Coordination complexes of some group (IV) halides

Jain, S. C.; Rivest, R.

doi:10.1016/0022-1902(70)80105-1

Cited by 20 publications

(1 citation statement)

References 16 publications

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“…Cyanamide and its JW-dialkylderivatives (XXXV) are the simplest ambident systems with sp 3 -and sp -hybridised nitrogen atoms. On interaction with MX4 (M = Sn, Ti, or Zn and X = Cl or Br), cyanamide itself behaves as a bidentate ligand, while its dialkyl derivatives are coordinated via the harder nitrogen atom of the nitrile group 323 . Probably in the case of sp 3 and sp -hybridised nitrogen atoms the direction of coordination attack is determined mainly by the negative π-electron densities §, although one §The sp -hybridised nitrile nitrogen has a much higher negative ν -electron charge density (-0.279) than that of the amino-nitrogen (-0.064).…”

Section: R = R' = P-t>mentioning

confidence: 99%

The Principle of Hard and Soft Acids and Bases and the Problem of Competitive Coordination in Complex Compounds

Гарновский¹,

Osipov²,

Bulgarevich³

1972

Russ. Chem. Rev.

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Section: R = R' = P-t>mentioning

confidence: 99%

The Principle of Hard and Soft Acids and Bases and the Problem of Competitive Coordination in Complex Compounds

Гарновский¹,

Osipov²,

Bulgarevich³

1972

Russ. Chem. Rev.

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Halides and Oxyhalides of the Early Transition Series and their Stability and Reactivity in Nonaqueous Media

Walton

1972

Progress in Inorganic Chemistry

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Metal Complexes of Cyanamides and their Alkylation to Cyanamidium Salts. A General Synthesis of Highly Substituted Ureas, Isoureas, and Guanidines

et al. 1984

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The complexes 3a -p were prepared from disubstituted cyanamides and Lewis acids. According to a X-ray structural analysis, the antimony pentachloride complex 3 s is neither a a nor a n complex (9: C = N -S b 133"). The complexes 3 with SbCI, and FeCI, can be alkylated with tertiary alkyl chlorides, affording crystalline cyanamidium salts (5a -m) which were characterized by reactions with water, primary or secondary alcohols to give ureas (11) and uronium salts (8a-z), respectively. The guanidinium salts 9 a -s were obtained with ammonia, primary and secondary amines. Metallkomplexe von Cyanamiden und ihre Alkylierung zu Cyanamidiumsalzen. Eine ailgemeine Synthese hochsubstituierter Harnstoffe, lsoharnstoffe und GuanidineAus disubstituierten Cyanamiden und Lewis-Sauren werden die Komplexe 3a -p erhalten. Nach einer Rdntgenstrukturanalyse hat der Antimonpentachlorid-Komplex 3a weder a-noch n-Symmerrie ( 9: C = N -Sb 133 "). Die Komplexe 3 mit SbCI, oder FeCI, kdnnen mit tertiaren Alkylchloriden zu den kristallinen Cyanamidiumsalzen 5 a -m alkyliert werden. Mit Wasser, primaren oder sekundaren Alkoholen reagieren die Verbindungen 5 zu Harnstoffen (11) bzw.Uroniumsalzen (8a -z), mit Ammoniak, primaren oder sekundaren Aminen zu Guanidiniumsalzen (9a -s).Disubstituted cyanamides react with many metal centres to form stable complexes.There have to be considered three sites at a cyanamide to which the metal may be coordinated: a lone pair of electrons at each nitrogen and the nitrile n-electrons. The spectral properties of the known cyanamide complexes seem to be consistent with coordination to the nitrile group only. Usually, an increase in the energy of the nitrile antisymmetric stretching vibration (e.g. dimethylcyanamide: vCN = 2221 cm-'; 0.1 M in CCI,')) on complexation is taken as evidence for a coordination to the nitrile lone pair (a complex) (e.g. (CH3),NCN.BF3: vCN = 2307 cm-'; 0.1 M in CCI,')), while a shift to smaller wave numbers is believed to demonstrate complexation to the nitrile n system (n complex) (e.g. 1: vCN = 2008 cm-'; KBr2)). The Cr(0) complex 2 of diethylcyanamide has been shown by an X-ray structural analysis to be a a complex3). Similar complexes with other transition metals are known4vS). On the other hand, in the nitrile complex 16) and related compounds7~*) the nitrile group acts as a four electron donor forming a a bond to one metal atom and a A bond to an other. In such cases there is no simple relation between the position of va in the IR spectra and the structure of the cyanamide complex. Therefore, the classifi-0

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Coordination complexes of some group (IV) halides

Cited by 20 publications

References 16 publications

The Principle of Hard and Soft Acids and Bases and the Problem of Competitive Coordination in Complex Compounds

The Principle of Hard and Soft Acids and Bases and the Problem of Competitive Coordination in Complex Compounds

Halides and Oxyhalides of the Early Transition Series and their Stability and Reactivity in Nonaqueous Media

Metal Complexes of Cyanamides and their Alkylation to Cyanamidium Salts. A General Synthesis of Highly Substituted Ureas, Isoureas, and Guanidines

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