic hole sizes of the compounds ( 11 and 12) are 1.25 and 1.10 Å, respectively. The structures of the new compounds ( 9– 12) have also been examined by FTIR, 1H-, 13C-, 31P-NMR, MS and elemental analysis. Compound ( 11) crystallizes in the Pcab space group with a=9.8474(13), b=18.466(2), c=38.9375(19) Å, V=7080.7(14) Å 3, Z=8 and D x =1.317 g cm −3, while compound ( 12) crystallizes in P-1 space group with a=9.3724(5), b=11.2613(9), c=20.401(2) Å, α=93.177(8), β=102.115(7), γ=105.360(5)°, V=2016.0(3) Å 3, Z=2 and D x =1.268 g cm −3. The structures of ( 11 and 12) consist of nearly planar and non-planar trimeric phosphazene rings with spiro-cyclic bulky N 2O 3 and N 2O 2 macrocycles, respectively.