Inorganic Ring Research Articles

Inorganic Chelate Rings in Organolead(IV) Derivatives of Organophosphorus Ligands from 6-Membered to 16-Membered Rings

New organolead(IV) complexes of the type R3Pb[(OPPh2)(XPPh2)N], R2Pb[(OPPh2)(XPPh2)N]2 (R = Me, Ph; X = O, S) and Me3Pb(O2PPh2) have been prepared and characterized by IR and multinuclear (1H, 13C, 31P) NMR spectroscopy. The X-ray molecular structure of the Me2Pb[(OPPh2)2N]2 and Me3Pb(O2PPh2) is discussed.

Organoantimony Derivatives of Organophosphorus Ligands Containing Inorganic Chelate Rings

Organoantimony complexes of the type PhSbCl2-xLx and Me3SbL2(L = [(OPPh2)(XPPh2)N]−, X = O, S; x = 1,2) were prepared and investigated by means of IR and multinuclear (1H, 13C, 31P) NMR spectroscopy. The PhSb(Cl)L compounds exhibited a redistribution process to give PhSbL2 and PhSbCl2. The molecular structures of PhSb[(SPPh2)2N]2 and Me3Sb[(OPPh2)(SPPh2)N]2 were established by single crystal X-ray diffractometry.

Metal Containing New Inorganic Ring Systems Based on Siloxane and Phosphazane Frameworks

Metal Containing New Inorganic Ring Systems Based on Siloxane and Phosphazane Frameworks

Comparative DFT Study of Group 13–15 Rings: Structure, Bonding and Thermochemistry

Dimeric inorganic rings [X2MYH2]2 and [XMYH]2 (X=H,F,Cl,Br,I; M=Al,Ga,In; Y=N,P,As) and related monomer compounds X2MYH2, XMYH were theoretically investigated at B3LYP /LANL2DZP level of theory. Optimized structures and standard thermodynamic parameters of gas phase dissociation reactions were obtained. Nitrogen and Al-containing rings have higher stability compared to P,As and Ga,In systems; substituents X have minor effect on M-Y dissociation energy. [X2MNH2]2 dimers are stable in the gas phase up to 1100–1300K.

Metal Containing New Inorganic Ring Systems Based on Siloxane and Phosphazane Frameworks

High-field 31P NMR spectroscopy and single crystal X-ray diffraction studies have been used to study the ring opening and nucleophilic substitution reactions of the λ3-cyclotriphosphazane [EtNPCl]3. The synthesis of the ring opened silicophosphonate [RSi(OH){OP(O)(H)(OH)}]2O (R = (2,6-iPr2C6H3)NSiMe3) (1) represents the first ever molecular silicophosphonate to be isolated bearing free reactive hydroxyl groups. The structure and conformation of the bulky aryloxide substituted λ3-cyclotriphosphazane derivative [EtNP(OAr)]3 (Ar = 2,6-iPr2C6H3) (2) has also been investigated. Interaction of 2 with transition metal precursor complexes leads to the isolation of phosphazane metal complexes with different mode of co-ordination of 2. Further, the reaction of Cp ★Ti(OAr)Cl2 (Ar = 2,6-(CH3)2C6H3OH) with O{SiPh2(OH)}2 gave the eight-membered trititanosiloxane [Cp ★Ti(Cl) (O(SiPh2O)2SiPh2O) (3). Siloxane chain expansion effects, presumed to be a consequence of ring strain, have been observed in the product. The presence of reactive Ti-Cl bond in 3 offers opportunities for its reaction chemistry to be explored.

Comparative DFT Study of Group 13-15 Rings: Structure, Bonding and Thermochemistry

Dimeric inorganic rings [X2MYH2]2 and [XMYH]2 (X=H,F,Cl,Br,I; M=Al,Ga,In; Y=N,P,As) and related monomer compounds X2MYH2, XMYH were theoretically investigated at B3LYP /LANL2DZP level of theory. Optimized structures and standard thermodynamic parameters of gas phase dissociation reactions were obtained. Nitrogen and Al-containing rings have higher stability compared to P,As and Ga,In systems; substituents X have minor effect on M-Y dissociation energy. [X2MNH2]2 dimers are stable in the gas phase up to 1100–1300K.

Silsesquioxane Chemistry, 5. Retention of the Cu 4O 4 core upon formation of the first copper(I) silsesquioxane from tetrameric copper(I)- t-butoxide

The first copper(I) silsesquioxane derivative, Cu 4O 4[Cy 7Si 7O 9(OSiMe 3)] 2 ( 4) was prepared by reacting tetrameric copper(I)- t-butoxide, (CuO tBu) 4 ( 3), with the monosilylated silsesquioxane precursor Cy 7Si 7O 9(OH) 2(OSiMe 3) ( 2) in a 1:2 molar ratio. An X-ray diffraction study revealed the presence of a centrosymmetric dimer. A slightly puckered Cu 4O 4 ring forms the central part of a complex structure comprising nine eight-membered inorganic ring systems.

