The kinetic parameters in acetonitrile of the nucleophilic substitution reaction: N₃P₃C1₆ + KCNS -> N₃P₃C1₅NCS + KC1 have been determined. The Arrhenius activation energy is 15.5 ± 5 Kcal moleˉ¹ and the common logarithm of the pre-exponential factor is 10.2 ± 3. The reaction is first order in each reagent and is probably bimolecular. Comparison with similar reactions indicates a lone pair electron donation from the nitrogen to the phosphorus atoms of the ring. The compound, N₄P₄(NMe₂)₈HCuCl₃ was prepared by the reaction of tetrameric phosphonitrilic dimethylamide with copper (II) chloride in butanone. The infra-red spectrum indicates that the copper atom is bound to one ring nitrogen atom, and the proton to the opposite nitrogen atom. The ring is found to be too small to allow chelation of the copper atom. The salt, N₆P₆(NMe₂)₁₂CuCl⁺CuCl₂ˉ was prepared by the dehydro-halogenation of N₆P₆(NMe²)₁₂HClCu₂Cl₃. The hydrochloride was prepared by the reaction of hexameric phosphonitrilic dimethylamide (H.P.D.) with ' copper (II) chloride in the reducing solvent butanone. The salt was also produced by the reaction of H.P.D. with an equimolar mixture of copper (I) chloride and copper (II) chloride in acetonitrile. Chemical and magnetic studies on the salt showed it to have one copper (II) atom per molecule. The x-ray crystal structure showed the copper (II) atom to be in a distorted square pyramidal environment, bonded to four ring nitrogen and one chlorine atom. The salt contains the first known example of the CuC1₂ˉ anion. This is linear with a Cu-C1 bond length of 2.11A. The anion is also one of the few examples of a finite species containing a two co-ordinate copper (I) atom. The infra-red spectrum of the salt was very similar to that of the parent H.P.D. The main difference was in the frequencies of the stretching modes of the phosphorus nitrogen ring bonds; which is consistent with copper chelation. Conductiometric and analytical studies showed that the salt does not retain the form form N₆P₆(NMe₂)₁₂CuCl⁺CuCl₂ˉ in acetonitrile solution; the limiting molecular conductance 377 ± 10 Ohmsˉ¹ being too large to be consistent with a 1:1 electrolyte. / Science, Faculty of / Chemistry, Department of / Graduate

The main part of this thesis is concerned with the study of the reactions of fluorocyclophosphonitriles, (NPF₂)₃₋₅, with methyllithium, which exhibit a new orientation pattern, and which appear to involve inductive interactions of the substituent (the CH₃ group) with a homomorphic π-system. Nuclear magnetic resonance spectroscopy has been the principal tool for deducing the structures of the isomers isolated by gas liquid chromatography from reactions of the fluorocyclophosphonitriles with methyl-lithium. ⁵JCH₃F and ⁴JFF have been observed for the first time in phosphonitrilic derivatives. Although the assignments of the frequencies in the infrared spectra of the methylfluoro- and methylcyclophosphonitriles are inadequate for a complete vibrational analysis, the pattern of frequencies found for trans-1,5-N₄P₄F₆Me₂, shows that it is not centro-symmetrical and neither is the derivative 1,1,5,5-N₄P₄F₄Me₄. In the crystal the latter compound has a saddle shape, and it is likely that the flexibility is caused by the interconversion of the tub to saddle forms, which can take place by bond torsional movements only, without angular deformation. The most important aspect of the work is the fresh evidence which is provided on the nature and extent of delocalisation within effect of the substituents is seen in the significant alternation of bond lengths in 1, l-N₄P₄F₆Me₂. Since the molecular framework is nearly planar, the conditions for the application of simple Huckel theory are satisfied, and the effect of a π-inductive perturbation at P has therefore been estimated through the calculation of bond-atom polarisabilities πr₅,t = [formula omitted] for a delocalised π-system based on an 8-membered ring. The close correspondence in pattern of the observed deviations in the individual bond lengths from the mean and the bond-atom polarisabilities seems very direct evidence for electronic delocalisation in phosphonitrilic molecules, and suggests that simple Huckel methods can provide a useful guide to their chemistry. The predominantly geminal substitution observed in the reaction of (NPF₂)₄ with LiMe has been well explained by an inductive effect of the methyl substituent on the π-system of the phosphonitrilic ring. The atom-atom polarisabilities for the three ring systems investigated have been calculated using simple Huckel theory, which show that, from this cause alone, a second nucleophilic substitution should take place principally at P₁, as found. Also the atom-atom polarisabilities explain the observed geminal and antipodal substitution, an orientation pattern which has not been recognised previously. This is the first case in which cyclic delocalisation has been shown to have a decisive effect on phosphonitrilic chemistry. / Science, Faculty of / Chemistry, Department of / Graduate

