Trihalides simple adducts

The trihalides of arsenic and antimony are known to act as acceptor molecules and to form adducts with various donor molecules. The complexes formed with 2,2 -bipyridyl are appreciably ionized in nitrobenzene 9,1 and simple ionization has been proposed 91> 92h... 

Only a small number of zirconium(III) and hafnium(III) complexes are known. Nearly all of these are metal trihalide adducts with simple Lewis bases, and few are well characterized. Just one zirconium(III) complex has been characterized structurally by X-ray diffraction, the chlorine-bridged dimer [ ZrCl PBu,) ]- Although a number of reduced halides and organometallic compounds are known in which zirconium or hafnium exhibits an oxidation state less than III, coordination compounds of these metals in the II, I or 0 oxidation states are unknown, except for a few rather poorly characterized Zr° and Hf° compounds, viz. [M(bipy)3], [M(phen)3] and M Zr(CN)5 (M = Zr or Hf M = K or Rb). 

The chemistry of the boron trihalides has been extensively studied. These compounds are strong Lewis acids and form a wide range of simple 1 1 adducts that have served as model compounds for the study of Lewis acid-base interactions. Many reviews of their coordination chemistry have appeared (41, 60, 66,120, 174, 178) and these are summarized in the more recent reviews appearing in the mid-1960s (41,120). 

Detection of BF C14 species by NMR has been used as evidence for the formation of ionic boron trihalide adducts D2BF2+BFnCl4 from simple covalent adducts (82, 83) and as evidence for the abstraction of chloride ion from (C6H5)3PC12 by BF3 (32). Boron trihalides are often used as halide abstraction reagents, and when two different halogens are involved the mixed-halogen species should be formed, but often only indirect evidence has been obtained (51). 

Photoelectron spectra for the antimony trihalides and Sb, Cl, and Br n.q.r. spectra for a number of adducts of the trichloride and bromide have been reported. The complex SbCl3,GaCl3 has been isolated, whereas a simple eutectic only is observed in the SbCl3-AlCl3 system. Antimony and bismuth halide complexes with substituted l,2-dithiol-3-thiones can be obtained, and the... 

Nucleophilic attack at other atoms. The chemistry of phosphine-borane adducts has continued to generate interest. Simple borane adducts of primary vinyl-, ethynyl- and allenyl-phosphines have been prepared and studied by a range of spectroscopic and theoretical techniques. The same group has also shown that attachment of the BH3 unit to a variety of primary phosphines results in a substantial increase in the intrinsic acidity of the system in the gas-phase. Group III halide adducts of the type Bu 2PH EX3 (E = B, Al, Ga or In X = Cl or Br) are accessible from the reactions of the secondary phosphine with the trihalides at room temperature. The solid state structure and reactivity of these adducts was also reported. Treatment of l,8-bis(diphenylphosphino)naphthalene with the borane-dimethylsulfide complex in ether solvents affords a simple monoborane adduct of the diphosphine irrespective of the molar ratio of the... 

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