Question

The correct IUPAC name of $[\text{PtBr}_2(\text{PMe}_3)_2]$ is:

• A. bis(trimethylphosphine)dibromoplatinum(II)
• B. bis[bromo(trimethylphosphine)]platinum(II)
• C. dibromobis(trimethylphosphine)platinum(II)
• D. dibromodi(trimethylphosphine)platinum(II)

Answer 1

The Correct Option is C

To establish the IUPAC nomenclature for the complex $[\text{PtBr}_2(\text{PMe}_3)_2]$, adhere to the following systematic naming conventions for coordination compounds:

1. Ligand Identification: The complex contains two ligand types:
   • Two bromide ions (Br^-), classified as anionic ligands.
   • Two trimethylphosphine (PMe₃) moieties, classified as neutral ligands.
2. Ligand Naming Order: Ligands are enumerated alphabetically, irrespective of their charge. Therefore, "bromo" precedes "trimethylphosphine." The nomenclature for PMe₃ is "trimethylphosphine."
3. Application of Multiplicative Prefixes: Given the presence of two units for each ligand, the prefix "di" is applied. However, for ligands with complex names, "bis" is employed:
   • "dibromo" denotes the two bromide ligands.
   • "bis(trimethylphosphine)" denotes the two trimethylphosphine ligands, using "bis" as "trimethylphosphine" itself is a multi-word name.
4. Metal and Oxidation State Designation: The central metallic element is platinum (Pt). Its oxidation state is indicated in Roman numerals. In this specific complex, platinum exhibits a +2 oxidation state.

The determination of the platinum's oxidation state is as follows: The complex is electrically neutral. Each bromide ligand imparts a charge of -1, and the PMe₃ ligands are neutral: \([\text{Pt} + 2(-1) + 2(0) = 0 \Rightarrow \text{Pt} = +2]\)

1. Name Assembly: The integrated name, following the established order and terminology, is "dibromobis(trimethylphosphine)platinum(II)."

Consequently, the definitive IUPAC designation for $[\text{PtBr}_2(\text{PMe}_3)_2]$ is dibromobis(trimethylphosphine)platinum(II), aligning with option three.