Main-Group Element, Organic, and Organometallic Derivatives of Polyoxometalates.

Organoborane compounds present a class of versatile synthetic intermediate for myriad organic transformations. The direct addition of a B–H bond across unsaturated bond—namely, hydroboration—is a powerful tool for the preparation of organoborane derivatives. This review outlines recent advances in catalytic hydroboration of unsaturated organic compounds, specifically those involving C-X (X = N, O) bonds. We will discuss the chemical behavior of both transition metal catalysts and main group catalysts in hydroboration. Emphasis will also be placed on the reaction mechanism of these catalytic reactions. Furthermore, recent achievements in catalytic hydroboration of carbon dioxide CO2 will be highlighted.

Catalytic Hydroboration of Carbonyl Derivatives, Imines, and Carbon Dioxide

The first metal-free catalytic hydroboration of carbonyl derivatives has been developed in which a catalytic amount of 1,3,2-diazaphospholene effectively promotes a hydroboration reaction of aliphatic and aromatic aldehydes and ketones. The reaction mechanism involves the cleavage of both the PO bond of the alkoxyphosphine intermediate and the BH bond of pinacolborane as well as the formation of PH and BO bonds. Thus, the reaction proceeds through a non-metal σ-bond metathesis. Kinetic and computational studies suggest that the σ-bond metathesis occurred in a stepwise but nearly concerted manner.

Metal‐Free σ‐Bond Metathesis in 1,3,2‐Diazaphospholene‐Catalyzed Hydroboration of Carbonyl Compounds

In industries and academic laboratories, several late transition metal-catalyzed prerequisite reactions are widely performed during single and multistep synthesis. However, besides the desired products, these reactions lead to the generation of numerous chemical waste materials, by-products, hazardous gases, and other poisonous materials, which are discarded in the environment. This is partly responsible for the creation of global warming, resulting in climate adversities. Thus, the development of environmentally benign, cheap, easily accessible, and earth-abundant metal catalysts is desirable to minimize these issues. Certainly, iron is one of the most important metals belonging to this family. The field of iron catalysis has been explored in the last two-three decades out of its rich chemistry depending on its oxidation states and ligand cooperation. Moreover, this field has been enriched by the promising development of iron-catalyzed reactions namely, C–H bond activation, including organometallic C–H activation and C–H functionalization via outer-sphere pathway, cross-dehydrogenative couplings, insertion reactions, cross-coupling reactions, hydrogenations including hydrogen borrowing reactions, hydrosilylation and hydroboration, addition reactions and substitution reactions. Thus, herein an inclusive overview of these reaction have been well documented.

Organic synthesis with the most abundant transition metal–iron: from rust to multitasking catalysts

https://www.rsc.org/suppdata/cc/c1/c1cc14508h/c1cc14508h.pdf

Catalytic hydroboration by an imido-hydrido complex of Mo(IV)

Synthesis and characterization of a Zn(II) complex of a pyrazole-based ligand bearing a chiral l-alaninemethylester