“Wheeling Templates” in Molecular Oxothiomolybdate Rings: Syntheses, Structures, and Dynamics

The influence of three dicarboxylate anions, oxalate, (C2O4)2-, glutarate, (H6C5O4)2-, and pimelate, (H10C7O4)2-, on the self-condensation process of the [Mo2S2O2]2+ dithiocation has been investigated. [Mo8S8O8(OH)8(C2O4)]2- ([Mo8-ox]2-), [Mo10S10O10(OH)10(H6C5O4)]2- ([Mo10-glu]2-), and [Mo12S12O12(OH)12(H10C7O4)]2- ([Mo12-pim]2-) have been prepared and characterized in aqueous solution by 1H NMR and electrospray mass spectroscopy and in the solid state by elemental analyses, X-ray crystallography, and infrared spectroscopy. The molecular arrangement of [Mo8-ox]2-, [Mo10-glu]2-, and [Mo12-pim]2- exhibits the same type of topology derived from the neutral cyclic {Mo2nS2nO2n(OH)2n} backbone. {Mo2nS2nO2n(OH)2n} inorganic rings encapsulate the organic guest with direct covalent interactions between Mo centers and carboxylate groups. Excess of glutarate does not change the molecular arrangement of the anion but modifies the solid-state arrangement of [Mo10-glu]2-. Rb4(C5H6O4)[Mo10S10O10(OH)10(H6C5O4)]·5H2O (Rb4glu[Mo10-glu]·5H2O) has been crystallized and structurally characterized by X-ray diffraction. The structure of Rb4glu[Mo10-glu]·5H2O contains the same decameric molecular anion as that found in Cs2[Mo10-glu]·20H2O with an additional glutarate capping the molecular wheel. The supramolecular interactions developed in Rb4glu[Mo10-glu]·5H2O are ensured by hydrogen bonds involving the hydroxo bridges of the inorganic ring and the carboxylate groups of the additional glutarate. Negative-ion electrospray mass spectroscopy (ESMS) has been performed on aqueous solution containing the {Mo2S2O2} building block and the templating agent at pH 4.5. The anions [Mo8-ox]2-, [Mo10-glu]2-, and [Mo12-pim]2- were clearly identified by their parent peaks observed in the ESMS spectra. Experimental m/z ratios are fully consistent with the corresponding X-ray diffraction results. The templated anionic Mo2n rings have been characterized by 1H NMR spectroscopy in aqueous solution and in acetonitrile-d3. The 1H NMR spectra of [Mo8-ox]2-, [Mo10-glu]2-, and [Mo12-pim]2- as Li+ salts in CD3CN unambiguously contain the resonances of the hydroxo bridges belonging to the ring and those of the inner CH2 groups of the alkyl chain in [Mo10-glu]2- and [Mo12-pim]2-. Variable-temperature 1H NMR spectra recorded in CD3CN revealed the fluxionality of [Mo10-glu]2- and [Mo12-pim]2- in contrast to the rigidity of [Mo8-ox]2-. At low temperature (T = 226 K), the motion of the guest, i.e., the central template in Mo10 and Mo12 rings, becomes slow enough on the NMR time scale to postulate the presence of conformational isomers in solution.

Si-O and P-O motifs in inorganic rings and clusters

This article presents a brief overview of different kinds of silanols and the important reactions of N-bonded silanetriols. The synthesis and characterization of silanediols containing Si-N and Si-C bonds, (2,4,6-Me3C6H2)N(SiMe3)Si(Me)(OH)2 (1e) is described. 1e shows a polymeric crinkled tape type of structure due to extensive intermolecular hydrogen bonding. We also describe the formation of a neutral copper(II) complex derived from the reaction of CuCl2 with (O)P(3,5-Me2Pz)3 where the ligand undergoes a facile P-N bond cleavage and functions as an N2O type of tridentate ligand.

A spirobicyclic complex of Schmidpeter's ligand, bis(tetraphenylimidodiphosphinato)beryllium, Be(OPh2PNPPh2O)2, an inorganic analog of beryllium bis(?-diketonates)

The crystal structure of bis(tetra-phenylimidodiphosphinato)beryllium (as a benzene solvate), Be(OPh2PNPPh2O)2. C6H6, was determined by X-ray diffraction and compared with that of beryllium acetylacetonate, Be(OCMeCHCMeO)2. The imidodiphosphinate is an inorganic spirobicyclic system, Be(OPNPO)2, with tetrahedrally coordinated beryllium. Unlike the planar BeO2C3 rings in the acetylacetonate, the two six-membered BeO2P2N inorganic rings are nonplanar and display a skew boat conformation. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:244–248, 2000

Synthesis and Structural Characterization of Tin(IV)N-nitroso-N-phenylhydroxylaminato Complexes: Crystal Structures of Sn(O2N2Ph)4, Ph2Sn(O2N2Ph)2 and [Me2Sn(O2N2Ph)2

