Monodentate coordination

Supposed coordinated monodentate C104 b Supposed chelate CIOJ. c Band associated with ionic C104. ... 

Ni(Me3AsO)4XY SqPy 3.56 833-866s X = C104 Y = C104, BPh4 X = N03 Y = BPh4 coordinated monodentate X 1804... 

When nickel salts of coordinating anions are used, for example Ni(NCS)2 and Ni(N03)2, complexes with a number of coordinated monodentate ligand molecules less than six are obtained.1888,1889,1892 Assignment of IR spectra of the Ni(DMSO)2+ cation using lsO isotope shifts has been reported.1893... 

The reduction in the number of potential coordination sites from four to three on monosubstitution of squaric acid restricts the variety of possible coordination modes possible for these hgands. In the majority of the complexes prepared by HaU et al., the monosubstituted squarate ligands adopt a /u.-l,3 role, although in a few instances the ligands coordinate monodentately, adopting a pendant role 111, 123,132-137). Expectedly, as a consequence of bite-parameter considerations, chelation is observed only in the case of the large lead(II) ion (76). In... 

Fig. 23. The monomeric lanthanum(III) diphenylaminosquarate complex La[(C6H5)2 NC403]3(H20)e 5H2O (133) showing the three diphenylaminosquarate ligands to be coordinated monodentately in one, the substituent is oriented cis to the ligating oxygen, whereas in the other two it is trans.

Sheldrick and Heeb [98] reported the preparation of the amino acid complex [(ri -benzene)Ru(L-alanine-N,0)Cl]. The crystals contained enantiomers with opposite chirality at the Ru centre. This complex reacted with 9EtG to give [(r -benzene)Ru(L-alanine)(9EtG)] which contains N7-bound 9EtG stabilized by a C60 H-N H-bond. Reaction of [(r] -benzene)Ru(L-alanine-methyl ester)Cl2] with 9EtG led to displacement of coordinated monodentate L-alanine methyl ester. These workers observed that aquation of the Ru-Cl bonds occurs readily in water, as noted by Dersnah and Baird [99]. 

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