The reactions of 2-thienylamidoxime and 2-thienylmethylamidoxime with [MoO2(acae)2] or x-(NBu4 [Mo8O26]. in alcohols or acetonitrile, yield a number of compounds with different nuclearities and various molybdenum cores, such as the compact {Mo4O10(OMe)2}2+ the cyclic {Mo4O12}, and the open {Mo11On211-1}2+ (n= 2 or 4) cores. Addition of NH2OH to the reaction mixtures results in the formation of nitrosyl complexes containing either the Mo(NO)3 or the Mo(NO)22 units. The amidoxime component may be present either as RC(NH2)NHO. RC(NHi2), RC(NH)NHO or RC(NH)NO2: ligands, or as hydrogen-bonded RC(NH2)NOH molecules. The crystal structures of [MoO(acac)RIC'(NH2)NO] {RJC(NH)NO}](1), [Mo(NO)(acae)2 {RIC(NH2)NO}] (4), (NBu4)2[Mo4O10(OMe)2{RIC(NH) NO}2] (12a),(NBu4)2(H3O)[Mo5O13(OMe)4(NO)].2R1C(NH2)NOH(13b) and [R1C(NH2)2)]3[Mo5O13(OEt)4(NO)] (14) (R1=2-thienyl) are reported. The cryslallographic data for these compounds are as follows:1, mono-clinic. P21 a.a=24.547(4)A. b=8.188(4)A. c=9.607(3)A, s=96.18(3)c, R=0.046. R10=0.050: 4. monoclinic, P21c.a=8.265(2)A, b=9.381(2)A,c=24.770(4)A, c = 24.7701(4) A, s=93.99(2). R=0.039. R=0.042;12a, monoclinic, C2/c, a= 19.570(5)A. b=16.883(4)A, c = 19.82(l)A. s= 114.36(5)°, R=0.064,R.=0.074;13b monoclinic;. P21 c.a=18.197(5)A, b=15.857(14) A, c = 23.075(17) A, β=93.20(3). R=O.050. Rw=0.057;14, trictinic PI, a = 9.871(3),b= 14.138(3).c= 14.781(8)A. α=92.67(2)c β=99.36(1)° γ=90.52(2)°. R = 0.044. Rw = 0.049. Particular attention is focused on the various coordination modes that the different ligand forms adopt: µ- κO, κ2N,O, κ2N',O, µ-κN: κ2O. and μ3- κN:κN:κ2O.

Coordination chemistry of polyoxomolybdates: The versatile behavior of amidoximes

Synthesis and crystal structure of bis[(μ-κO:κO′-acetato)(μ-κO:κ2O′-acetato)][(η5-Cp)tris(dimethylphosphito-P)cobalt-O,O′,O″]yttrium(III)

Syntheses and reactivities of new bis(imido)Mo(VI) complexes of hydrotris(3,5-dimethyl-1-pyrazolyl)borate and X-ray molecular structures of [{HB(3,5-Me2C3N2H)3}Mo(Nmes)2X] (X=Cl or OH; mes=2,4,6-trimethylphenyl)

MoOCl2(LOMe) as catalyst, where LOMe is CpCo[P(O)(OMe)2]3, reacts with p-tolyl isocyanate to afford the title compound, C23H23N3O2. The structural features are the intramolecular hydrogen bond forming a six-membered ring and a nearly planar arrangement of the biuret moiety. Each p-tolyl phenyl ring is twisted by approximately 60–80° with respect to the others. The bond lengths N1—C22 of 1.357 (3) A and N2—C23 of 1.333 (3) A indicate that they are partial double bonds.

Soo-Gyun Roh

Papers

Synthesis and characterization of a Zn(II) complex of a pyrazole-based ligand bearing a chiral l-alaninemethylester

Coordination chemistry of polyoxomolybdates: The versatile behavior of amidoximes

Synthesis and crystal structure of bis[(μ-κO:κO′-acetato)(μ-κO:κ2O′-acetato)][(η5-Cp)tris(dimethylphosphito-P)cobalt-O,O′,O″]yttrium(III)

Syntheses and reactivities of new bis(imido)Mo(VI) complexes of hydrotris(3,5-dimethyl-1-pyrazolyl)borate and X-ray molecular structures of [{HB(3,5-Me2C3N2H)3}Mo(Nmes)2X] (X=Cl or OH; mes=2,4,6-trimethylphenyl)

1,3,5‐Tri‐p‐tolylbiuret

Soo-Gyun Roh

Papers

Synthesis and characterization of a Zn(II) complex of a pyrazole-based ligand bearing a chiral l-alaninemethylester

Coordination chemistry of polyoxomolybdates: The versatile behavior of amidoximes

Synthesis and crystal structure of bis[(μ-κO:κO′-acetato)(μ-κO:κ2O′-acetato)][(η5-Cp)tris(dimethylphosphito-P)cobalt-O,O′,O″]yttrium(III)

Syntheses and reactivities of new bis(imido)Mo(VI) complexes of hydrotris(3,5-dimethyl-1-pyrazolyl)borate and X-ray molecular structures of [{HB(3,5-Me2C3N2H)3}Mo(Nmes)2X] (X=Cl or OH; mes=2,4,6-trimethylphenyl)

1,3,5‐Tri‐p‐tolyl­biuret

1,3,5‐Tri‐p‐tolylbiuret