Reaction of cupferron [NH4L, L = PhN(O)NO–] with tin(IV), diphenyltin(IV) and dimethyltin(IV) halides yields the cupferronato complexes SnL4 (1), Ph2SnL2 (2) and [Me2SnL2]2 (3). All were characterized by FT-IR, FT-Raman, NMR (1H, 13C and 119Sn) spectroscopic methods and X-ray structural analysis. An almost ideal, very rare dodecahedral geometry is found in the structure of 1. The hexacoordinated tin center exhibits a bicapped tetrahedral geometry in complex 2. The tin centers are heptacoordinated in a pentagonal bipyramidal geometry in the dimeric complex 3. These complexes incorporate five-membered SnO2N2 and four-membered Sn2O2 inorganic rings. Vibrational spectral data are consistent with the structures determined. The 119Sn NMR spectra indicate that in solution 1 retains its octacoordinated nature; in compound 2 the tin atom is hexacoordinated, while in 3 the tin atom is pentacoordinated.

The bonding and structure of B–N sandwich complexes

The structures and bonding of π-complexes formed by the completely inorganic ring systems B 2N 2R 4 and B 2N 3R 4 − have been investigated using density functional calculations. These rings are isoelectronic with cyclobutadiene and the cyclopentadienyl anion, respectively and a detailed comparison of their bonding characteristics is described. The optimized structure of (η 5-B 2N 3H 4) 2Fe, a fully inorganic ferrocene analogue, is reported.

Synthesis and Ring-Opening Polymerization (ROP) of Strained Phosphorus-Containing Rings

Studies of inorganic and organometallic rings containing phosphorus are described. Novel skeletal substitution reactions are reported for B-N-P heterocycles and cyclic thionylphosphazenes are found to undergo ambient temperature ROP in the presence of GaCl3. The phosphorus-bridged [1]ferrocenophane Fe(η-C5H4)2PPh undergoes living anionic polymerization. This provides access to block copolymers such as poly(ferrocenylphosphine)-poly(dimethylsiloxane) which dissolve in hexanes to yield interesting micellar aggregates with organometallic cores.

ChemInform Abstract: Inorganic Rings in Thio‐ and Selenoborates

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Structure and stabilities of (HA1NH) n (n = 2-4)

Ab initio molecular electronic structure methods have been used to study the relative stability of the planar inorganic ring (HAlNH)n (n = 2–4) during homodesmotic and monomer polymerization reactions. Optimized geometries, frequencies and energies through restricted Hartree-Fock/6-31G* are reported, and energies at the self-consistent field optimized geometries including Moller-Plesset fourth perturbation theory with single, double and quadruple excitation (MP4SDQ) corrections are also reported for both reactions. Homodesmotic reactions with MP4SDQ −28.5 kcal/mol for (AlN)2, 1.9 kcal/mol for (AlN)3 and −0.97 kcal/mol for (AlN)4. On analysing a π-molecular orbitals diagram, only one, three and three strongly bonding π-molecular orbitals exist for the planar four-, six- and eight-membered AlN rings, respectively.

Si–O–based inorganic ring systems containing f-elements: structural characterization of novel siloxanediolates of the lanthanides and actinides†

Depending on the reaction conditions and the ionic radius of the lanthanide ion, tetraphenyldisiloxanediol, (Ph2SiOH)2O, reacts with [Ln{N(SiMe3)2}3{LiCl(thf)3}3] (Ln = Eu, Gd, Sm) to afford novel heterobimetallic rare earth disiloxanediolates, some of which can be regarded as ‘inorganic lanthanide metallocenes’; a ring expanded uranium(VI) derivative, [U{Ph2Si(OSiPh2O)2}2{(Ph2SiO)2O}] 4, is formed upon treatment of uranocene, [U(η8-C8H8)2], with (Ph2SiOH)2O.

An Evaluation of the Aromaticity of Inorganic Rings: Refined Evidence from Magnetic Properties

An Evaluation of the Aromaticity of Inorganic Rings: Refined Evidence from Magnetic Properties

Inorganic Rings in Thio- and Selenoborates

Inorganic Rings in Thio- and Selenoborates

Four- and Six-Membered Inorganic Rings in the "Butterfly" -Like [Mn{(Opph2)2N}2

Four- and Six-Membered Inorganic Rings in the "Butterfly" -Like [Mn{(Opph2)2N}2

The Fascination of Large Rings: Cyclic Metal Complexes of Polydendate Ligands

Coupling reactions in the coordination spheres of metal ions are the most important steps in the synthesis of very large inorganic ring complexes. The majority of such compounds can be categorized as coordination complexes. In addition, there are also examples from organometallic chemistry, such as the ferrocene scoop wheel presented by F. H. Köhler et al. in this issue. Before a planned synthesis of these compounds can be achieved, principles that govern the formation of these unusually large macrocycles must be determined. Insights into these principles are given herein.