Single crystal X-ray diffraction methods have been used to determine the structures of four cyclic phosphonitriles: 1,1,5,5-tetrafluoro-3,3,7,7-tetramethylcyclotetra- phosphonitrile, N(4)P(4)F(4)Me(4) ; 1,1,3,3,5,5-hexafluoro-7,7-dimethyl- cyclotetraphosphonitrile, N(4)P(4)F(4)Me(2); hexaphenoxycyclotriphosphonitrile, [NP(OPh)2](3) and dodeca(dimethylamino)-cyclohexaphosphonitrilechlorocopper (II) dichlorocuprate (I), [formula omitted]. Intensity measurements were made on a Datex automated General Electric diffractometer using a scintillation counter; Cu-K [symbol omitted], radiation being used for the first three structure determinations and Mo-K [symbol omitted] radiation for the fourth. The structure of N(4)P(4)F(4)Me(4) has been determined by Patterson and Fourier methods and refined by full-matrix least-squares. The molecule is situated on a C(2) axis, and the phosphonitrilic ring has the 'saddle' conformation. Different electronegativities of the substituent groups result in two distinct P-N bond lengths, 1.53 and 1.59 Å explicable in terms of π -bonding theories. Patterson, Fourier, and full-matrix least-squares methods have been used to determine the structure of N(4)P(4)F(6)Me(2). This molecule is also situated on a C(2) axis and has the 'saddle' conformation, but tends strongly towards planarity. The most interesting features of the ring are four distinct P-N bond lengths (1.584, 1.470, 1.532, and 1.487 Å), and large valency angles (145°) at nitrogen, which are explicable in terms of π -bonding theories. The structure of [NP(CPh)2]3 was determined from Patterson and Fourier syntheses, and refinement of positional and thermal parameters of the atoms by block-diagonal least-squares. The phosphonitrilic ring is slightly non-planar, with two nitrogen atoms displaced by 0.15 Å in opposite directions from the plane of the other four (3P and 1N) atoms. The conformations of the phenoxy groups are different at the three phosphorus atoms, and there are small deviations among chemically-equivalent angles; these differences are probably a result of intra- and intermolecular steric effects. There are no differences among chemically equivalent bond lengths, the mean distances being P-N 1.575(2), P-O 1.582(2), 0-C 1.406(3) Å. The structure of [formula omitted] was determined by Patterson, Fourier, and full-matrix least-squares methods. The structure is ionic with the cation and anion each situated on a C(2) axis. The cation consists of a Cu(II) bonded to four nitrogens of the phosphonitrilic ring (N-Cu 2.07 Å) and a chlorine (Cℓ-Cu 2.28 Å) in a distorted square pyramid. The Cu(I)Cℓ2¯ anion is linear with a Cu-Cℓ bond length of 2.11 Å. There are two distinct P-N bond lengths in the phosphonitrilic ring, 1.62 and 1.55 Å, explicable by π -bonding theory. The overall shape of the structure is determined primarily by steric effects and the distortion of the phosphonitrilic ring caused by the bonding to copper. / Science, Faculty of / Chemistry, Department of / Graduate

Complexes of dodeca(dimethylamino)cyclohexaphosphonitrile with, divalent first series transition metal ions manganese through zinc have been studied. Previous X-ray work has established that N₆P₆ (NME₂)₁₂ forrns five-coordinate complexes with transition metal chlorides in which the phosphonitrile donates to the metal through four ring nitrogen atoms and the metal atom is close to the centre of the phosphonitrilic ring. In the present work, the complexes with metal nitrates have been shown to have the formulae (M(N₆P₆ (NMe₂)₁₂)N0₃+)N0₃~, with M = Mn,Co,Ni,Cu, and Zn, on the basis of conductivity measurements and the electronic spectra of the Co, Ni, and Cu complexes. Magnetic susceptibility measurements indicate that the nitrate complexes with M = Mn,Co, and Ni are high spin complexes. For the copper nitrate complex the above formulation is probably correct in the solid state, but in solution coordination evidently depends on the solvent. The electronic spectra are best interpreted in terms of D₃[sub h] symmetry about the metal, and the crystal field parameters derived from published energy level diagrams are similar to corresponding values derived for five-coordinate complexes formed with N (CH₂CH₂N(CH₃)₂)₃ • a saturated tetradentate amine ligand. Infrared spectra of N₆P₆(NMe₂)₁₂ and its complexes are also discussed. In order to investigate changes in -the ligand geometry-occurring when other phosphonitrilic derivatives coordinate to transition metals or interact with other acceptor groups the crystal structures of (N₄P₄Me₉⁺)(Cr(CO)₅I⁻), ((NPMe₂)₅H₂²⁺)(CuCl₄²⁻)•H20, and (N₄P₄ (NMe₂)₈-W(CO)₄ have been determined. For all three structures intensity data were collected on a diffractometer and the positional and thermal parameters were refined by full-matrix least-squares methods. In (N₄P₄ (NPME⁺)(Cr(CO)₅l⁻) a ring nitrogen atom is bonded to a methyl group, and the N₄P₄ ring has an unusual 'distorted tub' conformation, most likely a result of steric requirements The P-N bond lengths are not equal around the ring, and the observed pattern of bond length variation agrees qualitatively with the pattern predicted by a simple Hiickel M.O. calculation The geometry of the Cr(CO)^I~ ion closely approaches the expected C4v symmetry. In ((NMe₂)₅ H₂²⁺)( CuCl₄²⁻)•H20 the 10-membered phosphonitrilic ring is protonated at two sites, and the P-N bond lengths show a variation which is explained in terms of perturbation of a homomorphic ring π-system. The conformation of the N₅P₅, ring is influenced primarily by hydrogen 2-bondmg considerations. The CuCl₄ ion has a distorted tetrahedral geometry. In N₄P₄(NMe₂)₈-W(CO)₄ the phosphonitrile acts as a bi-dentate ϭ-ligand, coordination occurring through a ring nitrogen atom and an exocyclic nitrogen atom on an adjacent phosphorus atom. The observed variation in the ring P-N bond lengths is understood in terms of perturbations of the ring π systems at two sites. The conformation of the phospho-nitrilic ring is different from that in N₄P₄(NMe₂)₈, the ring being formed from two nearly planar segments making an angle of 48°. The coordination geometry about W is distorted octahedral, the NWN angle being 65.4°. / Science, Faculty of / Chemistry, Department of / Graduate

