A Localized Molecular Orbital Study of the Halogen Substitution Effect on (103)Rh NMR Shielding in [Cp*RhX2]2, Where X = Cl, Br, or I.

(103)Rh NMR parameters and the bonding structure of three complexes of [Cp*RhX2]2, where X = Cl, Br, or I, have been studied with the help of natural bond orbitals (NBOs) and natural localized molecular orbitals (NLMOs). The complexes of [Cp*RhX2]2, where X = Cl, Br, or I, have similar bonding structures, with the major difference being in the degree of covalency of the Rh-X bonds. The decomposition of (103)Rh NMR shielding into diamagnetic, paramagnetic, and spin-orbit terms shows that normal halogen dependence (NHD) of the (103)Rh NMR shift is defined mostly by the paramagnetic term, with the spin-orbit term being significantly smaller. The decomposition of (103)Rh shielding into spin-free NBO and NLMO contributions shows that (103)Rh shielding is dominated by Rh d-orbital deshielding contributions. We explain the NHD of the (103)Rh NMR shift with the increase in the energies of the virtual antibonding Rh-X orbitals along the X = Cl, Br, and I series.

Synthesis and characterization of a new Keggin anion: [BeW12O40](6-).

The first Keggin-type Be-containing heteropolyanion [BeW12O40](6-) (1(6-)) has been obtained by hydrothermal synthesis from sodium tungstate and Be(NO3)2. It was crystallized as (Bu4N)4.8Na1.2[BeW12O40] (1a) and (Me2NH2)6[BeW12O40]·4H2O (1b) salts, which were characterized by (9)Be and (183)W NMR, ESI-MS, CV, and single crystal X-ray diffraction analysis.

New {RuNO} polyoxometalate [PW11O39Ru(II)(NO)]4-: synthesis and reactivity.

New Ru-containing polyoxometalate [PW11O39Ru(II)(NO)](4-) (1(4-)) was obtained in high yield by reaction of [Ru(NO)Cl5](2-) with [PW11O39](7-) and characterized by multinuclear NMR, cyclic voltammetry, IR spectroscopy, and electrospray ionization mass spectrometry (ESI-MS). The intrinsic reactivity of the {RuNO} site in 1(4-) toward various reagents has been studied using a versatile and simple ESI tandem mass spectrometric methodology for identification of the L attached at the Ru site; this approach relies on the preferential liberation of the L ligands attached at the Ru sites upon mass-selecting desired intermediates and subsequent promotion of their fragmentation. Reactions with both hydrazine and hydroxylamine lead to elimination of the nitroso group and quantitative formation of [PW11O39Ru(III)(H2O)](4-) (2(4-)) in aqueous solution. In the reaction with hydroxylamine, an intermediate with coordinated dinitrogen has been detected. An easy access to the NH3-coordinated [PW11O39RuNH3](4-) (3(4-)) complex was achieved upon reduction of 1(4-) with Sn(2+) in water.

Cd2+ complexation with P(CH2OH)3, OP(CH2OH)3, and (HOCH2)2PO2(-): coordination in solution and coordination polymers.

The coordination of Cd(2+) with P(CH(2)OH)(3) (THP) in methanol was followed by (31)P and (111)Cd NMR techniques. A cadmium-to-phosphine coordination ratio of 1:3 has been established, and effective kinetic parameters have been calculated. Air oxidation of THP in the presence of CdCl(2) at room temperature produces coordination polymer (3)(∞)[Cd(3)Cl(6)(OP(CH(2)OH)(3))(2)] (1). The same oxidation reaction at 70 °C gives another coordination polymer, (∞)[CdCl(2)(OP(CH(2)OH)(3))] (2). Complexes 1 and 2 are the first structurally characterized complexes featuring OP(CH(2)OH)(3) as a ligand that acts as a linker between Cd atoms. The addition of NaBPh(4) to the reaction mixture gives coordination polymer (∞)[Na(2)CdCl(2)(O(2)P(CH(2)OH)(2))(2)(H(2)O)(3)] (3) with (HOCH(2))(2)PO(2)(-) as the ligand. Coordination polymers 1-3 have been characterized by X-ray analysis, elemental analysis, and IR spectroscopy.

Organometallic derivatives of Rh- and Ir-substituted polyoxotungstates with Keggin structure: reactivity screening by electrospray ionization mass-spectrometry.

ESI-MS based methodology for the rapid reactivity screening of [PW(11)O(39)RhCl](5-) and [PW(11)O(39)Ir(H(2)O)](4-) toward various metalation-intended substrates (reagents with an activated C-H bond, boronic acids and organotin compounds) is presented. Formation of a series of new organometallic POM derivatives with Rh-R (R = malonate, phenylacetate, CH(3), Ph, ferrocenyl) and Ir-R (R = CH(3)) bonds is reported.

Self-assembly of polyoxotungstate with tetrarhodium-oxo core: synthesis, structure and 183W NMR studies.

A sandwich-type rhodium polyoxotungstate with unprecedented tetrarhodium-oxo core Na(12)[(Rh(4)(µ(3)-O)(2)(H(2)O)(2))(H(2)W(9)O(33))(2)]·38H(2)O (1) was obtained by hydrothermal reaction of rhodium(II) acetate and sodium tungstate; crystal structure was determined by X-ray diffractometry and was confirmed by (183)W NMR data; 1 is active in electrocatalytic water oxidation.

Synthesis and characterization of [PW11O39Ir(H2O)]4-: successful incorporation of Ir into polyoxometalate framework and study of the substitutional lability at the Ir(III) site.

The first Keggin-type heteropolyanion, [PW(11)O(39)Ir(H(2)O)](4-) (1), was synthesized by hydrothermal reaction from two different polytungstate precursors and [IrF(6)](2-). It was isolated as (Bu(4)N)(4)[PW(11)O(39)Ir(H(2)O)] (1a), which was completely characterized by multinuclear (31)P and (183)W NMR, ESI-mass spectrometry and cyclic voltammetry. A rapid screening methodology to ascertain the intrinsic substitutional lability at the Ir site is also presented, based on ESI-MS.