A study of the dielectric properties of some phosphonitrilic fluorides, chlorides and chloride-fluorides in cyclohexane solutions was carried out and evidence was found to support the hypothesis that these compounds all have a non-negligible atom polarization caused by low frequency vibrations of the molecules. The distortion polarization of one of the geminally substituted isomers of the compound N₄P₄F₄Cl₄ was measured and this datum was used as support for assigning the 1,1,3,3-isomer structure to the compound. / Science, Faculty of / Chemistry, Department of / Graduate

The ligands 2-cyanocyclopentyldiphenylphosphine and 2-cyanocyclohesyldiphenylphosphine were synthesized from 1-cyanocyclopentene and 1cyanocyclohexene by addition reactions using diphenylphosphine and aqueous base as the catalyst. These ligands reacted with Pt(II) and Pd(II) salts to yield complexes of the stoichiometry MX2L2 (X = C1, Br). In these complexes the ligands were found to function as monodentate phosphines. Infrared spectroscopic evidence suggested that the platinum complex was of cis and the palladium complexes were of trans geometries.The reactions of the ligands 2-cyanocyclopentyldiphenylphosphine and 2-cyanocyclohexyldiphenylphosphine or the ligand 2-cyanoethyldiphenylphosphine with the complexes dimethyyl(cyclooctadiene)platinun(II) or methyl) (chloro) (cyclooctadiene) platinum(II) resulted in complexes of the stoichiometries Pt(CH3)2L2 and Pt(CH3)(C1)L2. In these complexes the ligands also functioned as monodentate phosphines. hmr and far infrared spectroscopic evidence suggested that the dimethylplatinuin(II) complexes were cis and the (methyl)(chloro)platinum(II) complexes were trans.A complex of the stoichiometry Pd2Cl4(Ph2PC6H10CN)2 was isolated from the reaction of a 1:1 mole ratio of PdC12 with Ph2PC6H10CN. Far infrared and Raman spectroscopic evidence 'suggested that the complex was a chlorine bridged dieter with the ligands at symmetrical positions. The nitrile groups in this complex reacted rapidly with alcohols to yield monomeric imino ether complexes.The Pt(CH3)(C1)L2 complexes reacted with AgPF6 to yield cationic salts of the stoichiometry [Pt(CH3)L2]n+n with one ligand in each [Pt(CH3)L2]+ unit presumably serving as a bridging ligand and the other as a monodentate phosphine. The coordinated nitrite groups in these complexes reacted slowly with methanol to yield amino ether complexes.

The ligands o-cyanophenyl(diphenyl)phosphine and bis(dimethylamino)(o-cyanophenyl) phosphine were synthesized from o-bromobenzonitrile and diphenylchlorophosphine and bis(dimethylamino)chlorophosphine, respectively. Both ligands were identified by IR, NMR and physical constant data. The reaction of bis(dimethylamino)(o-cyanophenyl)phosphine with sulfur or CH3I yields complexes of the stoichiometry [(CH3)2N]2(o-C6H4CN)P(X) (X=S, CH3I). NMR and IR spectral data suggest that the phosphorus is the site of reaction.Reaction of 2-cyanocyclohexyl(diphenyl)phosphine, 2-cyanocyclopentyl(diphenyl)phosphine or 2-cyanoethyl(dipheriyl)phosphine with M(CO)6 (M=Mo,W) and NaBH4 in refluxing ethanol yielded complexes of the stoichiometry M(CO4)L (L=2(aminomethyl)cyclohexyl(diphenyl) phosphine, 2(aminomethyl)cyclopentyl(diphenyl)phosphine, or 3-aminopropyl (diphenyl) phosphine). The infrared spectra of the complexes display two v(NH) bands at ca. 3360 cm-1 and 3308 cm-1 which are indicative of coordinated NH2 groups which result from the reduction of the CN groups. Four v(CO) bands are observed for the complexes which indicates that the compounds are of cis-configuration.Ball State UniversityMuncie, IN 47306